亚洲热带森林减少的增温效应及其影响机制

doi:10.3969/j.issn.1000-6362.2020.04.001

摘要/Abstract

摘要： 由于森林砍伐和火灾，近年来热带森林面积呈减少趋势，且森林减少的速率不断上升。热带森林覆盖的减少通过改变地表的热量、水分和物质循环，影响着热带气候。为了解热带森林减少对热带气候的影响，本研究采用窗口搜索的方法，利用森林变化遥感产品识别亚洲森林覆盖损失，计算同个窗口内相邻森林减少区与未改变森林覆盖区的地表温度（LST），地表净短波辐射（SW）和潜热通量（LE）的差异，从而评估2000-2017年亚洲热带雨林和季雨林两种森林类型的减少对地表温度的影响及其影响机制。结果表明：（1）亚洲热带雨林累计减少（2000-2017）使日均地表温度上升了1.7±0.7℃，地表净短波辐射下降7.2±0.9Wm-2，潜热通量增加8.9±4.4Wm-2。（2）热带季雨林减少使日均地表温度上升2.1±0.9℃，地表净短波辐射下降7.1±1.0Wm-2，潜热通量与热带雨林表现出相反的变化趋势，减少了3.9±9.2Wm-2。（3）热带雨林的减少对地表温度、地表净短波辐射和潜热通量变化影响的季节差异很小；热带季雨林的减少使地表温度、地表净短波辐射和潜热通量变化则存在明显的季节差异，这主要是由于季雨林区域降水对地表水分供应的季节性差异导致。（4）地表净短波辐射和潜热通量的净热量变化（△SW-△LE）一定程度上能够决定热带季雨林区地表温度的变化，但不能解释热带雨林区地表温度的变化。因此，在气候变化背景下，热带地区应采取措施阻止森林减少，缓解土地覆盖变化带来的变暖压力。

关键词: 森林减少, 增温效应, 能量变化, 热带雨林, 热带季雨林

Abstract: Tropical forest area has been decreasing in recent decades due to defores tation and wildfire. The rate of forest loss is rising. The loss of tropical forest cover modifies the surface heat, moisture and mass exchange, thus influences the tropical climate. In order to understand the impact of tropical forest loss on tropical climate, a window search method was applied by using remote sensing forest change products to identify forest cover loss from 2000 to 2017 in Asia tropics. The difference of surface temperature (LST), net surface shortwave radiation (SW) and latent heat flux (LE) between adjacent forest reduced grids and unchanged forest grids in the same window was calculated , thus evaluating the biophysical effect of forest loss on surface temperature and its influence mechanism in two different forest types, i.e. tropical rainforest and tropical monsoon forest. The results showed that:(1) the cumulative reduction of Asian tropical rainforest between 2000 and 2017 has led to warming impact (1.7±0.7℃) on daily surface temperature. Downward shortwave radiation has decreased 7.2±0.9Wm-2, and the latent heat flux has increased 8.9±4.4Wm-2 due to rainforest loss.(2) The loss of tropical monsoon forest has led to stronger warming impact (2.1±0.9℃) than tropical rainforest. Downward shortwave radiation has decreased 7.1±1.0Wm-2 due to monsoon forest loss. Latent heat flux has decreased 3.9±9.2Wm-2due to monsoon forest loss, which is opposite to the change due to rainforest loss. (3)The loss of tropical rainforest has a limited effect on the seasonal distribution of surface temperature, downward shortwave radiation and latent heat flux. However, the loss of tropical monsoon forest has caused contrasting seasonal changes in surface temperature, downward shortwave radiation, and latent heat flux. This is mainly due to contrasting seasonal precipitation in monsoon forest which determines the surface water supply for evapotranspiration. (4)The net change of downward shortwave radiation and latent heat flux (△SW-△LE) can explainthe surface temperature change of monsoon forest to some extent, but not that of tropical rainforest.Therefore, in the context of climate change, it needsto take measures to prevent forest loss in tropical areas and mitigate warming impact due to landcover change.

Key words: Forest loss, Warming effect, Energy change, Rainforest, Monsoon forest

中图分类号:

薛颖，徐希燕，胡正华，贾根锁，张潇艳，马薇. 亚洲热带森林减少的增温效应及其影响机制[J]. 中国农业气象, 2020, 41(04): 191-200.

XUE Ying，XU Xi-yan,HU Zheng-hua，JIA Gen-suo，ZHANG Xiao-yan，MA Wei. Warming Effect of AsianTropical Forest Loss and Its Influence Mechanism[J]. Chinese Journal of Agrometeorology, 2020, 41(04): 191-200.

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