Taylor Grace - April 7

Weather and Climate Systems Seminar

An Applied Definition for Heat Waves across the Southern Great Plains

   Taylor Grace

Friday, April 7th

2:00pm

Join Google Meet:

https://meet.google.com/jdv-kpfr-gnu

Heat waves are common to the Southern Great Plains (SGP), yet throughout the research community there are over 16 definitions used to quantify this extreme event. Gaining a better understanding and predictability of heat wave events will reduce critical impacts on agriculture, infrastructure, human health, ecosystems, and water resources. To achieve this goal, a novel and comprehensive heat wave definition needs to be established. With the use of this identification method, a climatology of heat waves can be generated on local-to-global scales. Two reanalysis datasets, ERA-20C and North American Regional Reanalysis (NARR), were utilized to assess the robustness of our novel definition for heat waves for two different time periods (1941-1970 and 1979-2019, respectively). Probability density functions (PDFs) were derived for two variables: daily maximum and minimum standardized temperature anomalies. From the PDFs, the relative threshold of the 90^th percentile was determined to be ideal for the heat wave identification methodology. From this assessment, heat waves are identified when the daily maximum and minimum standardized temperature anomalies are greater than or equal to the 90^th percentile for three or more consecutive days. Using the NARR dataset, this heat wave definition was applied on multiple percentages of spatial coverage (e.g., 10%, 25%, and 50%) to generate a preliminary climatology for the SGP from 1979 through 2019. It was found that the spatial percentage used in the novel definition has an impact on the frequency and duration of the distinguished heat wave events from the respective climatology.