Radiative effect of aerosols on the Arctic Climate during Spring

As we all know, Arctic is the most vulnerable region to global warming caused by increasing greenhouse gases. From the observations of recent years, there is still not enough evidence to draw the conclution of the Arctic warming as most Global Circulation Models (GCMs) suggested. the uncertainties are not only from lack of obsevation data, but also numerical simulation itself as the unclear unique atmospheric compositions and physical processes over the polar region. Aerosol and dehydration effects have been recognized early by Blanchet and Girard (1994) to be cooling the warming trend from the increasing radiatively active trace gases. In this study, we have used the Northern aerosol regional climate model (NARCM) to quantify the aerosol effect on the Arctic climate change. The direct and indirect radiative forcing and climate effect of aerosols such as Arctic haze sulfate, black carbon, organic and dust will be estimated from our NARCM simulations.

In order to identify the drawbacks of our current climate model simulations, the Arctic Regional Climate Model Intercomparison Project (ARCMIP) has offered us excellent chance for validation and inter-comparison of parameterization methods of sea ice, radiation, clouds and surface processes. The enhanced observation datasets such as the Surface Heat Budget of the Arctic Ocean (SHEBA) and the Atmospheric Radiation Measurement (ARM) can be directly compared to our model simulations of time period from October 1997 to October 1998. From our preliminary results, We find our model simulation is colder than the observation over the Alaska region. The aerosols have significent impacts on the Arctic climate change. Dehydration strongly occured at the lower of troposphere.