edu.ucar.opensky::articles:42363 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T18:01:30.442521 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.net/ark:/85065/d7cj8jtg Evaluation of the mountain hydroclimate across the Western United States in dynamically downscaled climate models 2024-12-01T00:00:00Z publication https://n2t.net/ark:/85065/d7cj8jtg https://doi.org/10.1175/JHM-D-24-0063.1 Adhikari, P. author Geerts, B. author Rahimi-Esfarjani, S. author Smith, K. author Shuman, B. N. author Schneider, Timothy author UCAR/NCAR - Library publisher This study evaluates the ability of 15 CMIP6 global climate models (GCMs), dynamically downscaled to a 9-km grid, to effectively simulate the observed regional hydroclimate across the complex terrain of the western United States. The evaluation focuses on orographic precipitation, surface temperature, and snow water equivalent (SWE), evaluated over a 33-yr period (1981&#8211;2014) using gridded gauge- and station-based datasets and a snowpack reanalysis product. Additional comparisons are made against two ERA5-driven climate reconstructions: one at 9-km resolution, with the same physical choices, and one at 4-km resolution. The latter better captures the terrain and orographic processes and uses different physics. Model performance is evaluated in four geographic regions, and mountains are contrasted against the surrounding plains. The evaluation is challenged by the fact that gridded observational estimates of climate parameters in complex terrain have a poorly quantified uncertainty related to measurement and/or representativeness issues. The ensemble mean of the downscaled GCMs overestimates cold-season precipitation, its orographic enhancement, and peak SWE in the mountains. Its diurnal temperature cycle and its mountain&#8211;plain temperature contrast are suppressed, compared to observations: its temperature estimates err toward the mean on both sides of both distributions. But the same applies to the identically downscaled (9 km) ERA5, indicating that these biases are due to model physics, not a misrepresentation of the climate system. The 4-km ERA5-based reconstruction has smaller biases in terms of precipitation and temperature, especially over mountains, but underestimates SWE. Model performance differs between mountains and plains, and the differences vary by region. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication <style type="text/css"></style><span style="font-family:Arial;font-size:10pt;font-style:normal;" data-sheets-root="1">Copyright 2024 American Meteorological Society (AMS).</span> None eng geoscientificInformation