基于MODIS的三江源地区不同类型草地草产量的遥感监测

MODIS-based Remote Sensing Monitoring of Different Types of Grassland in Three-river Headwater Region

面对大面积草原草场牧草估产,遥感监测已成为最普遍、最快速的先进手段。针对三江源地区草地,基于改进的CASA模型,利用2000—2010年MODIS的MOD13A1(净初级生产力NPP)遥感数据和每年4—9月的降水和温度数据,运用ArcGIS软件建立了三江源地区不同类型天然草地牧草产量卫星遥感估产模型,得出三江源草场亩产量结果:湖盆河滩草甸160～180kg,整体趋势略有上升;山地草原48～56kg,高原宽谷荒漠39～45kg,山地荒漠40～50kg,整体分布趋势很稳定;高山草甸110～130kg,高原宽谷草原70～80kg,整体趋势相对稳定;山地稀疏森林草场130～160kg,整体趋势略有下降;山地灌丛草场128～160kg。空间上因东南地区降水较多,湿润度高,地势相对平坦,因此草产量呈现出从东南—西北逐渐递减的规律,其中高山草甸草场和高原宽谷草原草场占绝大部分,为三江源地区进行草地生物量研究、草场资源的可持续利用和畜牧业的发展提供指导。

Remote sensing monitoring has become the most popular and fastest advanced method of grass yeild estimation in pastoral areas. Based on the modified CASA model and the MODIS MOD13A1（Net Primary Productivity, NPP） remote sensing data during 2000—2010 and the precipitation and temperature data from April to September each year, the satellite remote sensing model of grass yield estimation of different types of grassland in the three-river headwater region were established by using ArcGIS software. The results show that with a yield of 160-180 kg per mu , the overall trend of grassland yield in lake basin and river shoal is slightly increased; with a yield of 48- 56 kg per mu in mountain grassland, 39-45 kg per mu in plateau valley and desert grassland, and 40-50 kg per mu in mountain wilderness grassland, the overall distribution trend is very stable; with a yield of 110-130 kg per mu in alpine meadow, and 70-80 kg per mu in plateau wide valley grassland, the overall trend is relatively stable; with a yield of 130-160 kg per mu in mountain sparse forest grassland, the overall trend is on slight decline; and the yield of mountain shrub pasture is 128-160 kg per mu . Due to the great amount of rainfall, the high degree of moisture, and the relatively flat terrain of the southeastern region, the grass yield shows a pattern that gradually decreases from southeast to northwest. The study of alpine meadows and plateau grasslands, which occupy the vast majority of the grasslands, can provide some guidance for grassland biomass research, the sustainable utilization of grassland resources and the sustainable development of animal husbandry.