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Title: Exploring topography-based methods for downscaling subgrid precipitation for use in Earth System Models

Abstract

Topography exerts major control on land surface processes. To improve representation of topographic impacts on land surface processes, a new topography-based subgrid structure has been introduced to the Energy Exascale Earth System Model to represent the subgrid heterogeneity of surface elevation. To take advantage of the new subgrid structure for improving land surface modeling, this study explores four variations of topography-based methods for downscaling grid precipitation to the corresponding subgrids. In the first three methods, the deviation of the subgrid precipitation from the grid’s is equal to the grid precipitation multiplied by the ratio of the elevation difference between the subgrid and grid mean to a specified elevation equals to the grid elevation, the difference between the maximum and minimum subgrid elevation, and the maximum subgrid elevation, respectively. The second method limits the ratio to 0.5 to avoid extreme values on mountains and the third method accounts for the slope effect. The fourth method is similar to the third method except that the Froude Number is used to limit the numerator in a blocking regime of the ambient flow. The downscaled precipitation is evaluated using the PRISM precipitation data over the U.S. using statistical metrics. Results show that by accountingmore » for topographic slope besides elevation, the third and fourth methods show clear advantages over the first and second methods. Furthermore, introducing the Froude Number in the fourth method improves downscaling skill and shows consistent advantages over the third method in areas with larger subgrid heterogeneity across different grids sizes.« less

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [2]
  1. BATTELLE (PACIFIC NW LAB)
  2. EMERITUS PROGRAM
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1606318
Report Number(s):
PNNL-SA-146636
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Geophysical Research: Atmospheres
Additional Journal Information:
Journal Volume: 125; Journal Issue: 5
Country of Publication:
United States
Language:
English

Citation Formats

Tesfa, Teklu K., Leung, Lai-Yung, and Ghan, Steven J. Exploring topography-based methods for downscaling subgrid precipitation for use in Earth System Models. United States: N. p., 2020. Web. doi:10.1029/2019JD031456.
Tesfa, Teklu K., Leung, Lai-Yung, & Ghan, Steven J. Exploring topography-based methods for downscaling subgrid precipitation for use in Earth System Models. United States. https://doi.org/10.1029/2019JD031456
Tesfa, Teklu K., Leung, Lai-Yung, and Ghan, Steven J. 2020. "Exploring topography-based methods for downscaling subgrid precipitation for use in Earth System Models". United States. https://doi.org/10.1029/2019JD031456.
@article{osti_1606318,
title = {Exploring topography-based methods for downscaling subgrid precipitation for use in Earth System Models},
author = {Tesfa, Teklu K. and Leung, Lai-Yung and Ghan, Steven J.},
abstractNote = {Topography exerts major control on land surface processes. To improve representation of topographic impacts on land surface processes, a new topography-based subgrid structure has been introduced to the Energy Exascale Earth System Model to represent the subgrid heterogeneity of surface elevation. To take advantage of the new subgrid structure for improving land surface modeling, this study explores four variations of topography-based methods for downscaling grid precipitation to the corresponding subgrids. In the first three methods, the deviation of the subgrid precipitation from the grid’s is equal to the grid precipitation multiplied by the ratio of the elevation difference between the subgrid and grid mean to a specified elevation equals to the grid elevation, the difference between the maximum and minimum subgrid elevation, and the maximum subgrid elevation, respectively. The second method limits the ratio to 0.5 to avoid extreme values on mountains and the third method accounts for the slope effect. The fourth method is similar to the third method except that the Froude Number is used to limit the numerator in a blocking regime of the ambient flow. The downscaled precipitation is evaluated using the PRISM precipitation data over the U.S. using statistical metrics. Results show that by accounting for topographic slope besides elevation, the third and fourth methods show clear advantages over the first and second methods. Furthermore, introducing the Froude Number in the fourth method improves downscaling skill and shows consistent advantages over the third method in areas with larger subgrid heterogeneity across different grids sizes.},
doi = {10.1029/2019JD031456},
url = {https://www.osti.gov/biblio/1606318}, journal = {Journal of Geophysical Research: Atmospheres},
number = 5,
volume = 125,
place = {United States},
year = {2020},
month = {3}
}

Works referenced in this record:

Dynamic Modeling of the Spatial Distribution of Precipitation in Remote Mountainous Areas
journal, April 1993


Guidelines for assessing the suitability of spatial climate data sets
journal, January 2006


Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States
journal, December 2008


A Statistical-Topographic Model for Mapping Climatological Precipitation over Mountainous Terrain
journal, February 1994


Winter Precipitation Efficiency of Mountain Ranges in the Colorado Rockies Under Climate Change
journal, March 2018


Application of physical scaling towards downscaling climate model precipitation data
journal, March 2017


Physically Based Global Downscaling: Climate Change Projections for a Full Century
journal, May 2006


Statistical downscaling of GCM simulations to streamflow using relevance vector machine
journal, January 2008


The DOE E3SM Coupled Model Version 1: Overview and Evaluation at Standard Resolution
journal, July 2019


The Intermediate Complexity Atmospheric Research Model (ICAR)
journal, March 2016


An intercomparison of statistical downscaling methods used for water resource assessments in the United States
journal, September 2014


Orographic effects on precipitating clouds
journal, January 2012


Blocking in Areas of Complex Topography, and Its Influence on Rainfall Distribution
journal, February 2009


New Global Hydrography Derived From Spaceborne Elevation Data
journal, January 2008


A subgrid parameterization of orographic precipitation
journal, January 1995


North American Regional Reanalysis
journal, March 2006


Statistical Downscaling in Climatology: Statistical Downscaling
journal, April 2013


A Linear Theory of Orographic Precipitation
journal, June 2004


Orographic Precipitation and Oregon’s Climate Transition
journal, January 2005


Exploring new topography-based subgrid spatial structures for improving land surface modeling
journal, January 2017


Downscaling of precipitation for climate change scenarios: A support vector machine approach
journal, November 2006