Wet and Dry Spell Variability in Southwestern Ohio

Abstract:

The warming of our planet changes drives changes in precipitation characteristics.  Understanding wet and dry spell variability is important as precipitation changes across the United States, including Ohio. The objectives of this study were to (1) calculate wet and dry spells, 2) analyze variability of spell length on annual and seasonal scales, and 3) establish a climatology of wet and dry spells in Southwestern Ohio. Using the National Oceanic and Atmospheric Association’s (NOAA) Global Historical Climatology Network daily (GHCNd) precipitation data from 1936-2023, we investigated wet and dry spell variability at four sites in Ohio: Urbana, Dayton, Hamilton, and Cincinnati. Mann-Kendall tests were employed to identify significant changes in the frequency of wet and dry spells by varying lengths. Major findings from this study include (1) the percent of wet days per year increased across Southwestern Ohio (p<0.05), (2) wet spells became longer in Urbana and Cincinnati (p<0.05), and (3) multi-day wet and dry spells occurred preferentially in the spring. These results and trends can be explained by local and global weather patterns. Overall, these results demonstrate that the climate in Southwestern Ohio is shifting, and further research is required to explore the extent and impacts of these changes.

Keywords: climate, wet spells, dry spells, precipitation

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