Impact Of Dongting Lake On Local Weather And Climate

Using ground real-time information and 30 year's compiled data, by means of numerical simulation and sensitivity tests of mesoscaleη-coordinate storm model, we analysed the impact of Dongting Lake on local weather and climate of Hunan, the results are as follows:1,The Dongting Lake can affect on the pressure field and the front that are generated by the middleway,eastway and westway cold air, and the isobaric line can present w-type in the south of the middle and lower reaches of the yangtze river, turning points turn up the south of Dongting Lake, the east of Poyang Lake and the southern coast. The impact of Dongting Lake on the front Often happened in the september to april of the following year, also occured in May and August, a little in June and July, it is more obvious when the cold air force is weak,2,Numerical simulations demonstrate that mesoscale terrain play an important role in the two Lakes cyclones'generation and development, and directly affect the center strength and distribution of storm, but water surface' effect is not clear in the two lake region.3. The mean annual temperature have a warm tongue in the Dongting Lake; Apart from mean monthly temperature of Hunan is higher figure in the south than in the north, also exhibited higher figure in the east than in the west and transition form, because of the Dongting Lake's existence. Exception for February, Monthly mean temperature is higher than in the same latitude, and such feature is the most notability in summer, autumn to spring, the weakest in winter. The Dongting Lake region is an area of low value of the mean annual highest and extreme maximum temperature, is an area of high value of the mean annual lowest and extreme minimum temperature, and the high value is more obvious.4. The mean annual daily temperature range of lake area is lesser than the surrounding area.5. In the lake region, temperature of is relatively low in daytime, is relatively high in night, so the daily temperature variation curve is steady; the daily maximum temperatures appear later about 2 hours; In the same kind of weather conditions, the daily variation of temperature is always smaller; in the different weather conditions, the differences of daily maximum temperatures and daily minimum temperature is the largest in the fine day, rainy day to cloudy.6. In The Dongting Lake and surrounding areas, the maximum daily precipitation is lesser than in the same latitude. the rainfall in rainy season,Dry seasons and growing season of Main crop plant account for the percentage of yearly precipitation are all lesser.7. The influence of Dongting Lake is not every obvious on the distribution of The mean annual rainfall days, the average monthly rainfall days and the days that precipitation is more than 50 millimetres or 100 millimetres, is not evident on the distribution of the days that precipitation is more than 150 millimetres.The above analysis study will help people understand the the impact of Dongting Lake on weather and climate profoundly,such as pressure field,front,precipitation,cyclone,and so on.