Ryan R. Neely, III., Ph.D. - US grants

In 2010, the observatory at Summit, Greenland, in the center of the Greenland Ice Sheet (GIS), was expanded to include a comprehensive suite of cloud-atmosphere observing instruments including microwave and infrared spectrometers, cloud radar, depolarization lidar, ceilometer, precipitation sensor, sodar, and a twice-daily radiosonde program. This observing effort was termed ICECAPS (Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit). A continuation of this project is proposed here, with moderate enhancements to include atmospheric aerosol observations. Measurements from this expanded instrument suite will be used to derive critical baseline atmospheric data products including:
* Atmospheric State - tropospheric temperature, moisture, and wind profiles
* Aerosols - concentration of total particles and cloud condensation nuclei
* Cloud Macrophysics - occurrence, vertical boundaries, temperature
* Cloud Microphysics - phase, water content, and characteristic particle size
* Precipitation - type and rate
Together these products, when combined with similar ongoing measurements at Summit, can be used to study processes that impact the surface energy budget and precipitation at the site, as well as addressing questions related to atmospheric stability, cloud phase composition, the persistence of stratiform clouds, and aerosol-cloud interactions. It is further anticipated that these observations will continue to be used by a broad cross-section of the scientific community to promote understanding of GIS and Arctic climate, validate satellite observations, and evaluate model simulations. Graduate students play significant roles in most aspects of this project, gaining valuable experience with polar field work, operating instruments, and processing data. In addition, this research team has developed a unique education and outreach plan to work with students from local schools using simple, proxy instrumentation to help develop their understanding of atmospheric principles and observations, and to enhance the scientific curriculum in their schools via a wide range of outreach activities.

A better understanding of Arctic cloud and aerosol properties, structure and formation is essential to understand the specific response of the Arctic in the context of global climate change. A lack of coherent high vertical and temporal resolution observations of cloud particles, aerosols moisture advection (i.e. water vapor) and thermodynamics, creates large uncertainties in current model estimates of cloud properties and inhibits our understanding of cloud radiative and precipitation impacts on the surface. As a result, current weather and climate models poorly parameterize clouds over the Arctic and more specifically over the Greenland Ice Sheet (GIS). A reduction in this uncertainty is particularly important above the GIS, where clouds act as sinks and sources to the ice mass balance by modulating the surface radiation budget and available precipitable water. To gain the understanding necessary to reduce this uncertainty, a new autonomous multi-wavelength, polarized Raman lidar is proposed for development and deployment at the NSFʼs observatory in Summit, Greenland. The new lidar observations will employ multiple wavelengths and polarizations to observe elastic and inelastic scattering from the Arctic atmosphere enabling regular retrieval of temperature, water vapor and extinction profiles. This combination of observational capability will create a coherent dataset of high-resolution thermodynamic, cloud and aerosol observations through the Arctic troposphere and lower stratosphere above Summit. Broadly, this addition to the NSF Observatory at Summit, Greenland as part of the larger Arctic Observing Network fits well within the Study of Environmental Arctic Change (SEARCH) implementation plan. Thus, this instrument will significantly enhance Arctic observing infrastructure and advance observations and understanding of change in the Arctic. The proposed instrumentation and observations are the first of their kind on the GIS and will expand the existing, although modest, network of such measurements across the Arctic. This project will also provide a unique experience and educational opportunity through the combination of fieldwork and subsequent data processing for graduate students at the University of Colorado.