scholarly journals Investigation of WRF Microphysics Schemes and Dynamics During an Extreme Precipitation Event in East Idaho

2018 ◽  
Vol 12 (1) ◽  
pp. 58-79
Author(s):  
Thomas A. Andretta
Keyword(s):  
Sensitivity Study ◽  
Environmental Modeling ◽  
Precipitation Event ◽  
Weather Research And Forecasting ◽  
Weather System ◽  
Feeder Mechanism ◽  
Double Moment ◽  
Major Factors ◽  
River Plain ◽  
Weather Research

Background:The 26 December 2003 snowstorm was a rare and long-lived weather system that affected east Idaho. Light snow began falling Christmas night, became steadier and heavier during the next day, and tapered off during the morning on the 27th. Snowfall estimates of 20.3-38.1 cm (8.0-15.0 in) were observed over a 24-hour period on 26 December 2003 in the lower part of the Snake River Plain, paralyzing local communities and transportation centers with snowdrifts and poor visibilities.Methods:The Weather Research and Forecasting Unified Environmental Modeling System was used to conduct a sensitivity study of five precipitation microphysics schemes at two grid scales during the event.Results:A comparison of the model accumulated total grid scale precipitation at 12-km and 4-km scales with the observed precipitation at several stations in the lower plain, indicated small negative biases (underprediction) in all of the schemes. The Purdue-Lin and Weather Research and Forecasting Double-Moment 6-Class microphysics schemes contained the smallest root mean squared errors.Conclusion:The Purdue-Lin and Weather Research and Forecasting Double-Moment 6-Class schemes provided several insights into the dynamics of the snowstorm. A topographic convergence zone, seeder-feeder mechanism, and convective instability were major factors contributing to the heavy snowfall in the lower plain.

Wind modelling, validation and sensitivity study using Weather Research and Forecasting model in complex terrain

2017 ◽  
Vol 90 ◽  
pp. 107-125 ◽  
Author(s):  
Muhammad Omer Mughal ◽  
Mervyn Lynch ◽  
Frank Yu ◽  
Brendan McGann ◽  
Francois Jeanneret ◽  
...  
Keyword(s):  
Complex Terrain ◽  
Sensitivity Study ◽  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Weather Research

scholarly journals Community Support and Transition of Research to Operations for the Hurricane Weather Research and Forecasting Model

2015 ◽  
Vol 96 (6) ◽  
pp. 953-960 ◽  
Author(s):  
L. Bernardet ◽  
V. Tallapragada ◽  
S. Bao ◽  
S. Trahan ◽  
Y. Kwon ◽  
...  
Keyword(s):  
Multicomponent System ◽  
Community Support ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Environmental Modeling ◽  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Developmental Cycle ◽  
Distributed Development ◽  
Weather Research

Abstract The Hurricane Weather Research and Forecasting Model (HWRF) is an operational model used to provide numerical guidance in support of tropical cyclone forecasting at the National Hurricane Center. HWRF is a complex multicomponent system, consisting of the Weather Research and Forecasting (WRF) atmospheric model coupled to the Princeton Ocean Model for Tropical Cyclones (POM-TC), a sophisticated initialization package including a data assimilation system and a set of postprocessing and vortex tracking tools. HWRF’s development is centralized at the Environmental Modeling Center of NOAA’s National Weather Service, but it incorporates contributions from a variety of scientists spread out over several governmental laboratories and academic institutions. This distributed development scenario poses significant challenges: a large number of scientists need to learn how to use the model, operational and research codes need to stay synchronized to avoid divergence, and promising new capabilities need to be tested for operational consideration. This article describes how the Developmental Testbed Center has engaged in the HWRF developmental cycle in the last three years and the services it provides to the community in using and developing HWRF.

scholarly journals Influence of Bulk Microphysics Schemes upon Weather Research and Forecasting (WRF) Version 3.6.1 Nor'easter Simulations

2016 ◽  
Author(s):  
Stephen D. Nicholls ◽  
Steven G. Decker ◽  
Wei-Kuo Tao ◽  
Stephen E. Lang ◽  
Jainn J. Shi ◽  
...  
Keyword(s):  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Large Variability ◽  
Mixing Ratios ◽  
Simulated Precipitation ◽  
Single Moment ◽  
Double Moment ◽  
Order Of Magnitude ◽  
The Impact ◽  
Weather Research

Abstract. This study evaluated the impact of five, single- or double- moment bulk microphysics schemes (BMPS) on Weather Research and Forecasting (WRF) model (version 3.6.1) winter storm simulations. Model simulations were integrated for 180 hours, starting 72 hours prior to the first measurable precipitation in the highly populated Mid-Atlantic U.S. Simulated precipitation fields were well-matched to precipitation products. However, total accumulations tended to be over biased (1.10–2.10) and exhibited low-to-moderate threat scores (0.27–0.59). Non-frozen hydrometeor species from single-moment BMPS produced similar mixing ratio profiles and maximum saturation levels due to a common parameterization heritage. Greater variability occurred with frozen microphysical species due to varying assumptions among BMPSs regarding ice supersaturation amounts, the dry collection of snow by graupel, various ice collection efficiencies, snow and graupel density and size mappings/intercept parameters, and hydrometeor terminal velocities. The addition of double-moment rain and cloud water resulted in minimal change to species spatial extent or maximum saturation level, however rain mixing ratios tended higher. Although hydrometeor differences varied by up to an order of magnitude among the BMPSs, similarly large variability was not upscaled to mesoscale and synoptic scales.

scholarly journals Influence of bulk microphysics schemes upon Weather Research and Forecasting (WRF) version 3.6.1 nor'easter simulations

2017 ◽  
Vol 10 (2) ◽  
pp. 1033-1049 ◽  
Author(s):  
Stephen D. Nicholls ◽  
Steven G. Decker ◽  
Wei-Kuo Tao ◽  
Stephen E. Lang ◽  
Jainn J. Shi ◽  
...  
Keyword(s):  
Radar Reflectivity ◽  
Spatiotemporal Variability ◽  
Weather Research And Forecasting ◽  
Mixing Ratios ◽  
The North ◽  
Simulated Precipitation ◽  
Double Moment ◽  
Reflectivity Data ◽  
The Impact ◽  
Weather Research

Abstract. This study evaluated the impact of five single- or double-moment bulk microphysics schemes (BMPSs) on Weather Research and Forecasting model (WRF) simulations of seven intense wintertime cyclones impacting the mid-Atlantic United States; 5-day long WRF simulations were initialized roughly 24 h prior to the onset of coastal cyclogenesis off the North Carolina coastline. In all, 35 model simulations (five BMPSs and seven cases) were run and their associated microphysics-related storm properties (hydrometer mixing ratios, precipitation, and radar reflectivity) were evaluated against model analysis and available gridded radar and ground-based precipitation products. Inter-BMPS comparisons of column-integrated mixing ratios and mixing ratio profiles reveal little variability in non-frozen hydrometeor species due to their shared programming heritage, yet their assumptions concerning snow and graupel intercepts, ice supersaturation, snow and graupel density maps, and terminal velocities led to considerable variability in both simulated frozen hydrometeor species and radar reflectivity. WRF-simulated precipitation fields exhibit minor spatiotemporal variability amongst BMPSs, yet their spatial extent is largely conserved. Compared to ground-based precipitation data, WRF simulations demonstrate low-to-moderate (0.217–0.414) threat scores and a rainfall distribution shifted toward higher values. Finally, an analysis of WRF and gridded radar reflectivity data via contoured frequency with altitude diagrams (CFADs) reveals notable variability amongst BMPSs, where better performing schemes favored lower graupel mixing ratios and better underlying aggregation assumptions.

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