Baseline Surface Radiation Network (BSRN)

The objective of BSRN is to provide top-quality observations of the shortwave and longwave irradiances at the Earth’s surface.

The Baseline Surface Radiation Network is a project of the World Climate Research Programme (WCRP) and the Global Energy and Water Experiment (GEWEX). This project aims at detecting changes in the radiation field at the Earth’s surface that may be related to climate change. The data are of primary importance for the validation and evaluation of satellite and model (GCM) estimates of radiative quantities. At a small number of stations in contrasting climatic zones, covering a latitude range from 80°N to 90°S, solar and atmospheric radiation is measured with instruments of the highest available accuracy and with high time resolution. Early 2004 BSRN was designated as the global baseline network for surface radiation for the Global Climate Observing System (GCOS).

The radiation station at the Cabauw Experimental Site for Atmospheric Research, CESAR, is part of BSRN since 2005 (a 10-year history is described by Knap and van Oort, 2015). Since then, KNMI submitted monthly quality controlled radiation data to the BSRN central database at the World Radiation Monitoring Center (WRMC) which is hosted by the Alfred-Wegener-Institut für Polar- und Meeresforschung (AWI) in Bremerhaven, Germany. The data are freely available via the Data Publisher for Earth & Environmental Science PANGAEA or the ftp server at AWI.

The key quantities measured in Cabauw (51.97°N, 4.93°E) are:

  • Direct, diffuse and global irradiance
  • Downward longwave irradiance
  • Upward shortwave and longwave irradiance
  • Narrowband direct irradiance (for Aerosol Optical Depth, AOD)
  • Sky temperature (Nubiscope)
  • Total sky images
  • Sunshine duration

One of the most profound studies done with BSRN data (including those measured in Cabauw) has been done by Wild et al. (2013), on the verfication of radiation in large scale climate models. This study reveals that CMIP5 models tend to overestimate downward shortwave and underestimate downward longwave radiation compared to BSRN observations. The observations provide the “ground truth” for improving the models and provide constraints for quantitative estimates of the Earth’s radiation budget.

BSRN data of Cabauw have also been used to evaluate a state-of-the-art radiative transfer model for clear-sky and cloudy conditions (Wang et al., 2009 and 2011). The study gave excellent results in terms of differences between modeled and measured irradiances and offered fundamental understanding of the process of radiative transfer in the Earth’s atmosphere.

BSRN data of Cabauw and other stations have been extensively used for the evaluation of satellite products. Wang et al. (2014), for example, used BSRN data of 19 stations for the evaluation of a surface solar irradiance product derived from the Ozone Monitoring Instrument (OMI).

 

References

Knap, W. H. and C. van Oort. 2015. Tien jaar Baseline Surface Radiation Network
(BSRN) in Cabauw. Meteorologica, 2, 20-23 (in Dutch).

Wang, P., W. H. Knap, P. Kuipers Munneke, and P. Stammes. 2009. Clear-sky shortwave radiative closure for the Cabauw Baseline Surface Radiation Network site, Netherlands, J. Geophys. Res., 114, D14206, doi:10.1029/2009JD011978.

Wang, P., W. H. Knap and P. Stammes. 2011. Cloudy-sky shortwave radiative closure for a Baseline Surface Radiation Network site. J. Geophys. Res, 116, D08202, doi:10.1029/2010JD015141.

Wang, P., M. Sneep, J. P Veefkind, P. Stammes and P.F. Levelt. 2014. Evaluation of broadband surface solar irradiance derived from the Ozone Monitoring Instrument. Remote Sens. Environ., 149, 88-99, doi:10.1016/j.rse.2014.03.036.

Wild, M., Folini, D., Schär, C., Loeb, N., Dutton, E.G., and König-Langlo, G., 2013: The global energy balance from a surface perspective, Clim. Dyn., 40, 3107-3134, Doi:10.1007/s00382-012-1569-8.

Global distribution of BSRN stations in January 2015. Operational stations produce quality-controlled data and submit data to the central BSRN datavase at AWI in Bremerhaven, Germany.
Global distribution of BSRN stations in January 2015. Operational stations produce quality-controlled data and submit data to the central BSRN datavase at AWI in Bremerhaven, Germany.
The BSRN station in Cabauw with in the background the 213 m tower. Central is the sun tracker with shadowed pyranometers (for diffuse irradiance), a pyrgeometer (downward longwave irradiance) and pyrheliometers (direct irradiance). Photo: Wouter Knap.
The BSRN station in Cabauw with in the background the 213 m tower. Central is the sun tracker with shadowed pyranometers (for diffuse irradiance), a pyrgeometer (downward longwave irradiance) and pyrheliometers (direct irradiance). Photo: Wouter Knap.