The shortening daylight and cooling temperatures of late summer triggers changes in the Northern Hemisphere–changes that can be viewed from space.
On September 21, 2019, the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of the transition from late summer to early autumn in New York State.
The waters of Lake Ontario are colored with swirls of pale blues and greens, often the tell-tale mark of the blooming of vast numbers of microscopic, plant-like organisms known as phytoplankton. With the warmth of late-summer waters, however, this is more likely the result of a “whiting event”. Such events commonly occur in late summer and are caused by changes in water temperature which allows fine particles of calcium carbonate to form in the water column. Increased photosynthesis by phytoplankton and other microscopic marine life can also reduce the amount of carbon dioxide in the water column and allowing calcium carbonate to form. The suspended particles of calcium carbonate cause the characteristic lighting (“whiting”) of the water color observed.
Viewed at high resolution, the blue waters of some of the Finger Lakes also appears slightly discolored. According to the New York State Department of Environmental Conservation’s Harmful Algal Blooms (HAB) map reviewed on September 25, harmful algae blooms have been reported on several of the Finger Lakes, especially Seneca and Owasco Lake.
In the east, the deep greens of the forests of the Adirondacks are spattered with bright oranges, marking the autumn color-up of deciduous trees within the forest. The Democrat & Chronicle, a local New York news site, reported that parts of the Adirondacks reported up to 45 percent color change on September 13.
