摘要
永定河流域的土壤类型及含水量与植被覆盖指数是影响该流域水量的重要因素,利用传统取样法对该流域土壤类型及含水量进行调查,耗费人力的同时还会因仪器误差等客观因素造成实验精度下降。选择永定河流域(北京地区)为研究区,利用全站仪进行野外调查测定34块样地并取样,结合1978—2009年6期的TM影像数据对土壤信息进行提取,研究该地区的土壤含水量与各类多光谱遥感因子间的相关关系,利用遗传算法对土壤归一化水体指数(NDWI)的主要影响因子进行筛选,因NDWI是基于绿波段与近红外波段的归一化比值指数,一般用来提取影像中的水体信息,效果较好。为了更准确的筛选与土壤含水量相关的因子,利用遗传算法全局择优的特点,通过控制迭代次数加速收敛来筛选关键因子。进而利用多元回归的方法建立NDWI反演模型,分析出模型的内符合精度为0.987,并利用边缘树种进行外符合精度检验,得出:土壤中速效氮、磷、钾的含量与经度相关性不明显,却与纬度和土层成正相关关系,当模型计算的迭代次数Maxgen达到最优时,内符合精度为87.6%。通过遥感影像与野外调查相结合的方法得到的土壤NDWI与植被盖度、地形、气候等相关因子的模型而计算得出的NDWI值与单纯利用传统土壤取样法得到的值进行对比分析,得出平均相对误差E为-0.021%,外符合精度P达到87.54%。该模型的建立可为日后对永定河流域土壤水分及有机质的分析与研究提供较好的实践及理论依据。
Basin soil type,moisture content and vegetation cover index are important factors affecting the basin water of Yong-ding River,using traditional sampling method to investigate soil moisture and the watershed soil type not only consuming a lot of manpower and material resources but also causing experimental error because of the instrument and other objective factors.This article selecting the Yongding River Basin-Beijing section as the study area,using total station instruments to survey field sam-pling and determination 34 plots,combined with 6 TM image data from 1978 to 2009 to extract soil information and the relation-ship between region’s soil type,soil moisture and remote sensing factors.Using genetic algorithms normalization to select key factors which influenced NDWI,which is based on the green band and near-infrared bands normalized ratio index,usually used to extract water information in the image.In order to accurate screening and factors related to soil moisture,using genetic algo-rithms preferred characteristics,accelerate the convergence by controlling the number of iterations to filter key factor.Using multiple regression method to establish NDWI inversion model,which analysis the accuracy of model is 0. 987,also use the spe-cies outside edges tree to meet accuracy test,which arrived that soil available nitrogen,phosphorus and potassium content and longitude correlation is not obvious,but a positive correlation with latitude and soil,inner precision researched 87. 6% when the number of iterations to achieve optimal model calculation Maxgen.Models between NDWI and vegetation cover,topography,cli-mate ect,through remote sensing and field survey methods could calculate the NDWI values compared with the traditional val-ues,arrived the average relative error E is -0. 021%,suits accord P reached 87. 54%.The establishment of this model will be provide better practical and theoretical basis to the research and analysis of the watershed soil moisture and organic of Yongding River.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2014年第6期1649-1655,共7页
Spectroscopy and Spectral Analysis
基金
国家科技支撑计划项目(2012BAH34B01)资助
关键词
多光谱
遗传算法
土壤类型
土壤含水量
永定河
Muhispectral technology
Genetic algorithm
Soil type
NDWI
Yongding River
