Interannual Variabilities in High Cloud Cover from AIRS Data and Comparison to Climate Models

The Atmospheric Infrared Sounder (AIRS) has been providing high quality data of global high cloud distribution since 2003. We identify the dominant modes of variabilities and associated spatial patterns, and relate them to sea surface temperature (SST). The first two empirical orthogonal functions (EOFs) are highly correlated to the El Niño-Southern Oscillation (ENSO) — including both EP-ENSO (canonical ENSO) and CP-ENSO (ENSO Modoki). These modes are compared with those obtained using the CloudSat data. The same EOF analysis is applied to simulations from 20 AMIP5 models. In general, the models are able to simulate the first EOF, the EP-ENSO, in the data. However, only about half of the AMIP5 models could realistically reproduce the second EOF, the CP-ENSO. Improved understanding of high cloud variabilities will advance climate model simulations and facilitate more accurate predictions of future climate, specifically the climate response to increasing greenhouse gases such as carbon dioxide.