Understanding the Cloud-dynamics Interactions in the Southern Oceans and Tropics by Using Legacy Satellites

Clouds and large-scale dynamical circulations do not exist isolatedly, but rather interact with each other intimately in different ways. Clouds play an important role in the climate science in that they modulate the shortwave and longwave radiation. The variability of climate patterns has been shown to have profound effects on global cloudy behaviors, such as cloud distribution and cloud types. The identification of the relationship between the climate variability and cloudiness, however, is made difficult by the lack of a consistent, spectrally resolved data record. A novel method was introduced to stitch together the cloud type data from the Advanced Very High Resolution Radiometer (AVHRR) and the spectrally resolved infrared data from the High Resolution Infrared Radiation Sounder (HIRS) to obtain such datasets. These two instruments have been flown on a series of NOAA polar orbiting satellites and providing data for decades. With the sufficient temporal and spatial coverage of the clouds over years recorded by the satellites, we are able to characterize the how the large scale climate patterns like El Nino Southern Oscillation (ENSO), barotropic and baroclinic annular modes in the southern oceans (SAM and SBAM) influence the cloudiness through dynamical processes. By analyzing the cloud brightness temperature statistics, we found our datasets show consistent signatures with other findings both in the mid-latitudes, where the storm tracks shift poleward, and ENSO characteristics in the Tropics.