Past IEM Features tagged: albedo
The featured chart presents local noon measurements of shortwave radiation from one of the NLAE Flux sites near Ames. The downwelling radiation is what makes it to the ground from the sun after passing through the atmosphere. The upwelling radiation is what is reflected by the surface and begins to travel back out into space. The ratio between these two values is known as albedo. A bare ground, a ground covered by snow, and a ground covered by vegetation have different values for albedo. The featured chart shows how the albedo changes over this year with noticeable differences appearing during periods of snow cover and as the corn crop vegetation increase its leaf area index and color.
The featured chart is a time series of local noon measured short wave radiation this year at one of the flux sites operated by the National Laboratory for Agriculture and the Environment. "Short wave" is a term used to describe the wavelengths at which most of the sun's radiated energy is found at. The top chart shows the energy arriving from the sun (downwelling) and the amount reflected by the surface (upwelling). The ratio between these two values is called "albedo" and is presented in the bottom chart. The last two days saw a dramatic change in albedo with the arrival of snow. This is one of the main reasons why our weather gets cold when it snows as the snowcover is a very efficient reflector of the sun's energy. The chart also shows some nice growing season effects as the corn canopy expands and harvest occurs in the fall.
Tags: albedo flux