92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Monday, 23 January 2012: 5:00 PM
Current Issues and Challenges in Climate Predictions of Coastal Upwelling
Room 338 (New Orleans Convention Center )
Darko Koracin, DRI, Reno, NV; and K. C. King, J. F. Mejia, C. E. Dorman, and K. E. Kunkel

Recent studies indicate that climate in the coastal band over the land and coastal waters is already showing contrasting behavior compared to areas further inland. There are indications from observations of apparent cooling of the land areas near the coastline due to differences of climate heating rates over the land and the ocean. Some studies of the coastal sea surface temperature indicate cooling of the surface coastal ocean while others show possible warming. One of the components which contributes to altering coastal climate is an increase of the land-sea pressure gradients and consequent increase of the onshore flows. This increase also generates more intense upwelling along the eastern boundaries of the ocean. However, global climate models cannot resolve coastal processes and this effect is missing in climate projections. Although fully coupled atmospheric ocean models will provide insight into this issue, there are new downscaling tools that can be used for investigating this process. For example, historical and future DRI-RCM simulations are available over the western United States at 36 and 12 km resolution. Historical DRI-RCM datasets (1980-2010) use boundary forcing from NCEP/NCAR reanalysis and the GCM-CCSM3; future datasets are limited to CCSM3 (2040-2070)using only SRES-A2. Other data set include the the North American Regional Climate Change Assessment Program (NARCCAP), focused on regional climate simulations in future SRES-A2 climate change scenario and on uncertainty in the predictions. Current runs from 1980-2000 and future runs from 2041-2070 with a horizontal resolutions of 12, 36 and 50 kms were used to assess how well this type of modeling tools can be used to predict variations of coastal climate and upwelling through the representation of the winds, wind stress, and wind stress curl. Modulation of upwelling will have a significant impact on nutrients, productivity and venting CO2 back to the atmosphere. Improved understanding and prediction of coastal upwelling will lead to better operational forecasts of surface temperature in coastal regions as well as to proper treatment of this process in climate predictions.

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