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]
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.
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:
Previously: Mapping Nitrogen Dioxide Pollution.
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.”
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.
Yesterday the European Space Agency released a sky map based on the first 14 months of data collected by the Gaia spacecraft, an astrometric observatory whose mission is to create a precise catalogue of astronomical objects’ position and relative motion. Several versions are available: annotated, unannotated, annotated with titles (above), unannotated with titles. The maps contain artifacts (curves and stripes) from Gaia’s scanning procedures, but they’ll improve as more data is added over the course of Gaia’s five-year mission.
The European Space Agency has released this false-colour composite image of Ireland based on 16 radar scans by the Sentinel-1A satellite in May 2015. The colours show change over the 12 days of coverage: “The blues across the entire image represent strong changes in bodies of water or agricultural activities such as ploughing. […] Vegetated fields and forests appear in green. The reds and oranges represent unchanging features such as bare soil or possibly rocks that border the forests, as is clear on the left side of the image, along the tips of the island.” [ESA]
The European Space Agency has released a map showing the northern hemisphere’s biomass — specifically, its growing stock volume (GSV), which is the amount of wood per hectare in cubic metres. The map is based on radar images taken by the now-defunct Envisat satellite between October 2009 and February 2011.
Previously: Herbal Earth.