Variability in the Earth Radiation Budget as Determined from the NIMBUS ERB Experiments
Data taken by the Earth Radiation Budget (ERB) experiments on board the Nimbus-6 and Nimbus-7 satellites is examined. The goal is an understanding of the bounds of variability of the radiation budget components. This variability is examined on daily, monthly, and annual time scales. An in-flight characterization of the instrument is performed, and a set of calibration adjustments for the Nimbus-7 ERB are developed that enable interannual climate studies to be made. A technique for the transfer of this calibration to the Nimbus-6 ERB experiment is derived that enables the creation of a decadal joint ERB data set. For the first time, error bars for the data set are established. These show that the WFOV calibration is accurate to 7 W/m('2) regionally and 3 W/m('2) zonally. Based on a solar calibration transfer, the stability of this data is shown to be better than 1/2% over the entire period. The radiation budget component (albedo and longwave emission) responses to the 1982 eruptions of the El Chichon volcano are examined. Based on the observations, an understanding of the global distribution, evolution, and persistence of the resultant aerosol cloud is achieved. Specific results include evidence that, although the eruptions occurred in the spring of 1982, the maximum optical depths at the higher latitudes in the northern hemisphere were not reached until the winter of 1982-1983. Further evident is the fact that the majority of the aerosols are retained in the northern hemisphere, with the aerosol content of the two hemispheres (as measured by the signal enhancements) not reaching equilibrium until two years after the eruption. The evolution of the major 1982/1983 ENSO event is monitored for the first time by broad-band radiometers. Quasi -stationary, planetary-scale tropical and mid-latitude teleconnection patterns are shown to emerge as the event reaches its peak intensity. The onset, intensification, and withdrawal of drought over Indonesia, Australia, the Pacific Ocean island chains, and the Amazon River Valley is monitored based on inferred irrotational, three-dimensional flow fields. Anomalous subsidence, forced by the ENSO episode is noted over all drought regions.
- Pub Date:
- EL NINO;
- EL CHICHON;
- Physics: Atmospheric Science