April 14, 2021 - Spring Bursts Forth in the United States


“If Spring came but once a century, instead of once a year, or burst forth with the sound of an earthquake, and not in silence, what wonder and expectation there would be in all hearts to behold the miraculous change!” These words were penned by Henry Wadsworth Longfellow and published in his 1847 novel, Kavanagh.

In Longfellow’s day, spring was a day-by-day experience and the year’s transition could only be recalled through memory. Yes, with difficulty, a determined photographer could capture a single scene in two seasons, allowing the comparison of a pair of black-and-white daguerreotypes. But neither memory nor daguerreotype comparison could exactly be called “bursting forth”. Today, with satellite imagery, we can more easily and fully behold the miraculous and dramatic change of spring as it sweeps over the landscape.

On April 14, 2021, the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of a gentle spring day in the United States. From the Atlantic Coast westward to the Mississippi River, the dominant color is “springtime green”—a patchwork of dark forest, mid-toned grasslands and shrubland, and a light green wash over agricultural land that marks transition from the tans of just-plowed open soils to the first emergence of crops. In some areas where dense growth of flowering deciduous trees—maple, redbud, cherry, and others—dominates, the forest takes on a pinkish hue. This is most notable in the Appalachian Mountains just north of the spider-web-like set of gray pixels that mark the city of Atlanta, Georgia.

The image above captures a stunning picture of early spring across the Eastern United States. However, to appreciate the dramatic change that has swept over the landscape in just seven weeks, we turn to the NASA Worldview App. This app allows us to view a roll-over comparison between this MODIS image taken on April 14 and one acquired on February 23, when snow coated the Appalachians and well-chilled tans dominated more of the landscape. To view the sweeping changes of spring, click here.

Image Facts
Satellite: Aqua
Date Acquired: 4/14/2021
Resolutions: 1km (1.4 MB), 500m (4 MB), 250m (2.9 MB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC