摘要
采用Field Spec 4便携式光谱仪对科尔沁5种典型沙生植被进行光谱测量,并对其特征进行提取分析,结果表明:(1)黄柳(Salix flavida)、冷蒿(Artemisia frigida)、麻黄(Herbal ephedrae)、差巴嘎蒿(Artemisia halodeudrou)和小叶锦鸡儿(Caragana microphylla)5种典型沙生植被的光谱形态大致相同,但又略有差异。在600~690和750~900 nm波段处差异较大,根据光谱差异波段和导数光谱参数可以区分冷蒿、麻黄和差巴嘎蒿,但不能区分黄柳和小叶锦鸡儿。(2)随着植被生长期的推移,"绿峰"位置先向蓝光方向偏移再向红光方向偏移,黄柳、冷蒿、麻黄和小叶锦鸡儿4种沙生植被光谱对应的"红边"均具有明显的"双峰",而差巴嘎蒿光谱"红边"区的"双峰"现象不甚明显;黄柳、麻黄和小叶锦鸡儿光谱的"红边"区出现明显的"红移"现象,黄柳和冷蒿的"红边"区在9月末出现"蓝移"现象,而冷蒿和差巴嘎蒿的"红边"位置呈微弱向蓝光方向偏移态势,"红移"现象并未出现。5种典型沙生植被在8、9月均具有"红边平台",其中,差巴嘎蒿和小叶锦鸡儿在日期09-27均持续处于"红边平台"位置。(3)5种典型沙生植被在红光波段处的吸收明显比蓝光波段处强烈,吸收深度也比蓝光波段处深。随着植被的生长,5种沙生植被的吸收深度和吸收峰面积变化趋势相同。在夏季,麻黄变化比其他4种植被更明显。同时,对不同生长时期5种沙生植被归一化植被指数(NDVI)进行分析可知,NDVI的变化趋势与吸收深度大体相同,与吸收峰面积的变化趋势相反。(4)不同生长时期的"红边"参数、"吸收"参数和时序NDVI数据识别植被的效果明显好于其他参数。在对研究区植被进行分类时,应选择春季(植被生长初期)和秋季中晚期(植被生长衰退期)的多时相遥感影像进行联合解译会取得更好的效果。
A FieldSpec 4 portable spectrometer was used to measure spectra of five types of psammo-vegetation typical of the Horqin sandy land for extraction and analysis of spectral characteristics of the vegetations. Results show that the five types of psammo-vegetation （Salix ylavida,Artemisia frigida,Herbal epAedrae,Artemisia Aalodendrou and Caragana mi- cropAylla）,though quite similar in spectral shape,varied slightly. Differences were apparent on bands of 600-690 and 750-900 nm. Based on bands showing difference in spectrum and derivative spectrometric parameters,it was feasible to distinguish Artemisia ^rigida,Herbal epAedrae and Artemisia Aalodendrou,but not Salix flavida and Caragana micropAylla from the five. With the vegetation growing season going on,” green peak” tended to offset toward the blue light zone and then back toward the red light one. The spectra of the vegetations of Salix ylavida,Artemisia igida,Herbal epAedrae and Caragana micropAylla all exhibited obvious ” twin peaks” on their corresponding “red edges”,but that of the vegetation of Artemisia Aalodendron did not so obviously; In the spectra of Salixylavida,Herbal epAedrae and Caragana micropAylla ”redshiftn appeared so significantly in the “red edge” zone, while in the spectra of the vegetations of Salixflavida and Arte-misia frigida n blue shiftn was observed in the u red edgen zone at the end of September, and in the spectra of the vegeta-tions of Artemisia frigida and Artemisia halodendrou, the u red edgen tended to move very slightly tow,ards the blue light zonetrend and no sign of ”red shift” ＂was ever observed. ”Red edge platforms” ＂were observed in the spectra of all the five types of psammo-vegetation in August and September, and the spectra of the vegetations of Artemisia halodendrou and Ca- ragana microphylla kept on staying in ” red edge platfor^n” on September 27. The five types of psammo-vegetations ab-sorbed more light of the red light band than that of the blue light band and in absorption depth, too. With the vegetations growing on, their spectra varied similarly in absorption depth and in absorption peak area. In summer, the spectrum of the vegetation of Herbal ephedrae varied more significantly than those of the other four. Meanwhile NDVI analysis of the five types of psammo-vegetations at various growth stages shows that the variation of NDVI was quite similar in trend to that of adsorption depth, but reverse to that of absorption area. The ” red edge” parameters, ” absorption” parameters and sequen-tial NDVI data of the vegetations at different growth stages were better than all the others when used to identify vegetation. In classifying vegetation in the study area, it is more advisable to perform interpretation of multi temporal remote sensing images of the vegetation in spring （early vegetation growth season） and the middle and late autumn （vegetation growth re-cession season） in combination for better effect.
出处
《生态与农村环境学报》
CAS
CSCD
北大核心
2017年第7期632-644,共13页
Journal of Ecology and Rural Environment
基金
国家自然科学基金重点国际(地区)合作研究项目
重点项目和面上项目(51620105003,51139002,51479086)
内蒙古水利科技项目
教育部科技创新团队发展计划(IRT13069)
科技部重点领域创新团队项目(2015RA4013)
内蒙古自治区草原英才产业创新创业人才团队
内蒙古农业大学寒旱区水资源利用创新团队项目(NDTD2010-6)
