Severe convective environments in Reanalyses

Wednesday, 17 December 2014
Grant Gutierrez and Aaron D Kennedy, University of North Dakota, Grand Forks, ND, United States
Climate change implies an altering of weather patterns that may change the frequency of high impact events such as severe thunderstorms and their associated dangers (damaging winds, torrential rains, hail, and tornadoes). Presently, very little is known about how climate change will impact these events. Since these phenomenon are not resolved by climate models, proxies are required to understand how these events may change in the future.

Prior to investigating how convective environments change in the future, a reference must be obtained to understand the current climatology of convective environments. Studies such as Kennedy et al. (2011) have shown there are significant differences in reanalyses for regions prone to severe weather.

Severe weather parameters such as Convective Available Potential Energy (CAPE), Lifted Index, K Index, Total Totals, 0-1 km shear, 0-3 km shear and 0-6 km shear are calculated using soundings from reanalyses for known severe convective environments. Reanalyses included in this study are the North American Regional Reanalysis (NARR), Modern-Era Retrospective Analysis for Research and Applications (MERRA), 20th Century Reanalysis (20CR), Climate Forecast System Reanalysis (CFSR), Japanese 25-year Reanalysis (JRA25), and Japanese 55-year Reanalysis (JRA55). Preliminary findings are presented. If time allows, multi-parameter indices such as Energy Helicity Index, Bunkers storm motion, Significant Tornado Parameter, and Supercell Composite Parameter will also be compared.