Seasonal sea ice and snow cover visualizations

This is the SVS Demo Reel presented at SIGGRAPH 2019 in Los Angeles, CA. Related pages

Snow and sea ice play follow-the-leader as winter descends and spring arrives. Data from NASA's AMSR-E instrument captures the connected patterns of snow and sea ice cover in North America. Snow and sea ice in the Northern and Southern Hemispheres pulse at exact opposite times of year, constantly out of phase. Antarctic sea ice generally reaches its minimum extent in March around the time Arctic sea ice grows to its maximum extent. NASA scientist Thorsten Markus measures the thickness and temperature of Antarctic sea ice. Seen from the vantage point of a satellite, snow covers much of North America for half the year like a white curtain that begins its descent in fall and isn't drawn up until spring. Lagging behind the snow by a month or so, sea ice spreads across the Arctic Ocean and infiltrates the channels, islands and bays of Alaska and Canada. Snow and sea ice share this leading-and-lagging relationship because of the different rates at which the ground and oceans absorb and emit heat. Land temperatures drop more quickly, and extensive snow cover settles in by October. The ocean has a longer memory of temperature. Arctic waters retain enough heat in fall to keep ice from forming well after snow has accumulated on solid ground at the same latitude. Likewise, Arctic sea ice doesn't reach its annual maximum extent until late March, typically more than a month after the snow cover peak. In the visualization below, keep an eye on the massive Hudson Bay in northern central Canada: Snow encircles the frigid body of water before the first sea ice creeps into the bay. In spring, snow retreats past the bay completely before its sea ice even begins to dissipate. Related pages

The advance-and-retreat cycle of snow cover drastically changes the whiteness and brightness of Earth. Seasonal snow cover waxes and wanes across the globe from Sept. 2010 to Aug. 2011. At the height of winter in North America snow cover can stretch from the Arctic Circle to the southeastern United States. The difference in the Northern Hemisphere's minimum and maximum snow cover drastically alters the reflectivity of the Earth. Heavy snow cover blanketed the U.S. from the Great Lakes to the Deep South on Feb. 11, 2011. A massive snowstorm covered much of continental Europe and the United Kingdom on Dec. 29, 2010. The Himalayan and Tian Shan mountain ranges, as well as much of Siberia, had a heavy coat of snow on Feb. 28, 2010. NASA scientists use satellite data to produce daily snow cover maps. One of their biggest hurdles: distinguishing between white clouds and snow. This mostly cloud-covered map from the MODIS Snow & Sea Ice Global Mapping Project shows snow cover from the same day as the previous image. For More InformationSee [NASA.gov](http://modis-snow-ice.gsfc.nasa.gov/) Related pages