Monthly Weather Review最新文献_第5页

Evaluation of probabilistic forecasts of binary events with the Neighborhood Brier Divergence Skill Score 用邻域布赖尔分歧技能得分评估二元事件的概率预测

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-14 DOI: 10.1175/mwr-d-22-0235.1

Joël Stein, Fabien Stoop

{"title":"Evaluation of probabilistic forecasts of binary events with the Neighborhood Brier Divergence Skill Score","authors":"Joël Stein, Fabien Stoop","doi":"10.1175/mwr-d-22-0235.1","DOIUrl":"https://doi.org/10.1175/mwr-d-22-0235.1","url":null,"abstract":"\u0000A procedure for evaluating the quality of probabilistic forecasts of binary events has been developed. This is based on a two-step procedure: pooling of forecasts on the one hand and observations on the other, on all the points of a neighborhood in order to obtain frequencies at the neighborhood length scale and then to calculate the Brier divergence for these neighborhood frequencies. This score allows the comparison of a probabilistic forecast and observations at the neighborhood length scale and therefore the rewarding of event forecasts shifted from the location of the observed event by a distance smaller than the neighborhood size. A new decomposition of this score generalizes that of the Brier score and allows the separation of the generalized resolution, reliability and uncertainty terms. The Neighborhood Brier Divergence Skill Score BDnSS measures the performance of the probabilistic forecast against the sample climatology. BDnSS and its decomposition have been used for idealized and real cases in order to show the utility of neighborhoods when comparing at different scales the performances of ensemble forecasts between themselves or with deterministic forecasts or of deterministic forecasts between themselves.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140242905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assimilation of radar reflectivity via a full-hydrometeor assimilation scheme based on the WSM6 microphysics scheme in WRF 4D-Var 通过基于 WRF 4D-Var 中 WSM6 微物理方案的全流体流星同化方案同化雷达反射率

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-11 DOI: 10.1175/mwr-d-23-0137.1

Sen Yang, Deqin Li, Xiang-yu Huang, Zhiquan Liu, Xiao Pan, Yunxia Duan

{"title":"Assimilation of radar reflectivity via a full-hydrometeor assimilation scheme based on the WSM6 microphysics scheme in WRF 4D-Var","authors":"Sen Yang, Deqin Li, Xiang-yu Huang, Zhiquan Liu, Xiao Pan, Yunxia Duan","doi":"10.1175/mwr-d-23-0137.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0137.1","url":null,"abstract":"\u0000The microphysical parameterization scheme employed in four-dimensional variational data assimilation (4D-Var) plays an important role in the assimilation of humidity and cloud-sensitive observations. In this study, a newly developed full-hydrometeor assimilation scheme, integrating warm-rain and cold-cloud processes, has been implemented in the Weather Research and Forecasting (WRF) 4D-Var system. This scheme is based on the WSM6 single-moment microphysical parameterization scheme. Its primary objective is to directly assimilate radar reflectivity observations, with the goal of evaluating its effects on model initialization and subsequent forecasting performance. Four assimilation experiments were conducted to assess the performance of the full-hydrometeor assimilation scheme against the warm-rain assimilation scheme. These experiments also investigated reflectivity assimilation using both indirect and direct methods. We found that the nonlinearity of the radar operator in the two directly reflectivity assimilation experiments requires more iterations for cost function reduction than in indirect assimilation method. The hydrometeor fields were reasonably analyzed using the full-hydrometeor assimilation scheme, particularly improving the simulation of ice-phase hydrometeors and reflectivity above the melting layer. The assimilation of radar reflectivity led to improvements in short-term (0-3 hour) precipitation forecasting with the full-hydrometeor assimilation scheme. Assimilation experiments across multiple case studies reaffirmed that assimilating radar reflectivity observations with the full-hydrometeor assimilation scheme can accelerated model spin-up and yielded enhancements in 0-3 hour total accumulate precipitation forecasts for a range of precipitation thresholds.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140253490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Sensitivity of Supercell Cold Pools to the Lifting Condensation Level and the Predicted Particle Properties Microphysics Scheme 超级暴风雪冷池对提升凝结水平和预测粒子特性微观物理方案的敏感性

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-11 DOI: 10.1175/mwr-d-23-0092.1

S. Murdzek, Yvette P. Richardson, P. Markowski

{"title":"The Sensitivity of Supercell Cold Pools to the Lifting Condensation Level and the Predicted Particle Properties Microphysics Scheme","authors":"S. Murdzek, Yvette P. Richardson, P. Markowski","doi":"10.1175/mwr-d-23-0092.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0092.1","url":null,"abstract":"\u0000Previous work found that cold pools in ordinary convection are more sensitive to the microphysics scheme when the lifting condensation level (LCL) is higher owing to a greater evaporation potential, which magnifies microphysical uncertainties. In the current study, we explore whether the same reasoning can be applied to supercellular cold pools. To do this, four perturbed-microphysics ensembles are run, with each using an environment with a different LCL. Similar to ordinary convection, the sensitivity of supercellular cold pools to the microphysics increases with higher LCLs, though the physical reasoning for this increase in sensitivity differs from a previous study. Using buoyancy budgets along parcel trajectories that terminate in the cold pool, we find that negative buoyancy generated by microphysical cooling is partially countered by a decrease in environmental potential temperatures as the parcel descends. This partial erosion of negative buoyancy as parcels descend is most pronounced in the low-LCL storms, which have steeper vertical profiles of environmental potential temperature in the lower atmosphere. When this erosion is accounted for, the strength of the strongest cold pools in the low-LCL ensemble is reduced, resulting in a narrower distribution of cold pool strengths. This narrower distribution is indicative of reduced sensitivity to the microphysics. These results suggest that supercell behavior and supercell hazards (e.g., tornadoes) may be more predictable in low-LCL environments.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140253963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Observed sub-daily variations in air–sea turbulent heat fluxes under different marine atmospheric boundary layer stability conditions in the Gulf Stream 湾流中不同海洋大气边界层稳定性条件下观测到的海气湍流热通量亚日变化

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-11 DOI: 10.1175/mwr-d-24-0003.1

Xiangzhou Song, Xuehan Xie, Yunwei Yan, Shang‐Ping Xie

{"title":"Observed sub-daily variations in air–sea turbulent heat fluxes under different marine atmospheric boundary layer stability conditions in the Gulf Stream","authors":"Xiangzhou Song, Xuehan Xie, Yunwei Yan, Shang‐Ping Xie","doi":"10.1175/mwr-d-24-0003.1","DOIUrl":"https://doi.org/10.1175/mwr-d-24-0003.1","url":null,"abstract":"\u0000Based on data collected from 14 buoys in the Gulf Stream, this study examines how hourly air–sea turbulent heat fluxes vary on sub-daily timescales under different boundary layer stability conditions. The annual mean magnitudes of the sub-daily variations in latent and sensible heat fluxes at all stations are 40 and 15 W·m−2, respectively. Under near-neutral conditions, hourly fluctuations in air–sea humidity and temperature differences are the major drivers of sub-daily variations in latent and sensible heat fluxes, respectively. When the boundary layer is stable, on the other hand, wind anomalies play a dominant role in shaping the sub-daily variations in latent and sensible heat fluxes. In the context of a convectively unstable boundary layer, wind anomalies exert a strong controlling influence on sub-daily variations in latent heat fluxes, whereas sub-daily variations in sensible heat fluxes are equally determined by air–sea temperature difference and wind anomalies. The relative contributions by all physical quantities that affect sub-daily variations in turbulent heat fluxes are further documented. For near-neutral and unstable boundary layers, the sub-daily contributions are О(2) and О(1) W·m−2 for latent and sensible heat fluxes, respectively, and they are less than О(1) W·m−2 for turbulent heat fluxes under stable conditions.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140252136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Stochastic Statistical Model for U.S. Outbreak-level Tornado Occurrence based on the Large-scale Environment 基于大尺度环境的美国爆发级龙卷风发生率随机统计模型

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-06 DOI: 10.1175/mwr-d-23-0219.1

Kelsey Malloy, Michael K. Tippett

{"title":"A Stochastic Statistical Model for U.S. Outbreak-level Tornado Occurrence based on the Large-scale Environment","authors":"Kelsey Malloy, Michael K. Tippett","doi":"10.1175/mwr-d-23-0219.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0219.1","url":null,"abstract":"\u0000Tornado outbreaks — when multiple tornadoes occur within a short period of time — are rare yet impactful events. Here we developed a two-part stochastic tornado outbreak index for the contiguous United States (CONUS). The first component produces a probability map for outbreak tornado occurrence based on spatially-resolved values of convective precipitation, storm relative helicity (SRH), and convective available potential energy. The second part of the index provides a probability distribution for the total number of tornadoes given the outbreak tornado probability map. Together these two components allow stochastic simulation of location and number of tornadoes that is consistent with environmental conditions. Storm report data from the Storm Prediction Center for 1979–2021 period are used to train the model and evaluate its performance. In the first component, the probability of an outbreak-level tornado is most sensitive to SRH changes. In the second component, the total number of CONUS tornadoes depends on the sum and grid point maximum of the probability map. Overall, the tornado outbreak index represents the climatology, seasonal cycle, and interannual variability of tornado outbreak activity well, particularly over regions and seasons when tornado outbreaks occur most often. We found that the El Niño-Southern Oscillation (ENSO) modulates the tornado outbreak index such that La Niña is associated with enhanced U.S. tornado outbreak activity over the Ohio River Valley and Tennessee River Valley regions during January through March, similar to the behavior seen in storm report data. We also found an upward trend in U.S. tornado outbreak activity during winter and spring for the 1979–2021 period using both observations and the index.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140262845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Data assimilation impact of GNSS RO measurements from cube satellites on Arctic weather forecasts 立方体卫星的全球导航卫星系统 RO 测量数据同化对北极天气预报的影响

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-06 DOI: 10.1175/mwr-d-23-0146.1

Yonghan Choi, Joo-Hong Kim, Joo-Hong Kim, Dong-Hyun Cha

{"title":"Data assimilation impact of GNSS RO measurements from cube satellites on Arctic weather forecasts","authors":"Yonghan Choi, Joo-Hong Kim, Joo-Hong Kim, Dong-Hyun Cha","doi":"10.1175/mwr-d-23-0146.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0146.1","url":null,"abstract":"\u0000In this study, the effects of assimilating global navigation satellite system (GNSS) radio occultation (RO) observations from existing and recently added commercial cube satellites on analyses and forecasts over the Arctic region were investigated by conducting observing system experiments (OSEs). Profiles of refractivity were assimilated with a local observation operator using the three-dimensional variational method. The analyses and forecasts from the OSEs were verified against ERA5 reanalysis, radiosonde observations, and buoy observations. In addition to the averaged impact on forecast skill, the impact of GNSS RO observations was further examined for an individual Arctic cyclone case, focusing on the added value of the cube satellite data.\u0000The effects of GNSS RO observations from existing satellites on analyses and forecasts over the Arctic region are positive, and the assimilation of GNSS RO observations from cube satellites leads to additional improvements, particularly for temperature in the upper troposphere and lower stratosphere (UTLS). Temperature biases in the UTLS are significantly reduced in the analyses, and the improved analyses result in better forecasts of upper-level potential vorticity and cyclone development when GNSS RO observations from cube satellites are assimilated. This result demonstrates the potential of GNSS RO data from cube satellites to enhance forecasts over the Arctic region.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140261519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Iterative ensemble smoothers for data assimilation in coupled nonlinear multiscale models 耦合非线性多尺度模型数据同化的迭代集合平滑器

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-05 DOI: 10.1175/mwr-d-23-0239.1

G. Evensen, F. Vossepoel, Peter Jan van Leeuwen

{"title":"Iterative ensemble smoothers for data assimilation in coupled nonlinear multiscale models","authors":"G. Evensen, F. Vossepoel, Peter Jan van Leeuwen","doi":"10.1175/mwr-d-23-0239.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0239.1","url":null,"abstract":"\u0000This paper identifies and explains particular differences and properties of adjoint-free iterative ensemble methods initially developed for parameter estimation in petroleum models. The aim is to demonstrate the methods’ potential for sequential data assimilation in coupled and multiscale unstable dynamical systems. For this study, we have introduced a new nonlinear and coupled multiscale model based on two Kuramoto-Sivashinsky equations operating on different scales where a coupling term relaxes the two model variables towards each other. This model provides a convenient testbed for studying data assimilation in highly nonlinear and coupled multiscale systems. We show that the model coupling leads to cross-covariance between the two models’ variables, allowing for a combined update of both models. The measurements of one model’s variable will also influence the other and contribute to a more consistent estimate. Secondly, the new model allows us to examine the properties of iterative ensemble smoothers and assimilation updates over finite-length assimilation windows. We discuss the impact of varying the assimilation windows’ length relative to the model’s predictability time scale. Furthermore, we show that iterative ensemble smoothers significantly improve the solution’s accuracy compared to the standard ensemble-Kalman-filter update. Results and discussions provide an enhanced understanding of the ensemble methods’ potential implementation and use in operational weather and climate-prediction systems.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140263168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Water vapor lidar observation and data assimilation for a moist low-level jet triggering a mesoscale convective system 针对引发中尺度对流系统的潮湿低空喷流的水汽激光雷达观测和数据同化

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-03-05 DOI: 10.1175/mwr-d-23-0094.1

Satoru Yoshida, Tetsu Sakai, Tomohiro Nagai, Yasutaka Ikuta, Teruyuki Kato, Koichi Shiraishi, Ryohei Kato, H. Seko

{"title":"Water vapor lidar observation and data assimilation for a moist low-level jet triggering a mesoscale convective system","authors":"Satoru Yoshida, Tetsu Sakai, Tomohiro Nagai, Yasutaka Ikuta, Teruyuki Kato, Koichi Shiraishi, Ryohei Kato, H. Seko","doi":"10.1175/mwr-d-23-0094.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0094.1","url":null,"abstract":"\u0000We conducted field observations using two water vapor Raman lidars (RLs) in Kyushu, Japan, to clarify the characteristics of a moist low-level jet (MLLJ), which plays a fundamental role in the formation and maintenance of mesoscale convective systems (MCSs). The two RLs observed the inside and outside of an MLLJ, providing moisture to an MCS with local heavy precipitation on 9 July 2021. Our observations revealed that the MLLJ contained large amounts of moisture below the convective mixing layer height of 1.6 km. The large amount of the moisture in the MLLJ might be intensified by low-level convergences and/or water vapor buoyancy facilitated by strong horizontal wind. We conducted four data assimilation experiments; CNTL assimilated Japan Meteorological Agency operational observation data, and other three experiments that ingested the lidar-derived vertical moisture profiles as well as the operational observation data. The experiments assimilating lidar-derived vertical moisture profiles caused intensification and southwestward extensions of the low-level convergence zone, resulting in local heavy precipitation at lower latitudes in experiments assimilating lidar-derived moisture profiles than in CNTL. All three experiments ingesting vertical moisture profiles generally produced better nine-hour precipitation forecasts than CNTL, implying that the assimilation of vertical moisture profiles could be well suited for numerical weather prediction of local heavy precipitation. Moreover, experiment assimilating both two RL sites data reproduced better forecast fields than experiments assimilating single RL site data, implying that data assimilation of vertical moisture profiles at multiple RL sites enables us to improve initial conditions compared to single RL site.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140264096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Why was the weakening of Typhoon IN-FA (2021) to the east of Taiwan Island not forecasted in the GFS? 为什么 GFS 没有预测到台风 IN-FA（2021 年）在台湾岛以东减弱？

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-28 DOI: 10.1175/mwr-d-22-0262.1

Jia-yi Liang, Liguang Wu, Chunyi Xiang, Qingyuan Liu

{"title":"Why was the weakening of Typhoon IN-FA (2021) to the east of Taiwan Island not forecasted in the GFS?","authors":"Jia-yi Liang, Liguang Wu, Chunyi Xiang, Qingyuan Liu","doi":"10.1175/mwr-d-22-0262.1","DOIUrl":"https://doi.org/10.1175/mwr-d-22-0262.1","url":null,"abstract":"\u0000Typhoon IN-FA (2021) experienced a weakening process on July 22–23 in a large-scale environment favorable for tropical cyclone (TC) intensification. All operational forecasts and the Global Forecast System (GFS) forecasts predicted a continuous intensification, which deviated significantly from the observation. The analysis of the GFS analysis product shows a coalescence process of Typhoon IN-FA with an intraseasonal monsoon gyre during the period, resulting in an increased outer size of IN-FA and well-organized convection to the east, which prevented transporting the mass and moisture into the inner-core area of IN-FA, thus leading to the weakening. Nevertheless, this essential coalescence process was not captured in the GFS forecasts due to the poor prediction of the monsoon gyre. The analysis shows that the forecasted monsoon gyre on July 20–22 had an eastward location at 72 h and 96 h lead times and a weaker intensity and outer circulation at 24 h and 48 h lead times, leading to the forecasted TC always moving in its north and west, in agreement with numerical simulation results that the monsoon gyre with a weaker outer circulation is not conducive to the coalescence. Thus, the deep convection to the east of IN-FA preventing the inward transportation of mass and moisture did not develop in the GFS forecasts. As a result, the GFS forecasted that IN-FA would continue intensifying in a favorable environment on July 22–23. The findings of this study would prompt forecasters to pay attention to the prediction of the monsoon gyre and its influence on the TC intensity in forecast products available to them.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140419576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the Sensitivity of Large Eddy Simulations of the Atmospheric Boundary Layer Coupled with Realistic Large Scale Dynamics 论大气边界层大涡模拟与现实大尺度动力学耦合的敏感性

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-26 DOI: 10.1175/mwr-d-23-0101.1

P. Giani, Paola Crippa

{"title":"On the Sensitivity of Large Eddy Simulations of the Atmospheric Boundary Layer Coupled with Realistic Large Scale Dynamics","authors":"P. Giani, Paola Crippa","doi":"10.1175/mwr-d-23-0101.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0101.1","url":null,"abstract":"\u0000We present a new ensemble of 36 numerical experiments aimed at comprehensively gauging the sensitivity of nested Large Eddy Simulations (LES) driven by large scale dynamics. Specifically, we explore 36 multiscale configurations of the Weather Research and Forecasting (WRF) model to simulate the boundary layer flow over the complex topography at the Perdigão field site, with five nested domains discretized at horizontal resolutions ranging from 11.25 kilometers to 30 meters. Each ensemble member has a unique combination of the following input factors, (i) large-scale initial and boundary conditions, (ii) subgrid turbulence modeling in the gray zone of turbulence, (iii) subgrid-scale (SGS) models in LES simulations and (iv) topography and land cover datasets. We probe their relative importance for LES calculations of velocity, temperature and moisture fields. Variance decomposition analysis unravels large sensitivities to topography and land use datasets and very weak sensitivity to the LES SGS model. Discrepancies within ensemble members can be as large as 2.5 m s−1 for the time-averaged near-surface wind speed on the ridge, and as large as 10 m s−1 without time averaging. At specific time points, a large fraction of this sensitivity can be explained by the different turbulence models in the gray zone domains. We implement a horizontal momentum and moisture budget routine in WRF to further elucidate the mechanisms behind the observed sensitivity, paving the way for an increased understanding of the tangible effects of the gray zone of turbulence problem.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140428034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0