Evaluation of WRF Cloud Microphysics Schemes Using Radar Observations

Min, Ki‐Hong; Choo, Sunhee; Lee, Daehyung; Lee, GyuWon

doi:10.1175/waf-d-14-00095.1

Cited by 48 publications

(49 citation statements)

References 27 publications

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“…Zhang, NOAA, personal communication, 2016). Domain 4-based CFADs (not shown) depict little to no aggregation and are inconsistent with CFADs from previous convection Min et al, 2015) and midlatitude winter storm (Shi et al, 2010) studies. The larger spatial extent and better radar overlap in domain 3 leads to more realistic CFADs with aggregation.…”

Section: Stage IV Precipitation Analysiscontrasting

confidence: 76%

“…Shown radar reflectivity differences are as indicated. Min et al, 2015) and occurs due to errors stemming from increased entrainment of ambient air near cloud top and underlying aggregation assumptions made by each BMPS. Although each scheme fully collapses by 7500 m a.m.s.l., the Goddard-based CFADs indicate a considerably steeper tilt in the maximum frequency core as compared to other schemes, which is a likely byproduct of its higher snowfall mixing ratios (Fig.…”

Section: Mrms and Radar Reflectivity Analysismentioning

confidence: 99%

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

Nicholls¹,

Decker²,

Tao³

et al. 2017

Geosci. Model Dev.

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Abstract. This study evaluated the impact of five singleor double-moment bulk microphysics schemes (BMPSs) on Weather Research and Forecasting model (WRF) simulations of seven intense wintertime cyclones impacting the midAtlantic 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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Section: Stage IV Precipitation Analysiscontrasting

confidence: 76%

Section: Mrms and Radar Reflectivity Analysismentioning

confidence: 99%

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

Nicholls¹,

Decker²,

Tao³

et al. 2017

Geosci. Model Dev.

View full text Add to dashboard Cite

show abstract

“…CFADs are not shown here because NOAA radar quality control measures for nonprecipitating echoes tend to artificially curtail radar echoes at 5 dBZ, especially near the dataset edges (Jian Zhang, NOAA, personal communication). Domain 4-based CFADs (not shown) depict little to no aggregation and are inconsistent with CFADs from previous convection , Min et al 2015 and mid-latitude winter storm (Shi et al 2010) studies. The larger spatial extent and better radar overlap in Domain 3 leads to more realistic CFADs with aggregation.…”

Section: Stage IV Precipitation Analysiscontrasting

confidence: 73%

“…Above 6,000 m AMSL the WRF-based CFADs all collapse toward smaller reflectivity values. This collapse is well documented in the literature (Shi et al 2010;Lang et al 2011, Min et al 2015 and occurs due to errors stemming from increased entrainment of ambient air near cloud top and underlying aggregation assumptions made by each BMPS. Although each scheme fully collapses by 7,500 m AMSL, the Goddard-based CFADs indicate a considerably steeper tilt in the maximum frequency core as compared to other schemes, which is a likely byproduct of its higher snowfall mixing ratios (Fig.…”

Section: Nasa Author Manuscriptmentioning

confidence: 61%

Response to Reviewer2

Nicholls¹

2016

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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 winter time cyclones impacting the Mid-Atlantic United States. Five-day long WRF simulations were initialized roughly 24 hours prior to the onset of coastal cyclogenesis off the North Carolina coastline. In all, 35 model simulations (5 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 lead to considerable variability in both simulated frozen hydrometeor species and radar reflectivity. WRF-simulated precipitation fields exhibit minor spatio-temporal 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 (CFAD) diagrams reveals notable variability amongst BMPSs, where Correspondence to: Stephen D. Nicholls (stephen.d.nicholls@nasa.gov). brought their extensive knowledge and expertise on model microphysics, which helped shape the project methodology and rationalize the results. Finally, K. I. Mohr helped to facilitate connections between the research team, supervised S. Nicholls' research, and was pivotal in revising the manuscript. better performing schemes favored lower graupel mixing ratios and better underlying aggregation assumptions.

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“…Ground weather radar is a straightforward and convenient tool for testing the representation of clouds in numerical weather prediction models. It has been used to test microphysical (Caine et al, ; Min et al, ) and convective parameterization schemes (Niemelä et al, ). As the viewing area of the radar was narrow below 1.7 km, we limited our analysis to the model layers centered above this level.…”

Section: Results: Meteorologymentioning

confidence: 99%

Observations and Cloud‐Resolving Modeling of Haboob Dust Storms Over the Arabian Peninsula

et al. 2018

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Strong mesoscale haboob dust storms in April 2007 in the central Arabian Peninsula were studied using the cloud-resolving Weather Research and Forecasting-Chemistry (WRF-Chem) modeling system and observations collected during an intensive atmospheric field campaign. The field campaign provided the valuable aircraft and Doppler weather radar measurements. Active convection persisted for several days during the study period. Dust generation was caused by both strong large-scale winds and locally produced density currents. Because of insufficient spatial resolution, the event was not resolved accurately by the conventional reanalyses. However, the WRF-Chem model did successfully capture the primary features of the convection, its location, and precipitation patterns. Although the amount of rainfall in the model was slightly underestimated compared to the satellite measurements, it was approximately double the rainfall in the reanalysis. The convection-associated dust outbreaks were simulated well, with the aerosols optical depth magnitude and the temporal variability being in good agreement with both the ground-based and satellite aerosol retrievals. The model captured the major dust generation patterns, transport pathways, and several of the largest haboobs identified from the satellite observations. About 25 Tg of dust was emitted in the Arabian Peninsula during the 10-day period. Approximately 40% of the locally deposited dust was subject to wet removal processes. During periods of high local dust production, the WRF-Chem model underestimated the PM 10 mass concentration (associated mostly with dust particles larger than 3 μm in diameter) by nearly a factor of 2. This suggests that the current dust parameterizations, which prescribe the size distribution of the emitted dust, underestimate the number of large particles that increases at strong wind conditions.Plain Language Summary In this study, we use a sophisticated numerical model of atmospheric circulation with an aerosol component to simulate a series of local-scale haboob dust storms that occurred in the central Arabian Peninsula during April 2007. This type of dust storm is associated with a cold air outflow from thunderstorms and is specific to the wet spring season in this region. We compare the model results with the data obtained from aircraft and meteorological radar during a field campaign conducted at that time. The high-resolution model produces good results that capture the atmospheric convection, rainfall features, and major dust outbreaks recorded at a ground station in Riyadh. We demonstrate that it performs better than other global reanalysis products. However, our results show that the aerosol component of the numerical model needs to be improved, as the model underestimates the concentration of coarse dust particles. This is caused by the uncertainties introduced when prescribing the physical properties of dust aerosols generated from the surface.

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Evaluation of WRF Cloud Microphysics Schemes Using Radar Observations

Cited by 48 publications

References 27 publications

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

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

Response to Reviewer2

Observations and Cloud‐Resolving Modeling of Haboob Dust Storms Over the Arabian Peninsula

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