Trends in Raindrop Kinetic Energy with Modeled Climate Warming in the Lake Tahoe Basin. (5th March 2020)

• Record Type: Journal Article
• Authors: Lewis, Jack; Coats, Robert
• Is Part Of: Journal of the American Water Resources Association. Volume 56:Number 3(2020)
• Page Start: 472
• Page End: 485
• Publication Date: 2020-03-05
• Subjects: climate change -- Lake Tahoe -- raindrops -- kinetic energy -- snow hydrology -- extreme values; Water-supply -- Periodicals; Hydrology -- Periodicals; Water resources development -- Periodicals; Water resources development -- Environmental aspects -- Periodicals; 333.9100973
• DOI: 10.1111/1752-1688.12834
• Languages: English
• ISSNs: 1093-474X

Abstract

Abstract: Two means by which climate change may increase surface soil erosion in mountainous terrain are: (1) increasing the frequency of extreme rainfall events and (2) decreasing the duration of snow cover on bare soil. We used output from four general circulation models (GCMs) and two greenhouse gas trajectories to produce a suite of hydrologic variables at a daily time‐step for historic and projected 21st Century conditions. We statistically disaggregated the daily rainfall to hourly, using hourly rainfall from a network of nine weather stations in the Tahoe Basin, and filtered out rain falling on a snowpack. We applied published equations to convert hourly intensity to raindrop kinetic energy (KE) for each day and grid cell in the Basin, averaged across grid cells, and created time series of total annual and maximum annual hourly kinetic energy (TKE and MKE) on snow‐free ground. Using the Generalized Extreme Value distribution, we calculated the significance of long‐term trends in KE on snow‐free ground, and estimated energy levels for return periods of 2, 20, and 100 years. We then detrended the snowpack data and compared the resulting trends in KE with the trends resulting from changes in both rainfall energy and snowpack under two GCMs. Principal findings include (1) upward trends in MKE, (2) stronger upward trends in TKE; and (3) an effect of increasing rainfall intensities on KE in some cases, and a strong effect of reduced snowpack in all cases examined. Abstract : Research Impact Statement : More precipitation falling as rain and briefer snow cover would increase the kinetic energy of rain falling on snow‐free ground, hence may increase surface soil erosion in the Lake Tahoe Basin.