National Aeronautics and Space Administration

National Climate Assessment

NASA National Climate Assessment (NCA) Activities

NASA Centers Call for Proposals

National Climate Assessment - 2011 NASA Centers Call For Proposals

Lead PI and Center: Thomas Painter, Jet Propulsion Laboratory
Title:  Snow and Ice Climatology of the Western United States from MODIS
Proposal Type: Assessment Capabilities & Products

The climate and hydroclimate of the Western US and Alaska are tightly coupled to their snow and ice cover.  The Western US depends on mountain snowmelt and, to a lesser degree, glacier melt for the majority of its water supply to agriculture, industrial and urban, hydroelectric generation, and recreation. Alaskan snow and glacier cover modulate regional climate.

Projections of climate change in the Western US and Alaska suggest that the most pronounced impacts will include reductions of the mountain snow and ice cover, earlier runoff, and a greater fraction of rain instead of snow. Surface observations show a declining snowpack over the last few decades and spring runoff starting up to three weeks earlier. Increasing dust emitted from the deserts of the Western US has been accelerating snowmelt and shortening snow cover by several weeks since the mid 1800s. Mass wasting of Alaskan glaciers has contributed 25-40% of the observed global sea level rise. However, these conclusions have been anchored by point observations or sparse remote sensing observations, but not with temporally and spatially dense remote sensing products that NASA data can provide.

In the coming National Climate Assessment, the Northwest, Southwest, and Alaska/Arctic regional assessments will focus on higher resolution mesoscale climate and hydroclimate modeling that treat snow and ice cover explicitly.  The spatial resolution of the modeling grids will better resolve mountain topography and therefore the spatial and temporal dynamics of snow and ice cover. Unfortunately, snow mapping from NASA EOS satellites over the last decade has continued the use of imprecise band difference algorithms that exhibit severe errors of omission during the periods most critical for snow cover and ice cover observations. Glacier cover is currently only represented sparsely by the Global Land Ice Measurements from Space (GLIMS) program, with snapshots of glacier outlines, where available, and no means by which to update these outlines annually. No remote sensing retrieval of radiative forcing by dust and black carbon (BC) exists for assessment of the snowmelt impact of aerosols.

Proposed Effort:
We propose to use the established, physically based MODIS-derived MODSCAG, MODICE, and MOD-DRFS algorithms to produce more accurate and complete data records of fractional snow covered area, annual minimum exposed snow and ice, and dust/BC radiative forcing in snow, respectively, for the Western US and Alaska/Arctic across the Earth Observing System (EOS) record 2000-2012.

These quantitative products will fill marked voids in the available data sets that are needed to constrain and validate the higher resolution modeling of climate and hydroclimate in the Northwest, Southwest, and Alaska/Arctic regions of the National Climate Assessment. The products are also immediately portable to the NPOESS Preparatory Project (NPP) and Joint Polar Satellite System (JPSS) Visible Infrared Imaging Radiometer Suite (VIIRS) when those data are available and thereby provide the robust foundation for the long-term framework, called for by the NCA, for evaluation of climate change.

Project Publications:

Bryant, A. C., Painter, T.  H., Deems, J. S., and  Bender, S. M. (2013), Impact of  dust radiative forcing in snow on accuracy  of operational runoff prediction  in the Upper Colorado  River Basin, Geophysical Research  Letters, in press, doi: 10.1002/grl.50773.

Micheletty, P. D., Kinoshita, A.  M., and Hogue, T. S.  (2014), Application of MODIS snow  cover products: wildfire impacts on snow  and melt in the  Sierra Nevada, Hydrology and Earth System  Sciences, 18: 4601‐4615

Wrzesien, M. L., Pavelsky, T. M., Kapnick,  S. B., Durand, M. T., and Painter,  T. H. (2014), Evaluation of  snow cover fraction for regional  climate simulations in the Sierra  Nevada, International Journal of  Climatology, doi: 10.1002/joc.4136.