Mark C. Serreze - US grants

Using a unique data set of ten spring-summer seasons, a series of hypotheses will be tested to define more precisely the seasonal and interannual variability of snow melt, surface albedo and late-summer ice extent, its climatic significance, and relationships with surface pressure fields and heights, temperature anomalies and other atmospheric indices. This will constitute an expansion of previous work under NSF support for 1) an initial study of snow melt/climate interactions based on four seasons (1977, 1979, 1984, 1985) of data and 2) the basic data set preparation only (no analysis) of six additional seasons (1975, 1978, 1980, 1986-1988). The analysis will be performed using digitized ten-season data sets of snow melt stages and parameterized surface albedo constructed from Defense Meteorological Satellite Program (DMSP) imagery for May through mid-August and coincident sea ice and atmospheric data from other sources. The timing and extent of snow melt atop the Arctic pack ice is an important climatic forcing factor of northern high latitudes, with implications for the long-term mass balance and stability of the ice and potential climatic impacts in other parts of the Northern Hemisphere. It may also serve as an indicator of climatic change forced by increasing greenhouse gas concentrations.

This project will attempt to quantify the effects of variations in the major ice-atmosphere energy budget terms on the arctic sea ice concentration and distribution. Observational studies have shown the existence of a variety of interrelationships between the atmosphere and the sea ice, but modeling studies are required to identify and quantify forcing mechanisms, directions of operation, and the sensitivity of the interactions to changes in the state of the ocean and the atmosphere. Specifically, this project will make use of a ten-year data set to construct forcing functions for a coupled sea ice-radiative transfer model. Sensitivity studies will be conducted to identify specific climatically interesting regions, to determine if intense short- term events affect the long-term sea ice state, and to define the overall limits of the arctic climate system.

This award is part of the Arctic System Science (ARCSS) Program, a U.S. Global Change Program. The research program will focus existing documentation of the variability of water vapor-related fields over the Arctic on seasonal and longer time scales, to identify contributions to this variability form sub-portions of the region, and to relate this variability to synoptic activity. Knowledge of the distribution of water vapor over both Arctic land and ocean areas is needed for improving satellite-derived estimates of surface energy fluxes, snow depth and extent, and sea ice conditions. In terms of climate change, alterations of the flux of atmospheric moisture into the Arctic may influence Arctic surface radiation budgets through effects on atmospheric emissivity, cloud cover and snowfall. Associated changes in precipitation may influence surface runoff, with subsequent impacts on sea ice production and upper ocean salinities.

Abstract ATM-9315351 Serreze, Mark Barry, Roger G. University of Colorado, Boulder Title: Collaborative Research: Atmospheric Controls on Northern Hemisphere Cryosphere Variability This award supports comprehensive study of relationships between atmospheric variability and fluctuations in the snow and sea ice covers the Northern Hemisphere. The primary thrust of the work is to provide a hemispheric synthesis of the sensitivity of the cryosphere to regional changes in the atmospheric circulation, and to diagnose this sensitivity with respect to associated interactions between precipitation, temperature, winds and the modes of large-scale teleconnection patterns. The PIs will identify those regions of the cryosphere warranting focused monitoring for potential climate change, and possible future responses of the cryosphere to changes in circulation regimes. As part of these efforts, they will perform a series of intercomparisons between observed snow cover patterns and those simulated by different GCMs under present and project future climatic conditions. The study will address at least six basic questions: 1) What are the relationships between variations in northern hemisphere sea ice extent and terrestrial snow cover? 2) What areas of the cryosphere exhibit strong or weak responses to atmospheric circulation changes and why? 3) Which areas contribute most strongly to northern hemisphere cryosphere variability? 4) What are the responses of the cryosphere to the modes of Large-scale teleconnections patterns, and how do these compare with parallel anomalies in synoptic activity, temperature and precipitation? 5) How well do different GCMs depict the present day distribution and variability of snow cover, and are changes in the cryosphere projected by GCMs in response to enhance CO2 warming reasonable from the viewpoint of modeled circulation changes? 6) Can the cryosphere be used as a robust indicator of climate change? For the snow and sea ice analyses, gridded NOAA charts of Northern Hemisphere snow extent and Navy/NOAA ice concentration data will be combined with available station records of snow depth, snow fall, precipitation and surface temperature. For atmospheric analyses, the PIs will use once to twice-daily NMC surface and upper-air fields from the early 1960s to present, used to calculate grid- point and regional time series of the frequency, position and strength of cyclones and anticyclones, storm tracks, and other indices of synoptic activity (e.g, positive vorticity advection), as well as temperature. Rawinsonde data from an existing archive will be used to analyze patterns of moisture flux convergence and their associations with snow cover and precipitation variations at high northern latitudes. Output from different GCMs will be obtained for doubled CO2 (equilibrium) runs, transient runs (in which CO2 is continually increased), as well as for runs using identical present-day boundary conditions. The research is a collaborative effort between University of Colorado (Drs. Mark Serreze and Roger G. Barry) and Rutgers University (Dr. David Robinson). The work is important because it seeks to clarify the role of the cryosphere in climate variability.

9321547 Key This three-year program will quantify the individual energy streams that make up the arctic surface radiation budget, and will relate the observed radiation distribution to synoptic-scale wind, pressure, and moisture patterns. It will be the first effort to produce a comprehensive radiation climatology for the Arctic. The arctic surface energy budget, particularly that of the Arctic Ocean, has been identified as a major component of the global climate system that is potentially sensitive to climate-scale perturbations due to feedback mechanisms involving the surface albedo, the stability of the lower troposphere, and water vapor transport. The project includes four main tasks: (1) The analysis of solar and long-wave radiation data obtained directly at manned observing sites in the arctic. (2) The calculation of radiative fluxes at the surface and at the top of the atmosphere using a satellite-based cloud data product from the International Satellite Cloud Climatology Project (ISCCP). (3) For selected months, the ISCCP-derived fluxes will be compared to the corresponding synoptic regime, and (4) a study to assess the effects of the sampling and analysis procedure on the radiation statistics and their temporal variability will be undertaken. ***

ABSTRACT: 9504201 Serreze Research supported by this grant is under the auspices of the Arctic Systems Science (ARCSS) Global Change Research Program and is jointly sponsored by the Division of Ocean Sciences and the Office of Polar Programs. Work to be performed represents prelim- inary steps towards a major 5-year research project named SHEBA, which is envisioned to study the heat budget of the Arctic Ocean and its impact on global change. The primary goals of SHEBA are: (1) to develop, test and implement models of arctic ocean- atmosphere-ice processes that demonstrably improve simulations of the present day arctic climate, including its variability, using General Circulation Models (GCMs), and (2) to improve the interpre- tation of satellite remote sensing data in the Arctic for analysis of the arctic climate system and provide reliable data for model input, model validation and climate monitoring. In order to place the field experiment phase of SHEBA at the best location, the climatological regime of the proposed site must be analyzed. Researchers at the University of Colorado will compile existing data on sea ice and atmospheric conditions in the region and publish the results on CD ROM about one year before final planning of the site location. Other researchers in the SHEBA project are expected to use the data to plan individual experiments on heat budget measurements. ??

Abstract OPP-9732126, 9732461 CHAPIN, LYNCH UNIV. ALASKA, UNIV. COLORADO This project is designed to test the primary hypothesis that the surface energy and moisture exchange between atmosphere, ecosystem, snow, permafrost, and soil is the principal mechanism for coupling the land surface to the climate on seasonal to decadal timescales. Understanding the characteristics, mechanisms and feedback processes of this exchange is necessary to incorporate their effects into predictive tools for pan-Arctic climate change. This proposal will take a comprehensive view of the study of the land surface energy and moisture budgets, involving collection of field data, detailed data analysis, model development, and spatial and temporal extrapolation. The PIs plan to integrate the field work closely with the simulation work, and investigations of ecosystems and physical climate systems are undertaken together.

This project will collect meteorology and hydrology data from river systems that discharge into the Arctic Ocean. The dataset will be used to develop an integrated system of discharge and meteorology data that will be available in near real-time on the world Wide Web. The data set will provide a valuable resource for characterizing water budgets for an ocean that collects 10% of the global freshwater runoff. The discharge data will be used in models to determine the temporal variations in runoff. Those models are important for predicting the effect of global climate change on the freshwater balance of the Arctic Ocean which, in turn, has a major climate feedback through its influence on the formation of sea ice.

Abstract
ATM-9900687
Nolin, Anne W.
University of Colorado
Title: Local, Regional and Remote Effects of Northern Hemisphere Snow Cover on Western U.S. Climate and Water Resources: A Multiscale Investigation

The primary goal of this collaborative investigation is to identify, characterize, and quantify the local, regional and remote effects of snow cover on the western US climate and water resources. The present proposal considers snow not as a passive responder but as an active driver of climate variability on multiple scales. The effects of snow cover within the western US and the climate signals due to remote snow forcing will be considered. Empirical analyses and a suite of model experiments will be conducted. The work is important because it will lead to enhanced understanding of the role of snow cover in climate variability on a range of spatial and temporal scales.

This three-year study will investigate the average characteristics and potential changes in the hydrology of three major Russian rivers, the Ob, Lena, and Yenesei Rivers. These three rivers are important for the Arctic region because they carry much of the freshwater runoff from the continents into the Arctic Ocean. Also, it is likely that climate change may interact with the hydrology of these rivers in ways that will have cascading affects on terrigenous and marine ecosystems. In this study, past weather archives will be used to evaluate a time-series of important atmospheric characteristics such as the difference between precipitation and evaporation. Records of precipitation and river runoff and satellite-based data on snow distributions will be incorporated to test whether winter precipitation in regions south of the Arctic Circle control the spring river runoff of these rivers, while summer precipitation is largely water recycled from terrestrial evaporation. Long-termed changes in the water cycle will be examined from these data. The results should lead to better understanding of the controls on the water cycle in central and northern Siberia, which will be important in future efforts to predict impacts of climate change on the Arctic region.

0138018
Serreze

Changes in the freshwater budget of the Arctic Basin have potentially large impacts on the circulation and sea ice of the Arctic Ocean, which is in turn coupled to the global ocean circulation and climate. However, the atmospheric components of the arctic freshwater budget are characterized relatively poorly and difficult to model. This project will utilize state-of-the-art computational methods to improve climatological simulations of the atmospheric freshwater budget of the Arctic.

The salient aspect of high latitude numerical modeling difficulties is the extreme range of scales that must be simulated adequately. Modeling moisture processes requires appropriate treatment of interactions at small spatial scales. By contrast, numerous observational studies have suggested that arctic climate variability is dominated by decadal time scales and planetary spatial scales.

These requirements necessitate a trade-off between temporal and spatial scales that cannot be addressed readily with current Eulerian modeling methods, due to computational stability constraints. This study will implement semi-Lagrangian transport for state and dynamical atmospheric variables within the context of a fully coupled atmosphere-ocean-sea ice model. This new implementation would allow both long-term simulations of the fully coupled arctic climate at high resolution, as well as increased use of ensemble techniques for an uncertainty analysis of crucial components of the atmospheric hydrologic cycle. Model experiments will be used to address the following primary research questions:

1. What is the sensitivity of the arctic hydrologic cycle to variability in the simulated atmospheric circulation?

2. To what extent does the Northern Hemisphere semiannual oscillation influence surface moisture fluxes and/or atmospheric moisture transport? What factors influence interannual variability and trends in the arctic semiannual oscillation?

3. What is the influence of anomalous sea ice and/or snow cover on the atmospheric moisture budget over subsequent seasons? Do anomalies in wintertime climate indices translate into anomalous precipitation in other seasons? What summertime or year-round structures in the arctic climate can be identified in atmospheric moisture variables?

4. Does atmospheric convection over land play a significant role in the arctic hydrologic cycle during the summer season?

ABSTRACT
OPP-0240984
Serreze
Barry

This study will improve our understanding of the development and decay of extra-tropical cyclones in northern high latitudes and their hydrologic impacts. The study will focus on two key regions: 1) the northern North Atlantic, in particular the area around the Icelandic Low and the marginal ice zones of the Greenland and Barents seas; and 2) a domain comprising northeast Eurasia extending to the central Arctic Ocean.

The first region, representing the terminus of the North Atlantic cyclone track, has first order impacts on heat and moisture transports into the Arctic basin and the circulation of the sea ice cover, in particular, the flux of sea ice through Fram Strait. Variability in this ice flux has potentially strong influences on the ocean's thermohaline circulation. Past studies have shown that cyclone variability in this region is closely tied to the phase of the Arctic Oscillation /North Atlantic Oscillation (AO/NAO), but relatively little attention has been paid to the role of local development processes. Synoptic activity in this region during the winter season appears to be strongly influenced by vorticity production in the lee of southeast Greenland and enhanced baroclinicity along the sea ice margins. The hypothesis is that, 1) such local development processes are important in modulating the Fram Strait ice flux; and 2) the intensity of these local development processes is associated with differences in the general synoptic environment associated with the positive/negative phases of the AO/NAO.

Studies for the second domain will focus on summer. Summer is characterized by development of a pronounced baroclinic region along the shores of northeast Eurasia. It is interpreted to arise from strong differential heating between the cold Arctic Ocean and snow free land. Development of the baroclinic region over northeast Eurasia is attended by frequent cyclogenesis in the same region where a particularly large fraction of annual precipitation falls during the summer months. Cyclones generated over northeast Eurasia often migrate into the central Arctic Ocean. The hypothesis is that the cyclogenesis maximum can be explained through interactions between coastal baroclinicity and orographic development processes. A second hypothesis is that cyclones forming in this region significantly impact on the wind driven sea ice circulation in the central Arctic Ocean and are primary drivers of the summer maximum in precipitation over the central Arctic Ocean and coastal zone.

These studies will use the suite of atmospheric fields from the National Center for Environmental Protection (NCEP) and ERA-40 reanalysis systems, along with generated data sets. These include six hourly time series of cyclone activity, frontal location and intensity, and Q vector fields. Use will also be made of daily satellite derived fields of sea ice motion and concentration together with daily precipitation over both land and the Arctic Ocean.

The primary goal of this proposed study is to explore the progressive integration of the impacts and processes of the arctic freshwater cycle on the local, pan-Arctic and global scales. This study will focus on analyses of the physical processes, as represented by global scale models, in the arctic water cycle. This will involve the study of processes that modify arctic freshwater budgets in the terrestrial, atmospheric and oceanic environments, the integration of these processes to produce the exchange of freshwater between the Arctic and North Atlantic, and ultimately the influence of these processes on the thermohaline circulation (THC) and global climate. The following research questions provide a framework for investigations: (1) How will changes in land cover, the amount and seasonality of precipitation and temperature influence river discharge to the Arctic Ocean? (2) How will changes in the summer Arctic frontal zone influence the location and intensity of storm tracks and, as a consequence, the mean sea level circulation over the central Arctic Ocean? (3) How do changes in river runoff, precipitation, temperature and the atmospheric circulation influence the Arctic-North Atlantic oceanic and sea ice freshwater exchange, and how do these quantities impact the global thermohaline circulation? What are the directions and magnitudes of feedbacks associated with these processes? Alterations in the freshwater input to, and the atmospheric circulation over, the Arctic Ocean influence the sea ice and ocean transports, water mass structure, the oceanic heat flux to the sea ice, and the ice mass budgets. Such interactions are likely to be important in forcing changes in freshwater exports from the Arctic and, consequently in North Atlantic deep water formation. These changes have the potential to impact global climate through the THC, which in turn can produce or damp further changes in the Arctic system. Science education has always been a principal goal of NSF. As an integral part of our study, we propose to develop a seminar course within the University of Colorado Department of Geography. The course will focus on Arctic climate processes and their role in the global system, drawing strongly from the integrated analyses studies proposed here, along with material developed under prior NSF/ARCSS studies. M. Serreze will teach the course in collaboration with the other investigators on this project and a graduate student.

This proposal is a synthesis and integration study of the pan-Arctic water cycle. An Expanded Arctic Regional Integrated Monitoring System (E-RIMS) will be developed that links an existing, operational hydrological monitoring system for the pan-Arctic landmass and atmosphere (Arctic-RIMS) to an Arctic Ocean and sea ice component. On the terrestrial side, E-RIMS will produce time varying aerological and land surface water budgets including river and ice melt inputs to the Arctic Ocean. For the ocean, freshwater fluxes from the atmosphere and land will be used in concert with observed mass, heat and momentum forcing to drive a coupled ocean-sea ice-atmosphere model. The linked models will be used to examine the origin of freshwater fluxes in the atmosphere and landmass and how water is then partitioned between solid (sea ice) and liquid forms in the ocean. E-RIMS will also track freshwater transport off the shelf, downward below the mixed layer, and laterally toward the straits leading to the North Atlantic Ocean.

The near real-time monitoring program and historical analysis (from 1960) provides an important benchmark for understanding future change to the arctic hydrologic cycle. In keeping with current Arctic-RIMS protocols, provisional data sets (ca. 1-2 month delay) will be made available and then re-analyzed at yearly intervals for improved quality assurance. All key elements of the terrestrial and ocean water balance will be provided, including an assessment of potential error. Operational data sets will be freely accessible on partner institution web sites and through NSIDC.

E-RIMS will complement efforts by other investigators using more fully coupled air-land-ocean models, by providing to them initial and boundary conditions and by carrying-out a set of preliminary numerical experiments to help design their more computationally expensive feedback studies. As a final part of this work, NWP predictions and medium-term forecasts will be used to explore how much skill will have been developed over the course of this study.

This study will combine data synthesis and land surface modeling to assemble the best possible time series (20+ years) for the Arctic terrestrial drainage of land surface state variables (snow water equivalent, soil moisture, soil temperature) and moisture and energy fluxes (sensible, latent, and ground heat; radiation). Development of forcing fields will draw in part from an ongoing NSF effort known as Arctic-RIMS, geared at historical analysis and monitoring of the Arctic terrestrial hydrologic budget. The present effort both complements Arctic-RIMS and lays groundwork for a next-generation monitoring and prediction capability. The generated time series will be used to address spatial-temporal variability in sensible heat flux and evapo-transpiration, land surface feedbacks on precipitation, and development of the summer Arctic frontal zone.

This study will attempt to produce the best possible quality model forcing over the pan-Arctic domain by blending output from the new ERA-40 atmospheric reanalysis project with gridded in-situ observations and satellite data streams. Major challenges include maintaining physical consistency between time series of variables at different native spatial and temporal resolutions and providing realistic diurnal cycles. A particularly novel aspect of the proposed work will be use of a multi-model ensemble approach. Five different Land Surface Models will be used, all of which have been extensively tested for Arctic applications under the Project for Intercomparison of Land-Surface Parameterization Schemes (PILPS) Experiment 2e. The multi-model LSM ensemble average for each output variable should be superior to the values provided by a single run with any one LSM.

The data will also be useful for model validation efforts, such as the Arctic Regional Climate Model Inter-comparison Project, and in providing a source of high latitude evaluation data for the Atmospheric Model Inter-comparison Project. The project will contribute to educational goals through support of a graduate student and post-docs. Results from this study and related projects will be used as part of seminar course on the Arctic climate system to be taught at University of Colorado.

Abstract

The project is an integrated statistical analysis of a comprehensive set of long time series from the Arctic and subpolar North Atlantic. These multivariate records include meteorological and oceanographic measurements, sea ice observations and climate indices. The project data set will comprise: a subset of the multidecadal to century-scale 'Unaami' Data Collection, and a set of relatively unknown, century-scale time series from the subpolar North Atlantic (Nordic Seas, Greenland, Iceland, Faroe Islands and Norway) and Arctic that is new to the US community. These data will be organized and analyzed using a comprehensive set of advanced time-frequency statistical methods including organized temporal and spatial patterns of variability and covariability in the ocean-ice-atmosphere system over the past 50-200 years. The work will focus on modes other than the Arctic / North Atlantic Oscillation (AO/NAO), including the multidecadal low-frequency oscillation. To further understanding of the mechanisms, the synthesis will use new output from multi-century model runs from the first coupled atmosphere-ocean general circulation model (AOGCM) with independent stretched-coordinate systems for the atmosphere and ocean that have been resolution-optimized for the Arctic and subpolar North Atlantic.

A mechanism that may regulate both mid-tropospheric and surface air temperatures (SATs) in the Arctic region during the winter season will be examined. Regulation of observed mid-tropospheric arctic temperatures is hypothesized as follows: winter air in the Arctic has repeated contact with open ocean which allows warming to occur quickly through moist convection from the surface upward through at least the mid troposphere; and as these warmed air columns move over snow and ice covered surfaces, they cool from the bottom upwards, however, this process happens so slowly that it regulates SATs. The end result is that a warmer mid-troposphere will result in a warmer near surface layer during Arctic winter because of radiative equilibrium processes. The PIs will (1) perform a detailed observational analysis of the 500mb temperature field in the 4 x daily National Centers for Environmental Prediction reanalysis to track individual warming and cooling patterns spatially, and (2) use a low resolution General Circulation Model (planet simulator) and increase high latitude SSTs by several degree to examine the hypotheses proposed.

Intellectual merit: Completion of this work will offer new insights into the mechanism that regulates the Arctic wintertime surface and mid-troposphere air temperatures.

Broader impacts: The research will increase our understanding of the processes involved in the regulation of the wintertime Arctic surface and mid-troposphere air temperature. It has a potential to improve these processes' representation in general circulation models. It also provides learning experiences and training for a research assistant.

Accelerated and amplified changes have characterized the northern high latitude climate system in recent decades. While many important processes that are driving, and driven by, Arctic climate change have been extensively studied, one area of research that has received relatively less attention involves quantifying and accounting for large-scale changes in the extent and distribution of frozen ground, both permafrost and seasonally frozen ground. Frozen ground covers up to 50.5% of the Northern Hemisphere land areas, and the near-surface soil freeze/thaw cycle extends over an even larger area. Frozen ground is therefore the single largest component of the cryosphere in terms of maximum area extent. The existence of permafrost and seasonally frozen ground is due to heat exchange between the ground surface and the overlying atmosphere, and the area extent and geographic distribution is therefore primarily forced by climate.

Rather than provide component-based analysis of specific surface/atmosphere interactions, the PIs propose to study how the synoptic-scale circulation of the Northern Hemisphere atmosphere drives, and is driven by, changes in the freeze/thaw cycle in the Russian Arctic. The integrated effects of the atmosphere provide a first-order driver of changes in the distribution of frozen ground. Their work will thus address a missing link in the Arctic climate system, the interactions between the largest cryospheric component, frozen ground, and regional to large-scale variations in the Northern Hemisphere atmosphere.

The PIs hypothesize that (1) atmospheric circulation anomalies over and upstream of the Russian Arctic induce changes in the soil thermal regime, which responds via soil temperature and freeze/thaw depth anomalies; (2) these freeze/thaw cycle anomalies are stored in the soil and alter the surface energy flux during the onset of winter, which results in feedbacks on the overlying atmosphere; (3) snow and vegetation cover, also influenced by the atmosphere, provide further interactions and feedbacks between the ground thermal regime and atmospheric circulation.

Multivariate statistical analyses and modeling approaches will be employed to establish the patterns of variability and covariability in fields of soil temperature and freeze/thaw depth, and a number of atmospheric circulation variables, teleconnections, the polar vortex, and surface and tropospheric circulation fields. Snow cover and vegetation fields will also be analyzed to establish the precise interactions, feedbacks, and pathways linking the soil thermal regime and atmospheric circulation.

This project will develop an Arctic System Reanalysis (ASR). The ASR, which can be viewed as a blend of modeling and observations, will provide a high resolution description in space (20 km) and time (3 h) of the atmosphere-sea ice-land surface system of the Arctic. The ASR will ingest historical data streams along with measurements of the physical components of the Arctic Observing Network being developed as part of the IPY. Gridded fields from the ASR, such as temperature, radiation and winds, will also serve as drivers for coupled ice-ocean, land surface and other models, and will offer a focal point for coordinated model inter-comparison efforts. The ASR will permit reconstructions of the Arctic system's state, thereby serving as a state-of-the-art synthesis tool for assessing Arctic climate variability and monitoring Arctic change. The ASR will also shape the legacy observing network of the IPY by providing a vehicle for observing system sensitivity studies. The first generation ASR as outlined here will span the years 2000-2010.

This effort will test the hypothesis that the loss of arctic sea ice and northern high latitude snow cover will invoke changes in the seasonality, spatial distribution and magnitudes of precipitation (P) and net precipitation (P-E) over the Arctic, which along with attendant changes in temperature, have ramifications for the freshwater budget of the Arctic Ocean and the mass balance of the Greenland ice sheet.

The researchers expect that: (a) sea ice loss will lead to an increase in available water vapor over the Arctic Ocean and peripheral seas, most pronounced in autumn and winter, when delayed ice formation and thinner ice will promote large vertical fluxes of heat and moisture into the atmosphere; (b) loss of sea ice and terrestrial snow cover will invoke changes in arctic circulation patterns and hence patterns of water vapor convergence, driven in autumn and winter by enhanced vertical heat fluxes and during the warm season by altered differential heating over the Arctic Ocean and surrounding land; (c) in lying "downwind" of the Arctic Ocean as well as adjacent to the (presently) partially ice-covered East Greenland Sea and Baffin Bay, the Greenland ice sheet will feel these changes both through impacts on accumulation and surface melt.

The analysis tool will be Polar WRF, a recently developed regional climate model optimized for polar applications. Control simulations will be conducted for several arctic domains, focusing on recent years which are characterized by extremely low September sea ice extent, with lateral forcing supplied from the NCEP/NCAR reanalysis, and sea ice conditions prescribed from satellite-based observations. Generated fields of key hydrologic variables (precipitable water, precipitation, vapor flux convergence, net precipitation, temperature) and atmospheric circulation will be contrasted with those from a series of experiments with altered sea ice and snow cover. These will include simulations with climatological maximum winter ice extent and concentration through the annual cycle, prescribed reductions in ice extent and concentration larger than those observed, 100% and 0% terrestrial snow cover maintained over the annual cycle but with observed sea ice conditions, and observed sea ice conditions but with increased sea surface temperature over open water areas in summer.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

The Arctic system is strongly defined by its seasonality. The extreme annual cycle of solar radiation, interactions between the Arctic and lower latitudes, within-Arctic interactions between the land, ocean, and atmosphere, and the energetics of freeze and thaw, combine to lend a complexity and richness to Arctic seasonality not seen elsewhere on the planet. This seasonality is changing. Summer sea ice extent is declining, attended by strong autumn rises in air temperature over the Arctic Ocean. Active layer freeze-up in Siberia is occurring later in the winter. These and other emerging changes will become more prominent in coming decades, with impacts promising to cascade through the physical, chemical, biological, and socio-economic components of the system.

This research will identify the dominant climate forcings, feedbacks, and component linkages driving change in Arctic system seasonality, and they will shape the evolution of the system through the 21st century. This will require consideration of changes in global radiative forcing, energy and mass transports from lower latitudes into the Arctic, and between the land, ocean, and atmosphere within the Arctic, and how these influence the Arctic?s physical, chemical, and biological processes. A framework of passive versus active controls will help to organize the investigations. A passive control is the control by background warming. An example is how Arctic warming will lead to shorter seasonal duration of snow cover. An active control refers to altered seasonality driven by changes in energy or mass transports into the Arctic from lower latitudes or within the Arctic itself. An example is how reduced autumn sea-ice extent leads to warming over the ocean, which then, through regional atmospheric transport, may lead to warming over adjacent land. Changes in seasonality will likely often reflect both passive and active controls. Diagnostics such as seasonal anomaly structures, defined as the seasonal cycle of a state variable for a given year or years relative to the long-term climatology, will be used to evaluate how seasonality in different system elements has evolved through the instrumental record. These observational analyses will guide modeling experiments to examine the sensitivity of state variables to active and passive controls and how changing seasonality will shape the future of the system.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

While cryospheric research at National Snow and Ice Data Center (NSIDC) documents evidence of climate change, it is ironic that the carbon footprint of its computing systems is large. NSIDC is installing an energy-efficient, carbon footprint reduction upgrade to its research computing facility that includes reconfiguring the layout of its computer equipment; replacing conventional air conditioners with indirect evaporative cooling systems; installing a roof mounted solar power array; and upgrading connectivity to the Internet.

The upgraded facility positively impacts NSIDC's scientists conducting cryospheric research; assures the flow of critical data to hundreds of off-site scientists; expands NSIDC's IT systems reliability and ability to provide internet web services such as rapid data browse and online data analysis. It also illustrates several ways how similar data centers can reduce carbon footprints and sustain the cyberinfrastructure critical to future scientific activities.

NSIDC's scientists are working on NSF, NASA, and NOAA funded research addressing the Earth's cryosphere - its snow and sea ice cover, permafrost, glaciers and ice sheets - both as a key indicator and as a driver of climate change. Science questions include: why is the Arctic's sea ice cover shrinking at a faster rate than expected; how will Arctic warming affect the permafrost and could warming lead to release of carbon presently stored in these frozen soils; and how is the Antarctic ice sheet changing?

Several local partners join NSIDC in this effort. An undergraduate engineering research project is evaluating this energy conservation project and will develop a website to make monitoring and design support data available to the public. The National Renewable Energy Laboratory (NREL) is co-authoring a technical report, to distribute the concept to other data centers across the country.

Intellectual Merit: This is an effort to address the growing and increasingly diverse data management needs of the NSF arctic research community. Core activities of an Integrated Arctic Data Management Services (IADS) will include identifying and cataloging all data produced by NSF arctic investigators and providing assistance and tools to meet requirements to publish data and associated metadata. IADS will ensure that data are well documented to guarantee preservation and to promote interdisciplinary reuse, and it will enable data discovery through diverse portals, including a new IADS portal for publishing investigator metadata and data, special project support, and access by the broad community. IADS will foster scientific synthesis through its support services and help-desk functions, and by enabling integration of datasets stemming from NSF projects with data generated through activities of other U.S. agencies and other countries. The IADS will tackle the complexity of data types emerging from the Study of Environmental Arctic Change (SEARCH), the Arctic Observing Network (AON) and other efforts to serve diverse stakeholder needs. Along with advanced search and discovery capabilities, the IADS will include services such as reformatting (re-projection of gridded data, point to grid conversions, options to download data in a variety of formats), subsetting and visualization. Visualization services will include demos and instructions on how to use Integrated Data Viewer, Google Earth and other tools.

Broader Impacts: The core operation of this activity represents broader impacts. IADS will make its data holdings discoverable and usable, promote scientific synthesis and foster interagency collaboration crucial to meeting SEARCH objectives. Through activities and coordination with SEARCH/AON leadership via workshops and other venues, data management will be elevated to an integral part of scientific research. Support of groups before they go to the field will include metadata education, instruction on how to organize a data set before publishing, and provision of software tools to take to the field. The rewards of these various activities will be better data stewardship, services and data integration capabilities to benefit the arctic research community in coming years and decades.

The Arctic is experiencing rapid environmental change ranging from diminishing sea ice extent, to warming permafrost, to melting and mass loss on ice sheets and glaciers. It is important that we advance our fundamental understanding of the drivers, impacts, and feedbacks of changes in the Arctic?s physical system and how they relate to Arctic and global climate.

The potential thaw of permafrost has received much attention in recent years as a diagnostic measure of climate change, yet we still do not fully understand the physical role that permafrost plays in the climate system. The unique physical attributes of permafrost impose particular constraints upon aspects of the climate system. For example, annual freezing and thawing of the ground and water in the ground provides a seasonal damping mechanism through the consumption and release of latent heat. On longer timescales, cold ice-rich layers of deeper permafrost can draw in considerable amounts of energy before breeching an isothermal condition and rising above the freezing point. In essence, permafrost acts as a terrestrial subsurface freezer. The ice matrix in permafrost soils inhibits drainage, which leads to saturated near-surface soils and phenomena such as a perched water table and an ice-rich transient layer at the base of the active layer. Permafrost can in some respects be considered as a bathplug at the base of the active layer that causes the active layer bathtub to fill (often with snowmelt water) seasonally. The existence of such processes, their seasonality and spatial occurrence are all expected to change, but the impacts remain undiagnosed. Until recently, climate or Earth system models have not contained sufficient process representation to allow investigation into the coupled land-permafrost-atmosphere- climate system. Model capabilities in the Community Earth System Model (CESM) and its terrestrial component the Community Land Model (CLM) have advanced considerably in recent years to the level that the role of permafrost on the physical climate system, in both the present climate and in a possible future with much less permafrost, can now be meaningfully investigated.

To understand the contribution of permafrost to present and future climate trajectories, this project will conduct a series of targeted model experiments with the latest version of CESM-CLM. The researchers will seek answers to the questions: What control does permafrost, as a terrestrial ?freezer? and ?bathplug,? exert on Arctic climate? and How will a loss of permafrost feed back onto the amplitude, seasonality, or rate of Arctic climate change?

Numerical experiments will be conducted in both off-line and coupled simulations with various influences of permafrost on the climate system artificially manipulated to illuminate the present-day role of permafrost on the climate system and how its loss can feedback onto climate change.

The intellectual merit of the research begins with an evaluation of CLM?s capabilities in the Arctic. The CLM model is used extensively by the broader science community. Through a series of experiments they expect to gain an understanding of the mechanistic role of permafrost within the climate system and how those mechanisms will influence the trajectory of overall Arctic change.

The broader impacts of the work are several. Understanding the longer-term impacts of permafrost on the climate builds intellectual capital that can aid with seasonal to decadal prediction with feedbacks to forecasting. Arctic change both hinders and encourages socio-economic development, thus system-wide understanding will aid efficient and responsible use of regional resources. Through the support of a graduate student the project will contribute to the next generation of researchers and improve scientific literacy, as the student is exposed to the cutting edge of climate modeling and develops analytic skills that can also translate to numerous sectors of the economy.

The Arctic Ocean is rapidly losing its summer sea ice cover, leading to anomalous warming of the overlying atmosphere in autumn. Concurrent with this sea ice loss, the Greenland ice sheet has been losing mass recently, with increased surface melt and discharge rates. These changes are of great socioeconomic concern as continued negative trends in the extent of floating sea ice cover and ice sheet mass are likely to have widespread impacts on climate and global sea levels. The investigators propose that the simultaneous decreases in sea ice cover and increased melting of the Greenland ice sheet are connected. On the one hand, both may be largely responding to the same forcing to some degree, such as a generalized warming signal, amplified over the Arctic. On the other hand, it can be hypothesized that sea ice variability, through influences on mixed ocean layer temperatures, overlying air temperatures, column water vapor and atmospheric circulation, influences Greenland ice sheet surface melt and accumulation. Through a combination of data analysis, process studies and modeling, this project seeks to define the interactions between sea ice loss and Greenland ice sheet melt and accumulation. The following major research questions provide a framework for the study: 1) Does sea ice variability influence Greenland ice sheet surface melt (where, when, and how)? 2) What is the nature of storm activity around Greenland in the context of ice and ocean conditions and how might changes in the marine environment influence Greenland surface melt and accumulation in the future? This investigation will take advantage of up-to-date satellite sensor data, in combination with several new atmospheric reanalysis data products, station data and a state-of-the-art regional climate model, performed by a research team who are specialists in regional climate modeling, analysis of geospatial and sequential data analysis, satellite remote sensing and hydroclimatology in the Arctic and Greenland. This project will support students at the University of Colorado, the City College of New York and Rutgers University. The project also includes efforts to recruit undergraduates from underrepresented groups and will support a New Jersey high school teacher to develop lecture plans to be disseminated to a wide audience of K-12 educators at conferences and in journals.

Nontechnical

This project will explore the characteristics, variability and environmental impacts of a little-studied arctic seasonal atmospheric feature called the Summer Arctic Frontal Zone (AFZ), and how it may change over the next century. Little is known about variability in the AFZ or how it will change in the future. The feature is overlain by a high level jet-like feature, and areas where the AFZ are most pronounced are regions of frequent storm genesis, so understanding it is important to understand and predict weather events. In linking the arctic atmosphere, ocean, land surface and the hydrologic cycle, this study of the AFZ adopts a systems perspective, and steeping the next generation of researchers in systems studies is important for maintaining U.S. preeminence in environmental science, so the project is strongly geared towards support of a graduate student. Results from this study will be integrated into university classes and results will be featured in the National Snow and Ice Data Center?s Monthly Highlights. To communicate climate research to the general public, datasets created for this research will be formatted for Science on a Sphere technology. A research team member and the graduate student will present these data and their significance to the public as a part of science outreach shows at the University of Colorado?s Fiske Planetarium.

Technical

This is an effort to take advantage of data from a suite of advanced atmospheric reanalyses, satellite remote sensing and model experiments to address the characteristics, variability and environmental impacts of the Summer Arctic Frontal Zone (AFZ), and how this seasonal feature may change over the next century. Most prior research concludes that the AFZ develops primarily in response to summer heating contrasts between the Arctic Ocean and snow-free land. The AFZ is best developed along the Eurasian and Alaskan coasts, especially in Eastern Siberia and north of Alaska's Brooks Range, where it appears that temperature gradients are sharpened by topographic trapping of cold Arctic Ocean air. The AFZ at the surface is overlain by a jet-like feature at the tropopause. Areas where the AFZ are best expressed are regions of frequent cyclogenesis, and these cyclones have significant impacts on the summer precipitation regime not only along the Arctic coast, but also over the central Arctic Ocean, which is where many of the lows migrate into and decay. Migration of cyclones into the central Arctic Ocean also likely influences the sea ice state. This study will focus on: how seasonal development of the AFZ relates to variations in the seasonal timing of snow-free conditions over land, the location of the sea ice margin, surface temperatures, and topography; whether there is support for persisting views of ecological controls on the AFZ; how different patterns of atmospheric circulation influence the expression of AFZ; how variability in the AFZ is expressed in terms of patterns of cyclogenesis and summer precipitation; and how the AFZ will change through the 21st century in response to changes in seasonal snow cover, sea ice conditions and potential changes in atmospheric circulation patterns. The study will employ data from three atmospheric reanalyses, sea ice extent from the satellite passive microwave record, Reynolds sea surface temperature, satellite-derived terrestrial snow cover extent, experiments with the Weather Research and Forecasting regional model and output from coupled global models.

This grant supports an effort to assess and implement approaches to predict the timing of autumn freeze-up and spring-summer ice retreat in the Arctic coastal seas. The study is motivated by recognition that the Arctic Ocean is becoming more accessible for resource exploration, marine shipping, tourism and other activities, increasing the need for reliable seasonal predictions of ice conditions. The project will focus on regional scales addressing stakeholder needs. All Arctic coastal
seas and the channels of the Canadian Arctic Archipelago will be examined, but emphasis will be placed on the Chukchi and Beaufort Seas. This recognizes these regions as foci for resource exploration, where ships entering or exiting the Arctic Ocean via Bering Strait must pass, and as part of the seasonal bowhead whale migration route supporting subsistence hunting.

The core of the proposed approach is that the date of the spring/summer sea ice retreat to a given location (e.g., the continental shelf break) can be used to predict the date of the autumn advance back to that location (i.e. freeze-up), and hence the open water period. This reflects albedo feedback and ocean heat uptake processes that have always been part of the sea ice system. Briefly, earlier seasonal sea ice melt and retreat leads to earlier exposure of dark open water areas that readily absorb solar radiation, meaning more heat in the ocean mixed layer at summer's end, delaying autumn ice growth. This is manifested in observations that the upward trend in the open water period in the Chukchi Sea is driven more by later autumn return of ice than an earlier spring/summer retreat, and that there is a strong relationship between ice retreat and return in de-trended time series of the two variables.

Factors such as atmospheric variability and ocean heat transport are viewed as modulating expressions of albedo feedback and ocean heat uptake; such variables, along with seasonal climate forecasts, will be examined as additional predictors. It will be determined in which
sectors predictions are most and least skillful, the reasons for these differences, and whether
the changing sea ice regime (e.g., changing ice thickness) is changing predictability. In
addition, multiple processes, including winter atmospheric conditions, ocean heat transport, ice thickness and surface melt onset, will be examined as sources of predictability on the
date of retreat. The study will utilize satellite observations of sea ice extent and concentration, surface melt onset, ice motion, thickness and age, ocean heat flux measurements, and output
from the NCEP coupled Climate Forecast System, Version 2, along with fields of sea level pressure, temperature and other variables from two modern atmospheric reanalyses.

The Arctic Ocean, particularly the Chukchi and Beaufort seas, is of growing strategic importance
to our nation. The proposed
effort to provide skillful seasonal predictions of sea ice conditions at the regional scale
serves the goal of improving methods of connecting science with decision making through addressing diverse stakeholder needs, including marine
shipping agencies, extraction industries and subsistence hunting. Support is included for a graduate student and undergraduate students to help educate the next generation of scientists, and study results will be assimilated
into an Arctic climate course at the University of Colorado.

Arctic cyclones are an important contributor to sea ice deformation and oceanic mixing. Changes
in storm activity, and associated atmospheric feedbacks, have been linked to increased seasonality of the high north in the last decade, and with sea ice depletion during summer months. Cyclones are also likely to respond to changes in Arctic ice cover and ocean state indicating that
the atmosphere-ocean-ice system is tightly coupled through processes related to cyclones. Previous Arctic modeling studies typically used regional model simulations without full coupling
of the atmosphere-ocean-ice system, or fully coupled global climate models that do not permit year-on-year comparison with the observational record. This study will avoid such limitations by using
the Regional Arctic System Model (RASM), for which output corresponds directly with month-on-month observational records. This
will allow assessment of the ice-ocean-atmosphere coupling processes on multiple temporal
and spatial scales, and to relate them to limited Arctic Ocean measurements to build a more complete understanding of how increased cyclone activity may be helping to shift the surface climate of the Arctic to a new, warmer state with seasonal sea ice cover, and of how cyclones
will respond to this new Arctic Ocean state.

The impact of cyclones on Arctic stakeholder sectors in northern and western Alaska, including coastal communities and marine transport, will be assessed through a partnership with the Alaska Center for Climate Assessment and Policy and the project's inventory of Arctic cyclones and associated ocean and sea ice conditions will be archived at the National Snow and Ice Data Center. Historical time series of annual and seasonal Arctic cyclone activity, maps of tracks and intensities of Arctic cyclones, and case studies of intense or impactful cyclones will be made available on a project web page. The project will engage graduate students and a post-doctoral fellow,
and results will be used in atmospheric and oceanic science undergraduate and graduate level courses at the project institutions. Outcomes from this work will be address priorities in the US National Strategy for the Arctic Region and will address key uncertainties in understanding extreme events and their role in the Arctic climate system.

The recent loss of Arctic sea ice has increased the potential for ocean-atmosphere coupling
in the Arctic, especially in areas of low ice concentration or where the ice edge has receded. An important aspect of increased ocean-atmosphere Arctic coupling is the
 potential increase
of the ocean's response to storms. Where once mitigated by thick ice, wind-induced ice deformation and oceanic mixing are increasing as the ice pack thins. The decreasing Arctic ice cover and associated warming of the Arctic Ocean may also impact cyclone intensity and frequency. This grant will support investigation of changes in atmosphere-ice-ocean coupling in the presence of cyclones in the Arctic. It will advance our understanding of coupled atmosphere-ocean-ice processes with a focus on the role and response of cyclones in altering the state of the Arctic system. A cyclone tracking scheme will be applied to reanalyses, yielding an inventory of Arctic cyclone locations, tracks, and intensities that will provide a framework for analysis of ice and upper-ocean responses to storms. The responses of ice concentration, ocean temperature and salinity, and associated ice mass balance before, during, and after cyclones at a variety of intensities will be documented. The same analysis will be applied
to output from the high-resolution Regional Arctic System Model (RASM) and to output from
a suite of global climate models (GCMs). Using a novel set of metrics computed from the output of RASM, peak temporal and spatial scales of oceanic mixing, sea ice deformation, and turbulent fluxes associated with the passage of storms in the Arctic will be determined, in order to assess coupled cyclone-ocean-sea ice processes. Changes in the cyclone climatology between pairs of coupled RASM simulations, that differ only in sea ice and ocean state, and in current and end of the 21st century CMIP5 simulations will allow for assessment of cyclone response to changing ocean and ice state. This award is made by the Arctic Section of NSF Polar Programs and co-funded by the NSF GEO effort PREEVENTS.

NSFGEO-NERC Collaborative Research: Advancing Predictability of Sea Ice: Phase 2 of the Sea Ice Prediction Network (SIPN2)

The shrinking Arctic sea-ice cover has captured the attention of the world. A downward September trend has accelerated over the last decade, with the 10 lowest September sea-ice extents occurring in the last 10 years. An essentially ice-free Arctic during summer is expected by mid-century. Loss of the sea- ice cover has profound consequences for ecosystems and human activities in the Arctic, so there is an urgent need to advance sea-ice predictions in all seasons at both the pan-Arctic and regional scales. A better quantification of the role of oceanic heat and climate variations in the Pacific sector, new observational-based sea-ice products, and network activities will advance understanding of seasonal predictability of Arctic sea ice, the limits of this predictability, and the economic value of forecasts for stakeholders. The network supported by this grant will examine origins and impacts of extreme ocean surface warming in preconditioning the ice cover in the Pacific Arctic for continued major reductions in sea-ice extent and duration.

A key finding that emerged from the earlier Sea Ice Prediction Network (SIPN) effort is that predictions of September sea-ice extent tend to have less skill in extreme years that strongly depart from the trend line. The objective of proposed research under Phase 2 of SIPN (SIPN2) is to improve forecast skill through adopting a multi-disciplinary approach that includes modeling, new products, data analysis, scientific networks, and stakeholder engagement. This grant will: Investigate the sensitivity of subseasonal-to-seasonal sea-ice predictability in the Alaska Arctic to variations in oceanic heat and large- scale atmospheric forcing using a dynamical model Community Earth System Model (NCAR CESM) and statistical forecasting tools, focusing on spatial fields in addition to total extent summaries; Assess the accuracy of Sea Ice Outlook (SIO) submissions based on methodology and initialization; Develop new observation-based products for improving sea-ice predictions, including sea-ice thickness, surface roughness, melt ponds, and snow depth; Evaluate the socio-economic value of sea-ice forecasts to stakeholders who manage ship traffic and coastal village resupply in the Alaska Sector, and engage the public in Arctic climate and sea-ice prediction through blog exchanges, accessible SIO reports, bi-monthly webinars, and by making public data sources useful to non-scientists and scientists alike; and Continue and evolve network activities to generate SIO forecasts and reporting for September minima as in SIPN and expand SIPN2 forecasts to include full spatial resolution and emerging ice-anomaly-months (October - November).

This work will directly engage stakeholders that create and use sea-ice forecasts in Alaska and lead to improved safety around sea ice. Work under SIPN2 will also track public awareness and perceptions regarding sea ice, helping to raise understanding through accessible reports, discussions, and public data sources useful to non-scientists and scientists alike. Stakeholder engagement during the research process will potentially facilitate rapid research-to-operations implementation of the products of this work.

Navigating the New Arctic (NNA) is one of NSF's 10 Big Ideas. NNA projects address convergence scientific challenges in the rapidly changing Arctic. The Arctic research is needed to inform the economy, security and resilience of the Nation, the larger region and the globe. NNA empowers new research partnerships from local to international scales, diversifies the next generation of Arctic researchers, and integrates the co-production of knowledge. This award fulfills part of that aim.

Rain on Snow (ROS) and extreme precipitation events have significant impacts on Arctic wildlife, livestock, and the communities that depend on these resources for subsistence. The icy crusts that form after ROS events and deep snow can interfere with travel and searching for food. ROS events have been linked to massive die-offs of reindeer and caribou. Polar bear and ringed seal populations are also affected--rains early in the breeding season destroy dens built under the snow and increase cub/pup mortality. The purpose of this study is to better understand the frequency and cause of ROS and extreme precipitation events across the Arctic, how their frequency and severity are changing as the Arctic warms, and their social-ecological impacts. With a primary focus on hunting and reindeer herding livelihoods, this study involves close collaborations with Indigenous hunters and herders.

ROS and extreme precipitation events will be detected using various types of satellite data, weather data from atmospheric re-analyses, and surface observations. Indigenous hunters and herders will be engaged through extensive local observing, interviews, group discussions, and participatory workshops to validate the detection algorithms, and to assess effects of ROS and extreme precipitation events on wildlife and community activities. Similarly, the project will partner with reindeer herders to better understand implications for modern tundra reindeer nomadism and mortality episodes significant enough to have entered the oral record. Expert systems models will be developed to assess how ROS and extreme precipitation events impact wildlife, migratory reindeer herding, hunting, and other community activities in terms of event timing, geographic scale, snow/land cover, and existing community practices. A Data and Knowledge Hub, serving as the project website and a resource on the state of knowledge regarding Arctic ROS and extreme precipitation events and their impacts, will become the project's extension to the US Arctic Observing Network. The project also closely connects with the NSF ELOKA (Exchange for Local Observations and Knowledge of the Arctic) project, and long-time/on-going research collaboration with Inuit hunters, communities across Northern Alaska, and applied community-based ecological research in Lapland and Russia.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.