Long-term stability of UV multifilter rotating shadowband radiometers, part 2: lamp calibrations versus the Langley method

摘要

This is the second continuation of work begun by Dave Bigelow and James Slusser in their study of the same name published in 2000 in J. Geophys. Res., 105, 4833-4840, which studied only a few instruments over a limited in-service time span. Part 1 expanded the Langley stability analysis by using 42 instruments over 5 years of field service. This part 2 expands stability as expressed with repeated laboratory lamp calibrations of the instruments, and compares these to the prior Langley analysis. 115 cases representing 44 instruments covering seven years of deployment are studied. Complicating this analysis are the four versions of the UV-MFRSR instrument that span the analysis time frame, and the results are presented as such. These results show the mean annual drift in sensitivity for the seven nominal wavelengths of the UV-MFRSR instrument are: pre-Rev.M: 300nm -8.8%, 305nm -8.1%, 311nm -7.4%, 317nm -8.3%, 325nm -7.3%, 332nm -7.6%, 368nm -7.2%; Rev.M: 300nm -7.5%, 305nm -7.1%, 311nm -6.5%, 317nm -5.6%, 325nm -5.8%, 332nm -5.3%, 368nm -5.1%; Rev.N&P; 300nm -10.1%, 305nm -7.2%, 311nm -8.3%, 317nm -4.3%, 325nm -3.6%, 332nm -3.7%, 368nm -3.5%; and Rev.Q: 300nm -5.6%, 305nm -5.8%, 311nm -3.8%, 317nm -4.4%, 325nm -4.8%, 332nm -4.6%, 368nm -3.5%.