鄱阳湖湿地出露草洲分布特征的遥感研究

ANALYSIS OF DISTRIBUTION FEATURES OF THE EMERSED GRASSLAND IN POYANG LAKE BASED ON REMOTE SENSING

利用鄱阳湖区46景不同时相的Landsat MSS/TM/ETM+遥感影像,分别提取鄱阳湖的出露草洲范围,并假定只要一个时期是出露草洲就属于草洲,形成鄱阳湖湿地草洲潜在分布图,并分析鄱阳湖湿地出露草洲的分布特征。研究结果表明:(1)利用出露草洲面积与星子水文站观测水位得到二者的关系,表明出露草洲分布及范围受水位的影响显著,高水位时,大部分草洲被水淹没;低水位时,出露草洲面积大。此外,也受气象因素、草洲植物生长期的水位过程等因素影响;(2)出露草洲面积的季节变化明显:随水位的升高而减少,随水位的下降而增加;在植被生长期的春季和夏季,出露草洲面积逐渐减少,在秋季和冬季,出露草洲面积却逐渐增加;出露草洲面积最大在1月,最小在7月;(3)鄱阳湖潜在草洲的面积达2 441km2,草洲可能出现的范围占整个鄱阳湖面积的69.5%。

In this paper,Landsat MSS/TM/ETM＋ images taken on 46 different dates were used to pick up the emersed grassland of Poyang Lake in 1983~2009.We suggested the emersed grassland which appeared in one date was the grassland,got the potential grassland map,and analyzed the distribution of the emersed grassland.The correlation between the emersed grassland and the water level indicated the distribution range was significantly affected by water level：high water level,the majority of grassland flooded;low water level,the majority of grassland exposed.Furthermore,it also was affected by meteorological factors,the water level change process and etc.The area of the emersed grassland had obvious seasonal change：in spring and summer when the vegetation grows,the area dropped off,but in autumn and winter,the area increased.The maximum area was in January,the minimum was in July.The total area of potential grassland reached 2 441 km2,mainly distributed in the west bank,accounted 69.5% of the whole lake.The distribution feature of the increasing in the emersed grassland area was from the lakeshore to the middle with the flood to the low water.