Knowledge Resource Center for Ecological Environment in Arid Area
| 额济纳三角洲植被水分状况评估及典型河岸带植物(胡杨)水分来源探究 | |
| 其他题名 | Vegetation water condition evaluation and water sources research of typical riparian plant (Populus euphratica) in Ejina Delta |
| 陆凯 | |
| 出版年 | 2016 |
| 学位类型 | 硕士 |
| 导师 | 于静洁 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 额济纳三角洲位于西北极端干旱区，其植被恢复与水分条件间的相关性是生态水文学研究的热点。通过遥感技术可以评估不同时空下植被水分条件状况，在点尺度上可以利用稳定同位素示踪单株植物不同水文条件下的用水策略，两者的结合可以为干旱区水资源与生态保护一体化管理提供决策依据。本研究使用MODIS影像中的16日合成归一化植被指数（NDVI）和8日合成地表温度（Ts）计算温度植被干旱指数(TVDI)，进而评估该区域2001-2015生长季植被水分条件的时空变化。同时选取距离河道位置以及地下水位埋深不同的典型河岸带植物胡杨(Populus euphratica)为研究对象，同步采集2015年7-9月的植物样、土壤样、河水和地下水样，通过δ18O示踪分析不同水文条件下胡杨的用水策略。主要结论如下：（1）2001年至2015年额济纳三角洲植被水分条件在一定程度上总体变差，2008年以及2014年植被水分条件相比其他年份较差，2001年、2005年以及2010年植被水分条件相比其他年份较好；年内变化上，总体表现为4-6月的植被水分条件好于7-10月。空间变化上，占据研究区的绝大部分面积(超过70％)的戈壁带植被水分条件有所变差，而河岸带植被水分条件总体上逐渐改善(TVDI距平百分比斜率为-0.29）。（2）根据TVDI值可将植被水分条件分为四种等级：湿润(0-0.4)，中等(0.4-0.6)，干旱(0.6-0.8)以及极端干旱(0.8-1)。其中，湿润等级的区域面积百分比由7.7%（2001年）增加至14.2%（2015年），得到改善的区域主要位于东河下游以及西河上游部分地区。极端干旱等级的区域面积百分比也由0.6%(2001年)增加到了11.7%（2015年），植被水分条件主要在西居延海和班布尔河周围的一些区域发生恶化。基于地面观测数据来验证TVDI，通过TVDI与NEF/WDI(MAE分别为0.10、0.13)的直接验证，以及LE_TVDI和LE_EC(MAE为12.24)的间接验证，证明了本研究所选用的TVDI法在额济纳三角洲的应用是可靠的。（3）对于地下水位埋深较浅（2.0 m）、距离过水河道较近（75 m）的胡杨，在过水期间，其主要土壤水供给层位为1.0-2.0 m范围内，而在非过水期间为1.0-1.5 m范围内；对于地下水位埋深较深（3.3 m）、距离过水主河道较远（>2 km）的胡杨，主要土壤水供给层位在过水期间为1.4-3.2 m范围内，非过水期间则为1.65-3.2 m范围内。（4）胡杨水分来源受距过水河道远近及过水时间的影响。距离过水河道较近（75 m）的胡杨，在过水期间(7月) 胡杨水分来源中有93.7%为河水，在非过水期间(8、9月)，则河水贡献比例下降为76.3%(8月)和43.6%(9月)。距离过水河道较远（>2 km）的胡杨，地下水贡献比例在过水期间(7月)为80.0%，在非过水期间(8、9月)，地下水贡献比例分别为57.9%(8月)和90.2%(9月)。 |
| 英文摘要 | Ejina Delta is located in extreme arid area of northwest China, the relationship between its vegetation restoration and water conditions is a hot topic in eco-hydrology. With remote sensing technology, temporal and spatial vegetation water condition can be evaluated; the plant water use strategy of different hydrological conditions can be traced at point scale by using stable isotope. For decisions about ecology and integrated management of water resources protection in arid zone, the combination of vegetation water condition evaluation and plant water use strategy can provide suggestion. In present study, 16 day composite MODIS product normalized difference vegetation index (NDVI) and 8 day composite product surface temperature (Ts) were used to calculate the temperature vegetation drought index (TVDI), so as to assess the temporal and spatial vegetation water condition variation in growing season of 2001-2015. The typical riparian plants Populus euphratica, with different distance away from the river and different groundwater table depths were collected, meanwhile, soil samples, surface water and groundwater samples from July to September in 2015 were sampled at the same time. The plant water use strategy of Populus euphratica under different hydrological conditions can be traced with δ18O. The main conclusions are as follows:(1) From 2001 to 2015, the vegetation water conditions in Ejina Delta were generally deteriorated to some extent. In 2008 and 2014, the vegetation water conditions were worse than other years; on the contrary, in 2001, 2005 and 2010, the water conditions were better than average. The monthly change show that, the overall vegetation water conditions of April-June were better than that in July to October. Spatially, vegetation water conditions of the Gobi desert which occupies most of the study area (over 70%) were deteriorated, while the vegetation water conditions of the riparian zone were generally improved (negative TVDI anomaly percentage slope of -0.29). (2) Based on TVDI values, the vegetation water conditions can be classifed into four levels: wet (0-0.4), moderate (0.4-0.6), dry (0.6-0.8) and extreme dry (0.8-1). Of all these levels, the percentage of area in level wet increased from 7.7% (2001) to 14.2% (2015), the area whose vegetation water condition was improved was mainly part of regions in the downstream of the Donhe River and upstream of the Xihe River. The area percentage of extreme dry level also increased form 0.6% (2001) to 11.7% (2015), the deterioration mainly occur in regions around West Juyan Lake and Banbuer River. Based on in-situ observation data, direct validation was made by comparing TVDI and NEF/WDI (MAE 0.10,0.13 respectively), as well as indirect verification between LE_TVDI and LE_EC (MAE 12.24), the validation results proved that the evaluation results made by TVDI in this study were reliable for Ejina Delta.(3) For the Populus euphratica standing 75m away from riverbank and with 2.0m groundwater table depth, mainly absorbs water from 1.0-2.0 m soil depth during water conveying period (July) and 1.0-2.0 m soil depth during no surface water flowing period(August and September). The Populus euphratica whose groundwater table depth is 3.3 m and is 2 km away from riverbank, mainly absorbs soil water in depth of 1.4-3.2 m in July and 1.65-3.2 m in August and September. (4) The water source of Populus euphratica is influences by distance away from the riverbank and the time of water conveying. For Populus euphratica that is close to the riverbank (75 m), 93.7% of its water sources in water conveying period (July) is river water, in no water conveying period (August and September) the contribution percentage decreased to 76.3% (August) and 43.6% (September). In area that is far away from the riverbank (> 2 km), the Populus euphratica there mainly absorbs water from groundwater, the contribution percentage of groundwater in water conveying period and no water conveying period are 80.0% (July), 57.9% (August) and 90.2%(September) respectively. |
| 中文关键词 | 额济纳三角洲 ; 植被水分条件 ; TVDI ; 胡杨用水策略 ; δ18O |
| 英文关键词 | Ejina Delta Vegetation water condition TVDI Populus euphraticawater use strategy δ18O |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 环境科学 |
| 来源机构 | 中国科学院地理科学与资源研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287659 |
| 推荐引用方式 GB/T 7714 | 陆凯. 额济纳三角洲植被水分状况评估及典型河岸带植物(胡杨)水分来源探究[D]. 中国科学院大学,2016. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [陆凯]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [陆凯]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [陆凯]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
