陈厚兵, 陈耀亮, 宋清海, Montri Sanwangsri, Nuttapon Khongdee, 张晶. 2001-2020年澜湄流域热带地区土地覆被变化对蒸散发的影响[J]. 农业工程学报, 2022, 38(22): 113-122. DOI: 10.11975/j.issn.1002-6819.2022.22.012
    引用本文: 陈厚兵, 陈耀亮, 宋清海, Montri Sanwangsri, Nuttapon Khongdee, 张晶. 2001-2020年澜湄流域热带地区土地覆被变化对蒸散发的影响[J]. 农业工程学报, 2022, 38(22): 113-122. DOI: 10.11975/j.issn.1002-6819.2022.22.012
    Chen Houbing, Chen Yaoliang, Song Qinghai, Montri Sanwangsri, Nuttapon Khongdee, Zhang Jing. Effects of land cover change on evapotranspiration in the tropical Lancang-Mekong River Basin from 2001 to 2020[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(22): 113-122. DOI: 10.11975/j.issn.1002-6819.2022.22.012
    Citation: Chen Houbing, Chen Yaoliang, Song Qinghai, Montri Sanwangsri, Nuttapon Khongdee, Zhang Jing. Effects of land cover change on evapotranspiration in the tropical Lancang-Mekong River Basin from 2001 to 2020[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(22): 113-122. DOI: 10.11975/j.issn.1002-6819.2022.22.012

    2001-2020年澜湄流域热带地区土地覆被变化对蒸散发的影响

    Effects of land cover change on evapotranspiration in the tropical Lancang-Mekong River Basin from 2001 to 2020

    • 摘要: 准确量化土地覆被变化对蒸散发的影响是深刻理解全球变化背景下的水资源响应机理的重要前提。该研究基于土地覆被产品MCD12Q1、蒸散发产品MOD16及涡动相关等数据,通过构建剔除气候变化的动态分析方法,量化了2001-2020年间澜湄流域热带地区土地覆被变化对蒸散发耗水量的动态影响。结果表明:1)MCD12Q1与MOD16在该流域的精度较高,其中MCD12Q1的总体精度为82.3%,MOD16在8 d以及月尺度上的RMSE仅略大于1 mm/d;2)2001-2020年研究区植被整体退化明显,其中森林转变为灌木和灌木转变为农田约占流域变化面积的61.2%;3)2001-2020年期间主要土地覆被变化导致区域蒸散发耗水量减少约278.87亿m3,主要土地覆被变化区气候差异导致蒸散发耗水量增加190.96 亿m3。总体上,澜湄流热带地区植被整体呈现出退化的趋势,主要表现为森林转变为灌木和灌木转变为农田。该地区土地覆被变化区域也使得其近20年内蒸散发耗水量减少,改变了土地覆被变化区域水资源循环过程。以上研究结果可为澜湄流域热带地区水资源安全提供有效监测,对地区土水资源合理配置提供重要的科学参考依据。

       

      Abstract: Abstract: Land cover types have changed dramatically in the tropics as human activity is ever increasing in recent years. These changes can cause great impacts on regional water security. Therefore, it is a high demand to accurately quantify the effect of land cover change on evapotranspiration (ET) for a better understanding of the mechanism of the water cycle under global warming. This study aims to investigate the effects of land cover change on the ET in the tropical Lancang-Mekong River Basin (LMRB) from 2001 to 2020. Firstly, the land cover data was reclassified and we corrected the unreasonable change types. The land cover product (MCD12Q1) was then evaluated using high spatial resolution images with Google Earth Pro. Secondly, the ET product (MOD16) was assessed using a total of 10 eddy covariance observation sites. Pearson's correlation coefficient (r), Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Mean Relative Percentage Error (MRPE) were also used to analyze the land cover changes and ET trends in this region. Finally, a dynamic analysis was developed to accurately quantify the effect of land cover changes on ET water consumption, where the impacts of climate change were excluded. The results show that: 1) The MCD12Q1 performed better with an overall accuracy beyond 82%, the forests and cropland of which were 90.5% and 89.4%, respectively. The RMSE values of MOD16 on the 8-day and monthly scales were only slightly larger than 1 mm/day. Therefore, the two products (land cover and ET) can be expected to analyze the ET changes in the study area. 2) The changing area accounted for 24.7% of the total. There was a degradation trend of the overall vegetation, where the conversion areas of the forest to shrubs and shrubs to cropland accounted for 61.2% of the changing area. 3) The trend analysis showed that there was an increasing average ET of 5 mm/a in the entire region. 4) A significant difference was observed in the annual average ET of each land cover type. Generally, the annual average ET of the forest was higher than that of shrubs, and the annual average ET of shrubs was higher than that of cropland. 5) The major types of land cover change caused a total decrease of 27.89 billion m3 of water consumption, whereas, climate change led to an increase of 19.10 billion m3 of ET water consumption. 6) Although there was a decrease of ET in the land cover change area, there was no significant influence of the land cover change area on the increasing ET. In general, the vegetation degradation resulted in a decrease in ET and water consumption, indicating the conversion of forests to shrubs and shrubs to cropland from 2001 to 2020. A better understanding of the water cycle response to global change can provide useful knowledge to effectively monitor the water resources security and the allocation of land and water resources in the tropical LMRB.

       

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