Virginia Norwood, called “the mother of Landsat” for her invention of Landsat 1’s multispectral scanner system, died on March 26th at the age of 96. See also Landsat’s memorial. [Lat × Long]
Previously: The Mother of Landsat.
Tag: satellite
Mapping the Russian Invasion of Ukraine: Roundup #2
Content warning: Some of these links contain disturbing images: I’ve marked them with a †.
More on the question of whether theatre maps accurately reflect the ground situation. Nathan Ruser’s maps have been used to argue that Russian forces are controlling roads rather than territory, but Ruser complains that his maps are being misinterpreted: they were never meant to show territorial control, just troop movements. See also this Twitter thread from Jennifer Cafarella, in which she explains the methodology and reasoning behind her team’s maps.
3D models of bombing damage.† Satellite imagery and 3D photogrammetric data are used to create 3D models of bombing damage in Ukraine. [Maps Mania]
A map of attacks on civilian targets† with photo and video documentation. [Nataliya Gumenyuk]
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.”
A Ukrainian map of alleged Russian casualties† and where they were deployed from. [Michael Weiss]
A map of checkpoint traffic. More than two million Ukrainians have fled the Russian invasion. Overwhelmingly, they’re fleeing westward. This map shows how busy each border checkpoint is: Polish border crossings are extremely congested. [Kyiv Independent]
Meanwhile, Kenneth Field has been working on ways to map Ukraine’s refugees. Here’s his most recent iteration:
Update to my illustrative #Ukraine refugee map.
Adds more displaced grey dots to major populated areas.
Adds same stippled symbology to Russian incursion to indicate fuzziness of invasion (neither lines nor areas).#cartography #StandWithUkraine 💙💛 pic.twitter.com/QOyA8RaRi0
— Kenneth Field (@kennethfield) March 8, 2022
Ukraine’s population density. More than 41 million people live in Ukraine. This map from Airwars shows the population density per square kilometre. Which shows how many people in an area are affected by a particular military strike.
Apple says Crimea is Ukrainian. Mashable: “Apple’s Maps and Weather apps now mark Crimea as part of Ukraine when accessed outside of Russia. It appears the company has quietly updated its stance on the territorial dispute.” Apple had marked Crimea as Russian in 2019, which pissed Ukraine off at the time. [TechCrunch]
Finally, this striking bit of art:
By Ukrainian tattoo artist Eugene Anatsky pic.twitter.com/qVybeGYAuE
— Olga Tokariuk (@olgatokariuk) March 5, 2022
Alaskan Ice in Retreat
This NASA Earth Observatory video looks at the retreat of Alaska’s Columbia Glacier since 1986. Transcript here.
Looking for Lightning, Finding Meteors
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.)
How Satellites Revealed the Hunga-Tonga Hunga-Ha’apai Eruption
The BBC’s Jonathan Amos looks at the ways satellites have collected imagery and data on the Hunga-Tonga Hunga-Ha’apai1 volcanic eruption.
The Mother of Landsat
Virginia Tower Northwood is sometimes called “the mother of Landsat” for her invention of the multispectral scanner that was launched aboard Landsat 1. An alumna of MIT, she is the subject of this long profile by Alice Dragoon in the MIT Technology Review, which looks her entire career, which prior to Landsat involved radar and antenna design—including, notably, the transmitter on the Surveyor 1 lunar lander. See also this profile on NASA’s Landsat Science page.
Climate from Space
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.
Online Map Tracks Nitrogen Dioxide Concentrations
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]
Previously: Mapping the Lockdown-Related Drop in Emissions; Emissions Drop Due to Coronavirus Outbreak.
Mapping the Lockdown-Related Drop in Emissions
The European Space Agency maps the drop in nitrogen dioxide concentrations in the atmosphere in the wake of coronavirus lockdowns in many countries (see above). [GIS Lounge]
Meanwhile, CESBIO researcher Simon Gascoin built a map that compares NO2 concentrations over the last 30 days with the same period in 2019.
Data for these analyses generally come from the Copernicus Programme’s Sentinel-5P satellite. The Copernicus Atmosphere Monitoring Service issued a warning last week about using the data improperly.
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.
Previously: Emissions Drop Due to Coronavirus Outbreak.
Emissions Drop Due to Coronavirus Outbreak
As you may have seen elsewhere, the coronavirus pandemic is having an impact on air pollution, as countries shut down human and economic activity in an attempt to deal with the outbreak. Take nitrogen dioxide. Tropospheric NO2 density decreased significantly over China between January and February, and the same seems to be happening in northern Italy, which normally has some of the most severe air pollution in Europe. See the ESA’s animation:
More broadly, try this online map, which compares NO2 emissions before and after 20 February 2020 anywhere on the planet. [Maps Mania]
Previously: Mapping Nitrogen Dioxide Pollution.
Mapping Ground Displacement from the California Earthquakes
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’s Heat Wave, as Seen from Orbit
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.”
California Wildfire Roundup
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.)
Two Esri maps: a general wildfire map and a map of smoke from wildfires [Maps Mania]. Add to that a map of field damage reports in the area hit by the Camp Fire [Maps Mania].
The Jet Propulsion Laboratory has produced a map of the damage from the Camp Fire based on satellite radar images. NASA Earth Observatory has maps and animations showing the impact of the Camp Fire on air quality and satellite images of the Woolsey Fire burn scar.
The New York Times has a map tracking air quality in California. Smoke from the fires has reached the east coast: an outcome predicted by atmospheric models (see above map).
This interactive map from NBC News that superimposes the Camp Fire on any location to help people outside California get a sense of how big these fires are. [Maps Mania]
Antarctica at Eight-Metre Resolution
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]
Mapping Global Fresh Water Availability
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]
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