Improving the representation of clouds, radiation, and precipitation using spectral nudging in the Weather Research and Forecasting model

Spero, Tanya L.; Otte, Martin J.; Bowden, Jared H.; Nolte, Christopher G.

doi:10.1002/2014jd022173

Cited by 45 publications

(46 citation statements)

References 43 publications

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“…Spectral nudging has proven to be dampening physical parameterizations variability less than analysis nudging [59]. Also, studies for regional climate modelling have shown that analysis nudging is less efficient for sensitivity analyses in high resolution as it results in extinguishing fine-scale variability [60]. Additionally, spectral nudging can fade out extreme events as it drives the model toward a smoother, larger-scale state [61].…”

Section: Spectral Nudgingmentioning

confidence: 99%

Analysis of a Mediterranean Tropical-Like Cyclone. Sensitivity to WRF Parameterizations and Horizontal Resolution

et al. 2019

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Due to their rarity and intensity, Mediterranean Tropical-Like Cyclones (TLCs; also known as medicanes) have been a subject of study over the last decades and lately the interest has undoubtedly grown. The current study investigates a well-documented TLC event crossed south Sicily on November 7-8, 2014 and the added value of higher spatial horizontal resolution through a physics parameterization sensitivity analysis. For this purpose, Weather Research and Forecasting model (version 3.9) is used to dynamically downscale ECMWF Re-Analysis (version 5) (ERA5) reanalysis 31 km spatial resolution to 16 km and 4 km, as parent and inner domain, respectively. In order to increase the variability and disparity of the results, spectral nudging was implemented on both domains and the outputs were compared against satellite observations and ground-based stations. Although, the study produces mixed results, there is a clear indication that the increase of resolution benefits specific aspects of the cyclone, while it deteriorates others, based on both ground and upper air analyses. The sensitivity of the parent domain displays an overall weak variability while the simulations demonstrate a positive time-lag predicting a less symmetric cyclone with weak warm core. On the contrary, inner domain analysis shows stronger variability between the model simulations reproducing more distinct clear tropical characteristics with less delayed TLC development for most of the experiments.

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Section: Spectral Nudgingmentioning

confidence: 99%

Analysis of a Mediterranean Tropical-Like Cyclone. Sensitivity to WRF Parameterizations and Horizontal Resolution

et al. 2019

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“…Successfully constraining the mesoscale simulation to follow the synoptic-scale driving fields by spectral nudging was key to reproducing the precipitation in the southern Great Plains in our case. This benefit, while maintaining the ability of the mesoscale models to develop small-scale dynamics, allowed successful applications of spectral nudging in dynamical downscaling of precipitation (García-Valdecasas Ojeda et al, 2017;Huang et al, 2016;Liu et al, 2012;Lo et al, 2008;Mabuchi et al, 2002;Miguez-Macho et al, 2004;Paul et al, 2016;Spero et al, 2014;von Storch et al, 2000). To achieve the best simulation of August precipitation climatology in this study, we used the spectral nudging configurations (including nudging strength, nudging height, and wave numbers) as suggested by Wang and Kotamarthi (2014) on the WRF downscaling simulations for the August of all 14 years.…”

Section: High-resolution Dynamic Downscaling Of August Climatementioning

confidence: 99%

The Importance of Soil‐Type Contrast in Modulating August Precipitation Distribution Near the Edwards Plateau and Balcones Escarpment in Texas

Xue

McPherson

2017

JGR Atmospheres

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The Balcones Escarpment in central Texas is a sloped region between the Edwards Plateau and the coastal plain. The metropolitan areas located along the Balcones Escarpment (e.g., San Antonio, Austin, and Dallas‐Fort Worth) are prone to heavy rain and devastating flood events. While the associated hydrological issues of the Balcones Escarpment have been extensively studied, the meteorological impacts of the Edwards Plateau and Balcones Escarpment are not well understood. The indeterminate impacts of the thermal and dynamic effects of the Edwards Plateau on August climatological precipitation are investigated in this study using the multisensor Stage IV precipitation data, high‐resolution dynamic downscaling, and short‐term sensitivity simulations. Analysis results indicate that the total August precipitation east of the Balcones Escarpment is suppressed and precipitation over the eastern part of the Edwards Plateau is enhanced. Locally initiated moist convection in the afternoon contributes most to the total precipitation during August in the region. The dynamic downscaling output captures the spatial pattern of afternoon precipitation, which is well aligned with the simulated upward motions. The clay‐based soil types that dominate the Edwards Plateau have great potential to retain soil moisture and limit latent heat fluxes, consequently leading to higher sensible heat flux than over the plain to the east. As a result, vertical motion is induced, triggering the afternoon moist convection over the Edwards Plateau under favorable conditions. In comparison, the sloping terrain plays a smaller role in triggering the convection. Short‐term sensitivity simulations for a clear day confirm and further prove such a diagnosis.

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“…However, in general, there exist large uncertainties with dynamic downscaling. RCMs have been found to be sensitive to spatial resolution (Lee et al, ; Tripathi & Dominguez, ; Yamada et al, ), nudging strategies (Bowden et al, ; Bullock et al, ; Harkey & Holloway, ; Liu et al, ; Miguez‐Macho et al, ; Omrani et al, ; Otte et al, ; Spero et al, ; Wang & Kotamarthi, ), model reinitialization frequency (Lo et al, ; Pan et al, ; Qian et al, ), and physics parameterizations such as cumulus schemes (Choi et al, ; Gochis et al, ; Liang et al, ; Pohl et al, ; Qiao & Liang, ) and land surface models (Bukovsky & Karoly, ; Chen et al, ; Vidale et al, ). Given these uncertainties, confidence in RCM‐downscaled projections of future climate can only be achieved when the credibility of RCM downscaling of historical climate has been proven (Gutowski et al, ; Harding & Snyder, ; Kendon et al, ; Liang et al, ; Mearns et al, ; Wehner, ; Xue et al, ).…”

Section: Introductionmentioning

confidence: 99%

Precipitation Dynamical Downscaling Over the Great Plains

Xue

McPherson

et al. 2018

J Adv Model Earth Syst

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Detailed, regional climate projections, particularly for precipitation, are critical for many applications. Accurate precipitation downscaling in the United States Great Plains remains a great challenge for most Regional Climate Models, particularly for warm months. Most previous dynamic downscaling simulations significantly underestimate warm‐season precipitation in the region. This study aims to achieve a better precipitation downscaling in the Great Plains with the Weather Research and Forecast (WRF) model. To this end, WRF simulations with different physics schemes and nudging strategies are first conducted for a representative warm season. Results show that different cumulus schemes lead to more pronounced difference in simulated precipitation than other tested physics schemes. Simply choosing different physics schemes is not enough to alleviate the dry bias over the southern Great Plains, which is related to an anticyclonic circulation anomaly over the central and western parts of continental U.S. in the simulations. Spectral nudging emerges as an effective solution for alleviating the precipitation bias. Spectral nudging ensures that large and synoptic‐scale circulations are faithfully reproduced while still allowing WRF to develop small‐scale dynamics, thus effectively suppressing the large‐scale circulation anomaly in the downscaling. As a result, a better precipitation downscaling is achieved. With the carefully validated configurations, WRF downscaling is conducted for 1980–2015. The downscaling captures well the spatial distribution of monthly climatology precipitation and the monthly/yearly variability, showing improvement over at least two previously published precipitation downscaling studies. With the improved precipitation downscaling, a better hydrological simulation over the trans‐state Oologah watershed is also achieved.

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Improving the representation of clouds, radiation, and precipitation using spectral nudging in the Weather Research and Forecasting model

Cited by 45 publications

References 43 publications

Analysis of a Mediterranean Tropical-Like Cyclone. Sensitivity to WRF Parameterizations and Horizontal Resolution

Analysis of a Mediterranean Tropical-Like Cyclone. Sensitivity to WRF Parameterizations and Horizontal Resolution

The Importance of Soil‐Type Contrast in Modulating August Precipitation Distribution Near the Edwards Plateau and Balcones Escarpment in Texas

Precipitation Dynamical Downscaling Over the Great Plains

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