Swot satellite is scheduled to be launched Thursday morning to conduct a comprehensive survey of Earth'svital resource. By using advanced microwave radar technology it will collect height-surface measurements of oceans, lakes and rivers in high-definition detail over 90% of the globe. It's rally the first time to observe nearly all water on the planet's surface.
The major mission is to explore how oceans absorb atmospheric heat and carbon dioxide in a natural process that adjusts climate change. Oceans are estimated to have absorbed more than 90%, of the extra heat trapped in the Earth's atmosphere by human-caused greenhouse gases. Swot will scan, the seas and precisely measure fine differences in surface elevations (高度) around smaller currents and eddies (漩涡), where much of the oceans' decrease of heat and carbon is believed to occur. "Studying the mechanism will help climate scientists answer a key question: What is the turning point at which oceans start releasing, rather than absorbing, huge amounts of heat back into the atmosphere and speed up global warming, rather than limiting it," said NadyaShiffer, Swot's program scientist.
By comparison, earlier studies of water bodies relied on data of rivers or oceans taken at specific, points, or from satellites that can only track measurements along a one-dimensional line, requiring scientists to fill in data gaps through extrapolation (外推法). Thanks to the radar instrument, Swot can scan through cloud cover and darkness over wide ranges of the Earth. This enables scientists to accurately map their observations in two dimensions regardless of weather or time of day and to cover large geographic areas far more quickly than was previously possible.
"Rather than giving us a line of elevations, it's giving us a map of elevations, and that's just a total game changer," said Tamlin Pavelsky, Swot freshwater science leader.
