Some of the most striking maps of the recent bout of hurricanes have involved the sheer amount of water dropped by these storms. (See previous posts on Harvey and Irma.) Above, a is a short NASA video showing Maria’s track through the Caribbean, dumping water in its wake.
A new gravity map of Mars that shows the thickness of the Martian crust based on gravity measurements from Martian orbiters, reveals a crust that is less dense and shows less variation than earlier maps. “The researchers mapped the density of the Martian crust, estimating the average density is 2,582 kilograms per meter cubed (about 161 pounds per cubic foot). That’s comparable to the average density of the lunar crust. Typically, Mars’ crust has been considered at least as dense as Earth’s oceanic crust, which is about 2,900 kilograms per meter cubed (about 181 pounds per cubic foot).”
NASA’s page on Hurricane Harvey has been updated many times, sometimes several times a day, since Harvey began its life as Tropical Depression 9 on 17 August. It includes plenty of satellite imagery of the storm, as well as temperature and rainfall maps.
At All Over the Map, Betsy Mason posts 11 Ways to See How Climate Change Is Imperilling the Arctic, a collection of maps and infographics depicting several different indicators of global warming, including sea ice extent, atmospheric temperatures, growing season, polar bear populations, as well as projected shipping routes for an ice-free Arctic Ocean.
Meanwhile, NASA Earth Observatory points—while it still can—to a study mapping the extent of existing and potential thermokarst (thawed permafrost) landscapes. On the Earth Observatory maps (see North America, above), “[t]he different colors reflect the types of landscapes—wetlands, lakes, hillslopes, etc.—where thermokarst is likely to be found today and where it is most likely to form in the future.”
NASA Earth Observatory: “In November, the sea ice extent averaged 9.08 million square kilometers (3.52 million square miles)—the lowest November extent in the satellite record. The yellow line shows the median extent from 1981 to 2010, and gives an idea of how conditions this November strayed from the norm.” Also shows sea ice extent for previous years dating back to 1978. Hudson Bay was icebound in November not that long ago.
Something’s going on in the Arctic. As the Washington Post reported last month, the Arctic Ocean was far, far warmer than normal—about 20 degrees Celsius higher than average. (Meanwhile, the air over Sibera is at record cold levels.) According to the Post, the higher temperatures are the result of record low amounts of thinning sea ice, as well as warm air being brought north by an increasingly errant jet stream.
NASA has been tracking sea ice levels and thickness by looking at the age of the ice in the sea ice cap. The video above shows “how Arctic sea ice has been growing and shrinking, spinning, melting in place, and drifting out of the Arctic for the past three decades. The age of the ice is represented in shades of blue-gray to white, with the brightest whites representing the oldest ice.”
The ESA reports that their CryoSat satellite “has found that the Arctic has one of the lowest volumes of sea ice of any November, matching record lows in 2011 and 2012.” The animated GIF below shows the change in November sea ice from 2011 to 2016, as observed by CryoSat.
NASA Earth Observatory: “Days of intense rainfall in August 2016 led to widespread flooding in southern Louisiana, as rivers swelled high above their banks and many crested at record-high levels. […] The animation above shows satellite-based measurements of the rainfall as it accumulated over the southern United States. Specifically, it shows rainfall totals every three hours over the span of 72 hours from August 12-14, 2016. These rainfall totals are regional, remotely sensed estimates, and local amounts can be significantly higher when measured from the ground.”
NASA: “NASA researchers have helped produce the first map showing what parts of the bottom of the massive Greenland Ice Sheet are thawed— key information in better predicting how the ice sheet will react to a warming climate.”
The maps were created using data from NASA’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), which uses a technique known as interferometric synthetic aperture radar (InSAR). InSAR compares radar images of Earth’s surface over time to map surface deformation with centimeter-scale precision. It measures total surface elevation changes from all sources—human and natural, deep seated and shallow. Its data must be carefully interpreted to disentangle these phenomena, which operate at different time and space scales. UAVSAR’s spatial resolution makes it ideal for measuring subsidence in New Orleans, where human-produced subsidence can be large and is often localized.
NASA Earth Observatory: “Clouds may seem like distant, ephemeral features that have little to do with life on Earth. In fact, they affect everything from the viability of ecosystems, to how much carbon plants absorb, to the reproductive success of reptiles. So by mapping clouds, new research shows, scientists can indirectly map life.”
NASA Earth Observatory: “The map above, based on data provided by the National Snow and Ice Data Center, shows the extent of Arctic permafrost. Any rock or soil remaining at or below 0 degrees Celsius (32 degrees Fahrenheit) for two or more years is considered permafrost.” The map differentiates between continuous, discontinuous, sporadic and isolated permafrost. [NASA Earth]
A new gravity map of Mars, based on data from three orbiting spacecraft, has been released. “Slight differences in Mars’ gravity changed the trajectory of the NASA spacecraft orbiting the planet, which altered the signal being sent from the spacecraft to the Deep Space Network. These small fluctuations in the orbital data were used to build a map of the Martian gravity field.”
The data enables the crustal thickness of Mars to be determined to a resolution of approximately 120 kilometres. Here’s a short video explaining the significance: