Author: Travis Swaim

133 – Polar Climate System
Principal Investigator(s): L. Boisvert

A polynya is a persistent opening or hole in sea ice that occurs in locations or times when sea ice is otherwise thought to be present. They come in many different shapes and can range in size from hundreds to thousands of square kilometers. Even though their relatively small size in comparison so the sea ice itself, polynyas have a large impact on the Arctic in a number of ways. Polynyas affect the surrounding atmosphere, the radiation budget, the local ocean salinity, the ocean circulation, and wildlife. In the winter months their effects are most prominent. They provide the surrounding air with excess heat and moisture, which cools the ocean and heats up the surrounding boundary layer. This excess moisture leaves the ocean surface, quickly cools and condenses, and creates plume clouds, which can be transported downstream via winds. Polynyas are relatively under sampled due to their remote locations and harsh wintertime conditions. Observations are done on field campaigns, on ships and by weather stations, but data is collected for short time periods and instrument error can occur due to harsh conditions.

In the past decade there has been an abundance of satellite data that has spatial and temporal scales that provide much more coverage of the Arctic and polynyas than field campaigns. Being able to use this valuable data to study polynyas in detail would greatly enhance our understanding of polynyas and their effects on the Arctic system.

228a – Toward Routine Mapping of Land-Surface Carbon, Water and Energy Fluxes at Field to Regional Scales
Principal Investigator(s): R. Houborg

In the absence of clouds, remotely sensed observations in the reflective solar and thermal infrared (TIR) domains have great utility for monitoring the terrestrial biosphere and vegetation dynamics at a range of spatial and temporal scales. The satellite signal in these wavebands is indirectly related to a variety of key biophysical and vegetation biochemical descriptors of the land surface that are needed for reliable assessments of land-surface carbon, water and energy fluxes.

132 – Analysis and Evaluations of Passive Microwave Measurements
Principal Investigator(s): Nai-Yu Wang

Measurements from polar orbiting satellites, in particular, microwave sensors, offer perhaps the most viable means to develop global precipitation retrievals. Measurements from the Tropical Rainfall Measuring Mission (TRMM) and the Global Precipitation Mission (GPM) will exploit such data to provide global, three-hourly precipitation monitoring. Much research and development needs to be done to prepare for the GPM core satellite launch in 2013. The next three years is the most critical time to develop and deliver the pre-launch algorithms. We’ll work closely with several Precipitation Measurement Missions (PMM) science team working groups (WGs) and team members to develop and deliver the baseline precipitation algorithms over land.

131 – Impact of Moisture Conditions on Twomey Effect
Principal Investigator(s): Z. Li

In the Twomey effect, increasing aerosol concentration enhances cloud albedo by acting as cloud condensation nuclei (CCN) and creating more, smaller cloud droplets when the liquid water content (LWC) is constant. However, the impact of varying LWC on the Twomey effect is not determined yet, as well as the impacts of other variables characterizing moisture conditions, such as relative humidity (RH) and mixing ratio that affect the CCN nucleation and droplet growth. Between January and June 2009, an aircraft field campaign aiming at Routine AAF Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) was conducted in the vicinity of the ACRF Southern Great Plains site. During the campaign, 57 flights were taken, and half of them were inside the boundary layer clouds. The obtained long-term representative statistics of cloud microphysical and aerosol properties of the atmosphere make the statistical average methods possible. This provides a more accurate measurement than the satellite, as the cloud 3D effect and other retrieving algorithms limitation do not exist here. These data could also support model simulations of boundary layer clouds.

128 – Pilot Applications of the Chesapeake Bay Forecast System
Principal Investigator(s): A. Busalacchi

A project aimed at demonstrating the value and utility of applications of the Chesapeake Bay Forecast System (CBFS), a prototype regional integrated Earth System Model being developed and implemented at the University of Maryland Earth System Science Interdisciplinary Center. This pilot effort will develop several Pilot User Collaborations aimed at identifying and testing methods for applying CBFS forecast products to sector-specific needs.

228 – Integrating Enhanced GRACE Terrestrial Water Storage data into the U.S. and North American Drought Monitors
Principal Investigator(s): R. Houborg

NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites measure time variations of the Earth’s gravity field enabling reliable detection of spatio-temporal variations in total terrestrial water storage (TWS), including groundwater. The U.S. and North American Drought Monitors are two of the premier drought monitoring products available to decision-makers for assessing and minimizing drought impacts, but they rely heavily on precipitation indices and do not currently incorporate systematic observations of deep soil moisture and groundwater storage conditions. Thus GRACE has great potential to improve the Drought Monitors by filling this observational gap. We expect that the integration of the enhanced GRACE data into the operational production of objective drought indicator blends will lead to more accurate depictions of short and long-term drought conditions, ultimately benefitting the many stakeholders who depend on these products.

127 – Validation and Calibration of Airborne Lidar Data Collected Using NASA’s Laser Vegetation Imaging Sensor in Support of the DESDynI Lidar Mission
Principal Investigator(s): M. Hofton

This project coordinates high-altitude airborne lidar data experiments in the Antarctic and Greenland to collect elevation and surface structure information in support of NASA’s Operation Ice Bridge and DESDynI lidar missions. After processing and quality checking, data precision and accuracy are assessed using crossover analyses and comparison with available in situ data. Data are released publically and are used in pre-mission studies by the DESDynI Lidar Science Definition Team and others. The study results in the collection, analysis and validation of the precision and accuracy of elevation and topographic structure products derived from the 25m-footprint, waveform LVIS lidar over ice and vegetation targets.

124 – Evaluating Potential for Satellite Observations to Improve Soil NOx Emissions Estimates by Satellite/Emissions/Photochemical Model Intercomparison
Principal Investigator(s): S. Ehrman

Soil NOx emissions contribute to the tropospheric NO2 column. Soil bacteria produce NO through the processes of nitrification and denitrification. Field experiments, model simulations [e.g., Davidson et al., 1998] and satellite observations indicate that NO emissions pulse following rain on dry soils, particularly after recent application of fertilizer. Satellite-based observations have been instrumental in determining the magnitude of soil NOx emissions. Globally, soil emissions of NO contribute perhaps 5-10 Tg N per year to the global NOx budget. Jaeglé et al. [2004, 2005] and Bertram et al. [2005] estimated the soil NOx source using top-down approaches based on satellite data from the GOME and SCIAMACHY instruments, respectively. Their results suggest that biospheric models underestimate soil NOx emissions by a factor of 2. The increasingly high resolution of satellite data makes it possible to constrain emission sources over smaller and smaller regions. Reducing uncertainties in this source is an active area of research.