Scientists have been tracking seasonal freeze-thaw patterns for 30 years. This map, produced from data collected by NASA’s Soil Moisture Active Passive satellite, “shows the freeze-thaw status of areas north of 45 degrees latitude on March 5, 2015, as spring approached. Frozen land is blue; thawed land is pink. The measurement is possible because frozen water forms crystalline structures that can be detected by satellites.” NASA Earth Observatory.
Hotter than usual? Yes. This map shows how much land surface temperatures during the week of June 17-24, 2012 have been above or below the average for 2000-2011. Now this map measures something very specific: land surface temperatures (LSTs) aren’t the same as air temperatures: “LSTs indicate how hot the surface of the Earth would feel to the touch. From a satellite vantage point, the ‘surface’ includes a number of materials that capture and retain heat, such as desert sand, the dark roof of a building, or the pavement of a road. As a result, daytime land surface temperatures are usually higher than air temperatures.” Via Bad Astronomy.
