Impact of Vegetation Feedback on Climate Predictions at the Seasonal and Multi-Decadal Time Scales

Abstract:

Vegetation feedback plays an important role in regional and global climate variability at various time scales, ranging from seasonal to multi-decadal. Its impact is especially pronounced in regions of strong land-atmosphere coupling. Climate predictions in these regions should therefore account for the role of interactive vegetation. This can be accomplished through including a predictive phenology scheme for seasonal predictions and including a dynamic vegetation model for decadal or longer time scale predictions. At the seasonal time scale, plant phenology responds to hydro-meteorological anomalies, and the resulting anomalies in vegetation density then modify the severity and persistence of regional climate anomalies. At the decadal and longer time scales, changes in regional climate lead to changes of vegetation distribution and structure, which feed back to further change the regional climate. The direction and magnitude of the impact attributable to vegetation feedback are likely region dependent and model dependent. Using a regional climate model (RegCM4.3.4) coupled with the NCAR community land model (CLM4/4.5) including a carbon-nitrogen model (CN) and a dynamic vegetation model (DV), this study demonstrates how vegetation feedback may influence climate predictions at different time scales. North America and West Africa are chosen as the geographic focus due to strong land-atmosphere coupling in these regions.