Monthly Weather Review最新文献_第6页

A simple statistical post-processing scheme for enhancing the skill of seasonal SST predictions in the tropics 提高热带季节性 SST 预测技能的简单统计后处理方案

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-23 DOI: 10.1175/mwr-d-23-0266.1

Ingo Richter, J. V. Ratnam, Patrick Martineau, Pascal Oettli, Takeshi Doi, Tomomichi Ogata, T. Kataoka, François Counillon

{"title":"A simple statistical post-processing scheme for enhancing the skill of seasonal SST predictions in the tropics","authors":"Ingo Richter, J. V. Ratnam, Patrick Martineau, Pascal Oettli, Takeshi Doi, Tomomichi Ogata, T. Kataoka, François Counillon","doi":"10.1175/mwr-d-23-0266.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0266.1","url":null,"abstract":"\u0000Seasonal prediction systems are subject to systematic errors, including those introduced during the initialization procedure, that may degrade the forecast skill. Here we use a novel statistical post-processing correction scheme that is based on canonical correlation analysis (CCA) to relate errors in ocean temperature arising during initialization with errors in the predicted sea-surface temperature fields at 1–12 months’ lead time. In addition, the scheme uses CCA of simultaneous SST fields from the prediction and corresponding observations to correct pattern errors. Finally, simple scaling is used to mitigate systematic location and phasing errors as a function of lead time and calendar month.\u0000Applying this scheme to an ensemble of seven seasonal prediction models suggests that moderate improvement of prediction skill is achievable in the tropical Atlantic and, to a lesser extent in the tropical Pacific and Indian Ocean. The scheme possesses several adjustable parameters, including the number of CCA modes retained, and the regions of the left and right CCA patterns. These parameters are selected using a simple tuning procedure based on the average of four skill metrics.\u0000The results of the present study indicate that errors in ocean temperature fields due to imperfect initialization and SST variability errors can have a sizable negative impact on SST prediction skill. Further development of prediction systems may be able to remedy these impacts to some extent.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140435797","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

Analysis of Snow Multi-Bands and Their Environments with High-Resolution Idealized Simulations 利用高分辨率理想化模拟分析雪地多波段及其环境

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-21 DOI: 10.1175/mwr-d-23-0211.1

Nicholas M. Leonardo, B. Colle

{"title":"Analysis of Snow Multi-Bands and Their Environments with High-Resolution Idealized Simulations","authors":"Nicholas M. Leonardo, B. Colle","doi":"10.1175/mwr-d-23-0211.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0211.1","url":null,"abstract":"\u0000Nested idealized baroclinic wave simulations at 4-km and 800-m grid spacing are used to analyze the precipitation structures and their evolution in the comma head of a developing extratropical cyclone. After the cyclone spins up by hour 120, snow multi-bands develop within a wedge-shaped region east of the near-surface low center within a region of 700-500-hPa potential and conditional instability. The cells deepen and elongate northeastward as they propagate north. There is also an increase in 600-500-hPa southwesterly vertical wind shear prior to band development. The system stops producing bands 12 hours later as the differential moisture advection weakens, and the instability is depleted by the convection.\u0000Sensitivity experiments are run in which the initial stability and horizontal temperature gradient of the baroclinic wave are adjusted by 5-10%. A 10% decrease in initial instability results in less than half the control run potential instability by 120 h and the cyclone fails to produce multi-bands. Meanwhile, a 5% decrease in instability delays the development of multi-bands by 18 h. Meanwhile, decreasing the initial horizontal temperature gradient by 10% delays the growth of vertical shear and instability, corresponding to multi-bands developing 12-18 hours later. Conversely, increasing the horizontal temperature gradient by 10% corresponds to greater vertical shear, resulting in more prolific multi-band activity developing ∼12 hours earlier. Overall, the relatively large changes in band characteristics over a ∼12-hour period (120-133 h) and band evolutions for the sensitivity experiments highlight the potential predictability challenges.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140442583","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

Implementation of All-sky Assimilation of Microwave Humidity Sounding Channels in Environment Canada’s Global Deterministic Weather Prediction System 在加拿大环境部全球确定性天气预报系统中实现全天空微波湿度探测信道同化

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-19 DOI: 10.1175/mwr-d-23-0227.1

M. Shahabadi, Mark Buehner

{"title":"Implementation of All-sky Assimilation of Microwave Humidity Sounding Channels in Environment Canada’s Global Deterministic Weather Prediction System","authors":"M. Shahabadi, Mark Buehner","doi":"10.1175/mwr-d-23-0227.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0227.1","url":null,"abstract":"\u0000Cloud-affected microwave humidity sounding radiances were excluded from assimilation in 4D-EnVar system of the Global Deterministic Prediction System (GDPS) at Environment and Climate Change Canada (ECCC). This was due to the inability of the current radiative transfer model to consider the scattering effect from frozen hydrometeors at these frequencies. In addition to upgrading the observation operator to RTTOV-SCATT, quality control, bias correction, and 4D-EnVar assimilation components are modified to perform all-sky assimilation of Microwave Humidity Sounder (MHS) channels 2-5 observations over ocean in the GDPS. The input profiles to RTTOV-SCATT are extended to include liquid cloud, ice cloud, and cloud fraction profiles for the simulation and assimilation of MHS observations over water. There is a maximum 35% increase in number of channel 2 assimilated MHS observations with smaller increases for channels 3-5 in the all-sky compared to the clear-sky experiment, mostly because of newly assimilated cloud-affected observations. The stddev of difference between the observed GPSRO refractivity observations and the corresponding simulated values using the background state was reduced in lower troposphere below 9 km in the all-sky experiment. Verifications of forecasts against the radiosonde observations show statistically significant reductions of 1% in stddev of error for geopotential height, temperature, and horizontal wind for all-sky experiment between 72- and 120- hr forecast ranges in troposphere in Northern Hemisphere domain. Verifications of forecasts against ECMWF analyses also show small improvements in zonal mean of error stddev for temperature and horizontal wind for all-sky experiment between 72- and 120-hr forecast ranges. This work is planned for operational implementation in the GDPS in Fall 2023.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140450929","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

Impact of Assimilation of the Tropical Cyclone Strong Winds Observed by Synthetic Aperture Radar on Analyses and Forecasts 合成孔径雷达观测到的热带气旋强风同化对分析和预测的影响

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-14 DOI: 10.1175/mwr-d-23-0103.1

Yasutaka Ikuta, Udai Shimada

{"title":"Impact of Assimilation of the Tropical Cyclone Strong Winds Observed by Synthetic Aperture Radar on Analyses and Forecasts","authors":"Yasutaka Ikuta, Udai Shimada","doi":"10.1175/mwr-d-23-0103.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0103.1","url":null,"abstract":"\u0000A few high-wind observations have been obtained from satellites over the ocean around tropical cyclones (TCs), but the impact of data assimilation of such observations over the sea on forecasting has not been clear. The spaceborne synthetic aperture radar (SAR) provides high-resolution and wide-area ocean surface wind speed data around the center of a TC. In this study, the impact of data assimilation of the ocean surface wind speed of SAR (OWSAR) on regional model forecasts was investigated. The assimilated data were estimated from SAR onboard Sentinel-1 and RADARSAT-2. The bias of OWSAR depends on wind speed, the observation error variance depends on wind speed and incidence angle, and the spatial observation error correlation depends on the incidence angle. The observed OWSAR is screened using the variational quality control method with the Huber norm. In the case of Typhoon Hagibis (2019), OWSAR assimilation modified the TC low-level inflow, which also modified the TC upper-level outflow. The propagation of this OWSAR assimilation effect from the surface to the upper troposphere was given by a four-dimensional variational method that searches for the optimal solution within strong constraints on the time evolution of the forecast model. Statistical validation confirmed that errors in the TC intensity forecast decreased over lead times of 15 h, but this was not statistically significant. The validation using wind profiler observations showed that OWSAR assimilation significantly improved the accuracy of wind speed predictions from the middle to the upper-level of the troposphere.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139837824","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

Variable-dependent and selective multivariate localization for ensemble-variational data assimilation in the tropics 用于热带地区集合变异数据同化的变异依赖性和选择性多变量定位

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-14 DOI: 10.1175/mwr-d-23-0201.1

Joshua Chun Kwang Lee, Javier Amezcua, Ross Noel Bannister

{"title":"Variable-dependent and selective multivariate localization for ensemble-variational data assimilation in the tropics","authors":"Joshua Chun Kwang Lee, Javier Amezcua, Ross Noel Bannister","doi":"10.1175/mwr-d-23-0201.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0201.1","url":null,"abstract":"\u0000Two aspects of ensemble localization for data assimilation are explored using the simplified non-hydrostatic ABC model in a tropical setting. The first aspect (i) is the ability to prescribe different localization length-scales for different variables (variable-dependent localization). The second aspect (ii) is the ability to control (i.e., to knock-out by localization) multi-variate error covariances (selective multivariate localization). These aspects are explored in order to shed light on the cross-covariances that are important in the tropics and to help determine the most appropriate localization configuration for a tropical ensemble-variational (EnVar) data assimilation system. Two localization schemes are implemented within the EnVar framework to achieve (i) and (ii). One is called the isolated variable-dependent localization scheme (IVDL) and the other is called the symmetric variable-dependent localization (SVDL) scheme. Multi-cycle Observation System Simulation Experiments are conducted using IVDL or SVDL mainly with a 100-member ensemble, although other ensemble sizes are studied (between 10 and 1000 members). The results reveal that selective multivariate localization can reduce the cycle-averaged root-mean-square error (RMSE) in the experiments when cross-covariances associated with hydrostatic balance are retained and when zonal wind/mass error cross-covariances are knocked-out. When variable-dependent horizontal and vertical localization are incrementally introduced, the cycle-averaged RMSE is further reduced. Overall, the best performing experiment using both variable-dependent and selective multivariate localization leads to a 3-4% reduction in cycle-averaged RMSE compared to the traditional EnVar experiment. These results may inform the possible improvements to existing tropical numerical weather prediction systems which use EnVar data assimilation.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139778736","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

Variable-dependent and selective multivariate localization for ensemble-variational data assimilation in the tropics 用于热带地区集合变异数据同化的变异依赖性和选择性多变量定位

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-14 DOI: 10.1175/mwr-d-23-0201.1

Joshua Chun Kwang Lee, Javier Amezcua, Ross Noel Bannister

{"title":"Variable-dependent and selective multivariate localization for ensemble-variational data assimilation in the tropics","authors":"Joshua Chun Kwang Lee, Javier Amezcua, Ross Noel Bannister","doi":"10.1175/mwr-d-23-0201.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0201.1","url":null,"abstract":"\u0000Two aspects of ensemble localization for data assimilation are explored using the simplified non-hydrostatic ABC model in a tropical setting. The first aspect (i) is the ability to prescribe different localization length-scales for different variables (variable-dependent localization). The second aspect (ii) is the ability to control (i.e., to knock-out by localization) multi-variate error covariances (selective multivariate localization). These aspects are explored in order to shed light on the cross-covariances that are important in the tropics and to help determine the most appropriate localization configuration for a tropical ensemble-variational (EnVar) data assimilation system. Two localization schemes are implemented within the EnVar framework to achieve (i) and (ii). One is called the isolated variable-dependent localization scheme (IVDL) and the other is called the symmetric variable-dependent localization (SVDL) scheme. Multi-cycle Observation System Simulation Experiments are conducted using IVDL or SVDL mainly with a 100-member ensemble, although other ensemble sizes are studied (between 10 and 1000 members). The results reveal that selective multivariate localization can reduce the cycle-averaged root-mean-square error (RMSE) in the experiments when cross-covariances associated with hydrostatic balance are retained and when zonal wind/mass error cross-covariances are knocked-out. When variable-dependent horizontal and vertical localization are incrementally introduced, the cycle-averaged RMSE is further reduced. Overall, the best performing experiment using both variable-dependent and selective multivariate localization leads to a 3-4% reduction in cycle-averaged RMSE compared to the traditional EnVar experiment. These results may inform the possible improvements to existing tropical numerical weather prediction systems which use EnVar data assimilation.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139838428","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

Impact of Assimilation of the Tropical Cyclone Strong Winds Observed by Synthetic Aperture Radar on Analyses and Forecasts 合成孔径雷达观测到的热带气旋强风同化对分析和预测的影响

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-14 DOI: 10.1175/mwr-d-23-0103.1

Yasutaka Ikuta, Udai Shimada

{"title":"Impact of Assimilation of the Tropical Cyclone Strong Winds Observed by Synthetic Aperture Radar on Analyses and Forecasts","authors":"Yasutaka Ikuta, Udai Shimada","doi":"10.1175/mwr-d-23-0103.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0103.1","url":null,"abstract":"\u0000A few high-wind observations have been obtained from satellites over the ocean around tropical cyclones (TCs), but the impact of data assimilation of such observations over the sea on forecasting has not been clear. The spaceborne synthetic aperture radar (SAR) provides high-resolution and wide-area ocean surface wind speed data around the center of a TC. In this study, the impact of data assimilation of the ocean surface wind speed of SAR (OWSAR) on regional model forecasts was investigated. The assimilated data were estimated from SAR onboard Sentinel-1 and RADARSAT-2. The bias of OWSAR depends on wind speed, the observation error variance depends on wind speed and incidence angle, and the spatial observation error correlation depends on the incidence angle. The observed OWSAR is screened using the variational quality control method with the Huber norm. In the case of Typhoon Hagibis (2019), OWSAR assimilation modified the TC low-level inflow, which also modified the TC upper-level outflow. The propagation of this OWSAR assimilation effect from the surface to the upper troposphere was given by a four-dimensional variational method that searches for the optimal solution within strong constraints on the time evolution of the forecast model. Statistical validation confirmed that errors in the TC intensity forecast decreased over lead times of 15 h, but this was not statistically significant. The validation using wind profiler observations showed that OWSAR assimilation significantly improved the accuracy of wind speed predictions from the middle to the upper-level of the troposphere.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139778045","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 Water Vapor Retrievals from ZDR Columns Using the 3DVar Method for Improving the Short-Term Prediction of Convective Storms 利用 3DVar 方法同化来自 ZDR 柱的水汽检索结果以改进对流风暴的短期预测

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-13 DOI: 10.1175/mwr-d-23-0196.1

Haiqin Chen, Jidong Gao, Tao Sun, Yaodeng Chen, Yunheng Wang, Jacob T. Carlin

{"title":"Assimilation of Water Vapor Retrievals from ZDR Columns Using the 3DVar Method for Improving the Short-Term Prediction of Convective Storms","authors":"Haiqin Chen, Jidong Gao, Tao Sun, Yaodeng Chen, Yunheng Wang, Jacob T. Carlin","doi":"10.1175/mwr-d-23-0196.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0196.1","url":null,"abstract":"\u0000The differential reflectivity (ZDR) column is a notable polarimetric signature related to updrafts in deep moist convection. In this study, pseudo water vapor (qv) observations are retrieved from observed ZDR columns under the assumption that humidity is saturated within the convection where ZDR columns are detected, and are then assimilated within the 3DVar framework. The impacts of assimilating pseudo qv observations from ZDR columns on short-term severe weather prediction are first evaluated for a squall line case. Radar data analysis indicates that the ZDR columns are mainly located on the inflow side of the high-reflectivity region. Assimilation of the pseudo qv observations leads to an enhancement of qv within the convection, while concurrently reducing humidity in no-rain areas. Sensitivity experiments indicate that a tuned smaller observation error and a shorter horizontal decorrelation scale are optimal for a better assimilation of pseudo qv from ZDR columns, resulting in more stable rain rates during short-term forecasts. Additionally, a 15-minute cycling assimilation frequency yields the best performance, providing the most accurate reflectivity forecast in terms of both location and intensity. Analysis of thermodynamic fields reveal that assimilating ZDR columns provides more favorable initial conditions for sustaining convection, including sustainable moisture condition, a strong cold pool, and divergent winds near the surface, consequently enhancing reflectivity and precipitation. With the optimal configuration determined from the sensitivity tests, a quantitative evaluation further demonstrates that assimilating the pseudo qv observations from ZDR columns using the 3DVar method can improve the 0-3 hour reflectivity and accumulated precipitation predictions of convective storms.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139781296","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 Water Vapor Retrievals from ZDR Columns Using the 3DVar Method for Improving the Short-Term Prediction of Convective Storms 利用 3DVar 方法同化来自 ZDR 柱的水汽检索结果以改进对流风暴的短期预测

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-13 DOI: 10.1175/mwr-d-23-0196.1

Haiqin Chen, Jidong Gao, Tao Sun, Yaodeng Chen, Yunheng Wang, Jacob T. Carlin

{"title":"Assimilation of Water Vapor Retrievals from ZDR Columns Using the 3DVar Method for Improving the Short-Term Prediction of Convective Storms","authors":"Haiqin Chen, Jidong Gao, Tao Sun, Yaodeng Chen, Yunheng Wang, Jacob T. Carlin","doi":"10.1175/mwr-d-23-0196.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0196.1","url":null,"abstract":"\u0000The differential reflectivity (ZDR) column is a notable polarimetric signature related to updrafts in deep moist convection. In this study, pseudo water vapor (qv) observations are retrieved from observed ZDR columns under the assumption that humidity is saturated within the convection where ZDR columns are detected, and are then assimilated within the 3DVar framework. The impacts of assimilating pseudo qv observations from ZDR columns on short-term severe weather prediction are first evaluated for a squall line case. Radar data analysis indicates that the ZDR columns are mainly located on the inflow side of the high-reflectivity region. Assimilation of the pseudo qv observations leads to an enhancement of qv within the convection, while concurrently reducing humidity in no-rain areas. Sensitivity experiments indicate that a tuned smaller observation error and a shorter horizontal decorrelation scale are optimal for a better assimilation of pseudo qv from ZDR columns, resulting in more stable rain rates during short-term forecasts. Additionally, a 15-minute cycling assimilation frequency yields the best performance, providing the most accurate reflectivity forecast in terms of both location and intensity. Analysis of thermodynamic fields reveal that assimilating ZDR columns provides more favorable initial conditions for sustaining convection, including sustainable moisture condition, a strong cold pool, and divergent winds near the surface, consequently enhancing reflectivity and precipitation. With the optimal configuration determined from the sensitivity tests, a quantitative evaluation further demonstrates that assimilating the pseudo qv observations from ZDR columns using the 3DVar method can improve the 0-3 hour reflectivity and accumulated precipitation predictions of convective storms.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139841175","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

Inter-Annual Lightning Variability within the TRMM LIS Dataset Using an ENSO Perspective 从厄尔尼诺/南方涛动角度看 TRMM LIS 数据集中的年际闪电变异性

IF 3.2 3区地球科学

Monthly Weather Review Pub Date : 2024-02-13 DOI: 10.1175/mwr-d-23-0115.1

Austin G. Clark, Daniel J. Cecil

{"title":"Inter-Annual Lightning Variability within the TRMM LIS Dataset Using an ENSO Perspective","authors":"Austin G. Clark, Daniel J. Cecil","doi":"10.1175/mwr-d-23-0115.1","DOIUrl":"https://doi.org/10.1175/mwr-d-23-0115.1","url":null,"abstract":"\u0000The Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) was used to investigate inter-annual variability of lightning from 1998-2014 within the 38° S – 38° N range. Previous studies have indicated that the El-Niño/Southern Oscillation (ENSO) phenomenon is one significant contributor to inter-annual lightning variability, potentially the dominant mechanism on the global scale. This period of 16 years contained 4 warm- (El Niño), 8 cold- (La Niña), and 4 neutral-phase ENSO years based on the Oceanic Niño Index. Large magnitude lightning anomalies were found during the warm phase of ENSO, with mean warm-phase anomalies of > 10 Fl (1000 km)−2 min−1 in north-central Africa and Argentina. This includes a +35 Fl (1000 km)−2 min−1 anomaly in Argentina during the 2009 El Niño. In general, large-scale anomalies of thermodynamic properties and upper atmospheric vertical motion coincided with the lightning anomalies observed in both Africa and South America. The anomaly over north-central Africa however was characterized by a 6-week shift in the annual lightning maximum with the warm phase, a result of the more complex environmental response to ENSO over the Sahel. The most consistent ENSO anomalies with appreciable lightning were found in southeastern Africa, northwestern Brazil, central Mexico, and the southern Red Sea. Of these, all but the Mexico region had enhanced lightning with the cold phase and suppressed lightning with the warm phase.","PeriodicalId":18824,"journal":{"name":"Monthly Weather Review","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139840011","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