Radiation Station Information Monitors collects radiation data to support its activities in Cocoa, Florida (28.4 N, 80.8 W). Eighteen years of data are available from our previous station in Cape Canaveral, FL, and since 1995 at our current site. Please note that this is research data, being collected automatically every 6-minutes. We attempt to keep the data as accurate as possible but we make no waranty on the accuracy of this data.

Data Acquisition System

• Total horizontal solar radiation
• Total solar radiation on a tilted plane
• Direct normal solar radiation
• Total normal solar radiation
• Total horizontal infrared sky radiation

The radiation sensors are class 1 instruments manufactured by Eppley Laboratories. The Precision Spectral Pyranometer (PSP) is used for total radiation, the Normal Incident Pyrheliometer (NIP) for direct normal, and the Precision Infrared Radiometer (PIR) for infrared sky radiation. All solar radiation sensors (PSP and NIP) are calibrated annually by comparison with model H-F absolute cavity radiometer. The absolute cavity itself has participated in the New River Intercomparison of Absolute Cavity Solar Pyrheliometers (NRIP VII) and the First Regional Pyrheliometric Intercomparison, providing traceability of the NOAA primary reference standard and the World Meteorological Organization working standard group.

Solar Radiation The instrument used to measure solar radiation is called a pyranometer. It consists of a blackened disk containing temperature measuring sensors. The disk is protected from the environment by two domes of glass. When exposed to the sun, the disk heats up. The glass domes prevent cooling by the wind. The temperature of the disk is a function of the amount of solar radiation hitting it. Calibration against more sophisticated radiation measuring devices gives a repeatable multiplier to convert the pyranometer's output to units of solar radiation.

Direct Solar Radiation

Direct normal solar radiation is that part of the radiation coming directly from the sun without bouncing off clouds or the atmosphere. This measurement gives an indication of the clearness of the sky. It is also measured for researching concentrating solar collectors which can utilize only this portion of the solar radiation. The instrument used to measure Direct Normal solar radiation is called a normal incidence pyrheliometer (NIP). A NIP consists of a long tube placed over the sensing element of a pyranometer. The tube blocks out all solar radiation except that coming directly from the sun. This instrument must track the sun such that the sun is always shining directly down the tube. A tracker called an equatorial mount is used to keep the NIP pointed at the sun. To measure the total amount of available solar radiation, a pyranometer is also mounted on the tracker. The difference between the pyranometer and the NIP is called the diffuse solar radiation.