View of the SURFRAD instruments. On the left is the main platform, the solar tracker is in the center,

The downwelling instruments on the main platform (left) at Bondville. Shown, from left to right, are: Yankee Environmental Systems (YES) UVB-1 Ultraviolet Pyranometer, ventilated pyranometer, and LI-COR Photosynthetically Active Radiometer (PAR). The Sci-Tec 2AP Solar Tracker is to the right.

The Sci-Tec 2AP solar tracker, just north of the main instrument platform. On the shading platform of the tracker, a shaded and ventilated Eppley pyrgeometer (left) measures downwelling infrared irradiance. To the right is a shaded and ventilated pyranometer for measuring diffuse solar irradiance. Mounted on the near side of the tracker just below the tracker's quadrent sensor is an Eppley normal incidence pyranometer for measuring direct solar radiation. The quadrant sensor is used by the tracker to keep it aligned with the sun.

The SURFRAD ten-meter tower, located approximately 30 m north of the main instrument platform. The tower contains an RM Young wind monitor, a Vaisala temperature and relative humidity sensor, and a pyrgeometer and a pyranometer, both facing downward, for measuring upwelling infrared and solar radiation, respectively.

A close-up of the tower-mounted instruments.

Inside the data logger box. The newly improved system contains a rechargeable battery, CR10X data logger, multiplexer, modem, and pressure sensor.