| Summary: | Dissertation (Ph.D.) University of Alaska Fairbanks, 2018 This thesis includes four studies that explore and compare the impacts of four contributing factors resulting in regional climate change on the North Slope of Alaska based on a numerical simulation approach. These four contributing factors include global warming due to changes in radiative forcing, sea ice decline, earlier Arctic lake ice-off, and atmospheric circulation change over the Arctic. A set of dynamically downscaled regional climate products has been developed for the North Slope of Alaska over the period from 1950 up to 2100. A fine grid spacing (10 km) is employed to develop products that resolve detailed mesoscale features in the temperature and precipitation fields on the North Slope of Alaska. Processes resolved include the effects of topography on regional climate and extreme precipitation events. The Representative Concentration Pathway (RCP) 4.5 scenario projects lower rates of precipitation and temperature increase than RCP8.5 compared to the historical product. The increases of precipitation and temperature trends in the RCP8.5 projection are higher in fall and winter compared to the historical product and the RCP4.5 projection. The impacts of sea ice decline are addressed by conducting sensitivity experiments employing both an atmospheric model and a permafrost model. The sea ice decline impacts are most pronounced in late fall and early winter. The near surface atmospheric warming in late spring and early summer due to sea ice decline are projected to be stronger in the 21st century. Such a warming effect also reduces the total cloud cover on the North Slope of Alaska in summer by destabilizing the atmospheric boundary layer. The sea ice decline warms the atmosphere and the permafrost on the North Slope of Alaska less strongly than the global warming does, while it primarily results in higher seasonal variability of the positive temperature trend that is bigger in late fall and early winter than in other seasons. The ongoing and ...
|
|---|