多云天气下海南岛海风环流结构的数值模拟
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摘要
利用WRF-Noah耦合中尺度模式对海南岛2012年7月5日的多云海风个例进行三维高分辨率数值模拟,重点分析多云天气条件下复杂地形区域的海风环流结构及其演变特征。通过观测资料与模拟结果的对比发现,WRF模式能够合理地模拟出岛屿四周的海风演变特征。与少云海风日相似,多云海风日中全岛海风于12时开始形成,15时海风发展最为强盛,影响范围最广,18时全岛海风的辐合程度最强,海风辐合区是主要的潜在降水区域。对比山区与平坦地区的海风环流发现,山区海风环流强盛期为13—18时,而平坦地区海风环流强盛期为15—18时。复杂的山地对海风环流结构有直接和间接的影响:一方面在山地地形动力阻挡和抬升作用下,海风环流变得更加清晰完整,间接延长了海风环流的维持时间;另一方面局地地形热力作用形成的谷风环流与海风几乎同时产生和消亡,两者汇合后,谷风的瞬间加强会引起海风锋锋消,瞬间减弱会引起海风锋锋生;两者同相叠加会使得海风环流结构更加完整。相比之下,平坦地区的海风受到的地形动力和热力作用小,海风水平分布比较规则,海风环流垂直结构的变化主要取决于不同方向海风之间的相互作用。
In this study, to explore the strength and structure of sea breeze under cloudy conditions over Hainan Island,the 3 D high-resolution numerical simulation of sea breeze on July 5, 2012 was conducted by means of non-hydrostatic mesoscale model WRF,coupled with the Noah land-surface model.Hainan Island is a tropical island with oval topography.The frequency of occurrence of sea breeze is high throughout the island,due to its geographical location and unique topography.In addition,cloudy skies under weak stable weather conditions are conducive to the triggering of sea breeze,according to previous researches regarding the statistical analysis of sea breeze over Hainan Island.Therefore, it is significant to study the structure of sea breeze circulation on July 5, 2012,when the sea breeze observed was conspicuous,and there was a large number of clouds over the island during the evolution of the sea breeze.Compared with the observational data, the results show that the evolution and characteristics of sea breeze can be reasonably simulated by WRF.The evolution of sea breeze under cloudy conditions resembles sea breeze under clear conditions.Formed at 12: 00 BST throughout the whole island, sea breeze circulation was strong during the time range of 15: 00—18: 00 BST in flat areas,and strong during 13: 00—18: 00 BST in mountainous areas.A significant convergence line was finally observed on the island at 18: 00 BST.Strong convective weather could be easily triggered under the convergence of sea breezes for the deep convective instability energy and abundant water vapor,i.e.the convergence zone of sea breezes is the main potential precipitation area.Thecomplex terrain has direct and indirect effects on the structure of sea breeze circulation.It determines the distribution of the low-level horizontal wind field, then affects the characteristics of sea breeze in all directions indirectly.The sea breeze circulation becomes clear, the sea breeze front is almost perpendicular to the ground and its strength enhances, then the sea breeze convection can last for a longer time, indirectly due to the blocking and lifting effect of the mountain.At the same time, the valley breeze circulation forms and disappears almost simultaneously along with the sea breeze.Therefore, the valley breeze circulation interacts with the sea breeze circulation on the same side of the mountain.On one hand, this can cause frontolysis of the sea breeze front when the valley breeze strengthens suddenly,o therwise it causes frontogenesis of the sea breeze when the valley breeze weakens.On the other hand, the circulation becomes more pronounced and strengthened when the valley breeze overlaps with the sea breeze.However, in flat areas, the dynamic and thermal effects of the terrain are weak.The sea breeze pattern in flat areas is more regular than in mountain areas.Sea breezes from different directions gather together,and some convective clouds merge in the convergence of sea breezes.Furthermore, the variation of sea breeze circulation mainly depends on the interaction with sea breezes from different directions.
In this study, to explore the strength and structure of sea breeze under cloudy conditions over Hainan Island,the 3 D high-resolution numerical simulation of sea breeze on July 5, 2012 was conducted by means of non-hydrostatic mesoscale model WRF,coupled with the Noah land-surface model.Hainan Island is a tropical island with oval topography.The frequency of occurrence of sea breeze is high throughout the island,due to its geographical location and unique topography.In addition,cloudy skies under weak stable weather conditions are conducive to the triggering of sea breeze,according to previous researches regarding the statistical analysis of sea breeze over Hainan Island.Therefore, it is significant to study the structure of sea breeze circulation on July 5, 2012,when the sea breeze observed was conspicuous,and there was a large number of clouds over the island during the evolution of the sea breeze.Compared with the observational data, the results show that the evolution and characteristics of sea breeze can be reasonably simulated by WRF.The evolution of sea breeze under cloudy conditions resembles sea breeze under clear conditions.Formed at 12: 00 BST throughout the whole island, sea breeze circulation was strong during the time range of 15: 00—18: 00 BST in flat areas,and strong during 13: 00—18: 00 BST in mountainous areas.A significant convergence line was finally observed on the island at 18: 00 BST.Strong convective weather could be easily triggered under the convergence of sea breezes for the deep convective instability energy and abundant water vapor,i.e.the convergence zone of sea breezes is the main potential precipitation area.Thecomplex terrain has direct and indirect effects on the structure of sea breeze circulation.It determines the distribution of the low-level horizontal wind field, then affects the characteristics of sea breeze in all directions indirectly.The sea breeze circulation becomes clear, the sea breeze front is almost perpendicular to the ground and its strength enhances, then the sea breeze convection can last for a longer time, indirectly due to the blocking and lifting effect of the mountain.At the same time, the valley breeze circulation forms and disappears almost simultaneously along with the sea breeze.Therefore, the valley breeze circulation interacts with the sea breeze circulation on the same side of the mountain.On one hand, this can cause frontolysis of the sea breeze front when the valley breeze strengthens suddenly,o therwise it causes frontogenesis of the sea breeze when the valley breeze weakens.On the other hand, the circulation becomes more pronounced and strengthened when the valley breeze overlaps with the sea breeze.However, in flat areas, the dynamic and thermal effects of the terrain are weak.The sea breeze pattern in flat areas is more regular than in mountain areas.Sea breezes from different directions gather together,and some convective clouds merge in the convergence of sea breezes.Furthermore, the variation of sea breeze circulation mainly depends on the interaction with sea breezes from different directions.
引文
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陈训来,冯业荣,范绍佳,等,2008.离岸型背景风和海陆风对珠江三角洲地区灰霾天气的影响[J].大气科学,32(3):530-542.Chen X L,Feng Y R,Fan S J,et al.,2008.Effect of the off-shore background flowand sea-land breezes on haze weather over the Pearl River Delta region[J].Chin Atmos Sci,32(3):530-542.(in Chinese).
Crosman E T,Horel J D,2010.Sea and lake breezes:A reviewof numerical studies[J].Bound-Layer Meteor,137(1):1-29.
柯史钊,黄健,1993.华南海陆风的数值模拟[J].热带气象学报,9(2):169-176.Ke S Z,Huang J,1993.A numerical simulation of land and sea breezes in South China[J].J Trop Meteor,9(2):169-176.(in Chinese).
Kondo H,1990.A numerical experiment on the interaction between sea breeze and valley wind to generate the so-called“Extended Sea Breeze”[J].JMeteor Soc Japan,68(4):435-446.
Liang Z M,Wang D H,2015.Numerical study of the evolution of a sea-breeze front under two environmental flows[J].J Meteor Res,29(3):446-466.
Lin W S,Wang A Y,Wu C S,et al.,2001.A case modeling of sea-land breeze in Macao and its neighborhood[J].Adv Atmos Sci,18(6):1231-1240.
苗峻峰,2014.城市热岛和海风环流相互作用的数值模拟研究进展[J].大气科学学报,37(4):521-528.Miao J F,2014.An overviewof numerical studies of interaction of urban heat island and sea breeze circulations[J].Trans Atmos Sci,37(4):521-528.(in Chinese).
Miao J F,Kroon L J M,Vil1-Guerau de Arellano J,et al.,2003.Impacts of topography and land degradation on the sea breeze over eastern Spain[J].Meteor Atmos Phys,84(3/4):157-170.
Miao J F,Wyser K,Chen D,et al.,2009.Impacts of boundary layer turbulence and land surface process parameterizations on simulated sea breeze characteristics[J].Ann Geophys,27(3):2303-2320.
Miller S T K,Keim B D,Talbot R W,et al.,2003.Sea breeze:Structure,forecasting,and impacts[J].Rev Geophys,41(3):181-207.
Pielke R A,1974.A three-dimensional numerical model of the sea breezes over south Florida[J].Mon Wea Rev,102(2):115-139.
邱晓暖,范绍佳,2013.海陆风研究进展与我国沿海三地海陆风主要特征[J].气象,39(2):186-193.Qiu X N,Fan S J,2013.Progress of sea-land breeze study and the characteristics of sea-land breeze in three coastal areas in China[J].Meteor Mon,39(2):186-193.(in Chinese).
苏涛,苗峻峰,韩芙蓉,2016.海风雷暴的观测分析和数值模拟研究进展[J].气象科技,44(1):47-54.Su T,Miao J F,Han F R,2016.An overviewof observational and numerical studies of sea breeze thunderstorms[J].Meteor Sci Technol,44(1):47-54.(in Chinese).
Tu X L,Zhou MY,Sheng S H,1993.The mesoscale numerical simulation of the flowfield of the Hainan Island and the Leizhou Peninsula[J].Acta Oceanologica Sinica,12(2):219-235.
王静,苗峻峰,冯文,2016.海南岛海风演变特征的观测分析[J].气象科学,36(2):244-255.Wang J,Miao J F,Feng W,2016.An observational analysis of sea breeze characteristics over the Hainan island[J].Scientia Meteorologica Sinica,36(2):244-255.(in Chinese).
汪雅,苗峻峰,谈哲敏,2013.宁波地区海-陆下垫面差异对雷暴过程影响的数值模拟[J].气象学报,71(6):1146-1159.Wang Y,Miao J F,Tan Z M,2013.Numerical study of the impact of differences between sea and land underlying surface on thunderstorm in the Ningbo area[J].Acta Meteor Sinica,71(6):1146-1159.(in Chinese).
王语卉,苗峻峰,蔡亲波,2016.海南岛海风三维结构的数值模拟[J].热带气象学报,32(1):109-124.Wang Y H,Miao J F,Cai Q B,2016.Numerical simulation on the 3D structure of sea breezes over the Hainan Island[J].J Trop Meteor,32(1):109-124.(in Chinese).
辛吉武,许向春,蔡杏尧,2008.海南儋州雷暴天气气候特征分析[J].气象,34(1):100-106.Xin J W,Xu X C,Cai X Y,2008.Climatic and synoptic characteristics of thunder storm in Danzhou of Hainan province[J].Meteor Mon,34(1):100-106.(in Chinese).
许格希,郭泉水,牛树奎,等,2013.近50 a来海南岛不同气候区气候变化特征研究[J].自然资源学报,28(5):799-810.Xu G X,Guo Q S,Niu SK,et al.,2013.Research on climate characteristics of different climatic regions in Hainan Island in the last 50 years[J].J Nat Resour,28(5):799-810.(in Chinese).
杨薇,苗峻峰,谈哲敏,2014.太湖地区湖陆风对雷暴过程影响的数值模拟[J].应用气象学报,25(1):59-70.Yang W,Miao J F,Tan Z M,2014.Numerical simulation of the lake breeze impact on thunderstorm over the Taihu Area[J].J Appl Meteor Sci,25(1):59-70.(in Chinese).
Zeng L P,Lin W S,Fan Q,et al.,2012.Simulation of wind circulation and pollutant diffusion over the Pearl River Delta region[J].Environmental Modeling and Assessment,17(5):539-553.
翟武全,李国杰,孙斌,等,1997.海南岛附近四季风场的中尺度环流[J].热带气象学报,13(4):315-322.Zhai W Q,Li G J,Sun B,et al.,1997.Season's wind field of mesoscale circulation in Hainan Island[J].J Trop Meteor,13(4):315-322.(in Chinese).
张振州,蔡旭晖,宋宇,等,2014.海南岛地区海陆风的统计分析和数值模拟研究[J].热带气象学报,30(2):270-280.Zhang Z Z,Cai X H,Song Y,et al.,2014.Statistical characteristic and numerical simulation of sea land breezes in Hainan Island[J].J Trop Meteor,30(2):270-280.(in Chinese).
陈训来,冯业荣,范绍佳,等,2008.离岸型背景风和海陆风对珠江三角洲地区灰霾天气的影响[J].大气科学,32(3):530-542.Chen X L,Feng Y R,Fan S J,et al.,2008.Effect of the off-shore background flowand sea-land breezes on haze weather over the Pearl River Delta region[J].Chin Atmos Sci,32(3):530-542.(in Chinese).
Crosman E T,Horel J D,2010.Sea and lake breezes:A reviewof numerical studies[J].Bound-Layer Meteor,137(1):1-29.
柯史钊,黄健,1993.华南海陆风的数值模拟[J].热带气象学报,9(2):169-176.Ke S Z,Huang J,1993.A numerical simulation of land and sea breezes in South China[J].J Trop Meteor,9(2):169-176.(in Chinese).
Kondo H,1990.A numerical experiment on the interaction between sea breeze and valley wind to generate the so-called“Extended Sea Breeze”[J].JMeteor Soc Japan,68(4):435-446.
Liang Z M,Wang D H,2015.Numerical study of the evolution of a sea-breeze front under two environmental flows[J].J Meteor Res,29(3):446-466.
Lin W S,Wang A Y,Wu C S,et al.,2001.A case modeling of sea-land breeze in Macao and its neighborhood[J].Adv Atmos Sci,18(6):1231-1240.
苗峻峰,2014.城市热岛和海风环流相互作用的数值模拟研究进展[J].大气科学学报,37(4):521-528.Miao J F,2014.An overviewof numerical studies of interaction of urban heat island and sea breeze circulations[J].Trans Atmos Sci,37(4):521-528.(in Chinese).
Miao J F,Kroon L J M,Vil1-Guerau de Arellano J,et al.,2003.Impacts of topography and land degradation on the sea breeze over eastern Spain[J].Meteor Atmos Phys,84(3/4):157-170.
Miao J F,Wyser K,Chen D,et al.,2009.Impacts of boundary layer turbulence and land surface process parameterizations on simulated sea breeze characteristics[J].Ann Geophys,27(3):2303-2320.
Miller S T K,Keim B D,Talbot R W,et al.,2003.Sea breeze:Structure,forecasting,and impacts[J].Rev Geophys,41(3):181-207.
Pielke R A,1974.A three-dimensional numerical model of the sea breezes over south Florida[J].Mon Wea Rev,102(2):115-139.
邱晓暖,范绍佳,2013.海陆风研究进展与我国沿海三地海陆风主要特征[J].气象,39(2):186-193.Qiu X N,Fan S J,2013.Progress of sea-land breeze study and the characteristics of sea-land breeze in three coastal areas in China[J].Meteor Mon,39(2):186-193.(in Chinese).
苏涛,苗峻峰,韩芙蓉,2016.海风雷暴的观测分析和数值模拟研究进展[J].气象科技,44(1):47-54.Su T,Miao J F,Han F R,2016.An overviewof observational and numerical studies of sea breeze thunderstorms[J].Meteor Sci Technol,44(1):47-54.(in Chinese).
Tu X L,Zhou MY,Sheng S H,1993.The mesoscale numerical simulation of the flowfield of the Hainan Island and the Leizhou Peninsula[J].Acta Oceanologica Sinica,12(2):219-235.
王静,苗峻峰,冯文,2016.海南岛海风演变特征的观测分析[J].气象科学,36(2):244-255.Wang J,Miao J F,Feng W,2016.An observational analysis of sea breeze characteristics over the Hainan island[J].Scientia Meteorologica Sinica,36(2):244-255.(in Chinese).
汪雅,苗峻峰,谈哲敏,2013.宁波地区海-陆下垫面差异对雷暴过程影响的数值模拟[J].气象学报,71(6):1146-1159.Wang Y,Miao J F,Tan Z M,2013.Numerical study of the impact of differences between sea and land underlying surface on thunderstorm in the Ningbo area[J].Acta Meteor Sinica,71(6):1146-1159.(in Chinese).
王语卉,苗峻峰,蔡亲波,2016.海南岛海风三维结构的数值模拟[J].热带气象学报,32(1):109-124.Wang Y H,Miao J F,Cai Q B,2016.Numerical simulation on the 3D structure of sea breezes over the Hainan Island[J].J Trop Meteor,32(1):109-124.(in Chinese).
辛吉武,许向春,蔡杏尧,2008.海南儋州雷暴天气气候特征分析[J].气象,34(1):100-106.Xin J W,Xu X C,Cai X Y,2008.Climatic and synoptic characteristics of thunder storm in Danzhou of Hainan province[J].Meteor Mon,34(1):100-106.(in Chinese).
许格希,郭泉水,牛树奎,等,2013.近50 a来海南岛不同气候区气候变化特征研究[J].自然资源学报,28(5):799-810.Xu G X,Guo Q S,Niu SK,et al.,2013.Research on climate characteristics of different climatic regions in Hainan Island in the last 50 years[J].J Nat Resour,28(5):799-810.(in Chinese).
杨薇,苗峻峰,谈哲敏,2014.太湖地区湖陆风对雷暴过程影响的数值模拟[J].应用气象学报,25(1):59-70.Yang W,Miao J F,Tan Z M,2014.Numerical simulation of the lake breeze impact on thunderstorm over the Taihu Area[J].J Appl Meteor Sci,25(1):59-70.(in Chinese).
Zeng L P,Lin W S,Fan Q,et al.,2012.Simulation of wind circulation and pollutant diffusion over the Pearl River Delta region[J].Environmental Modeling and Assessment,17(5):539-553.
翟武全,李国杰,孙斌,等,1997.海南岛附近四季风场的中尺度环流[J].热带气象学报,13(4):315-322.Zhai W Q,Li G J,Sun B,et al.,1997.Season's wind field of mesoscale circulation in Hainan Island[J].J Trop Meteor,13(4):315-322.(in Chinese).
张振州,蔡旭晖,宋宇,等,2014.海南岛地区海陆风的统计分析和数值模拟研究[J].热带气象学报,30(2):270-280.Zhang Z Z,Cai X H,Song Y,et al.,2014.Statistical characteristic and numerical simulation of sea land breezes in Hainan Island[J].J Trop Meteor,30(2):270-280.(in Chinese).