Global Top-of-Atmosphere Broadband Shortwave and Longwave Fluxes Derived from AVHRR

Polar-orbiting satellites provide coverage over large portions of the globe, and as such can be a useful tool for monitoring the cloud and radiative properties essential to the study of climate change. Cloud and radiation budget information from March 2000 through present day has been provided through observations taken by the MODIS (cloud) and CERES (radiation) instruments aboard the Terra satellite, and the addition of the Aqua satellite in 2002.  Efforts are underway to extend this CERES Cloud Climate record by applying the VISST (Visible Infrared Solar Split-Window Technique) retrieval algorithm to AVHRR aboard past and present NOAA satellites; this endeavor affords an opportunity to produce a long time series of TOA broadband LW and SW fluxes, from the AVHRR instruments aboard this series of satellites.

While the NOAA-series satellites provide monitoring over a long time period from ~1980 on, they have done so using narrowband visible and infrared measurements comprising a small portion of the total radiative flux, whereas broadband shortwave and longwave fluxes have been measured from 1984- present by the ERBE and CERES instruments. To  derive climatically relevant information from AVHRR, empirical narrowband-to-broadband (NB-BB) fits are derived by matching the narrowband fluxes to the corresponding ERBE and CERES broadband fluxes.

These initial NB-BB flux fits have been derived on a monthly basis covering land, water and snow for the entire globe. The NB-BB fits have been implemented within the VISST satellite cloud and radiative property retrieval framework, and are initially applied to AVHRR aboard NOAA-9 and NOAA-18. Broadband fluxes derived from AVHRR for various domains in 1986 and 2007-2011 will be validated with respect to available ERBE and CERES BB fluxes.