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Harp, R. D., & Horton, D. E. (2023). Geophysical Research Letters.

Key Points
  • We find widespread robust changes in two measures of interannual precipitation variability across the United States

  • We detect increases (decreases) in annual mean precipitation and wet day frequency across the eastern (western) United States

  • We explore the interaction of changes in precipitation frequency and wet day precipitation intensity on interannual variability


Harp, R. D., & Horton, D. E. (2022). Geophysical Research Letters.

Key Points
  • We find consistent shifts from lower to higher daily precipitation intensities, particularly in the central and eastern United States

  • All contiguous United States domains show significant changes in their distributions of precipitation intensity from 1951–1980 to 1991–2020

  • Mean and standard deviation of wet day precipitation intensities increase for nearly all domains in the central and eastern United States


Harp, R. D., Colborn, J. M., Candrinho, B., Colborn, K. L., Zhang, L., & Karnauskas, K. B. (2021). GeoHealth.

Key Points
  • Interannual variability of malaria in Mozambique is dominated by two spatio-temporal patterns

  • These two spatio-temporal patterns are linked to the El Niño-Southern Oscillation and the Subtropical Indian Ocean Dipole

  • Results suggest that predictable modes of inter-annual climate variability can be utilized to enhance malaria early warning systems


Harp, R. D., & Karnauskas, K. B. (2020). Environmental Research Letters.

Key Points
  • The United States should expect an additional 2.3 to 3.2 million violent crimes between 2020 and 2099 depending on greenhouse gas emissions scenario

  • We project annual changes in violent crime count according to several temperature thresholds

  • Rough calculations place the economic valuation of these changes at $5 billion per year

Laidlaw, E. K., O'Neill, B. C., & Harp, R. D. (2019). Wiley Interdisciplinary Reviews: Climate Change.

Key Points
  • The Community Earth System Model (CESM) has been applied to a wide variety of societally relevant topics

  • The use of CESM in managed, societal, and ecological systems research is rapidly expanding


Harp, R. D., & Karnauskas, K. B. (2018). GeoHealth.

Key Points
  • The observed covariability between climate and crime rates was analyzed; regional and monthly averaging is critical for climate signal detection

  • Interannual regional violent crime rates are influenced by climate variability; strongest correlations exist with wintertime temperatures

  • Findings support Routine Activities Theory as the primary causal mechanism of this relationship linking climate and violent crime

Active Preprints

Harp, R. D., and Horton, D. E. (preprint, in revision): Observed Changes in Interannual Precipitation Variability in the United States. Authorea.

Harp, R. D., Blanco, D. T., Sharma, A., Wuebbles, D. J., and Horton, D. E. (preprint, in review): Recent changes in Great Lake hydrologic variability: an artifact of chance or a robust change? Authorea.

Ryan D Harp

NOAA-CDC Climate and Health Postdoctoral Researcher

Cooperative Program for the Advancement and Earth System Science

University Corporation for Atmospheric Research

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