Niklas Wittkamp, B. Adler, N. Kalthoff, O. Kiseleva
The flow in the atmospheric boundary layer (ABL) over cities is crucial for the urban climate as it controls the exchange of heat, moisture and pollutants within the ABL and with the surroundings. In particular for cities in mountainous terrain, the mesoscale flow shows a high spatial and temporal variability, which poses great challenges to the means of observation. We used the dual-Doppler lidar scan strategy of virtual towers (VT), to measure profiles of the horizontal wind in the ABL over the city of Stuttgart in southwestern Germany. To study the mesoscale variability of the horizontal wind, we placed six VTs in the topographically structured investigation area, which is characterised by a basin-shaped valley opening into a major valley. Comparisons with radiosonde data show that reliable wind information can be retrieved from the VT measurements after careful processing. A statistical analysis reveals a strong dependence of the flow in the valleys below ridge height on the bulk Richardson number (BRN). A critical BRN of 1.25 is identified for the area, below which the flow below ridge height is dynamically unstable and coupled to the ambient flow above. For BRNs greater than 1.25, the flow is dynamically stable and the flow below ridge height is dominated by thermally driven down-valley winds, which are decoupled from the ambient wind. This study shows that the VT technique is applicable in highly complex terrain and a promising tool for the investigation of the flow in areas which are difficult to access by traditional in situ or single lidar measurements, like complex urban terrain.
{"title":"Mesoscale wind patterns over the complex urban terrain around Stuttgart investigated with dual-Doppler lidar profiles","authors":"Niklas Wittkamp, B. Adler, N. Kalthoff, O. Kiseleva","doi":"10.1127/METZ/2020/1029","DOIUrl":"https://doi.org/10.1127/METZ/2020/1029","url":null,"abstract":"The flow in the atmospheric boundary layer (ABL) over cities is crucial for the urban climate as it controls the exchange of heat, moisture and pollutants within the ABL and with the surroundings. In particular for cities in mountainous terrain, the mesoscale flow shows a high spatial and temporal variability, which poses great challenges to the means of observation. We used the dual-Doppler lidar scan strategy of virtual towers (VT), to measure profiles of the horizontal wind in the ABL over the city of Stuttgart in southwestern Germany. To study the mesoscale variability of the horizontal wind, we placed six VTs in the topographically structured investigation area, which is characterised by a basin-shaped valley opening into a major valley. Comparisons with radiosonde data show that reliable wind information can be retrieved from the VT measurements after careful processing. A statistical analysis reveals a strong dependence of the flow in the valleys below ridge height on the bulk Richardson number (BRN). A critical BRN of 1.25 is identified for the area, below which the flow below ridge height is dynamically unstable and coupled to the ambient flow above. For BRNs greater than 1.25, the flow is dynamically stable and the flow below ridge height is dominated by thermally driven down-valley winds, which are decoupled from the ambient wind. This study shows that the VT technique is applicable in highly complex terrain and a promising tool for the investigation of the flow in areas which are difficult to access by traditional in situ or single lidar measurements, like complex urban terrain.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47454011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As a severe weather phenomenon, thunderstorms can cause casualties and economic loss to the human society. A reliable forecast of these weather events would help to avoid or at least mitigate this damage. To date, the forecasting of thunderstorms however is still a challenge, especially for lead times of one hour and beyond. In this study we present a methodology to forecast deep-convection for several hours lead time: Cb-Fusion estimates the likelihood of thunderstorm occurrence for up to 6 hours in advance over a part of Central Europe, using a data fusion technique that blends data of multiple sources from observations, nowcasts, and numerical weather predictions with a high update rate. The Cb-Fusion is set up to operate in near real time. The skill of Cb-Fusion is evaluated based on 1743 hours of thunderstorm observations collected during the months April to October, 2019. Three categories of thunderstorm size have been distinguished: ‘large’ for a coverage area larger than 5000 km2, ‘medium’ for a coverage area between 5000 km2 and 500 km2, and ‘small’ for a coverage area smaller than 500 km2. Compared to thunderstorm forecasts from numerical models alone, the combination of data from various sources by Cb-Fusion results in a significantly better forecast skill. The study reveals that the forecast is reliable for up to 3 hours lead time for ‘medium’ and ‘large’ scale thunderstorms (median POD of 0.6 – 0.9) but little skill is found for ‘small’ scale thunderstorms and lead times between 3 and 6 hours (median POD of 0.05). It is argued that Cb-Fusion provides meaningful improvements in forecasting thunderstorms for various users.
{"title":"Cb‑Fusion – forecasting thunderstorm cells up to 6 hours","authors":"Jingmin Li, C. Forster, J. Wagner, T. Gerz","doi":"10.1127/METZ/2020/1047","DOIUrl":"https://doi.org/10.1127/METZ/2020/1047","url":null,"abstract":"As a severe weather phenomenon, thunderstorms can cause casualties and economic loss to the human society. A reliable forecast of these weather events would help to avoid or at least mitigate this damage. To date, the forecasting of thunderstorms however is still a challenge, especially for lead times of one hour and beyond. In this study we present a methodology to forecast deep-convection for several hours lead time: Cb-Fusion estimates the likelihood of thunderstorm occurrence for up to 6 hours in advance over a part of Central Europe, using a data fusion technique that blends data of multiple sources from observations, nowcasts, and numerical weather predictions with a high update rate. The Cb-Fusion is set up to operate in near real time. The skill of Cb-Fusion is evaluated based on 1743 hours of thunderstorm observations collected during the months April to October, 2019. Three categories of thunderstorm size have been distinguished: ‘large’ for a coverage area larger than 5000 km2, ‘medium’ for a coverage area between 5000 km2 and 500 km2, and ‘small’ for a coverage area smaller than 500 km2. Compared to thunderstorm forecasts from numerical models alone, the combination of data from various sources by Cb-Fusion results in a significantly better forecast skill. The study reveals that the forecast is reliable for up to 3 hours lead time for ‘medium’ and ‘large’ scale thunderstorms (median POD of 0.6 – 0.9) but little skill is found for ‘small’ scale thunderstorms and lead times between 3 and 6 hours (median POD of 0.05). It is argued that Cb-Fusion provides meaningful improvements in forecasting thunderstorms for various users.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":"30 1","pages":"169-184"},"PeriodicalIF":1.2,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49539814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Barrel of Ilmenau: A large-scale convection experiment to study dust devil-like flow structures.","authors":"Alice Loesch, Ronald du Puits","doi":"10.1127/metz/2020/1046","DOIUrl":"https://doi.org/10.1127/metz/2020/1046","url":null,"abstract":"","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":"30 1","pages":"89-97"},"PeriodicalIF":1.2,"publicationDate":"2021-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63628894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The seventh triennial joint conference of the three national meteorological societies (DMG, ÖGM, SGM) of Germany, Austria and Switzerland, DACH2019, took place in Garmisch-Partenkirchen from March 18th until 22nd, 2019. The convention site was the municipal congress building in the city center of Garmisch-Partenkirchen. The conference was attended by about 480 participants who presented nearly 200 talks and about 150 posters. The local organization was headed by the Munich Section of the German Meteorological Society (DMG) which was supported by the German Aerospace Center (DLR), the German Meteorological Service (DWD), Munich University (LMU), the Karlsruhe Institute of Technology (KIT), and two colleagues from ÖGM and SGM. Earlier editions of these conferences (DACH2007 in Hamburg, DACH2010 in Bonn, and DACH2013 in Innsbruck) have already been covered in Special Issues of Meteorologische Zeitschrift (Behr et al., 2008; Hense et al., 2012; Mayer et al., 2014). The very first conference in this series was held in Vienna in 2001, followed by the second one in Karlsruhe in 2004. The previous, sixth conference took place in Berlin in 2016. Following the overall concept of these triennial joint conferences to offer a forum for the scientific activities of all members of the three meteorological societies, the scientific program was organised in 17 sessions covering a broad range of topics:
德国、奥地利和瑞士三个国家气象学会(DMG、ÖGM、SGM)的第七届三年一次的联合会议DACH2019于2019年3月18日至22日在Garmisch-Partenkirchen举行。会议地点是加尔米施-帕滕基兴市中心的市政会议大楼。约480名与会者出席了会议，发表了近200场演讲，并张贴了约150张海报。当地组织由德国气象学会慕尼黑分会(DMG)领导，得到德国航空航天中心(DLR)、德国气象局(DWD)、慕尼黑大学(LMU)、卡尔斯鲁厄理工学院(KIT)以及ÖGM和SGM的两位同事的支持。这些会议的早期版本(汉堡DACH2007，波恩DACH2010和因斯布鲁克DACH2013)已经在《气象专刊》(Behr et al.， 2008;Hense et al.， 2012;Mayer et al.， 2014)。该系列的第一届会议于2001年在维也纳举行，第二届会议于2004年在卡尔斯鲁厄举行。2016年，第六次会议在柏林举行。三年一次的联合会议旨在为三个气象学会的所有成员提供一个科学活动的论坛，按照这个整体概念，科学计划举办了17次会议，涵盖了广泛的主题:
{"title":"Papers from the DACH 2019 conference at Garmisch-Partenkirchen","authors":"Stefan Emeis","doi":"10.1127/METZ/2021/1067","DOIUrl":"https://doi.org/10.1127/METZ/2021/1067","url":null,"abstract":"The seventh triennial joint conference of the three national meteorological societies (DMG, ÖGM, SGM) of Germany, Austria and Switzerland, DACH2019, took place in Garmisch-Partenkirchen from March 18th until 22nd, 2019. The convention site was the municipal congress building in the city center of Garmisch-Partenkirchen. The conference was attended by about 480 participants who presented nearly 200 talks and about 150 posters. The local organization was headed by the Munich Section of the German Meteorological Society (DMG) which was supported by the German Aerospace Center (DLR), the German Meteorological Service (DWD), Munich University (LMU), the Karlsruhe Institute of Technology (KIT), and two colleagues from ÖGM and SGM. Earlier editions of these conferences (DACH2007 in Hamburg, DACH2010 in Bonn, and DACH2013 in Innsbruck) have already been covered in Special Issues of Meteorologische Zeitschrift (Behr et al., 2008; Hense et al., 2012; Mayer et al., 2014). The very first conference in this series was held in Vienna in 2001, followed by the second one in Karlsruhe in 2004. The previous, sixth conference took place in Berlin in 2016. Following the overall concept of these triennial joint conferences to offer a forum for the scientific activities of all members of the three meteorological societies, the scientific program was organised in 17 sessions covering a broad range of topics:","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45022717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Salutation to the 30th anniversary of “Meteorologische Zeitschrift/Contributions to Atmospheric Sciences”","authors":"H. Pichler, H. Richner, M. Kerschgens","doi":"10.1127/METZ/2021/1076","DOIUrl":"https://doi.org/10.1127/METZ/2021/1076","url":null,"abstract":"","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":"30 1","pages":"3-5"},"PeriodicalIF":1.2,"publicationDate":"2021-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49371018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Chan, K. Hon, P. Robinson, K. Kosiba, J. Wurman, Q.S. Li
The wind field of a waterspout that occurred near the Hong Kong International Airport was documented using dual-Doppler analysis from a dense network of Doppler Light Detection and Ranging (LIDAR) systems operated at the airport, and nearby surface weather station observations. The dual-Doppler winds are used in tandem with surface observations to analyze the wind structure of the waterspout. The performance of a numerical weather prediction system simulating the windshift line and the associated vortices is compared to the observations. The waterspout and the other vortices formed along a windshift line (convergence between the arriving northeast monsoon and background westerly/sea breeze) and were rather weak, with the surface wind gusting to about 10 m/s. However, the dense network of meteorological sensors at the airport provided unprecedented surface sampling of these vortices. The numerical model captured the convergence line and the vortices reasonably well and may provide earlier alerting to the aviation weather forecasters about the possible occurrence of small waterspout-type vortices near the airport, which may have implications to aviation safety.
{"title":"Analysis and numerical simulation of a waterspout at the Hong Kong International Airport","authors":"P. Chan, K. Hon, P. Robinson, K. Kosiba, J. Wurman, Q.S. Li","doi":"10.1127/metz/2021/1078","DOIUrl":"https://doi.org/10.1127/metz/2021/1078","url":null,"abstract":"The wind field of a waterspout that occurred near the Hong Kong International Airport was documented using dual-Doppler analysis from a dense network of Doppler Light Detection and Ranging (LIDAR) systems operated at the airport, and nearby surface weather station observations. The dual-Doppler winds are used in tandem with surface observations to analyze the wind structure of the waterspout. The performance of a numerical weather prediction system simulating the windshift line and the associated vortices is compared to the observations. The waterspout and the other vortices formed along a windshift line (convergence between the arriving northeast monsoon and background westerly/sea breeze) and were rather weak, with the surface wind gusting to about 10 m/s. However, the dense network of meteorological sensors at the airport provided unprecedented surface sampling of these vortices. The numerical model captured the convergence line and the vortices reasonably well and may provide earlier alerting to the aviation weather forecasters about the possible occurrence of small waterspout-type vortices near the airport, which may have implications to aviation safety.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44040885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Variation of leading-edge-erosion relevant precipitation parameters with location and weather type","authors":"Anna-Maria Tilg, M. Hagen, F. Vejen, C. Hasager","doi":"10.1127/METZ/2021/1063","DOIUrl":"https://doi.org/10.1127/METZ/2021/1063","url":null,"abstract":"","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63629540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Measurements of spatial variability of sub-micron particle number concentrations perpendicular to a main road in a built‑up area","authors":"Sabine Fritz, S. Schubert, Christoph Schneider","doi":"10.1127/metz/2021/1058","DOIUrl":"https://doi.org/10.1127/metz/2021/1058","url":null,"abstract":"","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63629674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Hieta, Mikko Partio, M. Laine, Marja-Liisa Tuomola, H. Hohti, T. Perttula, E. Gregow, Jussi Ylhaisi
{"title":"Smartmet nowcast – Rapidly updating nowcasting system at Finnish Meteorological Institute","authors":"L. Hieta, Mikko Partio, M. Laine, Marja-Liisa Tuomola, H. Hohti, T. Perttula, E. Gregow, Jussi Ylhaisi","doi":"10.1127/metz/2021/1070","DOIUrl":"https://doi.org/10.1127/metz/2021/1070","url":null,"abstract":"","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63630169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oliver Branch, A. Behrendt, Osama Alnayef, F. Späth, T. Schwitalla, M. Temimi, M. Weston, Sufian Farrah, Omar Al Yazeedi, Siddharth Tampi, Karel de Waal, V. Wulfmeyer
{"title":"Observing the pre-convective environment and convection initiation with Doppler Lidar and cloud radar in the Al Hajar Mountains of the United Arab Emirates","authors":"Oliver Branch, A. Behrendt, Osama Alnayef, F. Späth, T. Schwitalla, M. Temimi, M. Weston, Sufian Farrah, Omar Al Yazeedi, Siddharth Tampi, Karel de Waal, V. Wulfmeyer","doi":"10.1127/metz/2021/1100","DOIUrl":"https://doi.org/10.1127/metz/2021/1100","url":null,"abstract":"","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41364944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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