Green Up Since Early May
The animated image below shows the remarkable green up that occurs across the Upper Midwest in late Spring and early Summer. The images are from the high resolution polar orbit satellites known as MODIS (Courtesy CIMSS UW Madison), and span the period from May 3, 2009 to July 11, 2009. The area stretches from central Wisconsin to central Illinois...and eastern Iowa to northwest Indiana. Lake Michigan is clearly visible.
It is clear from the first image in the loop (May 3rd) that green up has not yet started. Much of the land is agricultural and therefore quite bare at that time of year. The river valleys and other non-agricultural regions have more permanent vegetation (trees, bushes, etc) and are the first to turn green. As Spring progresses and farmers get plants in the ground, you see the area gradually turn green. The last couple of frames really show the greening deepen in saturation as the corn and soybean crops mature. Unfortunately, it has been a rather cloudy Spring and early Summer with few cloud free days to capture for this animation sequence.