摘要
【目的】验证NDVI-DFI像元三分模型在新疆荒漠绿洲交错区提取植被信息的区域适用性,并应用该模型分析新疆某戈壁区植被的时空变化特征。【方法】选取新疆天山北坡—准噶尔盆地东缘荒漠绿洲交错带2008年和2017年两期Landsat8影像,基于NDVI-DFI像元三分模型反演研究区绿色光合植被(PV)、非绿色光合植被(NPV)和裸地(BS)的覆盖度(f_(PV)、f_(NPV)和f_(BS)),用回归分析验证反演精度。【结果】(1)研究区NDVI-DFI指数结构特征表现为三角形,满足像元三分模型的应用条件,但散点分布存在差异,说明某些地表要素发生了改变。(2)f_(PV)主要分布在南部绿洲农田,fNPV主要分布在绿洲和戈壁交错区域以及大片荒漠地区,f_(BS)主要分布在北部戈壁平原和荒山。回归分析结果表明,像元三分模型反演结果与高分2号影像重采样计算结果呈显著正相关(P<0.01)。【结论】(1)像元三分模型能反演出研究区PV、NPV和BS的覆盖度,且符合精度要求,对新疆荒漠绿洲交错区域植被信息的提取具有区域适用性。(2)研究区2008—2017年间Ⅰ、Ⅲ和Ⅳ级植被面积呈现减少的趋势,Ⅱ和Ⅴ级植被覆盖度均是增大的,植被覆盖由低级向高级转变,高等级植被面积有所增加,研究区总体植被恢复面积>退化面积。
【Objective】The present paper aimed to verify the regional applicability of NDVI-DFI tri-endmember linear mixture model to extract vegetation information in the crisscrossing region of desert oasis in Xinjiang and apply the model to analyze the spatial and temporal variation of vegetation in a gobi region in Xinjiang.【Method】Two periods of Landsat8 images in 2008 and 2017 were selected from the desert oasis interlacing zone on the northern slope of Tianshan-Jungaer Basin,Xinjiang,and estimation of fractional cover of photosynthetic vegetatio(f_(PV)),non-photosynthetic vegetation(fNPV)and bare soil(f_(BS))in the study area based on NDVI-DFI tri-endmember linear mixture model.Verify inversion accuracy with regression analysis.【Result】(i)The spatial location of the pixels identified as pure by the PPI operation and located close to the vertices of the NDVI/DFI triangle was examined by Landsat8 OLI,which meets the application conditions of NDVI-DFI model.However,there were differences in scatter distribution,indicating that some surface elements have changed.(ii)f_(PV)mainly distributed in the southern oasis farmland,f_(BS)mainly distributed in the northern Gobi plain and barren mountains,fNPVmainly distributed in the oasis and gobi interleaved areas and large desert areas.The results of regression analysis showed that there was a significant positive correlation(P<0.01)between the inversion results of NDVI-DFI model and the resampling calculation results of GF-2(high resolution)remote sensing imagery.【Conclusion】(i)The NDVI-DFI model can be applied to estimate fractional cover of f_(PV),f_(BS)and fNPVin Northern Slope of Tianshan Mountains-eastern margin of Junggar Basin.The accuracy of inversion results meet the requirements.It has regional applicability for the extraction of vegetation information in the desert oasis ecotone in Xinjiang.(ii)From 2008 to 2017,the levelⅠ,ⅢandⅣvegetation area in the study area showed a decreasing trend,while the levelⅡandⅤvegetation coverage increased.The vegetation coverage changed from low to high level,and the high level vegetation increased.The total vegetation restoration area in the study area is greater than the degraded area.
作者
宋吉梅
夏楠
海文月
唐梦迎
SONG Ji-mei;XIA Nan;HAI Wen-yue;TANG Meng-ying(School of Geographical Sciences,Xinjiang University,Urumqi 830017,China;General Institutes of Higher Learning Key Laboratory of Smart City and Environmental Modelling,Xinjiang University,Urumqi 830017,China;Xinjiang Institute of Environment and Science,Urumqi 830011,China)
出处
《西南农业学报》
CSCD
北大核心
2022年第12期2867-2875,共9页
Southwest China Journal of Agricultural Sciences
基金
新疆维吾尔自治区高校科研计划青年项目(XJEDU2021Y011)
新疆维吾尔自治区“天池博士”计划项目(tcbs201821)。
