Enabling Continuity of the Earth Radiation Budget Climate Data Record using the Clouds and Earth’s Radiant Energy System (CERES) Flight Model 5 instrument on S-NPP

摘要

The Clouds and Earth’s Radiant Energy System (CERES) instruments measure two components of the earth’s radiationbudget (ERB)- the reflected solar radiation and the outgoing longwave radiation. The measurements from CERES alongwith data from imagers as well as meteorological and aerosol assimilation data are combined to provide a climate datarecord (CDR) of the ERB at the top of atmosphere, surface and various levels in the earth’s atmosphere. There arecurrently six operational CERES instruments on board four spacecraft- Flight Models (FM) 1 and 2 are aboard the Terraspacecraft launched in December 1999, FMs 3 and 4 on Aqua launched in March 2002, FM5 on S-NPP launched inOctober 2011, and FM6 on NOAA-20 launched in November 2017. In order to continue the CDR as newer instrumentsare launched, a radiometric adjustment at the start of the mission of the new instrument is necessary to bring it to the sameabsolute radiometric scale as the predecessor. In this paper, we describe a process to place the S-NPP/FM5 instrument onthe same radiometric scale as the Aqua/FM3 instrument in order to continue the CDR. This involves using intercomparisondata from the two instruments viewing the same earth scene simultaneously when their orbits overlap. ALagrange multiplier objective constrainment technique is used to obtain the required adjustments to the SNPP/FM5spectral response within measurement uncertainties to match the measurements from the Aqua/FM3 instrument. Theresults from various validation studies are also shown before and after these adjustments have been applied.