Providing diurnal hemispherical cloud fraction data at ARM sites

 
Poster PDF

Authors

Dimitri Klebe — Solmirus Corporation
Ronald David Blatherwick — University of Denver
Victor R. Morris — Pacific Northwest National Laboratory

Category

Instruments

Description

The Solmirus Corporation has been funded by the U.S. Department of Energy to develop a diurnal hemispherical cloud fraction (HCF) data product utilizing the infrared (IR) radiometrically calibrated data from their all-sky infrared visible analyzer (ASIVA) instrument. Nighttime HCF has long been a critical programmatic gap in ARM’s observational data set and is an important factor in understanding the life cycle of clouds, one of the central themes of the ASR program. This poster paper describes a novel radiometric calibration procedure that has allowed accurate determination of the clear-sky IR radiance, paving the way to providing a superior diurnal HCF data product. The validity of the HCF algorithms developed under this award is being verified by direct comparison of daytime ASIVA data to cloud fraction data retrieved from the total sky imager (TSI). Comparison HCF data derived from Solmirus' ASIVA Campaign conducted at the ARM Southern Great Plains (SGP) site from May 21 to July 27, 2009, are presented. Radiometrically calibrated IR ASIVA data are also compared to concurrently observed AERI (atmospheric emitted radiance interferometer) radiances. In addition, Solmirus is developing a HCF data product utilizing ASIVA’s visible channels that closely mimics results from the TSI instrument. This comparison is also presented.