SURFRAD (Surface Radiation)


One of two mobile SURFRAD stations, this one deployed in the San Luis Valley of Colorado in 2014

SURFRAD observations stations collect measurements of upwelling and downwelling, solar and infrared are the primary measurements; ancillary observations include direct and diffuse solar, photosynthetically active radiation, UVB, spectral solar, and meteorological parameters. High quality, ground-based observations of solar irradiance, collected in differing climatic regions, are needed for verification of satellite-based estimates, which are used as inputs to weather models.

Currently seven SURFRAD stations are operating in climatologically diverse regions: Montana, Colorado, Illinois, Mississippi, Pennsylvania, Nevada and South Dakota. Data are downloaded, quality controlled, and processed into daily files that are distributed in near real time by anonymous FTP and the WWW ( Observations from SURFRAD have been used for evaluating satellite-based estimates of surface radiation, and for validating hydrologic, weather prediction, and climate models. Quality assurance built into the design and operation of the network, and good data quality control ensure that a continuous, high quality product is released.

  • Global horizontal irradiance
  • Direct normal irradiance
  • Diffuse horizontal irradiance
  • Aerosol optical depth and spectral at five wavelengths
  • Ultraviolet B
  • All-sky imaging
  • Thermal infrared
  • Upwelling global
  • Upwelling thermal infrared
  • Wind, temperature, humidity, and pressure

Additional Resources:

For more information about SURFRAD, visit: