A recent map of the earth’s atmosphere, released by the NASA Earth Observatory, shows the world as a dazzlingly colorful place from above; but that’s where the happiness ends, as each of those beautiful colors represents a particular type of, potentially, harmful aerosol suspended in the air we breathe.
The result of various factors such as fires, storms, emissions from vehicles and factories, saline sea spray, and desert dust, aerosols are, basically, solid particles and liquid droplets, so tiny that they are invisible to the naked eye.
The blue that you see in the visualizations above represents “giant swirls of sea salt aerosol” caused by storms; the red areas mark the black carbon particles in the air – the result of fires, as well as vehicle and factory emissions; and the purple sections of the map represents aerosols that are classified as dust.
By the way, whatever is visible on that map is a single day’s depiction of the earth’s atmosphere – August 23, to be precise – based on inputs from satellite-mounted instruments and ground-based sensors.
One such satellite data source was the Moderate Resolution Imaging Spectroradiometer (MODIS) – a key instrument aboard the Terra and Aqua satellites, referred to as Terra MODIS and Aqua MODIS, respectively.
While Terra is timed to pass over the equator in the morning as it travels north to south, Aqua does the same in the afternoon, moving south to north.
Both the MODIS view the “the entire Earth’s surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths,” says the MODIS website modis.gsfc.nasa.gov.
“These data will improve our understanding of global dynamics and processes occurring on the land, in the oceans, and in the lower atmosphere. MODIS is playing a vital role in the development of validated, global, interactive Earth system models able to predict global change accurately enough to assist policy makers in making sound decisions concerning the protection of our environment,” says the website.
Also used in the aerosol visualization was “a layer of nightlight data” collected by the Visible Infrared Imaging Radiometer Suite (VIRS) – an instrument aboard the Suomi NPP weather satellite that measures cloud and aerosol properties, ocean color, sea and land surface temperature, ice motion and temperature, fires, and Earth’s albedo.
Albedo is, basically, the reflective capability of an object; meaning, the higher the albedo the more reflective the object, a good example of which is snow, which has a high albedo.
All of the satellite data, plus data collected by ground sensors, were then processed by GEOS FP (Goddard Earth Observing System Forward Processing) – NASA’s state-of-the-art weather analysis and prediction software.
Using mathematical equations, along with the August 23 data input from all the different sources mentioned above, GEOS FP was able to create the colorful model of aerosols in the earth’s atmosphere, as can be seen in the illustrations above.
Visualizations such as these, which NASA regularly updates, are aimed at getting a clear insight into how natural and man-made aerosols influence Earth’s climatic conditions over a period of time, which would go a long way in helping scientists better understand and predict climate-related natural disasters in times to come.
Some of the events that appear so colorful and attractive in the GEOS FP aerosol map were, actually, creating havoc on terra firma as torrential rains lashed Hawaii, announcing the approach of Hurricane Lane.
People in South Korea and Japan were, meanwhile, bracing themselves for the destructive force of not one but two tropical cyclones, Soulik and Cimaron, approaching the region.
A plume of smoke hovering above central Africa was mainly the result of controlled fires lit by farmers to rejuvenate the land for crops and grazing.
“This could be due to the fact that these are most likely agricultural fires. The location, widespread nature, and number of fires suggest that these fires were deliberately set to manage land,” says NASA.
“Farmers often use fire to return nutrients to the soil and to clear the ground of unwanted plants. While fire helps enhance crops and grasses for pasture, the fires also produce smoke that degrades air quality.”
Plus, there were large wildfires raging in the United States and Canada, as is evident from the smoke representation above the North American continent on the map.
An August 23 image from NASA’s Earth satellites, posted by the space agency on Twitter the same day, shows the active fires burning on Earth on the day, denoted by red spots on the photograph.
“The world is on fire. Or so it appears in this image from our @NASAEarth satellites. Using thermal bands to detect active burning areas, each red dot is a fire. The fires in Africa are likely agricultural, while elsewhere, the fires are likely wildfires: https://go.nasa.gov/2woKh3T,” read the space agency’s message accompanying the image.