Monthly Weather Review最新文献

Relation Between Baroclinity, Horizontal Vorticity, and Mesocyclone Evolution in the 6-7 April 2018 Monroe, LA Tornadic Supercell During VORTEX-SE 2018年4月6日至7日VORTEX-SE期间洛杉矶门罗龙卷风超级单元的气压、水平涡度和中气旋演化之间的关系

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-09-04 DOI: 10.1175/mwr-d-22-0313.1

Michael J. Hosek, Conrad L. Ziegler, M. Biggerstaff, Todd A. Murphy, Zhien Wang

{"title":"Relation Between Baroclinity, Horizontal Vorticity, and Mesocyclone Evolution in the 6-7 April 2018 Monroe, LA Tornadic Supercell During VORTEX-SE","authors":"Michael J. Hosek, Conrad L. Ziegler, M. Biggerstaff, Todd A. Murphy, Zhien Wang","doi":"10.1175/mwr-d-22-0313.1","DOIUrl":"https://doi.org/10.1175/mwr-d-22-0313.1","url":null,"abstract":"\u0000This case study analyzes a tornadic supercell observed in northeast Louisiana as part of the Verification of the Origins of Rotation in Tornadoes Experiment Southeast (VORTEX-SE) on April 6-7 2018. One mobile research radar (SR1-P), one WSR-88D equivalent (KULM), and two airborne radars (TAFT and TFOR) have sampled the storm at close proximity for ~70 minutes through its mature phase, tornadogenesis at 2340 UTC, and dissipation and subsequent ingestion into a developing MCS segment. The 4-D wind field and reflectivity from up to four-Doppler analyses, combined with 4-D diabatic Lagrangian analysis (DLA, Ziegler 2013a,b) retrievals, has enabled kinematic and thermodynamic analysis of storm-scale boundaries leading up to, during, and after the dissipation of the NWS-surveyed EF-0 tornado.\u0000The kinematic and thermodynamic analyses reveal a transient current of low-level streamwise vorticity leading into the low-level supercell updraft, appearing similar to the streamwise vorticity current (SVC) that has been identified in supercell simulations and previously observed only kinematically. Vorticity dynamical calculations demonstrate that both baroclinity and horizontal stretching play significant roles in the generation and amplification of streamwise vorticity associated with this SVC. While the SVC does not directly feed streamwise vorticity to the tornado-cyclone, its development coincides with tornadogenesis and an intensification of the supercell’s main low-level updraft, although a causal relationship is unclear.\u0000Although the mesoscale environment is not high-shear/low-CAPE (HSLC), the updraft of the analyzed supercell shares some similarities to past observations and simulations of HSLC storms in the Southeast US, most notably a pulse-like updraft which is maximized in the low to mid-levels of the storm.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47544728","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

Identifying Important Microphysical Properties and Processes for Marine Fog Forecasts 确定海洋雾预报的重要微物理特性和过程

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-09-01 DOI: 10.1175/mwr-d-22-0294.1

Nathan Hexum Pope, A. Igel

{"title":"Identifying Important Microphysical Properties and Processes for Marine Fog Forecasts","authors":"Nathan Hexum Pope, A. Igel","doi":"10.1175/mwr-d-22-0294.1","DOIUrl":"https://doi.org/10.1175/mwr-d-22-0294.1","url":null,"abstract":"\u0000In this study, a marine fog event that occurred from 0000 to 1800 UTC 7 September 2018 near Canada’s Grand Banks is used to investigate the sensitivity of simulated fog properties to six model parameters found primarily in the microphysics scheme. To do so, we ran a large suite of regional simulations that spanned the life cycle of the fog event using the Regional Atmospheric Modeling System (RAMS). We randomly selected parameter combinations for the simulation suite and used Gaussian process regression to emulate the response of a variety of simulated fog properties to the parameters. We find that the microphysics shape parameter, which controls the relative width of the droplet size distribution, and the aerosol number concentration have the greatest impact on fog in terms of spatial extent, duration, and surface visibility. In general, parameters that reduce mean fall speed of droplets and/or suppress drizzle formation lead to reduced visibility in fog but also delayed onset, shorter lifetimes, and reduced spatial extent. The importance of the distribution width suggests a need for better characterization of this property for fog droplet distributions and better treatment of this property in microphysics schemes.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47293533","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

Equity, Inclusion, and Justice: An Opportunity for Action for AMS Publications Stakeholders 公平，包容和正义:AMS出版物利益相关者的行动机会

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-09-01 DOI: 10.1175/mwr-d-23-0173.1

引用次数: 0

Comments on “A Climatology of Cell Mergers with Supercells and Their Association with Mesocyclone Evolution” and “The Influence of Cell Mergers on Supercell Characteristics and Tornado Evolution on 27–28 April 2011” 关于“细胞与超级细胞合并的气候学及其与中气旋演化的关系”和“2011年4月27-28日细胞合并对超级细胞特征和龙卷风演化的影响”的评论

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-09-01 DOI: 10.1175/mwr-d-23-0120.1

Jannick Fischer, Matthew D. Flournoy, Anthony W. Lyza

引用次数: 0

Quantifying the impact of vertical resolution on the representation of marine boundary layer physics for global-scale models 量化垂直分辨率对全球尺度模型海洋边界层物理表示的影响

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-08-31 DOI: 10.1175/mwr-d-23-0078.1

M. Smalley, M. Lebsock, J. Teixeira

{"title":"Quantifying the impact of vertical resolution on the representation of marine boundary layer physics for global-scale models","authors":"M. Smalley, M. Lebsock, J. Teixeira","doi":"10.1175/mwr-d-23-0078.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0078.1","url":null,"abstract":"\u0000While GCM horizontal resolution has received the majority of scale improvements in recent years, ample evidence suggests that a model’s vertical resolution exerts a strong control on its ability to accurately simulate the physics of the marine boundary layer. Here we show that, regardless of parameter tuning, the ability of a Single Column Model (SCM) to simulate the subtropical marine boundary layer improves when its vertical resolution is improved. We introduce a novel objective tuning technique to optimize the parameters of a Single Column Model (SCM) against profiles of temperature and moisture and their turbulent fluxes, horizontal winds, cloud water, and rain water from Large Eddy Simulations (LES). We use this method to identify optimal parameters for simulating marine stratocumulus and shallow cumulus. The novel tuning method utilizes an objective performance metric that accounts for the uncertainty in the LES output, including the co-variability between model variables. Optimization is performed independently for different vertical grid spacings and value of time step, ranging from coarse scales often used in current global models (120 m, 180 s) to fine-scales often used in parameterization development and large eddy simulations (10 m, 15 s). Uncertainty-weighted disagreement between the SCM and LES decreases by a factor of ~5 when vertical grid spacing is improved from 120 m to 10 m, with time step reductions being of secondary importance. Model performance is shown to converge at a vertical grid spacing of 20 m, with further refinements to 10 m leading to little further improvement.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44693974","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

Semi-Implicit Computation of Fast Modes in a Scheme Integrating Slow Modes by a Leapfrog Method based on a Selective Implicit Time Filter 基于选择性隐式时间滤波器的跳跃法积分慢模方案中快模的半隐式计算

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-08-29 DOI: 10.1175/mwr-d-22-0311.1

M. Moustaoui, Bryce M. Barclay, E. Kostelich

{"title":"Semi-Implicit Computation of Fast Modes in a Scheme Integrating Slow Modes by a Leapfrog Method based on a Selective Implicit Time Filter","authors":"M. Moustaoui, Bryce M. Barclay, E. Kostelich","doi":"10.1175/mwr-d-22-0311.1","DOIUrl":"https://doi.org/10.1175/mwr-d-22-0311.1","url":null,"abstract":"\u0000A scheme for integration of atmospheric equations containing terms with differing time scales is developed. The method employs a filtered leapfrog scheme utilizing a fourth-order implicit time-filter with one function evaluation per time step to compute slow propagating phenomena such as advection and rotation. The terms involving fast-propagating modes are handled implicitly with an unconditionally stable method that permits application of larger time steps and faster computations compared to fully explicit treatment. Implementation using explicit and recurrent formulation is provided. Stability analysis demonstrates that the method is conditionally stable for any combination of frequencies involved in the slow and fast terms as they approach the origin. The implicit filter used in the method damps the computational modes without noticeably sacrificing the accuracy of the physical mode. The O[(Δt4)] accuracy for amplitude errors achieved by the implicitly filtered leapfrog is preserved in applications where terms responsible for fast propagation are integrated with a semi-implicit method. Detailed formulation of the method for soundproof non-hydrostatic anelastic equations is provided. Procedures for implementation in global spectral shallow water models are also given. Examples comparing numerical and analytical solutions for linear gravity waves demonstrate the accuracy of the scheme. The performance is also shown in more practical nonlinear applications, where numerical solutions accomplished by the method are evaluated against those computed from a scheme where the slow terms are handled by the third-order Runge-Kutta scheme. It demonstrates that the method is able to accurately resolve fine-scale dynamics of Kelvin-Helmholtz shear instabilities, the evolution of density current and nonlinear drifts of twin tropical cyclones.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46479839","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 moving wave implementation in WRF to study the impact of surface water waves on the atmospheric boundary layer WRF中用于研究地表水波对大气边界层影响的移动波实现

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-08-29 DOI: 10.1175/mwr-d-23-0077.1

P. Zhu, Tianyi Li, J. Mirocha, R. Arthur, Zhao Wu, O. Fringer

{"title":"A moving wave implementation in WRF to study the impact of surface water waves on the atmospheric boundary layer","authors":"P. Zhu, Tianyi Li, J. Mirocha, R. Arthur, Zhao Wu, O. Fringer","doi":"10.1175/mwr-d-23-0077.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0077.1","url":null,"abstract":"\u0000While numerous modeling studies have focused on the interaction of ocean surface waves with the atmospheric boundary layer, most employ idealized waves that are either monochromatic or synthetically generated from a theoretical wave spectrum, and the atmospheric solvers are typically incompressible. To study wind–wave coupling in real-world scenarios, a model that can simulate both realistic meteorological and wave conditions is necessary. In this paper we describe the implementation of a moving bottom boundary condition into the Weather Research and Forecasting model for large-eddy simulation applications. We first describe the moving bottom boundary conditions within WRF’s pressure-based vertical coordinate system. We then validate our code with idealized test cases that have analytical solutions, including flow over a monochromatic wave with and without viscosity. Finally, we present results from turbulent flows over a moving monochromatic wave with different wave ages, and demonstrate satisfactory agreement of the wave growth rate with results from the literature. We also compare atmospheric stress and wind parameters from two physically equivalent cases. The first specifies a wind moving in the same direction as a propagating wave, while the second involves a stationary wave with the wind adjusted such that the wind relative to the wave is the same as in the first case. Results indicate that the velocity and Reynolds stress profiles for the two cases match, further validating the moving bottom implementation.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47550570","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

Improving AHI radiance assimilation over land with the surface skin temperature constrained by station observations and its impact for quantitative precipitation forecasts 改善地表皮肤温度受台站观测约束的陆地上AHI辐射同化及其对降水定量预报的影响

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-08-25 DOI: 10.1175/mwr-d-23-0052.1

Xin Li, X. Zou, Mingjian Zeng, X. Zhuge, Weiguang Liu

{"title":"Improving AHI radiance assimilation over land with the surface skin temperature constrained by station observations and its impact for quantitative precipitation forecasts","authors":"Xin Li, X. Zou, Mingjian Zeng, X. Zhuge, Weiguang Liu","doi":"10.1175/mwr-d-23-0052.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0052.1","url":null,"abstract":"\u0000In this study, a new way to assimilate clear-sky Advanced Himawari Imager (AHI) surface-sensitive brightness temperature (TB) observations over land is investigated for improving quantitative precipitation forecasts (QPFs) in eastern China. To alleviate problems arising from inaccurate surface temperature in radiance simulations, surface-station observations of land surface skin temperature (LSST) together with conventional and AMSU-A observations are assimilated to improve AHI surface-sensitive TB simulations of the Community Radiative Transfer Model (CRTM) before AHI data assimilation. First, the Gridpoint Statistical Interpolation (GSI) three-dimensional variational (3DVar) system is updated with the additional control variable of surface temperature and its background error covariances. Second, surface temperature and emissivity sensitivity checks are designed for the quality control of the surface-sensitive AHI channels. Finally, the impacts of a two-time data assimilation strategy are assessed for a local convection rainfall case and a synoptic-scale precipitation case. The experiment in which AHI data are assimilated after assimilating LSST data (ExpL2) outperforms the traditional experiment in which the LSST is not updated (ExpL) in terms of its 24-h QPF skill score. A better description of atmospheric instability and moisture convergence forcing is obtained in ExpL2 than in ExpL. Both experiments show additional low-level temperature and humidity adjustments compared to the experiment that does not assimilate AHI surface-sensitive channels (ExpNL). Lower AHI TB simulation biases are found in the ExpL2 experiment, which improve the analyzed field and subsequent QPFs. The results in this study suggest the importance of proper utilization of LSST observations for AHI surface-sensitive TB assimilations over land.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41375558","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

Euro-Atlantic weather regimes and their modulation by tropospheric and stratospheric teleconnection pathways in ECMWF reforecasts 欧洲-大西洋天气状况及其在ECMWF重预报中对流层和平流层遥相关路径的调制

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-08-23 DOI: 10.1175/mwr-d-22-0346.1

C. Roberts, M. Balmaseda, L. Ferranti, F. Vitart

{"title":"Euro-Atlantic weather regimes and their modulation by tropospheric and stratospheric teleconnection pathways in ECMWF reforecasts","authors":"C. Roberts, M. Balmaseda, L. Ferranti, F. Vitart","doi":"10.1175/mwr-d-22-0346.1","DOIUrl":"https://doi.org/10.1175/mwr-d-22-0346.1","url":null,"abstract":"\u0000This study combines operational reforecasts (2001-2021) with results from a lower-resolution 41-year reforecast (1980-2020) to provide a robust assessment of wintertime Euro-Atlantic regimes and their modulation by tropospheric and stratospheric teleconnection pathways in the European Centre for Medium-Range Weather Forecasts (ECMWF) subseasonal-to-seasonal (S2S) prediction system. In both operational and lower-resolution reforecasts, the climatological properties of wintertime Euro-Atlantic regimes, including regime structures, frequencies, and transition probabilities, are accurately simulated at S2S lead times. However, the 41-year reforecasts allow us to diagnose substantial errors in regime statistics when conditioned on modes of intraseasonal-to-interannual variability. In particular, ECMWF reforecasts underestimate the response of the North Atlantic Oscillation (NAO) to the Madden-Julian Oscillation (MJO) and fail to reproduce the modulation of MJO-NAO teleconnections by the El Niño-Southern Oscillation (ENSO). Teleconnection and atmospheric wave diagnostics highlight two specific issues that are likely to contribute to these conditional errors in ECMWF reforecasts: (i) insufficient propagation of Rossby wave activity from the Pacific to the Atlantic following MJO phase 3 during El Niño conditions, when the direct tropospheric teleconnection pathway is most active, and (ii) an underestimated response of the stratospheric polar vortex following MJO phase 8 during La Niña conditions, when the indirect stratospheric teleconnection pathway is most active. Improving the representation of tropospheric and stratospheric teleconnection pathways is thus a priority for improving ECMWF forecasts of extratropical weather regimes and their associated surface impacts.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48716391","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 Statistical Forecast Model for Extratropical Cyclones including Intensity and Precipitation Type 包括强度和降水类型的温带气旋统计预报模式

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2023-08-21 DOI: 10.1175/mwr-d-23-0041.1

Rebekah Cavanagh, E. Oliver

{"title":"A Statistical Forecast Model for Extratropical Cyclones including Intensity and Precipitation Type","authors":"Rebekah Cavanagh, E. Oliver","doi":"10.1175/mwr-d-23-0041.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0041.1","url":null,"abstract":"\u0000Winter Extratropical Cyclones (ETCs) are dominant features of winter weather on the east coast of North America. These storms are characterized by high winds and heavy precipitation (rain, snow, and ice). ETCs are well predicted by numerical weather prediction models (NWPs) at short- to mid-range forecast lead times, but prediction on seasonal time scales is lacking. We develop a set of multiple linear regression models, using stepwise regression and cross-validation, to predict the number of storms expected to affect a specific location throughout the winter storm season. Each model in the set predicts a specific storm type (e.g. snow, rain, or bomb storms). This set of models is applied in a probabilistic forecast framework which uses the probability density function of the prediction in combination with climatological mean storm activity. The resulting forecast makes statements about the likelihood of below average, average, or above average activity for all storms and for each of the type-specific subsets of storms. Though this forecast framework could in theory be applied anywhere, we demonstrate its skill in forecasting the characteristics of the winter storm season experienced in Halifax, Nova Scotia, Canada.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47877668","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