| 姜田亮,粟晓玲,郭盛明,吴海江.西北地区植被耗水量的时空变化规律及其对气象干旱的响应[J].水利学报,2021,52(2):229-240 |
| 西北地区植被耗水量的时空变化规律及其对气象干旱的响应 |
| Spatiotemporal variation of vegetation water consumption and its response to meteorological drought in Northwest China |
| 投稿时间：2020-08-17 |
| DOI：10.13243/j.cnki.slxb.20200642 |
| 中文关键词: 植被耗水量 scPDSI 遥感 气象干旱 西北地区 |
| 英文关键词: vegetation water deficit quota scPDSI remote sensing meteorological drought Northwest China |
| 基金项目:国家自然科学基金项目（51879222，52079111） |
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| 中文摘要: |
| 准确评估西北地区植被耗水的时空变化规律及其对气象干旱的响应，对该区生态建设具有重要意义，然而大尺度区域植被耗水的量化存在方法上的挑战。本文提出了基于Penman-Monteith（PM）公式结合气象、水文、植被和土地利用遥感数据的大空间尺度植被耗水量的计算方法，采用Boosted Regression Trees（BRT）模型分析不同类型植被耗水量的主要贡献因子，利用Pearson相关系数分析耗水量与改进帕尔默干旱指数（scPDSI）的最大相关性和滞时，以此探讨西北地区9种植被类型和17个生态地理分区的植被耗水量演变规律及其对气象干旱的响应。结果表明：（1）本文提出的大空间尺度植被耗水量计算方法在西北典型地区与已有研究结果吻合较好；（2）西北地区耗水量总体表现为东南部多、西北部少，80.2%的格点呈上升趋势，植被生长期内耗水量东南部 > 西北部 > 中南部 > 西南部，1990—2015年间，各类植被的面积和耗水总量都呈增加趋势，区域耗水总量增加876.2亿m3，其中耕地、林地、草地耗水分别增加148.7亿、108.0亿和619.4亿m3；（3）潜在蒸散发（ET0）是旱地和草地耗水量的主要贡献项，归一化植被指数（NDVI）为水田和林地耗水量的主要贡献项；（4）草地耗水量对干旱的敏感度最高，林地次之，耕地最低，用耗水量代替NDVI能更好地表征气象干旱对植被产生的综合影响。研究方法可为较大时空尺度植被耗水量的计算提供参考，研究结果可为西北地区气象干旱应对策略的制定提供生态维度上的依据。 |
| 英文摘要: |
| It is of significance for ecological construction in Northwest China to assess the spatial-temporal change of vegetation water consumption (VWC). However,there are methodological challenges in quantify-ing VWC in macroscale area. Our study proposed a method for VWC based on the Penman-Monteith formu-la combined with remote sensing dataset including meteorology,hydrology,vegetation and land use change. Boosted Regression Trees (BRT) model was used to find key factors of different VWC. Finally,the maxi-mum correlation and lag time between the VWC and the self-calibrated Palmer Drought Index (scPDSI) were analyzed. The VWC of 9 vegetations and 17 eco-geographical districts were extracted to analyze its re-sponse to drought. The results show that:(1) the large scaled VWC calculation method proposed in this paper is in good agreement with the existing research results;(2) The VWC is generally higher in the southeast and lower in the northwest,of which 80 grids show an upward trend. The VWC in northeast > northwest > south central > southwest during the vegetation growth period. From 1990 to 2015, the area and the total VWC of various vegetation showed an increasing trend. The total region VWC increased by 87.62 billion m3, of which the cultivated land, woodland and grassland increased by 14.87 billion m3, 10.80 billion m3 and 61.94 billion m3,respectively;(3) Potential evapotranspiration (ET0) is the main con-tributor to VWC for dry land, grassland, and standardized normalization index (NDVI) for paddy fields and forestland. The VWD in central and western regions is higher from June to September which mainly dis-tribute herbaceous,while the higher values in southeastern within November to April of next year which is dominated by forests;(4) The VWC of grassland is more sensitive to drought,followed by woodland and cultivated land. In addition, the comprehensive impact of drought on vegetation could characterized by VWC better compared to NDVI. The results will provide ecological basis for combating meteorological drought in Northwest China,and the method can provide a reference for VWD calculation on large tempo-ral and spatial scale. |
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