Description and basic evaluation of Beijing Normal University Earth System Model (BNU-ESM) version 1

摘要

An earth system model has been developed at Beijing Normal University(Beijing Normal University Earth System Model, BNU-ESM); the model is basedon several widely evaluated climate model components and is used to studymechanisms of ocean-atmosphere interactions, natural climate variability andcarbon-climate feedbacks at interannual to interdecadal time scales. In thispaper, the model structure and individual components are described briefly.Further, results for the CMIP5 (Coupled Model Intercomparison Project phase5) pre-industrial control and historical simulations are presented todemonstrate the model's performance in terms of the mean model state and theinternal variability. It is illustrated that BNU-ESM can simulate manyobserved features of the earth climate system, such as the climatologicalannual cycle of surface-air temperature and precipitation, annual cycle oftropical Pacific sea surface temperature (SST), the overall patterns andpositions of cells in global ocean meridional overturning circulation. Forexample, the El Ni?o-Southern Oscillation (ENSO) simulated in BNU-ESMexhibits an irregular oscillation between 2 and 5 years with the seasonalphase locking feature of ENSO. Important biases with regard to observationsare presented and discussed, including warm SST discrepancies in the majorupwelling regions, an equatorward drift of midlatitude westerly wind bands,and tropical precipitation bias over the ocean that is related to the doubleIntertropical Convergence Zone (ITCZ).