A5088498310- Cryospheric studies and observations
- Arctic and Antarctic ice dynamics
- Climate change and permafrost
- Winter Sports Injuries and Performance
- Landslides and related hazards
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Geophysics and Gravity Measurements
- Atmospheric and Environmental Gas Dynamics
- Planetary Science and Exploration
- Meteorological Phenomena and Simulations
- Scientific Research and Discoveries
- Climate variability and models
- Astro and Planetary Science
- Oceanographic and Atmospheric Processes
- Remote Sensing and LiDAR Applications
- Space Exploration and Technology
- Icing and De-icing Technologies
- Polar Research and Ecology
- Atomic and Molecular Physics
- Geological Studies and Exploration
- Groundwater and Isotope Geochemistry
- Ionosphere and magnetosphere dynamics
- Atmospheric aerosols and clouds
- Hydrology and Watershed Management Studies
Earth System Science Interdisciplinary Center
2015-2023
University of Maryland, College Park
1968-2023
Goddard Space Flight Center
2010-2022
Naval Research Laboratory Information Technology Division
2011-2013
NASA Earth Science
2013
Deleted Institution
1986-2013
National Aeronautics and Space Administration
1985-2012
Stinger Ghaffarian Technologies (United States)
2006-2011
Cooperative Institute for Research in Environmental Sciences
2006
University of Colorado Boulder
2006
We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, models surface mass balance glacial isostatic adjustment to estimate the Earth's polar ice sheets. find that there is good agreement between different methods--especially in Greenland West Antarctica--and combining leads greater certainty. Between 1992 2011, sheets Greenland, East Antarctica, Antarctic Peninsula changed by -142 ± 49, +14 43, -65 26, -20...
The Mars Orbiter Laser Altimeter (MOLA), an instrument on the Global Surveyor spacecraft, has measured topography, surface roughness, and 1.064‐μm reflectivity of heights volatile dust clouds. This paper discusses function MOLA acquisition, processing, correction observations to produce global data sets. altimeter measurements have been converted both gridded spherical harmonic models for topography shape that vertical radial accuracies ∼1 m with respect planet's center mass. current...
Ice flow at a location in the equilibrium zone of west-central Greenland Sheet accelerates above midwinter average rate during periods summer melting. The near coincidence ice acceleration with duration surface melting, followed by deceleration after melting ceases, indicates that glacial sliding is enhanced rapid migration meltwater to ice-bedrock interface. Interannual variations are correlated intensity larger increases accompanying higher amounts indicated coupling between and ice-sheet...
Elevations measured by the Mars Orbiter Laser Altimeter have yielded a high-accuracy global map of topography Mars. Dominant features include low northern hemisphere, Tharsis province, and Hellas impact basin. The hemisphere depression is primarily long-wavelength effect that has been shaped an internal mechanism. consists two broad rises. Material excavated from contributes to high elevation southern scarp along hemispheric boundary. present three major drainage centers, with lowlands being...
We present our best estimate of the thickness and volume Arctic Ocean ice cover from 10 Ice, Cloud, land Elevation Satellite (ICESat) campaigns that span a 5‐year period between 2003 2008. Derived drafts are consistently within 0.5 m those submarine cruise in mid‐November 2005 4 years draft profiles moorings Chukchi Beaufort seas. Along with more than 42% decrease multiyear (MY) coverage since 2005, there was remarkable thinning ∼0.6 MY over years. In contrast, average seasonal midwinter (∼2...
The Geoscience Laser Altimeter System (GLAS) on the NASA Ice, Cloud and land Elevation Satellite (ICESat) has provided a view of Earth in three dimensions with unprecedented accuracy. Although primary objectives focus polar ice sheet mass balance, GLAS measurements, distributed 15 science data products, have interdisciplinary application to topography, hydrology, vegetation canopy heights, cloud heights atmospheric aerosol distributions. Early laser life issues been mitigated adoption 33‐day...
Satellite passive‐microwave data for November 1978 through December 1996 reveal marked seasonal, regional, and interannual variabilities, with an overall decreasing trend of −34,300±3700 km 2 /yr (−2.8%/decade) in Arctic sea ice extents over the 18.2‐year period. Decreases occur all seasons on a yearly average basis, although they are largest spring smallest autumn. Regionally, Kara Barents Seas have decreases, at −15,200±1900 (−10.5%/decade), followed by Okhotsk Japan, Ocean, Greenland Sea,...
Taking stock of our losses Earth's ice sheets are melting and sea levels rising, so it behooves us to understand better which climate processes responsible for how much the mass loss. Smith et al. estimated grounded floating change Greenland Antarctic from 2003 2019 using satellite laser altimetry data NASA's ICESat ICESat-2 satellites. They show changing flow, melting, precipitation affect different regions estimate that grounded-ice loss averaged close 320 gigatons per year over period...
Abstract Changes in ice mass are estimated from elevation changes derived 10.5 years (Greenland) and 9 (Antarctica) of satellite radar altimetry data the European Remote-sensing Satellites ERS-1 -2. For first time, dH/dt values adjusted for surface resulting temperature-driven variations rate firn compaction. The Greenland sheet is thinning at margins (–42 ± 2Gta¯ 1 below equilibrium-line altitude (ELA)) growing inland (+53 2Gta -1 above ELA) with a small overall gain (+11 3Gta –1 ; –0.03...
Satellite and aircraft observations have revealed that remarkable changes in the Earth's polar ice cover occurred last decade. The impacts of these changes, which include dramatic loss from sheets rapid declines Arctic sea ice, could be quite large terms level rise global climate. NASA's Ice, Cloud Land Elevation Satellite-2 (ICESat-2), currently planned for launch 2015, is specifically intended to quantify amount change provide key insights into their behavior. It will achieve objectives...
The principal characteristics of the variability Antarctic sea ice cover as previously described from satellite passive microwave observations are also evident in a systematically calibrated and analyzed data set for 20.2 years (1979–1998). total extent (concentration >15%) increased by 11,180 ± 4190 km 2 yr −1 (0.98 0.37% (decade) ). increase area within boundary is similar (10,860 3720 1.26 0.43% Regionally, trends positive Weddel Sea (1.4 0.9% ), Pacific Ocean (2.0 1.4% Ross (6.7 1.1%...
Mass changes of the Greenland Ice Sheet resolved by drainage system regions were derived from a local mass concentration analysis NASA-Deutsches Zentrum für Luftund Raumfahrt Gravity Recovery and Climate Experiment (GRACE mission) observations. From 2003 to 2005, ice sheet lost 101 +/- 16 gigaton/year, with gain 54 gigaton/year above 2000 meters loss 155 at lower elevations. The elevations show large seasonal cycle, losses during summer melting followed gains fall through spring. overall...
We have generated consistent sea ice extent and area data records spanning 18.2 years from passive‐microwave radiances obtained with the Nimbus 7 scanning multichannel microwave radiometer Defense Meteorological Satellite Program F8, F11, F13 special sensor microwave/imagers. The goal in creation of these was to produce a long‐term, set extents areas that provides means for reliably determining variability over 18.2‐year period also serves as baseline future measurements. describe method...
From November 1978 through December 1996, the areal extent of sea ice decreased by 2.9 ± 0.4 percent per decade in Arctic and increased 1.3 0.2 Antarctic. The observed hemispheric asymmetry these trends is consistent with a modeled response to carbon dioxide–induced climate warming. interannual variations, which are 2.3 annual mean Arctic, predominant period about 5 years, 3.4 Antarctic, 3 uncorrelated.
Abstract Mass changes of the Antarctic ice sheet impact sea-level rise as climate changes, but recent rates have been uncertain. Ice, Cloud and land Elevation Satellite (ICESat) data (2003–08) show mass gains from snow accumulation exceeded discharge losses by 82 ± 25 Gt a −1 , reducing global 0.23 mm . European Remote-sensing (ERS) (1992–2001) give similar gain 112 61 Gains 136 in East Antarctica (EA) 72 four drainage systems (WA2) West (WA) exceed 97 three coastal (WA1) 29 Peninsula (AP)....
The SEASAT‐I radar altimeter data set acquired over both the Antarctic and Greenland continental ice sheets is analyzed to obtain corrected ranges surface. functional response considerably more complex than oceans. Causal factors identified in this complicated include sloping surfaces, undulating surfaces with characteristic wavelengths on same spatial scale as beam‐limited footprint, off‐track reflections, dynamic lag of tracking circuit. Retracking methods using return pulse waveforms give...
Measurements of ice-sheet elevation change by satellite altimetry show that the Greenland surface south 72 degrees north latitude is increasing. The vertical velocity 0.20 +/- 0.06 meters per year from measured changes in elevations at 5906 intersections between Geosat paths 1985 and Seasat 1978, 0.28 0.02 256,694 during a 548-day period to 1986.
Sea ice freeboard heights in the Weddell of Antarctica are derived from Ice, Cloud, and Land Elevation Satellite (ICESat) laser altimeter measurements, which have a unique range precision to flat surfaces 2 cm within 70 m footprints spaced at 172 along track. Although elevations can be obtained an accuracy ∼10 (1 σ ) per footprint, direct determination is precluded by errors knowledge geoid temporal variability ocean surface. Therefore freeboards determined relative reference level detected...
Elevations from the Mars Orbiter Laser Altimeter (MOLA) have been used to construct a precise topographic map of martian north polar region. The northern ice cap has maximum elevation 3 kilometers above its surroundings but lies within 5-kilometer-deep hemispheric depression that is contiguous with area into which most outflow channels emptied. Polar topography displays evidence modification by ablation, flow, and wind consistent primarily H 2 O composition. Correlation images suggests was...
Abstract The microwave emission from a model snow field, consisting of randomly spaced ice spheres which scatter independently, is calculated. Mie scattering and radiative transfer theory are applied in manner similar to that used calculating optical properties clouds. extinction coefficient computed as function both wavelength ice-particle radius. Volume by the individual particles field significantly decreases for particle radii greater than few hundredths wavelength. Since mean annual...
The unprecedented accuracy of elevations retrieved from the Ice Cloud and Land Elevation Satellite (ICESat) laser altimeter is investigated used to characterize range errors in Environmental (Envisat) European Remote Sensing 2 (ERS-2) radar altimeters over continental ice sheets. Cross-mission crossover analysis between time-coincident ERS-2-, Envisat-, ICESat-retrieved comparisons an ICESat-derived digital elevation map are quantify error budget as a function surface slope investigate...