I have been conducting research to understand the climate variability associated with the ocean-atmosphere interactions on different time scales. For this purpose, I use state-of-the-art coupled ocean-atmosphere general circulation models to conduct numerical simulations and controlled experiments. One emphasis of these experiments is on the relative roles played by remote forcing from the El Niño/Southern Oscillation and the regional air-sea feedback in both the tropical Atlantic and Indian Oceans in determining the anomalous sea surface temperature (SST) patterns in these ocean basins that are important for regional climate. I have also been using coupled models to examine the multidecadal variability of the Atlantic meridional overturning circulation and its climate effects, including the mechanisms of the Atlantic multidecadal variability. Accompanying these modeling studies, I also conduct extensive statistical studies using comprehensive ocean-atmosphere datasets to examine historical climate variations.
To improve climate simulation and prediction, I am interested in improving the quality of the coupled climate models. In particular, I would like to find the sources of the systematic bias of current climate models in the ocean and atmosphere and their influences on the quality of the model simulations and predictions through diagnostic analysis and sensitivity experiments. I had conducted long-term ocean data assimilation analysis (1958-1998) to conduct climate analysis and to provide realistic oceanic initial conditions for the model forecast. I have also used a multiple analyses ensemble approach to initialize the ocean component of the coupled system, which better treats the uncertainty of current ocean analyses to improve forecast skill and reliability.
In addition to coupled models, I also use ocean general circulation models to simulate the upper ocean circulation of the tropical Atlantic and Pacific Oceans and to study the oceanic responses to the atmospheric forcing on seasonal and interannual time scales. These processes are important for us to understand the mechanisms of the anomalous phenomena in the tropical oceans, such as the El Niño events in the Pacific and the fluctuations of the meridional gradient of the sea surface temperature (SST) in the tropical Atlantic Ocean, which has significant impact on the climate conditions of the Atlantic Sector.