Performance of statistical and dynamical downscaling approaches for the analysis of convective storms over the Midwest and Great Lakes region
Abstract
Global Climate Models (GCMs) variables are commonly downscaled using either statistical or dynamical downscaling methods for many impact assessments studies that require fine-scale dataset. However, the appropriate use of each approach for different kinds of studies is rarely clearly defined. Analysis of extreme precipitation from small-scale convective storms is a case in point. Most statistical downscaling approaches, which rely on the observed relationship between small- and large-scale climate dynamics, are often considered to be less reliable for simulating fine-scale convective storms, because the spatial resolution of the large scale climate models is too coarse. By contrast, high-resolution dynamical downscaling methods which use physically-based Regional Climate Models (RCMs) are arguably better able to simulate small-scale storm dynamics, but high computation costs limit both the length of simulations and the number of ensembles available (limiting the ability to quantify extremes and estimate uncertainty). These constraints are strongly influenced by resolution, which raises questions about the role of model resolution on model performance. This study first evaluates dynamically-downscaled GCM projections driven by the Weather Research and Forecast (WRF) at 12-km resolution and 4-km resolution for their representation of historical convective storms for a 10-yr period. Then, we intercompare these dynamically-downscaled GCM projections of extreme precipitation with statistically-downscaled projections of precipitation produced using the Hybrid Delta (HD) method. Specifically, we focus on analyzing simulations of extreme precipitation in summer and winter from convective storms because we hypothesize that changes in these storms will have a critical impact on many physical and ecological processes over the Midwest and Great Lakes region.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H13U2057B
- Keywords:
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- 1807 Climate impacts;
- HYDROLOGYDE: 1817 Extreme events;
- HYDROLOGYDE: 1873 Uncertainty assessment;
- HYDROLOGYDE: 4321 Climate impact;
- NATURAL HAZARDS