多时相相对辐射校正的TM图像对钉螺孳生地环境变化的研究

A study of environmental changes on new snail habitat though multi-temporai relative radiometric normalized TM images

目的基于相对辐射校正的多时相 TM(专题制图仪)图像对南昌县五洲头地区进行分析,探测新螺区的环境变化。方法收集1998年4月3日、2000年4月16日和2004年5月5日的三景鄱阳湖 TM 图像,以2004年为参照对1998和2000年的图像进行相对辐射校正,对校正后的图像提取植被等信息并收集五洲头历年的螺情资料。结果 1998年4月3日五洲头地区植被覆盖率为4.76%,2000年4月16日和2004年5月5日五洲头滩地植被覆盖率都在80%以上;1998年4月3日的 NDVI(归一化植被指数)值在-0.4～0.2之间,而2000年4月16日年和2004年5月5日的 NDVI值主要在0.2～0.6之间,与1998年比较差异有统计学意义(q=162.385321,P<0.01;q=161.669725,P<0.01);3年的 K-T(穗帽变换)变换得到的绿度值间差异均有统计学意义(56.50,q=178.679245,P<0.01;235.18,q=130.320755,P<0.01;186.82,q=-48.358491,P<0.01)。结论多时相遥感影像结合现场资料可对血吸虫病流行区的环境变化进行监测,预测钉螺可疑孳生地,为更好地控制血吸虫病疫情提供科学参考。

Objective To study the environmental changes of new snail habital by using muhitemporal relative radiometric normalized TM images taken in Wuzhoutou of Nanchang, Jiangxi province. Methods TM images of Poyang Lake were collected on 3^rd April 1998, 16^th April 2000 and 5^th May 2004. Taking images in 2004 as a reference, the TM images in 1998 and 2000 were radiometric normalized. The images were analyzed to trace the vegetation background and snail historical information. Results The vegetation coverage rate of Wuzhaoutou on April 3^rd in 1998 was 4.76%, but the vegetation coverage rates of Wuzhoutou on April 16^th in 2000 and May 5^th in 2004 were above 80% ; the NDVI values of Wuzhoutou on April 3^rd in 1998 were zround -0. 4 to 0. 2 ,but the NDVI values of Wuzhoutou on April 16^th in 2000 and May 5^th in 2004 were mainly around 0. 2 to 0.6, which had statistical difference with that in 1998（q = 162. 285321, P 〈 0. 01 and q = 161. 669725, P 〈 0. 01 ）. The greenness of three images have statistical differences（q = 178. 679245, P 〈 0. 01 ; q = 130. 320755, P 〈 0. 01 and q = - 48. 358491, P 〈 0.01 ）. Conclusion Combining with the snail survey, the TM images could be an effective measure for setting up models to forecast the areas where snails might live to control the Schistosomiasis epidemic.