How Large-Scale Climate Patterns Influence Extreme Precipitation Seasonality Over the United States?

• Activity Number: 247 - Analyses in Climate and Epidemiology
• Type: Contributed
• Date/Time: Tuesday, August 9, 2022 : 8:30 AM to 10:20 AM
• Sponsor: Section on Statistics and the Environment
• Author(s): Bhikhari Tharu* and Nirajan Dhakal and Ali Aljoda
• Companies: Spelman College and Spelman College and Spelman College
• Keywords: Circular statistics; Seasonality; Large scale climate patterns; Extreme precipitation

Abstract

Temporal changes in the seasonality of extreme precipitation, as well as possible teleconnections between seasonality of extreme precipitation and large-scale climate patterns, are not well understood. In this study, we investigated temporal changes in the seasonality of Annual Daily Maximum (ADM) and Monthly Maximum (MM) precipitation indices over the period 1951 – 2014 for 1108 stations across the contiguous USA using circular statistics. Our results show that many climate regions within the contiguous USA display distinct seasonality pattern for both ADM and MM. While a spatial coherence of change in the mean date of occurrence of extreme precipitation across a large area is not visible, a cluster of stations showing a decrease in strength of seasonality for the recent time period is concentrated in the eastern Gulf Coast as well as coastal sites of Northeast and Northwest regions. The large-scale climate variabilities have a strong influence on the mean date of occurrence of extreme precipitation but a weak influence on the strength of seasonality in the contiguous USA.