AERONET Observations as a Source of Cloud Analysis and Forecast Verification for the 557WW

The 557th Weather Wing of the United States Air Force produces a variety of cloud analysis and forecast products for aviation forecast purposes, including the World Wide Merged Cloud Analysis (WWMCA), the Advect Cloud Model (ADV-CLD), and the Digital Cloud Forecast (DCF). Cloud analysis and forecast remains a critical meteorological piece for aviation safety. Point verification of clouds has been limited in the past due to the sparse geographical distribution of instruments such as the ARM data sets.

The Aerosol Robotics Network (AERONET) is a confederation of instrumentations designed to provide measurements of atmospheric aerosol properties at locations across the globe. Cloud filtering has been a consideration of aerosol measurement for years, including the use of triplet variability to exclude data considered to potentially be cloud. Recent advancements in the use of the instruments have also included a calculation of cloud optical depth calculation when the instruments are in aerosol sleep mode.

Our work uses the combination of the triplet variability and the cloud optical depth calculation to provide an AERONET Total Cloud Product (ATCP) for locations where data is available. Maximum triplet variability is calculated at each data point, compared against the .020 threshold described in literature. The paper explores the feasibility of the use of the ATCP as a verification methodology by examining its performance at locations from a variety of cloud regimes, including gauging the performance of the ATCP algorithm at various times of days and instrumental wavelength.