基于空间抽样调查的宁夏全区和吴忠市湿地面积估测

Estimation of Areas of Wetlands in Ningxia Hui Autonomous Region and Wuzhong City based on Spacial Sampling Investigation

利用第二次全国湿地资源调查数据和2013年、2015年和2016年遥感影像数据,提取出宁夏回族自治区各类型湿地信息,辅以地面验证,研究基于网格空间抽样调查的湿地面积估测方法。研究结果表明,宁夏回族自治区内的湿地分布呈现由北向南递减的趋势;利用210个4 km×4 km的抽样网格单元,估测得到的宁夏全区湿地总面积为21.85×104hm^2,大于第二次全国湿地资源调查的相关结果(20.72×104hm^2),预测精度和抽样精度分别为94.53%和99.78%,可靠性较高,但是抽样精度随着湿地抽样面积比例的下降而降低;在宁夏的5个地级市中,吴忠市的湖泊和沼泽面积都相对最大,利用吴忠市61个4 km×4 km大样地网格的前后两期湿地斑块数据,预测2016年吴忠市的湿地总面积为52 320.67 hm^2,比2013年净增了731.78 hm^2,总预测精度为98.58%。湿地空间抽样方法的抽样效率较高,湿地面积总体预测精度较好,降低了遥感影像购买和使用成本,减少了湿地斑块区划工作量,提升了湿地变化的动态监测能力,建议推广应用。

Using the data of remote sensing images of the years of 2013,2015 and 2016,the information of the wetlands in Ningxia Hui Autonomous Region was extracted;and the areas of various types of wetlands in Ningxia were estimated by spatial sampling method.The results showed that the wetlands declined from north to south in Ningxia;estimated total area of the wetlands in Ningxia was 21.85×104 ha using 210 sampling grids of 4 km×4 km,more than 20.72×104 ha from the second national wetland resource inventory database;estimated and sampling accuracy was 94.53%and 99.78%;the sampling accuracy declined with the decrease of proportion of sampling wetland area;among 5 prefecture-level city,the areas of lakes and marshes both were the maximum relatively in Wuzhong city,estimated total area of the wetlands was 52 320.67 ha in 2016 using the data of wetland patches with 61 sampling grids of 4 km×4 km for 2 periods,which increased by731.78 ha than that in 2013,total sampling accuracy was 98.58%.