Browsing by Author "Chen, Houbing"

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    Assessment and Inter-Comparison of Multi-Source High Spatial Resolution Evapotranspiration Products over Lancang–Mekong River Basin, Southeast Asia
    (Multidisciplinary Digital Publishing Institute, 2022-01-20) Chen, Houbing
    Evapotranspiration (ET) plays a crucial role in water balance within the global hydrological cycle. Timely assessment of ET products can provide the scientific basis for quantitative analysis of hydrological cycle processes and water resources assessment. In this paper, four high spatial resolution remote sensing ET products—the Moderate-resolution Imaging Spectroradiometer global terrestrial evapotranspiration product (MOD16), the ET product based on Penman–Monteith–Leuning equation version 2 (PML-V2), the ET product based on the Breathing Earth System Simulator (BESS) and the ET product of the Global LAnd Surface Satellite (GLASS)—were firstly assessed using the eddy covariance (EC) of different vegetation types in the Lancang–Mekong River Basin (LMRB). To fully assess the performances of these four products, spatiotemporal inter-comparisons and literature comparisons were also conducted across different climatic zones. The results are summarized as follows: (1) MOD16 does not perform well as compared to the other three products, with its Root Mean Square Error (RMSE) being higher than GLASS, PML-V2 and BESS, which are approximately 0.47 mm/8-day, 0.66 mm/8-day, and 0.90 mm/8-day, respectively; (2) the performance of each product varies across different vegetation types, and even within the same climate zone. PML-V2 performs best in evergreen broadleaf forests, BESS performs best in deciduous broadleaf forests and croplands, and GLASS performs best in shrubs, grasslands and mixed vegetation; (3) each product can well reflect the spatial difference brought by topography, climate and vegetation over the entire basin but all four ET products do not show either a consistent temporal trend or a uniform spatial distribution; (4) ET ranges of these four products over LMRB are consistent with previous literature in evergreen broadleaf forests, deciduous broadleaf forests, needleleaf forests and mixed forests in other regions with the same climate zones, but they show great differences in croplands, grasslands and shrubs. This study will contribute to improving our understanding of these four ET products in the different climatic zones and vegetation types over LMRB.
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    Land cover change mitigated 20 % of the total increased evapotranspiration in tropical Lancang-Mekong River Basin during 2001–2019
    (Elsevier BV, 2025-01-05) Chen, Houbing
    The tropical Lancang-Mekong River Basin (TLMRB), Southeast Asia. Accurately assessing evapotranspiration (ET) change derived from land cover changes (LCCs) is challenging in tropical regions due to the large bias in existing ET products and the difficulty in improving the ET al.gorithm for tropical ecosystems. This study quantified the LCCs-driven ET in the TLMRB from 2001 to 2019 by using scenario simulations based on an improved MOD16 algorithm. A soil moisture index was introduced to improve the soil evaporation of the original MOD16 model. The improved MOD16 algorithm showed better performance with the average Root Mean Square Error decreasing by 0.12 mm/day compared with the original MOD16 ET. The improved ET of the wet climate conditions was more significant than that under dry climate conditions. LCCs led to a 3.45 mm/yr decrease in average ET, and mitigated 20 % of increased ET. LCCs caused a net reduction of 7.44 billion m³ in ET water consumption. This decrease in ET, may intensify the surface runoff and raise the risk of extreme floods in the rain season. These findings enhance our understanding of the relationship between LCCs and ET in tropical regions, and provide valuable insights for trans-boundary collaborations and water resource management in the TLMRB. Land cover changes derived evapotranspiration was explored in Mekong River basin. Evapotranspiration was improved by using a soil moisture index in the MOD16 model. Evapotranspiration decreased by 7.44 billion m³due to dramatic land cover changes. Land cover changes mitigated 20 % of increased evapotranspiration.