Atmospheric Science Letters最新文献_第9页

An analytical representation of raindrop size distribution in a mixed convective and stratiform precipitating system as revealed by field observations 现场观测揭示的对流和层状混合降水系统中雨滴大小分布的解析表示

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-30 DOI: 10.1002/asl.1155

Megumi Okazaki, Satoru Oishi, Yasuhiro Awata, Tomoro Yanase, Tetsuya Takemi

{"title":"An analytical representation of raindrop size distribution in a mixed convective and stratiform precipitating system as revealed by field observations","authors":"Megumi Okazaki, Satoru Oishi, Yasuhiro Awata, Tomoro Yanase, Tetsuya Takemi","doi":"10.1002/asl.1155","DOIUrl":"10.1002/asl.1155","url":null,"abstract":"This study investigated a rainfall event under a typhoon influence using a 2D video disdrometer and weather radar observations to characterize raindrop size distribution (DSD) in a mixed convective and stratiform precipitating system. During the time period when both convective and stratiform rainfalls existed, the DSDs generally indicated a monotonically decreasing shape with increasing particle size, with a relatively gradual decrease at intermediate particle size observed at certain times; this feature is attributed to the combined effect of convective and stratiform rainfalls. During the transitional period between convective and stratiform rainfalls, the DSDs exhibited a bimodal shape. The DSDs were well approximated by a newly proposed gamma raindrop distribution combined with exponential (GRACE) distribution function, which was defined as the sum of the exponential distribution and the gamma distribution. A comparison of the volume ratio of the exponential and gamma components of the GRACE distribution revealed that the exponential component of the DSD was larger than the gamma component in the bimodal DSD. These results suggest that the DSD became bimodal during the period when stratiform rainfall predominated because of the weakening of convective rainfall. The GRACE distribution is useful for understanding cloud-microphysical processes in mixed stratiform and convective precipitation conditions.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44811379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of land surface processes on convection over West Africa in convection-permitting ensemble forecasts: A case study using the MOGREPS ensemble 在允许对流的集合预报中，陆地表面过程对西非上空对流的影响：使用MOGREPS集合的案例研究

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-14 DOI: 10.1002/asl.1167

Valiyaveetil Shamsudheen Semeena, Cornelia Klein, Christopher M. Taylor, Stuart Webster

{"title":"Impact of land surface processes on convection over West Africa in convection-permitting ensemble forecasts: A case study using the MOGREPS ensemble","authors":"Valiyaveetil Shamsudheen Semeena, Cornelia Klein, Christopher M. Taylor, Stuart Webster","doi":"10.1002/asl.1167","DOIUrl":"10.1002/asl.1167","url":null,"abstract":"Soil moisture (SM) affects weather through its impact on surface flux partitioning, influencing vertical atmospheric profiles and circulations driven by differential surface heating. In West Africa, observational studies point to a dominant negative SM-precipitation feedback, where dry soils help to initiate and maintain convection. In this context, serious concerns exist about the ability of models with parameterised convection to simulate this observed sensitivity of daytime convection to SM. Here, we evaluate the effect of initial SM perturbations in a short-range ensemble forecast over West Africa, comparing the UK Met Office Global and Regional Ensemble Prediction System (MOGREPS) with parameterised convection (GLOB-ENS) to its regional convection-permitting counterpart (CP-ENS). Results from both models suggest SM perturbations introduce considerable spread into daytime evaporative fraction (EF) and near-surface temperatures. This spread is still evident on Day 3 of the forecast. Both models also show a tendency to increased afternoon rainfall frequency over negative EF anomalies, reproducing the observed feedback. However, this effect is more pronounced in CP-ENS than GLOB-ENS, which illustrates the potential for process-based forecast improvements at convection-permitting scales. Finally, we identify persistent biases in rainfall caused by land cover mapping issues in the operational GLOB-ENS setup, emphasising the need for careful evaluation of different mapping strategies for land cover.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1167","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48088814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evolution and prediction of the extreme rainstorm event in July 2021 in Henan province, China 2021年7月河南省极端暴雨事件演变与预测

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-14 DOI: 10.1002/asl.1156

Dong Chen, Chaoying Pan, Shaobo Qiao, Rong Zhi, Shankai Tang, Jie Yang, Guolin Feng, Wenjie Dong

{"title":"Evolution and prediction of the extreme rainstorm event in July 2021 in Henan province, China","authors":"Dong Chen, Chaoying Pan, Shaobo Qiao, Rong Zhi, Shankai Tang, Jie Yang, Guolin Feng, Wenjie Dong","doi":"10.1002/asl.1156","DOIUrl":"10.1002/asl.1156","url":null,"abstract":"The Once-in-a-Century extreme rainstorm event caused severe floods over Henan province during July 18–21, 2021, which resulted in large casualty and property losses. Although the rainstorm event occurred in Henan after July 18, the excessive rainfall had occurred to the east of Henan before July 18, with the 4-day accumulated rainfall exceeding +130 mm during July 14–17, 2021. How the rainfall evolving westward and intensifying after July 18 remained a puzzle, which is the focus of this study. The prerainstorm stage (July 14–17) was related to the South Asian High (SAH) extending eastward and the western Pacific subtropical high (WPSH) extending northwestward, and a low vortex between the SAH and WPSH caused above-normal rainfall to the east of Henan. The rainstorm stage (July 18–21) was associated with an inverted trough and excessive southerly and southeasterly water vapor transportation above Henan, which resulted from the combined effects of a deep trough in the upper troposphere and typhoon activities. Additionally, three subseasonal forecasting systems predicted this rainstorm event 3 days in advance, with the European Center for Medium Range Weather Forecasts (ECMWF) performing the best, which was related to a better prediction of the inverted trough and the water vapor transportation in the middle-lower troposphere. These results advance our understanding of the extreme rainstorm event in July 2021 in Henan.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1156","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43989206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Variability in North Sea wind energy and the potential for prolonged winter wind drought 北海风能的变异性和延长冬季风干旱的可能性

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-08 DOI: 10.1002/asl.1158

Gillian Kay, Nick J. Dunstone, Anna Maidens, Adam A. Scaife, Doug M. Smith, Hazel E. Thornton, Laura Dawkins, Stephen E. Belcher

{"title":"Variability in North Sea wind energy and the potential for prolonged winter wind drought","authors":"Gillian Kay, Nick J. Dunstone, Anna Maidens, Adam A. Scaife, Doug M. Smith, Hazel E. Thornton, Laura Dawkins, Stephen E. Belcher","doi":"10.1002/asl.1158","DOIUrl":"10.1002/asl.1158","url":null,"abstract":"The United Kingdom is committed to substantially increasing offshore wind capacity in its drive to decarbonise electricity production and achieve net zero. If low wind episodes—or ‘wind drought’ events—occur during high energy demand periods, energy security may be threatened without alternative supply. The challenge of managing the variability of wind power will increase into the future as its share in the energy mix increases. This study focuses attention on the North Sea as a centre of current and planned offshore wind resource, and on the winter season, given the occurrence of weather patterns that risk security of supply. We use a large climate model ensemble, providing a dataset an order of magnitude larger than the reanalysis-based observations, to better sample wind drought events. This leads to a more robust estimate of their frequency and persistence and their dynamical teleconnections compared with the observational record. We define week-long wind drought events, based on a 20th percentile threshold in 10 m wind speed, during which wind power is estimated to be around half that in a typical week of winter. Wind drought events of up to two consecutive weeks have been observed, but the model indicates a 1-in-40 chance of three or more continuous weeks of wind drought each winter, with the single most prolonged simulated event lasting 5 weeks. There is a doubling of the likelihood of these prolonged wind drought events during El Niño, indicating that monitoring and predicting the state of the tropical Pacific may be useful in assessing the risk of wind drought events in an upcoming winter.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1158","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46680805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A statistical study on promoting effects of tropical cyclones over the Bay of Bengal on the South China Sea summer monsoon onset 孟加拉湾热带气旋对南海夏季风爆发促进作用的统计研究

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-07 DOI: 10.1002/asl.1164

Xiaoting Fan, Ying Li

引用次数: 0

Roles of eddy generation and jet characteristics in setting the annual cycle of Siberian storm track 涡流产生和喷流特征在设定西伯利亚风暴路径年周期中的作用

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-06 DOI: 10.1002/asl.1166

Meng Xiong, Hong-Li Ren, Yu Nie, Guolin Feng, Lei Wang

{"title":"Roles of eddy generation and jet characteristics in setting the annual cycle of Siberian storm track","authors":"Meng Xiong, Hong-Li Ren, Yu Nie, Guolin Feng, Lei Wang","doi":"10.1002/asl.1166","DOIUrl":"10.1002/asl.1166","url":null,"abstract":"The Siberian storm track is one of the drivers of the East Asian extreme weather events. Using the daily JRA-55 reanalysis data from 1980 to 2021, this study examines roles of eddy generation and jet characteristics in setting the annual cycle of Siberian storm track. It is found that there are two peaks of Siberian storm track intensity in boreal spring and autumn. The possible reason for such an annual cycle is explored by analyzing the maximum Eady growth rate over the Siberian region and jet characteristics. The stronger Siberian Eady growth rate in boreal spring and autumn, favoring a stronger baroclinic eddy generation, could contribute to the stronger intensity of Siberian storm tracks in these two seasons. Furthermore, the Siberian jet stream cores during boreal spring and autumn are located north of 50° N and resembles more an eddy-driven jet. While in winter, the subtropical jet stream enhanced and the eddy-driven jet becomes relatively weaker, which is less efficient to generate midlatitude baroclinic eddies. Besides, the eddy-driven jet can modulate the horizontal wave propagations from upstream, which also plays a role in amplifying the spring and autumn Siberian storm tracks.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1166","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47594781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

10–30-day moist static energy evolutions related to the persistent heavy rainfall event in different stages of flood season over South China 华南不同汛期持续强降水事件的10～30天湿静能量演变

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-06 DOI: 10.1002/asl.1157

Bin Zheng, Ailan Lin, Yanyan Huang

{"title":"10–30-day moist static energy evolutions related to the persistent heavy rainfall event in different stages of flood season over South China","authors":"Bin Zheng, Ailan Lin, Yanyan Huang","doi":"10.1002/asl.1157","DOIUrl":"10.1002/asl.1157","url":null,"abstract":"In this study, the flood season in South China (SC) was divided into three stages: two first rainy seasons (FRSs) around the South China Sea summer monsoon onset and one second rainy season when Typhoon prevails, denoted as FRS1, FRS2, and SRS, respectively, and then we diagnosed the moist static energy (MSE) budget associated with the 10–30-day persistent heavy rainfall (PHR) over SC during these periods. The results indicate that there are great differences in the recharge of PHR-related MSE in different stages of the flood season in SC: The FRS1 MSE associated with PHR moves southeastward from midlatitude; the large MSE is maintained in SC during the FRS2; during the SRS, the MSE perturbation propagates from the tropical western North Pacific to SC. From the perspective of the local MSE budget in SC, meridional and zonal advection play a key role in the maximum MSE change in the FRS1; the FRS2 and SRS MSE tendency is mainly determined by zonal advection and meridional advection, respectively. In contrast, the 10–30-day propagating perturbation of MSE changes during both the FRS1 and FRS2 are mainly affected by the zonal advection, while the meridional circulation is dominant in the SRS. The cumulative contribution of external forcing (including radiation and surface heat fluxes) during the SRS to the propagation of PHR-related MSE perturbation can reach more than 30%, and the closer to the land, the stronger the external forcing. During the FRS (including FRS1 and FRS2), however, the external forcing contributes little, even negatively.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1157","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47238446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Helicity characteristics of cyclonic vortexes and their effect on convection in a wide-ranging extreme rainstorm in China 中国一次大范围极端暴雨中气旋涡的螺旋度特征及其对对流的影响

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-04 DOI: 10.1002/asl.1162

Yongren Chen, Yueqing Li, Xinchao Liu, Li Zhu

{"title":"Helicity characteristics of cyclonic vortexes and their effect on convection in a wide-ranging extreme rainstorm in China","authors":"Yongren Chen, Yueqing Li, Xinchao Liu, Li Zhu","doi":"10.1002/asl.1162","DOIUrl":"10.1002/asl.1162","url":null,"abstract":"On 20–22 July 2012, a severe rainstorm occurred in the Sichuan basin of Southwest China and in the Beijing area of North China. This rainstorm was related to the activities of a Tibetan Plateau vortex (TPV) and Southwest China vortex (SWCV). By using radiosonde, satellite brightness temperature, and NCEP_FNL data, we investigated the helicity characteristics nearly the vortexes and their effect on convection. Results showed that (1) strong precipitation in the Sichuan basin was mainly related to the interaction between the TPV and SWCV, while strong precipitation in the Beijing area was related to the northward movement of a cyclonic vortex caused by a split in the SWCV. (2) During the occurrence of the rainstorm, four mesoscale convection systems (MCSs) were observed. Their vertical structure showed a positive vorticity–negative divergence in the lower levels, and negative vorticity–positive divergence in the upper levels, accompanied by vertical upward movement. This was an important factor in the development and maintenance of MCSs, as well as one of the mechanisms for producing heavy precipitation. On this basis, we further discussed the effect of helicity on the MCSs in the atmospheric environment with rotational characteristics. Results showed that the increase in negative water vapour helicity and storm-relative helicity were more likely to cause a strong development of MCSs.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1162","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41813814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Using early extremes to place the 2022 UK heat waves into historical context 利用早期极端事件将2022年英国热浪置于历史背景中

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-02 DOI: 10.1002/asl.1159

Emma L. Yule, Gabriele Hegerl, Andrew Schurer, Ed Hawkins

{"title":"Using early extremes to place the 2022 UK heat waves into historical context","authors":"Emma L. Yule, Gabriele Hegerl, Andrew Schurer, Ed Hawkins","doi":"10.1002/asl.1159","DOIUrl":"10.1002/asl.1159","url":null,"abstract":"As global surface temperatures continue to rise, both the duration and the intensity of heat waves across most land areas are expected to increase. The 2022 European summer broke a number of temperature records where a new record daily maximum temperature of 40.3°C was reached on 19th July making it the hottest July heat wave event in the UK. This paper aims to detect and analyse historical heat wave events, particularly prior to 1927 and compare these with recent events, particularly, 2022, which featured four summer heat wave events in the UK. This allows us to understand how noteworthy historical extremes are in comparison to those in recent decades, to place modern events into historical context, and to extend the sample of extreme events. Summer heat wave events have been detected between 1878 and 2022 from long station data in the UK. Heat wave extent, duration, and intensity have been analysed to compare past heat waves to the recent 2022 heat waves. For each of the summer months at least one of the top 10 most intense events between 1878 and 2022 occurred in the earliest third of the dataset (before 1927) emphasising the value of analysing early heat events. In all detected events, the anomalous UK heat was part of large-scale European extreme heat when examining 20th-century reanalysis data, associated with a high-pressure system. The 2022 July event resembles in pattern of warming and circulation some earlier events, for example, in 1925. While there is a clear trend in the monthly data and the overall frequency of anomalously hot days, heat wave activity on daily scales even in the period 1878 and 1926 is considerable and in some cases comparable to modern heat wave events in the UK. The most intense events detected led to societal impacts based on UK newspaper articles from the period including impacts on the agricultural sector, health impacts, and travel disruptions, broadly comparable to impacts from recent events.","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1159","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48455726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Column crossing and lateral transport in numerical weather models 数值天气模型中的柱交叉和横向输运

IF 3 4区地球科学

Atmospheric Science Letters Pub Date : 2023-03-01 DOI: 10.1002/asl.1163

Gabriel G. Rooney

引用次数: 0