摘要
本研究利用2020年8月-2021年4月天然草地野外逐月叶面积指数(Leaf area index,LAI)的封育观测试验,探究自然条件下高寒牧草叶面积冬季变化特征,结果表明:当年8月至次年4月,LAI总体呈现先降后稳的变化特征,且大致以11月为界,分为8-11月的衰减阶段与12月—次年4月的稳定维持两个阶段。而衰减阶段又可区分为8-10月的快速下降时期与10—11月的缓慢下降时段,其中,降幅度最大的9-10月,LAI降幅可达29.5%。青藏高原地区冬季牧草的这种阶段衰减变化特征,明显有异于我国北方地区。基于LAI冬季衰减过程,构建了三次多项式估算方程(R^(2)=0.99,P<0.001),并据此提出了冬季LAI逐月衰减变化查找表。进一步,在不同植被指数LAI估算能力对比基础上,建立了EVI和GF卫星的高寒牧草LAI遥感估算模型,实现了时空变化特征的遥感反演与估算。
To research the winter variation characteristics of leaf area index(LAI)of alphine grassland under natural conditions,monthly field observation experiments were conducted in a natural grassland enclosure area in Xihai Town,Haibei Tibetan Autonomous Prefecture,Qinghai Province during August 2020 to April 2021.The results showed that the LAI generally showed a change characteristic of first decreasing and then stabilizing from August of that year to the next April,and it is roughly divided into two stages:the attenuation stage from August to November and the stable maintenance stage from December to next April with the November as the boundary.The decay stages can be divided into a rapid decline period from August to October and a slow decline period from October to November,the biggest drop was appeared in September-October with a monthly drop of 29.5%.The characteristics of the attenuation stage change of grassland LAI in winter in the Qinghai-Tibet Plateau were obviously different from those in the grassland in northern China.Based on the attenuation process of LAI in winter,a cubic polynomial estimation equation was constructed(R^(2)=0.99,P<0.00),and a look-up table for the monthly attenuation change of LAI in winter was proposed.Further,the LAI estimation capabilities of different vegetation indices were compared,the LAI remote sensing estimation model for alpine grassland based on Enhanced Vegetation Index and GF satellites was established and remote sensing inversion and estimation of LAI temporal and spatial variation characteristics were realized.
作者
肖强智
徐维新
代娜
王淇玉
李全平
段旭辉
梁好
XIAO Qiang-zhi;XU Wei-xin;DAI Na;WANG Qi-yu;LI Quan-ping;DUAN Xu-hui;LIANG Hao(Chengdu University of Information Technology,Chengdu,Sichuan Province 610225,China;HaiBei Haiyan Meteorological Administration,Haibei,Qinghai Province 812200,China)
出处
《草地学报》
CAS
CSCD
北大核心
2023年第8期2436-2445,共10页
Acta Agrestia Sinica
基金
四川省科技计划项目(2022YFS0490)
青海省防灾减灾重点实验室开放基金项目(QFZ-2021-Z11)
西藏自治区科技计划项目(XZ202102YD0012C)
内蒙古自治区科技计划项目(2021GG0019)
国家自然科学基金项目(41971328)资助。
关键词
叶面积指数
冬季
衰减规律
卫星遥感
青藏高原
Leaf area index
Winter
Attenuation procedure
Satellite remote sensing
Qinghai-Tibet Plateau
