| 摘要: |
| 宜昌处在我国地形第二、第三级阶梯的过渡地带，又位于我国南北过渡带秦巴山地南麓的中低纬度过渡带，长江中上游结合部，山地河谷平原并存，地形复杂，垂直高差大。气候资料分析和文献调研表明，宜昌天气气候因特殊地理环境具有过渡性和特异性：（1）年平均气温主要随地形高度递减，年总降水量主要随纬度升高减小。（2）年暴雨日数、连阴雨天数，在中西部随纬度升高而递减，等值线近似纬向排列；东部随地形升高而递增，等值线近似经向排列。（3）山地平原过渡带地形的阻挡滞留、辐合抬升等对极端短时强降水有明显加强作用，这种作用在秦岭与黄淮过渡带、太行山与华北平原过渡带有相似的天气气候效应。（4）宜昌位于江淮梅雨的西界、华西秋雨的东界，具有天气气候“分水岭”特征。（5）宜昌是暴雨雨团、西南涡移动的主要通道之一。 |
| 关键词: 地理过渡带，气候过渡性，迎风坡，极端强降水，江淮梅雨，华西秋雨，分水岭， 暴雨雨团，西南涡，宜昌 |
| DOI： |
| 投稿时间：2022-02-20修订日期：2022-06-23 |
| 基金项目: |
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| The transition and specificity of climate in the geographical longitude latitude two-way transition zone and complex terrain——Take Yichang City as an example |
| maochengzhong,xiaozhanzhen,Lifang,leidongyang,mengfang,qinjinhua,huangcheng |
| (Three Gorges National Climate Observatory，Yichang Meteorological Bureau) |
| Abstract: |
| Yichang is located in the transition zone of the second and third steps of terrain in China, and in the middle and low latitudes transition zone at the southern foot of Qinba Mountains, the North-South transition zone in China. At the junction of the middle and upper reaches of the Yangtze River, mountains, valleys and plains coexist. The terrain is complex and the vertical elevation difference is large. Climate data analysis and literature research show that Yichang weather and climate have transition and specificity due to the special geographical environment: (1) the annual average temperature mainly decreases with the terrain height, and the annual total precipitation mainly decreases with the latitude. (2) The number of annual rainstorm days and continuous rainy days decrease with the increase of latitude in the central and western regions, and the isolines are approximately arranged in the latitudinal direction; The eastern part increases with the elevation of the terrain, and the isolines are arranged approximately longitudinally. (3) The blocking retention, convergence and uplift of the terrain in the transition zone between mountain and plain have a significant strengthening effect on the extreme short-term heavy precipitation. This effect has similar weather and climate effects in the transition zone between Qinling Mountains and Huang Huai River, Taihang Mountains and North ChinaPlain. (4) Yichang is located in the western boundary of Meiyu in the Yangtze Huaihe River and the eastern boundary of autumn rain in Western China, with the characteristics of "watershed" of weather and climate. (5) Yichang is one of the main channels for the movement of rainstorm and southwest vortex. |
| Key words: geographical transition zone, climatic transition, windward slope, extreme heavy precipitation, Jianghuai Meiyu, autumn rain in West China, watershed,Rainstorm rain mass, southwest vortex, Yichang |
