Climate projections over the Antarctic Peninsula region to the end of the 21st century. Part II: wet/dry indices

Abstract

Objective of the study is an assessment of possible climate change in the region of the Antarctic Peninsula from 1986 until the end of the 21st century projected by the RCMs' ensemble. During the last decades Antarctica has undergone predominantly warming, with the highest rate of surface air temperature increase found over the Antarctic Peninsula, where the Ukrainian Antarctic Akademik Vernadsky station is located. There is a unique ecosystem in the region which is vulnerable and under the growing impact of a changing weather regime due to rapid climate changes with consequent changes in sea ice, land distribution under snow/ice, etc. Thus, an important task for the region is an estimation of climate change trends and definition of possible subregionalization. Data and methods. Data of two regional climate models HIRHAM5 and RACMO21P forced by two global climate models EC-EARTH and HadGEM from the Polar-CORDEX (Coordinated Regional Downscaling Experiment -Arctic and Antarctic Domains) as part of the international CORDEX initiative were used in the study. Spatial distribution of the model output is 0.44°. Set of scripting codes developed by Climate4R project (An R Framework for Climate Data Access and Postprocessing) was modified in order to extract data for the Antarctic Peninsula region from the Antarctic domain and obtain climatological characteristics for individual RCMs and their ensemble mean. Projected changes in wet/dry climate indices for scenarios RCP4.5 and RCP8.5 for two periods 2041-2060 and 2081-2100 were assessed with respect to the historical experiment 1986-2005. Results. An analysis of projected wet/dry climate indices for both RCP4.5 and RCP8.5 scenarios is presented in Part II of the paper. An analysis of the cold temperature indices (FD, ID) is presented in Part I of the study. In the historical experiment Larsen Ice Shelf and leeward east coast are the regions with the lowest total precipitation in wet days (PRCPTOT, 200-300 mm) and simple daily intensity index (SDII, about 5 mm/day) with under 10 days of consecutive wet days (CWD) and up to 30 days consecutive dry days (CDD). In the cross of the 21st century, duration of dry spell is projected to shorten for the whole peninsula and for Akademik Vernadsky station by about 7-10% under the scenario RCP4.5 and 10-15% under the RCP8.5. Projected SDII changes are up to +20% till the end of the century under the scenario RCP8.5 at north-west coast of the Antarctic Peninsula. Conclusions. Over the Antarctic Peninsula region both scenarios project an average increase in total PRCPTOT and SDII; overall the maximum length of CWD is extended while the maximum length of the CDD is reduced. In combination with decreasing number of frost (FD) and ice (ID) days, the pattern of changes differs notably across the peninsula. It is shown in the first part of the paper that over the Antarctic Peninsula region, both scenarios project an average decrease in the cold season period. The most pronounced changes of ID and FD climate indices are for the Larsen Ice Sh...

Climate projections over the Antarctic Peninsula region to the end of the 21st century. Part III: clouds and extreme precipitation

“…Simulations data from the Coordinated Regional Downscaling Experiment -Arctic and Antarctic Domains (Polar CORDEX) remain one of the best tools that allow scientists to assess long-term variations in the Antarctica climate. We use the same initial data from Polar CORDEX, methodological approach, and periods as in Parts I and II of the research (Chyhareva et al, 2019a;2019b). Note that clouds and precipitation considered in the presented study could connect our understanding between temperature and wet/dry regimes analyzed in the previous parts of the study.…”

“…Total precipitation and other wet/dry indices have been analyzed in Chyhareva et al (2019b). Since we found that water clouds will increase and expected more liquid phase precipitation with further warming even in Antarctica (Vignon et al, 2021), we calculated the rain share of total precipitation for the considered domain.…”

“…The lowest liquid precipitation changes are about 5%, projected for the AP mountains, Palmer Land, Ellsworth Land, and part of the Weddell Sea. It is expected that the west part of the Weddell Sea and the leeward coast of the Antarctic Peninsula will undergo lower changes because of the lowest yearly total precipitation amount in the studied region (see Chyhareva et al, 2019b).…”

“…The papers (Chyhareva et al, 2019a;2019b) proposed zoning of the Antarctic Peninsula based on studied changes in temperature and precipitation regime. To continue the previous study, we choose five points of interest.…”

Precipitation phase transition in austral summer over the Antarctic Peninsula

“…The chances of rain and associated surface melt in West Antarctica and the AP increase markedly during warm air intrusions and atmospheric rivers (Wille et al, 2019;Nicolas et al, 2017). Recent studies of precipitation projections show increases in consecutive wet days (Chyhareva et al, 2019) and rain and melt days (Bozkurt et al, 2021;Vignon et al, 2021) in the AP region during the 21 st century, indirectly indicating that surface melt will continue.…”