PNNL

Abstract

Last year at the Science Team Meeting we presented the preliminary analysis of surface radiation measurement data quality at the SGP extended facilities (Shi & Long). The measured radiation data were tested against physically possible and globally extremely rare limits as defined and used in the Baseline Surface Radiation Network recommended data QC testing. Additional climatological limits and cross-comparisons derived through analysis of the historical data at these facilities were also used to test these data. We also presented an overview of data quality at each Extended Facility, and the methodology used for quality testing. In this study, we derive the best estimate of total downwelling shortwave radiation using the sum of direct and diffuse components, and fill any gaps in the sum time series using a fitted relationship between sum and unshaded pyronometer measurements. Four scenarios are classified for fitting unshaded pyronometer data to corresponding sum data: morning “clearish” data; morning cloudy data; afternoon “clearish” data; and afternoon cloudy data. Which of these four scenarios are appropriate is determined by the conditions present when the sum data are missing, as determined by examination of the pyronometer time series, and the conditions present when data are available near the missing time period of fitting. Additionally, corresponding MFRSR data are used in comparison as a data quality constraint. The unshaded pyrononmeter data in each scenario are linearly fitted to the sum data and the fitting coefficients are used to estimate the magnitude of the sum had it been available. Thus, we produce a continuous, quality tested “best estimate” of the surface radiative energy budget for the ARM Extended Facilities and ARCS sites.