A methodology to extend Spectral time Series and Improve Multichannel Radiometers Calibration

DIAZ SUSANA; BOOTH C; CABRERA S; CASSICCIA C; ARMSTRONG R; FUENZALIDA H; LOVENGREEN C; NELSON D; PALADINI A; PEDRONI J; ROSALES A; ZAGARESE H; BRUNAT C; CAMILION CAROLINA; DEFERRARI GUILLERMO

Mendoza Argentina

Congreso; workshop IAI; 2003

IAI

  After the discovery of the ozone hole, many efforts have been developed to measure UV radiation with spectral or multi-channel instruments but, time series for these measurements are still relatively short for the determination of, for example, trends applied in geophysical and biological studies.  However, systematic measurements of total column ozone have been performed since the late 1950s at several stations, and global coverage has been available since the late 1970s.  Long-term time series of broadband instruments (Pyranometers, UV and erythemally weighted) are also available from many sites around the world. A multi-regressive model, which allows estimation of spectral and biologically weighted irradiances from broadband measurements has been developed and tested using data of the NSF UV Radiation Monitoring Network and NOAA CMDL broadband insturments. Applying this model, biologically weighted irradiances back to 1979 were calculated and analyzed for Barrow and South Pole.   Also, the IAI Network for the measurement of ultraviolet radiation in Chile, Argentina and Puerto Rico is composed of ten multi-channel radiometers (GUV 511, Biospherical Instruments Inc.), which are periodically sun calibrated with a traveling reference GUV (RGUV). The RGUV is calibrated under solar light against a SUV100 spectroradiometer of the NSF UV Radiation Monitoring Network.  This calibration is then transferred to each instrument in the network through the RGUV. A modification of the above-mentioned multi-regression model was applied to improve the multi-channel instrument sun calibration.