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投稿时间：2017-02-06 修订日期：2018-01-31
投稿时间：2017-02-06 修订日期：2018-01-31
中文摘要: 利用中尺度数值天气模式TJ-WRF，通过对发生在天津城区的局地雷暴天气个例进行模拟，重点通过改变模式中下垫面土地利用类型进行敏感性模拟试验，研究天津城市热岛对海风（锋）环流强度及移动速度等的影响。结果表明：不同土地利用类型城市下垫面造成的城市热岛效应不同，当城市周边郊区下垫面土地类型改为城市建筑用地时，城市热岛效应更加明显且影响范围明显扩大；当城市下垫面改为旱作农地和牧场时，天津城区附近没有出现城市热岛效应。当海风（锋）环流向城区方向移动还未到城区附近时，城市热岛对其有明显加强和加速作用，城市热岛效应越明显其对海风（锋）环流的加强和加速作用越明显，海风（锋）环流移动加快的速度比没有城市热岛时快9.3 km·h-1。当海风（锋）环流移动到城区附近时与城市热岛环流相遇，海风（锋）环流受到城市热岛环流阻挡其移速又迅速减慢，其后侧气流南、北分支绕流和向上爬升现象变得明显，两环流相遇叠加后辐合上升运动也明显加强；城市热岛效应越明显其对海风（锋）环流的阻挡作用越明显，海风（锋）环流的移动速度减慢得越多，两环流相遇叠加后的辐合上升运动就越强。另外在向城区移动过程中，海风（锋）环流会使其经过地区低层空气增湿降温，但其后侧湿空气层厚度会因城市热岛效应的存在而明显减小；城市热岛效应越明显，海风（锋）环流后侧湿空气层厚度减小得越明显。
Abstract:Using the mesoscale TJ-WRF model, we studied the influence of Tianjin urban heat island effect on the sea breeze (front) circulation triggered local thunderstorms which tend to occur in urban areas by changing the land use type of the underlying surface in the sensitivity numerical simulation tests. The results show that the effect of urban heat island is different due to the different types of urban underlying surfaces. The urban heat island effect is more obvious and the impact scope is expanded when the land type of suburb surface is changed to urban and built-up land; when the urban surface is changed to dry land and pasture, there is no urban heat island effect near Tianjin City. At the same time, we can see that when there is urban heat island effect near urban area of Tianjin, the sea breeze (front) circulation is strengthened and its speed is accelerated. So, the more obvious the urban heat island effect is, the more obvious the strengthening and acceleration of the sea breeze (front) circulation is. The speed of the sea breeze (front) is faster than the speed without urban heat island by 9.3 km·h-1. But when it moves near the city and encounters the urban heat island circulation, the sea breeze (front) circulation is blocked and its speed slows down quickly. And the north-south branch flowing and climbing up of its rear airflow becomes obvious. The convergence and upward motion are also enhanced when the two circulations meet and superimposed. The more obvious the effect of urban heat island is, the more obvious the blocking effect of sea wind (front) circulation is, the slower down the speed of the sea breeze (front) circulation is, and the stronger the convergence and upward motion are when the two circulations meet and superimposed.In addition, when sea breeze (front) circulation moves toward the city, it will result in the decrease in temperature and the increase in moisture content of the lower-level air. However, due to the existence of the urban heat island effect, the thickness of the wet air layer in the airflow after the sea breeze (front) circulation is greatly reduced, and the more obvious the effect of the urban heat island is, the more obvious the thickness of the wet air layer decreases.
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基金项目:天津市科委自然科学基金项目(14JCYBJC21600)和国家自然科学基金项目(41575049)共同资助
| 作者 | 单位 |
| 东高红 | 天津市气象台，天津 300074 天津市环境气象中心，天津 300074 |
| 李英华 | 天津市气象科学研究所，天津 300074 |
| 刘一玮 | 天津市气象台，天津 300074 |
| 易笑园 | 天津市气象台，天津 300074 |
引用文本：
东高红,李英华,刘一玮,易笑园,2018.天津城市热岛效应对海风(锋)环流影响的数值模拟试验[J].气象,44(6):825-836.
DONG Gaohong,LI Yinghua,LIU Yiwei,YI Xiaoyuan,2018.Numerical Simulation Test of Tianjin Urban Heat Island Effect on Sea Breeze (Front) Circulation[J].Meteor Mon,44(6):825-836.
东高红,李英华,刘一玮,易笑园,2018.天津城市热岛效应对海风(锋)环流影响的数值模拟试验[J].气象,44(6):825-836.
DONG Gaohong,LI Yinghua,LIU Yiwei,YI Xiaoyuan,2018.Numerical Simulation Test of Tianjin Urban Heat Island Effect on Sea Breeze (Front) Circulation[J].Meteor Mon,44(6):825-836.
