A 26 year high‐resolution dynamical downscaling over the Wasatch Mountains: Synoptic effects on winter precipitation performance

Abstract

A 26 year high-resolution dynamical downscaling over the Wasatch Mountains of Utah, USA, was performed using the Weather Research and Forecasting model with initial and boundary conditions derived from Climate Forecast System Reanalysis. Precipitation validation was conducted on the inner (4 km resolution) domain with Snowpack Telemetry (SNOTEL) and Parameter-elevation Regressions on Independent Slopes Model data sets. Analysis of seasonal performance reveals the model's overall good skill at reproducing the spatial distribution of precipitation. Annual precipitation validates within ∼20% of SNOTEL. The largest monthly biases occurred in December-January (∼+30%) stemming from a small set of high-precipitation events. Composite analysis of cold season days with large positive or negative precipitation biases reveals two distinct synoptic regimes with significantly different moisture, temperature, and circulation patterns that respectively enhanced geopotential height and moisture biases consistent with the sign of their mean precipitation biases. The number of cold season days with large (>5 mm) positive precipitation bias was negatively correlated with El Niño (r = −0.55), indicating storm track-related effects on the sign of the bias consistent with the distinct synoptic regimes revealed by the above-noted composite analyses.

Impact of Climate and Land Use Change on Streamflow and Sediment Yield in a Snow‐Dominated Semiarid Mountainous Watershed

“…The projected climate results are consistent with other studies such as the climate projection for the Rocky Mountain headwaters of Colorado River (Christensen et al ; Ray et al ). The results of these downscaled climate projections in the State of Utah and the Jordan River basin are also reported in other studies (Scalzitti et al 2016a, b; Strong et al ; Khatri et al ).…”

“…The statistical downscaling (Reclamation ) was based on more than 20 global climate models forced by four greenhouse gas emission scenarios, referred to as Representative Concentration Pathways (RCPs; Vuuren et al ). For the dynamical downscaling, the high computational expense of our regional climate model configuration (Scalzitti et al 2016a, b) limited the simulation to a mid‐century decade (2035–2044) and a late‐century decade (2085–2094), both under the moderate greenhouse gas emission scenario RCP6.0. For consistency, we focus on climate inputs for the same two decades in the statistical downscaling archive.…”

Climate change impact on the roles of temperature and precipitation in western U.S. snowpack variability

“…Initial conditions at the surface, atmosphere, and lateral boundary were derived from 3‐hourly Climate Forecast System Reanalysis (CFSR) [ Saha et al , ] at 38 km grid spacing. Further details about this model's customization and performance in simulating winter precipitation on the inner domain d03 can be found in Strong et al [] and Scalzitti et al [, ]. For this study, we validated the historical simulation (hereafter denoted WRF Past ) on the middle domain d02 against Parameter‐elevation Regressions on Independent Slopes Model (PRISM) data [ Daly et al , , ].…”

Reference evapotranspiration from coarse-scale and dynamically downscaled data in complex terrain: Sensitivity to interpolation and resolution

“…The framework included a thermodynamic slab model of the Great Salt Lake with salinity adjustments to saturation vapor pressure over the lake (Strong et al, 2014). Additional configuration details and historical validation can be found in (Scalzitti et al, 2016). Although some of the input fields for E were available directly in the WRF output (e.g., net radiation), we used only T, V, p, S, and RH based on the water vapor mixing ratio from WRF, and derived the remaining variables as outlined in the ASCE-ET equation.…”