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:
Jason-3 is the latest earth observation satellite tasked with measuring global sea surface height; its data will be used in weather and climate research (e.g., El Niño, climate change). Launched on January 17, it’s now in its six-month checkout phase and has produced its first complete map, which corresponds well with the map produced by the still-operational Jason-2 satellite, so that’s a good sign. [via]
The ocean floor is still very much terra incognita: only 5 to 15 percent of it has been mapped via bathymetry. But using military satellite measurements of the Earth’s shape and gravity field, a new map of the ocean floor has been created. “The result of their efforts is a global data set that tells where the ridges and valleys are by showing where the planet’s gravity field varies. […] Shades of orange and red represent areas where seafloor gravity is stronger (in milligals) than the global average, a phenomenon that mostly coincides with the location of underwater ridges, seamounts, and the edges of Earth’s tectonic plates. Shades of blue represent areas of lower gravity, corresponding largely with the deepest troughs in the ocean.”
According to analyses by NASA and NOAA scientists, 2015 was the warmest year on record, with average surface temperatures the highest they’ve been since 1880. The above video shows the long-term warming trend since 1880 as a five-year rolling average. The baseline average is from 1951 to 1980; orange colours are warmer than that average, blue colours cooler. (Credit: GSFC Scientific Visualization Studio.)
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.
As I predicted, a new global map of Pluto has been released that incorporates the imagery that has been downlinked so far from the New Horizons flyby: with gridlines, without gridlines. If nothing else, the equatorial projection demonstrates how much of Pluto’s surface was not seen during the very brief encounter. From what I understand, imagery downlinks will resume in September and carry on for another year, so this map will almost certainly see many more updates.
The New Horizons spacecraft’s rendezvous with Pluto is next week, folks, but we’re already getting better views of our favourite dwarf planet than we’ve ever had before. NASA has assembled images taken between June 27 and July 3 into the above map, which despite its relatively low resolution shows some intriguing surface features: the so-called “whale” and “donut.” (Of course, low resolution is relative: this is already much better than the Hubble-based maps of Pluto released in 2005 and 2010.)