基于高分辨率遥感模型的叶尔羌绿洲及其下游河岸蒸散发研究

Study on evapotranspiration in the Yarkand Oasis and its downstream riparian areas based on a high-resolution remote sensing model

摘要

【目的】叶尔羌绿洲是我国西北重要的绿洲，面临着水资源短缺和生态系统脆弱的挑战。开展高空间分辨率的遥感蒸散发估算，认识叶尔羌绿洲及其下游河岸的耗水规律，有利于实现合理的水资源配置与区域的可持续发展。【方法】通过融合多源Landsat数据，构建了30 m分辨率遥感蒸散发模型，实现了2000—2020年研究区域的蒸散发精细化估算。【结果】模型估算的绿洲总蒸散发量与水量平衡法的结果基本一致(相对偏差约为10%)。高值区主要集中在绿洲耕地和河道两侧，峰值日均蒸散发量约为6.1 mm/d;低值区分布在绿洲边缘和远离河道的区域，日均蒸散发量不足0.4 mm/d。下游河岸蒸散发量从河道向两侧递减，两侧2 km范围内蒸散发量相对较高，部分区域超过1 mm/d。2002年以来，下游河道耗水总量呈波动增加趋势，多年平均耗水总量为4.66亿m³,2013年达到峰值(约8.8亿m³);月平均蒸散发量呈明显季节变化，7月达到峰值(约1.0 mm/d)。【结论】结果表明，绿洲及其下游河岸植被稀疏地区蒸散发量呈现明显的空间异质性，高分辨率模型能准确捕捉稀疏植被区蒸散发量在空间上的细微变化，揭示叶尔羌绿洲及下游河岸区域蒸散发量的显著空间和时序变化规律，为该地区的水资源管理和生态修复提供了重要的参考依据。

Abstract

[Objective] The Yarkand Oasis, a vital oasis in northwestern China, confronts severe water scarcity and ecosystem vulnerability. High-spatial-resolution estimation of evapotranspiration(ET) is essential to understand water consumption patterns and support sustainable water resource allocation in this region. [Methods] A 30 m resolution remote sensing ET model was developed by integrating multi-source Landsat data, enabling refined ET estimation across the oasis and downstream riparian areas from 2000 to 2020. [Results] Model validation showed a relative deviation of approximately 10% compared to water balance estimations for total oasis ET. High ET values were concentrated in the irrigated lands and along riverbanks, with a peak daily average ET of approximately 6.1 mm/d. In contrast, low-value zones(daily ET <0.4 mm/d) dominated oasis margins and regions distant from river channels. Downstream riparian ET decreased progressively from the riverbanks outward, with higher ET within 2 km of the riverbanks, exceeding 1 mm/d in some areas. Since 2002, total water consumption in the downstream river channels has shown a fluctuating upward trend, with a multi-year average of 466 million m³, peaking in 2013 at approximately 880 million m³. Monthly mean ET displayed distinct seasonal variations, reaching a maximum of 1.0 mm/d in July. [Conclusion] The high-resolution model effectively captures fine-scale ET variations in sparsely vegetated areas, revealing significant spatiotemporal patterns of water consumption. These findings provide critical insights for water resource management and ecological restoration in arid oasis-desert systems.

关键词

叶尔羌绿洲 / 稀疏植被 / Landsat / 遥感 / 降水 / 水资源 / 时空分布 / 蒸散发

Key words

Yarkand Oasis / sparse vegetation / Landsat / remote sensing / precipitation / water resources / spatiotemporal distribution / evapotranspiration

基金资助

国家自然科学基金项目(51979140)

塔里木河流域管理局2024 年新立项科研项目(TGJKSJJG-2024ZXFW0036)

青海黄河上游水电开发有限责任公司项目“黄河羊曲水电站工程对局地气候影响及生物多样性演变趋势研究”(2004-014-HHS-SD-X)