EARTH DAY April 22, 2020

Earth from space on the morning of April 21, 2020.

Earth is our home and we are its stewards. The human population is now in a fight against a coronavirus. For a brief moment, however, GARI would like to showcase 5 vistas of our planet for you to examine and consider your role as a steward of our home. In the image above, the sun is just rising over Central America and the terminator (separating light from dark) passes right over a gray, smooth blob. That is a large area of smoke from fires set to clear the landscape for agricultural activity to feed a hungry planet. On the eastern edge (right side) dust from the Sahel region is being blown out into the Atlantic representing a loss of fertile soils there. The rest of the image shows the greens, blues, whites, and browns that make earth unique in our solar system-a living planet.

Earth’s systems are connected. In this image below, the GOES weather satellite (in the water vapor channel) reveals how moisture from the tropical Pacific flows northeastward into the Southeast USA. The blue and white (with a little bit of green) moisture swath emerges from the far left central area of the image flows northward for some distance and then is blown to the east (right) making a swath of moisture that connects with another ribbon over Oklahoma. As these merge you can see them being swept into a swirling low pressure area off Nova Scotia and Newfoundland. Farther south in the yellow and orange zone very dry air is in place from most of Central America to the African coast. The more you look, the more you see as in the equatorial region, an expansive moisture belt straddles the two hemispheres. Farther south, the atmosphere seems to make a mirror image of a dry zone separating more ribbons of moisture. The earth’s great wind systems, sometimes given the title of The General Circulation, move moisture and heat around in a ceaseless cycle.

Early morning GOES natural color image of Ecuador and Peru coastline in South America

The image above highlights the incredible change in moisture caused by the Andes mountain chain. On the left, a few low clouds float out over the cold waters of the Humboldt Current closer to the center of the image, you can see the slender coastal plain and the abrupt change in elevation as the Andes rise quickly in height (dark reddish-brown) up on the Andean Plateau, the arid landscape boasts a few lakes and some early fall snow along some mountain ridges (white). As you look farther east (right) the mountain landscape sports some white clouds building up over the terrain outlining the valleys before the clouds push together and fill in the lower elevations before the emerald green of the interior plains captures your attention. But even though the green nearly saturates the image, one can see the telltale wiggling of large streams and rivers bringing the muddy sediment out of the Andes into the Amazon Valley passing through the Amazon Rainforest on its way to the Atlantic Ocean where the muddy sediment empties out on South America’s continental shelf (not pictured here).

Up next is a nice view of a Nor’easter, a low pressure system (the proper term is ‘cyclone’) swirling off the New England USA coast line. The familiar swirl of the low center is easy to spot. But to the west (left), you can see the snow the storm dumped on the landscape along with a few lingering clouds. Away from the low center, the cloud patterns form definite shapes hinting at how the cold air swirling off the continent picks up enough moisture from the ocean surface to form clouds that begin to rotate like a giant oblong pancake as they obediently follow the storm center on its journey across the North Atlantic. Farther south, the turquoise blue of the shallow waters off Florida’s west coast and surrounding the Bahamas contrast with the almost cobalt blue of the deeper Atlantic Ocean.

Finally, for this brief Earth Day celebration/contemplation, a nighttime mosaic of the Eastern Hemisphere shows the extent of human occupation and energy usage (actually wastage since the lights are going out into space) and energy consumption. The Nile River appears as a snaking ribbon of light before it fans out into the well-know delta that bears its name. Much of Africa is not lit up. Southern Europe is ablaze and there is no problem locating the famous boot-shape of Italy. Plenty of lights elsewhere as well.

A mosaic of the Eastern Hemisphere at night in the visible part of the spectrum. The thin crescent shape highlights the last glimmer of sunlight for this day.

Ken Nash Director, Physical Sciences and Climatology

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