Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background
Using a variety of unconventional observations,such as regional weather stations,island stations,wind towers,wind profiles and Doppler weather radars,and NCEP/NCAR 0.25×0.25° reanalysis data,on the west coast of Guangdong in the morning of June 22,2017,a comprehensive diagnosis was made for the cau...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | zho |
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Editorial Office of Torrential Rain and Disasters
2019-12-01
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| Series: | 暴雨灾害 |
| Subjects: | |
| Online Access: | http://www.byzh.org.cn/cn/article/doi/10.3969/j.issn.1004-9045.2019.06.004 |
| _version_ | 1827907472839409664 |
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| author | Langming YE Naigeng WU Hualong ZHANG Jingjiu CAI Zhifang WU |
| author_facet | Langming YE Naigeng WU Hualong ZHANG Jingjiu CAI Zhifang WU |
| author_sort | Langming YE |
| collection | DOAJ |
| description | Using a variety of unconventional observations,such as regional weather stations,island stations,wind towers,wind profiles and Doppler weather radars,and NCEP/NCAR 0.25×0.25° reanalysis data,on the west coast of Guangdong in the morning of June 22,2017,a comprehensive diagnosis was made for the cause of the local heavy rain event in which the forecast failed,focusing on the impact of local sea-land breeze and topography (mutual) on the event. The results show that:(1) The rainstorm occurs under the weak weather environment. There is no frontal nor high-altitude trough activity in South China. The ultra-low-level southward jet in the boundary layer provides unstable energy for the rainstorm. The thermal difference of the underlying surface with different properties leads to the mesoscale convergence line of the sea-land breeze (southerly) and northerly winds in front of Tianlu Mountain,triggering the initial convection in the key area. (2) When the warm and moist air in the south is blocked to the north,it develops into MCS under forced uplift of Tianlu Mountain topography. The difference in thermal friction between the underlying surface may exist between the mesoscale vertical shear and the precipitation forced by the piedmont. Positive feedback phenomenon extended the life history of β mesoscale convective system. (3) Convective cloud clusters are excited continuously on mesoscale convergence line,forming train effect of precipitation,which leads to this rare local heavy rain event,highlighting the important role of sea-land breeze circulation in this heavy rain in warm sector. (4) Before the occurrence of this event,all the objective numerical forecasting models in service did not predict significant precipitation. The numerical model is difficult to make short-term prediction precipitation with grade above storm in warm zones,especially under the weak weather conditions. Current monitoring and short proximity warnings are the main tools for forecasters. |
| first_indexed | 2024-03-13T01:09:20Z |
| format | Article |
| id | doaj.art-fbd4e4c890fc470b9df7b81abca01c71 |
| institution | Directory Open Access Journal |
| issn | 2097-2164 |
| language | zho |
| last_indexed | 2024-03-13T01:09:20Z |
| publishDate | 2019-12-01 |
| publisher | Editorial Office of Torrential Rain and Disasters |
| record_format | Article |
| series | 暴雨灾害 |
| spelling | doaj.art-fbd4e4c890fc470b9df7b81abca01c712023-07-06T05:04:09ZzhoEditorial Office of Torrential Rain and Disasters暴雨灾害2097-21642019-12-0138659760510.3969/j.issn.1004-9045.2019.06.0042616Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather backgroundLangming YE0Naigeng WU1Hualong ZHANG2Jingjiu CAI3Zhifang WU4Jiangmen Meteorological Bureau of Guangdong Province, Jiangmen, 512028Institute of Tropical and Marine Meteorology, CMA, Guangzhou 510641Meteorological Observatory of Guangdong, Guangzhou, 510640Meteorological Observatory of Guangdong, Guangzhou, 510640Meteorological Observatory of Guangdong, Guangzhou, 510640Using a variety of unconventional observations,such as regional weather stations,island stations,wind towers,wind profiles and Doppler weather radars,and NCEP/NCAR 0.25×0.25° reanalysis data,on the west coast of Guangdong in the morning of June 22,2017,a comprehensive diagnosis was made for the cause of the local heavy rain event in which the forecast failed,focusing on the impact of local sea-land breeze and topography (mutual) on the event. The results show that:(1) The rainstorm occurs under the weak weather environment. There is no frontal nor high-altitude trough activity in South China. The ultra-low-level southward jet in the boundary layer provides unstable energy for the rainstorm. The thermal difference of the underlying surface with different properties leads to the mesoscale convergence line of the sea-land breeze (southerly) and northerly winds in front of Tianlu Mountain,triggering the initial convection in the key area. (2) When the warm and moist air in the south is blocked to the north,it develops into MCS under forced uplift of Tianlu Mountain topography. The difference in thermal friction between the underlying surface may exist between the mesoscale vertical shear and the precipitation forced by the piedmont. Positive feedback phenomenon extended the life history of β mesoscale convective system. (3) Convective cloud clusters are excited continuously on mesoscale convergence line,forming train effect of precipitation,which leads to this rare local heavy rain event,highlighting the important role of sea-land breeze circulation in this heavy rain in warm sector. (4) Before the occurrence of this event,all the objective numerical forecasting models in service did not predict significant precipitation. The numerical model is difficult to make short-term prediction precipitation with grade above storm in warm zones,especially under the weak weather conditions. Current monitoring and short proximity warnings are the main tools for forecasters.http://www.byzh.org.cn/cn/article/doi/10.3969/j.issn.1004-9045.2019.06.004heavy rain in warm sectormesoscale convergence linesea-land breezetopographyultra low level jet |
| spellingShingle | Langming YE Naigeng WU Hualong ZHANG Jingjiu CAI Zhifang WU Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background 暴雨灾害 heavy rain in warm sector mesoscale convergence line sea-land breeze topography ultra low level jet |
| title | Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background |
| title_full | Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background |
| title_fullStr | Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background |
| title_full_unstemmed | Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background |
| title_short | Analysis of the influence of sea-land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background |
| title_sort | analysis of the influence of sea land breeze and topography on the extraordinary heavy rain in warm sector under a weak weather background |
| topic | heavy rain in warm sector mesoscale convergence line sea-land breeze topography ultra low level jet |
| url | http://www.byzh.org.cn/cn/article/doi/10.3969/j.issn.1004-9045.2019.06.004 |
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