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Observed Changes in Daily Precipitation Intensity in the United States
  • Ryan D. Harp,
  • Daniel E Horton
Ryan D. Harp
Institute for Sustainability and Energy at Northwestern; Northwestern University, Institute for Sustainability and Energy at Northwestern; Northwestern University

Corresponding Author:ryan.harp@northwestern.edu

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Daniel E Horton
Northwestern University, Northwestern University
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Relative to changes in annual mean and extreme precipitation, the characterization of changes in the full distribution of precipitation intensities remains overlooked and under-explored, despite their critical importance to natural hazard, agriculture, and infrastructure risk assessments. Here, we aggregate daily Global Historical Climatology Network precipitation observations within seventeen internally consistent NEON domains in the United States for two time periods (1951-1980 and 1991-2020). We find statistically significant changes in wet day precipitation distributions in fourteen of the domains–changes primarily driven by a shift from lower to higher wet day intensities. Patterns of robust change are geographically consistent, with increases in the mean (4.6-7.1%) and standard deviation (20-31%) of wet day intensity in the eastern U.S., but mixed signals in the western U.S. Beyond their critical importance to the aforementioned societal impact realms, these observational results can also inform climate model performance evaluations.