Susan K. Avery - US grants

The objective of this research is the deployment and operation of three stratospheric.tropospheric (ST) radars in the tropical Pacific to make new measurements of convection, atmospheric waves, and turbulence. The radars will be constructed using components of the larger MST radar originally constructed at Poker Flat, Alaska. Additionally, three boundary layer profilers, recently developed by the Aeronomy Laboratory, will be deployed to measure the field of motion from the surface to near 10,000 feet.

This grant will support a workshop entitled "Mechanisms for Tropospheric Effects of Solar Variability and the Quasi-Biennial Oscillation" to be held on June 20,21, 1989 in Boulder, Colorado preceding the annual CEDAR* meeting. The workshop objectives are to search for and evaluate hypotheses for mechanisms that might account for the solar variability/quasi-biennial oscillation/weather correlation as first discussed by Labizke (Free University, W. Berlin) and Van Loon (NCAR). This topic is part of the CEDAR and STEP** initiatives. The workshop format will have invited tutorials covering the possible range of topics that will be important for understanding and evaluating possible mechanisms and poster papers that will present recent data analysis and model results. The outcome of the workshop will be a narrowing of the most likely scenario for mechanisms and a set of recommendations for future research. * Coupled Energetics and Dynamics of Atmospheric Regions ** Solar Terrestrial Energy Program

To understand the transport of energy throughout the middle atmosphere requires observations around the globe. Many observational programs are currently in place providing such information at middle and high latitudes. This project is to continue studies of the equatorial mesosphere using meteor echo returns on VHF profilers on Christmas Island. These data will be analyzed for mean wind and tidal climatologies as well as the structure and evolution of large-scale wave motions and how they relate to the mesospheric semiannual oscillation and tropospheric wave patterns. Additional meteor echo detection and collection systems will be built and installed on VHF radars located in Pohnpei, Indonesia and Peru. These additional stations will allow study of mesospheric dynamics in four different tropospheric climatic regions. ***

The PI plans to study the tropical convective systems and their impact on the forcing of tropospheric and mesospheric circulation patterns by utilizing satellite data bases in conjunction with data obtained from wind profiles. She will also examine the relationships between satellite derived measurements of atmospheric water vapor and vertical wind profiles measured by the radars in the tropics in order to provide insight into the dynamics of vertical energy fluxes which couple the energy from the source regions to other heights. She also plans to obtain the statistics of cloud composites associated with convection in order to force a model of an atmosphere on a rotating sphere to establish the mode structures in the wind field that will be present in the troposphere, stratosphere, and mesosphere. The model-generated mode structures will be compared with the radar observed mesospheric structures of the diurnal tide, quasi two-day wave, and other longer period wave motions. Additionally, the PI plans to gain expertise in two other atmospheric radar probing techniques, the MF/HF radar and the 1 GHz boundary layer radar.

The objective of this research is the investigation of the field of motion in the tropical Pacific using four existing VHF (50 MHz) radars located in Peru, Christmas Island, Phonpei, and Biak, Indonesia. Topics for investigation include measured vertical motion, the vertical flux of horizontal momentum between the boundary layer and roughly 20 km. These measurements will be used in cognate studies of gravity waves, thermal convection and tidal oscillations. This research is a joint activity between the University of Colorado and NOAA's Aeronomy Laboratory.

The PIs wish to install and operate a partial reflection drifts and a meteor radar over a three-year period at Sondre Stomfjord, Greenland. Goals include studying high-latitude dynamics in the height range from approximately 60 to 110 km. The cooperative research effort with Clemson University and the University of Colorado will include the study of seasonal variations in tidal amplitudes and phases, gravity wave characteristics, climatology, and fluxes, and the scattering mechanisms producing the partial reflections.

We propose to conduct a study of the sources due to mesoscale variability of gravity waves at mesospheric heights. The mesospheric wind data for this study will be obtained from an HF radar installed on the island of Kauai, Hawaii in September of 1990. Gravity wave activity observed from this radar will be examined with reference to possible frontal, convective, and jet stream wave sources. We intend to use synoptic, radiosonde, and satellite imaging data in the search for these sources. We will also conduct a critical examination of the spaced antenna drift (SAD) technique in regard to measuring winds in the middle atmosphere.

This proposal seeks funds for meteor radar studies of the mesosphere and lower thermosphere using a meteor echo detection and collection system (MEDAC). The objectives of the work are to provide an understanding of the long period wave motions, including the migrating and non-migrating tides, and their interaction with the large scale wind circulation. The studies will use data collected from the equatorial Pacific wind profiler network , which has been augmented with MEDAC systems that allow the determination of the winds in the mesosphere and lower thermosphere. In order to generate the long data sets necessary for this work, an upgrade of the MEDAC sites is required. Because the MEDAC requires the use of a wind profiler that is often not optimized for meteor echo detection, the PIs propose to design a new portable meteor radar system that would stand alone. This new system, as well as the current system, will be augmented with new data analysis techniques utilizing genetic algorithms. A final aspect of the proposed work is to establish a cooperative research program with the University of Adelaide allowing experiments to be done on the Buckland Park radars.

This grant develops the Platteville Atmospheric Observatory, located in Platteville, Colorado. The observatory currently has VHF, UHF, and boundary layer wind profilers for lower atmospheric measurements of winds, waves and stability. The PI plans to establish a medium frequency radar and all-sky meteor radar, providing measurements of upper atmosphere winds. She will also upgrade the VHF wind profiler and UHF boundary layer profiler to provide greater sensitivity for atmospheric coupling and precipitation studies. In sum, these acquisitions, developments and upgrades will implement research of large scale wave motions and their influence on circulation, wave-wave interactions, coupling of energy and momentum between regions of the atmosphere via gravity waves, boundary layer evolution, and land-atmosphere hydrological processes.

ATM0000957abs

The investigators will study the dynamics of the mesosphere and lower thermosphere over Antarctica using measurements from the TIMED instruments and a meteor radar to be installed at South Pole station. Specific science objectives include: the space-time decomposition of wave motions; delineation of the spatial climatology over Antarctica with emphasis on the structure of the polar vortex; dynamical response to energetic events; and interannual variability. The proposed meteor radar is a VHF system that will be able to measure the spatial structure and temporal evolution of the horizontal wind field over the South Pole. The investigators will also make use of existing ground-based radars at Davis, Syowa, Rothera, and Scott Base in the determination of the spatial climatology. Wind and temperature measurements to be made by NASA's TIMED satellite during orbits over the South Pole will provide opportunities for combined ground-based and space-based experiments and validation activities.

This research project will conduct long-term observations of the mesosphere and lower thermosphere of the atmosphere for changes in temperature. The temperature will be determined from wind and optical measurements taken with meteor radars at four sites in the Arctic: Barrow, Alaska, Kangerlussuaq, Greenland, and Dixon and Heiss Islands, Russia. The measurement program is timed to take advantage of a NASA satellite measurement program that will focus on the same part of the atmosphere. Because the introduction of greenhouse gases influences atmospheric temperature, the long-term measurements will be affected by anthropogenic as well as natural changes in temperature. The researchers will attempt to separate the two signals and use temperature changes caused by introduction of carbon dioxide into the atmosphere to provide a warning that greenhouse gases are affecting atmospheric temperature. Observed temperature changes will be used to examine the dynamic coupling of the middle and lower atmospheres as well as the physical processes that affect changes in the thermal structure of the atmosphere. The long-term observations will be an important contribution to understanding of the long time-scale evolution of the middle/lower atmosphere at a time when the Arctic appears to be undergoing major changes in response to a climatic warming.

Because of concerns about global climate change, society is actively exploring the possibility of using forest ecosystems as a carbon sink. Tropical forests may offer more than two-thirds of such opportunities. The protection of tropical forests could offset global fossil fuel carbon emissions and reduce the cost of emissions limitations set in Kyoto. In addition, certified emissions credits (CERs) under the Clean Development Mechanism (CDM) established in Kyoto likely will incorporate tropical forest sinks within efforts to meet emissions targets. In principle, this could result in significant economic and sequestration benefits, although actual evidence on tropical carbon sinks is sparse. To advance knowledge and practice associated with this important topic, this collaborative research project has two major goals. First, the investigators will develop an integrated, spatially explicit model of that predicts how much additional carbon sequestration will occur in Costa Rica if financial rewards for sequestration are offered. This modeling effort will include both economic modeling of land use and ecological modeling of carbon storage. Both sets of models will be based on empirical observations of carbon and nitrogen stocks and flows, with systematic sampling of variations in soils, climate, and land uses. The second major goal of the research will be to contribute to the effective design of rules that allow carbon-sequestration efforts in tropical locations to replace emission-reduction efforts in more developed nations. This line of inquiry will involve the conduct of sensitivity analyses on the integrated model in order to derive simplified versions of state-of-the-art disciplinary and integrated models. This effort will facilitate the search for estimate how much carbon sequestration will be generated in Costa Rica in response to different kinds of monetary rewards for carbon sequestration. This project will increase understandings of the interplay of socioeconomic and ecological factors that influence land-use choices as well as the effects of land-use change on carbon sequestration in Costa Rica, a representative nation with significant tropical forests and readily available data sources. In addition to addressing these fundamental issues, the project will explore the potential for simplified models to identify the potential implications of different carbon-sequestration incentives on land-use decisions, thereby providing valuable new insights into critical aspects of the Kyoto accord to reduce atmospheric carbon.

A continuing series of grants since 1988 has made it possible for CIRES of the University of Colorado, in collaboration with the NOAA Aeronomy Laboratory, to construct, operate, and maintain VHF wind-profiling radars at four sites stretching across the equatorial Pacific: Biak, Indonesia; Pohnpei, Micronesia; Christmas Island, Kiribati; and Piura, Peru. Observations from the profiler at Christmas Island are now assimilated into operational forecast models on a routine basis. Ongoing research activities based on data from the network include: (1) documentation of seasonal and interannual variability of winds over the Tropical Pacific; (2) investigation of the structure of atmospheric Kelvin waves, Rossby waves, and gravity waves; (3) measurement of the vertical structure and amount of rainfall at the profiler sites; (4) obtaining data for the validation of atmospheric models. The network fills both research and operational needs for data on winds and precipitation in the Tropical Pacific - a region important for the global climate, but where other sources of data are scarce.

This proposal is for the study of electric field effects on meteor trails in the equatorial region. Additionally, the PIs seek to understand any deviation of the radar scattering properties of a meteor trail from traditional specular reflection processes.

These scientific goals require the upgrade and continued operation of an existing meteor radar at Piura, Peru (5S, 81W). The upgrade at this site consists of installing a complete all-sky meteor radar system, so that the angle-of-arrival of meteoric backscatter can be unambiguously determined. In addition, archive data from Christmas Island will be analyzed for meteor winds as well. As a byproduct of this work routine mean wind, tidal amplitudes and phases, and meteor decay statistics will be available to the scientific community via a web server.

The investigators will observe, model and study the spatial-temporal structure and variability of the semidiurnal tide in the middle atmosphere. The focus will be on the Arctic and Antarctic mesosphere and lower thermosphere horizontal wind and temperature fields. The mesosphere and lower thermosphere, at an altitude between 80 and 120km above the surface of the earth, is a highly dynamic region that couples the lower atmosphere (troposphere/stratosphere) with the upper atmosphere thermosphere/ionosphere). Of particular importance in this region are both the upward propagating thermally forced atmospheric tides and global scale planetary waves. Both of these phenomena transport heat and momentum from the lower atmosphere into the upper atmosphere. Studies in recent years have indicated that the high latitude (Arctic and Antarctic) mesosphere and lower thermosphere possess a rich spectrum of planetary waves that had previously gone undiscovered. These planetary waves can interact with the sun-synchronous migrating semidiurnal tide modifying its spatial and temporal structure while giving rise to the nonmigrating semidiurnal tide. Understanding the structure and variability of the semidiurnal tide is an important step to understanding the global heat and energy balance of the mesosphere and lower thermosphere. The data used for this project will include horizontal wind measurements from a global network of 30 ground-based meteor and medium frequency radars. Additionally, wind and temperature measurements from the NASA TIMED satellite will be combined with the radar data. It is expected, from previous observations, that planetary waves will play a significant role in the variability of the semidiurnal tide. For this reason the structure of the semidiurnal tide and the structure of the planetary waves will be estimated simultaneously. These estimates will be analyzed in conjunction with both linear mechanistic and global circulation models to aid in the interpretation of the observations and increase knowledge about the semidiurnal tide. As part of this effort a web based tool to ingest the radar data from the global network will be employed. Data submitted to the database will be processed and then disseminated via a website, the TIMED database and the CEDAR database. Such a database is required for this and future efforts that propose to make use of the global network of mesosphere and lower-thermosphere radar wind measurements.

The University of Colorado at Boulder (CU/Boulder) proposes to hire a new tenure-track faculty member in Solar Physics, to complement Boulder's strong community in solar and space physics both at CU and at institutions across the Boulder Valley (National Oceanic and Atmospheric Administration/Space Environment Center (NOAA/SEC), National Center for Atmospheric Research/High Altitude Observatory (NCAR/HAO), Southwest Research Institute (SwRI), etc). Currently, despite the large number of solar physicists in the Boulder community, there is no tenure track faculty member actively working in solar physics at CU, significantly inhibiting the growth of CU graduate programs in this space physics discipline. The potential addition of a faculty line in solar physics comes at an opportune time of overall transformation of the solar and space physics graduate and upper-division undergraduate programs on the CU/Boulder campus, including the development of a new integrative first-year graduate course in solar and space physics and new cross-departmental graduate courses. This proposal would enhance these endeavors, as well as support a named graduate student fellowship and an undergraduate research program.

Because the space industry is a mature and essential part of the global economy and the commercial and governmental interests of the United States, it is essential that the US cultivate the talent needed to thrive and excel in this arena. This proposal would develop new talent for the US work force through both enhanced graduate and undergraduate education, an imperative identified in the recent NRC Decadal Survey on space physics. Space weather and the concomitant threats it poses to our technological infrastructure present important societal impacts. The Laboratory for Atmospheric and Space Physics (LASP) at CU/Boulder, the research home of the new faculty hire, has a leading role in knowledge transfer and empirical modeling as part of the National Science Foundation (NSF)-sponsored Center for Integrated Space weather Modeling (CISM). LASP performs this work in close cooperation with NCAR and NOAA/SEC, pursuing efforts to consolidate and integrate results from many international research programs and campaigns. The strengthening of solar and space physics at CU/Boulder will directly enhance LASP's ongoing Education and Public Outreach program in space weather. This EPO program is gaining national recognition for its space physics curriculum enhancements, teacher workshops, distance learning programming, and its new planetarium show entitled "Space Storm."

The mesosphere and lower thermosphere (MLT), at an altitude between 80 and 120 km above the Earth's surface, is a highly dynamic region that couples the lower terrestrial atmosphere (troposphere and stratosphere) with the upper atmosphere near-Earth space environment (thermosphere and ionosphere). Of particular importance in this region are both the upward propagating thermally forced atmospheric tides and global scale planetary waves. Both of these phenomena transport heat and momentum from the lower atmosphere into the upper atmosphere. Studies in recent years have indicated that the Arctic and Antarctic MLT possess a rich spectrum waves and may be more sensitive to global change than the lower atmosphere. The primary goal of this research is to observe, quantify, model, and further understand the spatial-temporal structure and variability of the MLT circulation above Antarctica and its commonalities with the Arctic. A secondary goal is to quantify and understand the deposition of mass into the upper atmosphere through the ablation of meteors and the resulting effect on local and regional aeronomic processes. This includes the effect of meteor flux, temperature and dynamics on the seasonal distribution of sodium over the South Pole. Meteor radar was installed at the South Pole Amundsen-Scott station and has been running continuously since January 2002. A new sodium nightglow imager will be installed at the South Pole to infer the sodium abundance in the MLT. Observations from this instrument will be combined with the South Pole Fabry-Perot interferometer temperature measurements and the meteor radar wind and meteor flux measurements to improve our understanding of the sodium chemistry and dynamics. These observations will be interpreted using sophisticated numerical models and interpreted in conjunction with Arctic measurements along with current linear and nonlinear atmospheric models to advance the current understanding of processes important to the MLT region. This research also contributes to the training and education of the graduate and undergraduate students, a postdoc and early career tenure track faculty.