Improved Prediction of Intense Rainfall Events at Fine Spatial Resolution


DOE-funded scientists at LLNL studied the ability of the Community Atmospheric Model version 4 (CAM4) to simulate tropical rainfall at several resolutions – 2°, 1°, 0.5°, and 0.25° latitude-longitude – for a region encompassing the Tropical Warm Pool – International Cloud Experiment (TWP-ICE). The differences between the spatial pattern of observations and those predicted by models are unchanged over all resolutions. However, there was a substantial improvement in model predictions on daily time scales at the finest resolution. The circulations and land-sea breeze resolution over the Maritime continent are more realistically captured by the 0.25° simulation. Similarly, the prediction of very intense rainfall events and of little or no precipitation is also improved at higher resolution. Capturing the correct intensity of rainfall events will enable better prediction of extreme events that will become particularly important under climate change. These results also demonstrate that increasing the resolution of models can increase the accuracy of model predictions for climate events that occur on shorter time scales.


Boyle, J., and S. A. Klein. 2010. “Impact of Horizontal Resolution on Climate Model Forecasts of Tropical Precipitation and Diabatic Heating for the TWP-ICE Period,” Journal of Geophysical Research, 115, D23113. DOI: 10.1029/2010JD014262.