Where hot spots are literally hot spots. In a Twitter thread, Sotris Valkaniotis shows how military operations in Ukraine show up in Landsat spectral imagery: weapons fire turns up as hot spots showing “very high temperature in short-wave infrared band.”
It turns out that the Geostationary Lightning Mapper (GLM) aboard the GOES-16 and GOES-17 earth observing satellites can do more than just detect lightning—it can also detect bolides, or very bright meteors, thanks to a new automatic detection algorithm. NASA Earth Observatory: “The map above shows the distribution of more than 3,000 bolides detected by the GLMs aboard GOES-16 and GOES-17 between July 2017 and January 2022. Blue points are bolides detected by GOES-16; pink points were detected by GOES-17. The lone pink point over the Atlantic Ocean was detected by GOES-17 during its commissioning phase before it was moved into its operational orbit over the West Coast.” (Bolides in the middle of the map are detected by both, and as you can see there’s a bit of parallax.)
The European Space Agency’s new Climate from Space website presents satellite data on a host of different climate indicators, from aerosols to CO2, from land cover to sea ice, via 3D virtual globes. From the announcement:
The new, easy-to-use site provides access to the same satellite observations used by scientists to understand climate change and support international organisations such as the United Nations Framework Convention on Climate Change (UNFCCC) and Intergovernmental Panel on Climate Change (IPCC) to drive action.
There is a suite of 21 climate data records to explore, which are generated by ESA’s Climate Change Initiative. The suite includes sea level, sea surface temperature, soil moisture, snow depth and the greenhouse gases, carbon dioxide and methane, as well as new visualisations for the latest climate variables records such as permafrost and lakes.
A new online map tracks tropospheric global nitrogen dioxide concentrations—which we’ve seen drop sharply this year as the pandemic shut down economic activity. “This online platform uses data from the Copernicus Sentinel-5P satellite and shows the averaged nitrogen dioxide concentrations across the globe—using a 14-day moving average. Concentrations of short-lived pollutants, such as nitrogen dioxide, are indicators of changes in economic slowdowns and are comparable to changes in emissions. Using a 14 day average eliminates some effects which are caused by short term weather changes and cloud cover. The average gives an overview over the whole time period and therefore reflects trends better than shorter time periods.” [ESA]
Concentrations of NO2 in the atmosphere are highly variable in space and time: they typically vary by one order of magnitude within each day and quite substantially from one day to another because of the variations in emissions (for example the impacts of commuter traffic, weekdays and weekend days) as well as changes in the weather conditions. This is why, even if observations are available on a daily (currently available from satellites) or even hourly (ground-based observations) basis, it is necessary to acquire data for a substantial period of time in order to check that a statistically robust departure from normal conditions has emerged.
Cloud cover is a factor that needs to be taken into account as well.
This interferogram shows the ground displacement caused by last week’s earthquakes in southern California. Produced by NASA’s Jet Propulsion Laboratory, it’s based on synthetic aperture radar (SAR) images from JAXA’s ALOS-2 satellite taken both before (16 April 2018) and after (8 July 2019) the earthquakes. Each colour cycle represents 12 centimetres (4.8 inches) of ground displacement.
Europe is in the middle of a severe heat wave. The European Space Agency has released a map of land temperatures in Europe as of 26 June, produced from the Copernicus Sentinel-3 satellite’s temperature radiometer, “which measures energy radiating from Earth’s surface in nine spectral bands—the map therefore represents temperature of the land surface, not air temperature which is normally used in forecasts. The white areas in the image are where cloud obscured readings of land temperature and the light blue patches are either low temperatures at the top of cloud or snow-covered areas.”
The San Francisco Chronicle’s 2018 California Fire Tracker is an interactive map of ongoing and contained wildfires—notably, at this moment, the Camp and Woolsey fires. It includes fire perimeter and air quality data. (Note: it’s glitchy on desktop Safari.)
The Reference Elevation Model of Antarctica is a terrain map of nearly the entire continent at eight-metre resolution, assembled from observations from polar-orbiting satellites (mostly in 2015 and 2016). Version 1 covers 98 percent of Antarctica, and observations are ongoing. Notably, each grid point is timestamped, which will allow researchers to track changes over time (useful when your continent is melting). Raw data is available for download, as are map posters; the data is also available via web apps. [Geographical]
NASA Earth Observatory: “The map above depicts changes in water storage on Earth—on the surface, underground, and locked in ice and snow—between 2002 and 2016. Shades of green represent areas where freshwater levels have increased, while browns depict areas where they have been depleted. Data were collected by the GRACE mission, which precisely measured the distance between twin spacecraft as they responded to changes in Earth’s gravity field. In sensing the subtle movements of mass around the planet, the satellites could decipher monthly variations in terrestrial water storage.” The GRACE observations form the basis of a study published this month in Nature on changes in global fresh water availability. More at the JPL’s GRACE-FO project page. [Benjamin Hennig]
The deep freeze is unevenly distributed. NASA Earth Observatory published this temperature anomaly map based on data from the MODIS instrument on NASA’s Terra satellite. A temperature anomaly map shows how much warmer or colder temperatures are versus the average—in this case, land surface temperatures from 26 December 2017 to 2 January 2018 are compared to the 2001-2010 average for the same period. While it’s awfully cold in Canada, and the central and eastern United States, it’s warmer than normal in the southwest. And if you look beyond the North American continent (which is something people should do more often), it’s generally warmer worldwide, particularly in Europe and Asia: