Spatial and temporal analysis and trends of extreme precipitation over the Mississippi River Basin, USA during 1988-2017

Authors: DOMMO, ATANAS - University Of Missouri; ALOYSIUS, NOEL - University Of Missouri; LUPO, ANTHONY - University Of Missouri; Hunt, Sherry

Submitted to: Journal of Hydrology: Regional Studies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/27/2024
Publication Date: 9/13/2024
Citation: Dommo, A., Aloysius, N., Lupo, A., Hunt, S. 2024. Spatial and temporal analysis and trends of extreme precipitation over the Mississippi River Basin, USA during 1988-2017. Journal of Hydrology: Regional Studies. 56. Article 101954. https://doi.org/10.1016/j.ejrh.2024.101954.
DOI: https://doi.org/10.1016/j.ejrh.2024.101954

Interpretive Summary: The variability and trends in extreme precipitation events over the Mississippi River Basin (MRB). were examined. Our analyses of daily precipitation events recorded at nearly 800 locations within the MRB reveal that, on average, all the locations show an increasing trend in precipitation. The spatial patterns of the extreme precipitation events show an east to west gradient. The trends were statistically significant in most of the Northern MRB. In the future, the relationships between geographically distant weather phenomena, also known as teleconnections, could increase the difficulty of predicting extreme precipitation events. Such uncertainty in predictions may lead to severe consequences, particularly when floods threaten the stability of infrastructures such as levees and dams and prolonged droughts cause crop failures. USDA is an equal opportunity provider and employer.

Technical Abstract: Assessing the spatial and temporal variability of precipitation is necessary to solve hydrological and water managements problems. Of particular concern are the frequency of extreme precipitation events and subsequent economic losses and ecosystem damage due to floods, soil erosion, and infrastructure failures. The Mississippi River Basin (MRB) in the United States is highly vulnerable to these climatic changes. Based on daily precipitation observations of 769 meteorological stations over the MRB from 1988-2017, the spatio-temporal variability and trend of nine extreme precipitation indices were estimated and statistically assessed by the Mann-Kendall test. Their statistical correlations with seven large teleconnections index were also evaluated. The results show that, on average, almost all the indices exhibit an increasing trend (except Consecutive Dry Day, CDD). The indices evaluated include simple daily intensity index (SDII), the max-1-day precipitation (RX1day), the max-5-day precipitation (RX5day), and the number of wet days (RR1). Other indices evaluated are the number of heavy precipitation days (R10), the number of very heavy precipitation days (R20), and the number of consecutive wet days (CWD). The total wet day precipitation (PRCPTOT) exhibits a significant (p<0.05) increasing trend. Spatially, most of the significant increasing (decreasing) trends of the extreme's precipitation are located over the Upper (South) MRB; however, the CDD exhibits otherwise. The spatial distribution of the indices shows an East-West dipole with maximum values recorded east of the MRB. The exception to this trend is the CDD, which shows otherwise. Only a few stations exhibit a trend in CWD. Moreover, all the extremes’ precipitation except CDD have a strong correlation with PRCPTOT and SDII at 95% confidence level. The influence of large-scale teleconnections on extreme precipitation is noteworthy, and the strength between both vary depending on the spatial location within the MRB. However, the contrasting effect of large teleconnections on extreme precipitation could make it difficult to predict extreme precipitation events, as well as the prediction of flooding, with consequences to infrastructure failures, increasing vulnerable populations, risk zones and relocations populations USDA is an equal opportunity provider and employer.