Mass‐Conserving Downscaling of Climate Model Precipitation Over Mountainous Terrain for Water Resource Applications

Journal Article · 12 October 2023 · Geophysical Research Letters

DOI: https://doi.org/10.1029/2023GL105326 · OSTI ID:2067663

Rugg, A.  ^[1]; Gutmann, E. D.  ^[1]; McCrary, R. R. ^[1]; Lehner, F.  ^[2]; Newman, A. J.  ^[1]; Richter, J. H.  ^[1]; Tye, M. R.  ^[3]; Wood, A. W.  ^[1]

---

1. National Center for Atmospheric Research Boulder CO USA
2. National Center for Atmospheric Research Boulder CO USA, Department of Earth and Atmospheric Sciences Cornell University Ithaca NY USA, Polar Bears International Bozeman MT USA
3. National Center for Atmospheric Research Boulder CO USA, Whiting School of Civil Engineering Johns Hopkins University Baltimore MD USA

Abstract A mass‐conserving method to downscale precipitation from global climate models (GCMs) using sub‐grid‐scale topography and modeled 700‐mb wind direction is presented. Runoff is simulated using a stand‐alone hydrological model, with this and several other methods as inputs, and compared to runoff simulated using historical observations over the western contiguous United States. Results suggest the mitigation of grid‐scale biases is more critical than downscaling for some regions with large wet biases (e.g., the Great Basin and Upper Colorado). In other regions (e.g., the Pacific Northwest) the new method produces more realistic sub‐grid‐scale variability in runoff compared to unadjusted GCM output and a simpler downscaling method. The presented method also brings the runoff centroid timing closer to that simulated with observations for all subregions examined.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0022070
• OSTI ID: 2067663
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 20 Vol. 50; ISSN 0094-8276
• Publisher: American Geophysical Union (AGU)Copyright Statement
• Country of Publication: United States
• Language: English