Upwelling and Coastal Climate

According to recent studies, climate in the coastal areas shows different behavior compared to further inland areas. There is some discussion in the literature about temperature trends over the water and over the near-shore coastal land; however, the majority of studies indicate a possible increase of the mesoscale pressure gradients between the coastal ocean and land. Further implications lead to the hypothesis that there will be a consequent increase in the onshore flows and intensification of upwelling. This in turn can lead to a decrease in the sea surface temperature (SST) and further increase the mesoscale pressure gradients. Climate perspectives of these processes are not clear since the global climate models have too coarse resolution to accurately resolve coastal dynamics. Analysis of the global climate model results also reveals large biases of the SST in certain coastal areas, in particular - over the U.S. West Coast. Recent programs such as the North American Regional Climate Change Assessment Program (NARCCAP) offer variety outputs for different regional climate models with a resolution of 50 km and their boundary conditions supplied by various global climate models. Possible advantages and limitations of using the NARCCAP results and new efforts using regional climate simulations with 36 and 12 km resolutions will be discussed. The discussion will also include variations of the coastal pressure systems due to climate change and their impact on the direction and intensity of the coastal mesoscale pressure gradient.