1. Airborne Topographic Mapper (ATM) Study: The 13 year time series of Arctic surface measurements permits immediate ice sheet change analyses from ICESat data. Results: Recent results using ICESat data have shown: - Rapid thinning of major outlet glaciers that is coincident with recent acceleration of these same glaciers - an increase in ice loss to 57-105 GT/yr for the 1998/9-2004 time period as compared to 4-50 GT/yr in the 1993/4-1998/9 time period 1 Impact of Results: These results complement recent observations of increased melt and increased speeds of outlet glaciers. They also fill in major gaps that exist in radar altimetry coverage 2. Radar altimetry is not applicable to coastal regions, where changes are greatest. ATM Provides: -GPS/laser data for the Aqua/AMSR calibration/validation -Envisat/ICESat/airborne multi-sensor sea ice data set that includes sea ice roughness and freeboard height to enable thickness estimates 1 Thomas et al., 2006, GRL 2 Zwally et al., 2005, J. Glaciology (A) Rates of elevation change (dS/dt) at more than 16000 locations where ICESat data from Oct/Nov and May/June, 2004 overlay ATM surveys in 1998/9; (B) Estimated dS/dt averaged over 50-km grid squares; the GPS traverse is shown in red. Locations of rapidly- thinning outlet glaciers at Jakobshavn (J), Kangerdlugssuaq (K), Helheim (H) and along the southeast coast (SE) are shown, together with plots showing their estimated mass balance( M in Gt/yr) versus time [Rignot and Kanagaratnam, 2006]. William Krabill/Ocean Sciences Branch, Hydrospheric & Biospheric Sciences Laboratory Terms and Acronyms: freeboard: is the height of an ice floe above the water surface floe: a large flat body of ice less then five miles across GPS: Global Positioning System Envisat: Environmental Satellite ICESat: Ice, Cloud, and land Elevation Satellite

2. 2005 (orange) and 2006 (green) Arctic Ice Mapping Project Flights Alaska Glaciers In collaboration with the CoE and U. Alaska AQUA/AMSR calibration/validation support Canadian Arctic In collaboration with the Canadian Geological Survey Envisat and ICESat underflight In collaboration with NOAA and UCL Continuing Greenland Time Series

3. Ship-based aerosol optical depth measurements in the Atlantic Ocean: Comparison with satellite retrievals and GOCART model From the paper by Smirnov, Holben, Sakerin, Kabanov, Slutsker, Chin, Diehl, Remer, Kahn, Ignatov, Liu, Mishchenko, Eck, Kucsera, Giles, and Kopelevich, published in Geophys. Res. Lett., 33, L14817, 2006. Motivation: Substantial radiative effects of sea-salt aerosol, better understanding of the climate change forcing by aerosols, combined with very few systematic measurements over the oceans, especially in the South Ocean, create a demand for more data acquisition. Recently the AErosol RObotic NETwork (AERONET) established a few new island sites in the Southern Ocean; however, large areas south of 35º still have no coverage. Ship-based measurements can at least partly fill the gap which exists in our knowledge on the global aerosol distribution over the oceans. Biospheric Sciences Branch, Hydrospheric & Biospheric Sciences Laboratory Terms: aerosols: tiny solid particles or liquid droplets that remain suspended in the atmosphere for a long time and tend to absorb or reflect incoming sunlight, thus reducing visibility and increasing optical depth aerosol optical depth: measure of how much light airborne particles prevent from passing through a column of atmosphere

4. Approach: Aerosol optical depth measurements were made in October-December 2004 onboard the R/V Akademik Sergey Vavilov. The cruise track included a transect in the Atlantic from the North Sea to Cape Town, South Africa, and then a crossing in the South Atlantic to Ushuaia, Argentina. Ship-borne measurements were compared to satellite retrievals from various sensors and to the global transport model GOCART. Results: It was found that atmospheric aerosol optical parameters in the Southern Atlantic between 34ºS and 55ºS are close to other remote oceanic areas (for example, high latitude Northern Atlantic, Southern and Tropical Pacific, and South Indian Ocean). Aerosol optical depth was relatively low despite the wind speed range was 5-15 m/s for the area south of 40º latitude. Almost 60% of satellite retrieved optical depths, although highly correlated with the sunphotometer measurements are generally higher. The GOCART model calculated aerosol optical depths, on the other hand, are less correlated with sunphotometer measurements. Biospheric Sciences Branch, Hydrospheric & Biospheric Sciences Laboratory Acronyms: AVHRR-GISS: Advanced Very High Resolution Radiometer-Goddard Institute for Space Studies MISR: Multi-angle Imaging SpectroRadiometer MODIS-Terra: Moderate Resolution Imaging Spectroradiometer MODIS-Aqua: Moderate Resolution Imaging Spectroradiometer : AVHRR-NOAA 16: Advanced Very High Resolution Radiometer-National Oceanic and Atmospheric Administration 16 AVHRR-NOAA 17: Advanced Very High Resolution Radiometer-National Oceanic and Atmospheric Administration 17 GOCART: Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation Transport

5. Satellite vs Sunphotometer Comparison Ship-based Latitudinal Distribution of t a (500 nm) Biospheric Sciences Branch, Hydrospheric & Biospheric Sciences Laboratory

6. First Results from the Synthetic Aperture Radiometer: 2D-STAR David M. LeVine/Instrumentation Sciences Branch, Hydrospheric & Biospheric Sciences Laboratory Instrument: 2D-STAR is an airborne instrument designed to demonstrate new technology, called aperture synthesis, for remote sensing of Earth from space. Several important applications, such as:  monitoring soil moisture (agriculture, floods, water cycle)  ocean salinity (ocean circulation and climate change) These applications require large antennas in space. This is because they are best monitored at relatively long wavelengths (21 cm) in a portion of the microwave spectrum called L-band. Aperture synthesis is a technology for overcoming the limitation that large antennas place on remote sensing from space. In this technique pairs of small antennas and signal processing replace the conventional large antenna. Instrument History: 2D-STAR was developed at GSFC under NASA’s Instrument Incubator Program, and the instrument (radiometer) participated in a successful experiment to monitor soil moisture, called SMEX-03, during the summer, 2003, at instrumented fields in Alabama, Georgia and Oklahoma.

7. First 2D-STAR Images SMEX-03; Huntsville, AL Landsat TM (Spring, 2000) Red = Forest 2D-STAR Total power (TH + TV ) The images to the left shows a 2D-STAR image of the Alabama site near Huntsville compared with a Landsat image that indicates land cover (bottom). The contrast between forested areas to the east (right section of images) and the flat agricultural areas to the west are clear in both the 2D- STAR image and the Landsat image. The cool (blue) line at the lower right hand corner is the Tennessee River. The 2D-STAR image compares well with the patterns of moisture observed on the ground. These images represent the first for a remote sensing sensor employing aperture synthesis in two dimensions.