Agricultural expansion dominates climate changes in southeastern Amazonia: the overlooked non-GHG forcing
Agricultural expansion dominates climate changes in southeastern Amazonia: the overlooked non-GHG forcing
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DOI：
10.1088/1748-9326/10/10/104015
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发表时间：
2015-10-01
影响因子：
6.7
通讯作者：
Coe, Michael T.
中科院分区：
文献类型：
--
作者：
Silverio, DivinoV;Brando, Paulo M.;Coe, Michael T.
热带森林砍伐改变了地表能量平衡和水循环，但发生多大的变化取决于森林砍伐后的土地利用。在这里，我们量化了最近（2000-2010年）广泛土地利用（即森林、农田和牧场）的转变如何改变了亚马逊东南部新古地区的水和能量平衡。对多个卫星数据集的时空分析显示，森林到作物和森林到牧场的转变减少了净地表辐射（分别减少18%和12%）和潜热通量（分别减少32%和24%），而增加了感热通量（分别增加6%和9%）。2000年代以来，新古地区的土地利用转变使同期蒸散发（ET）减少了35 km(3)，使地表温度（LST）升高了0.3℃。森林到牧场和森林到作物的转变分别使ET减少了25.5 km(3)和7 km(3)，地表温度增加了0.2℃和0.07℃。牧场到作物的转变使ET减少了2.5 km(3)，使地表温度增加了0.03℃。如果该地区保护区内的土地利用以类似的速度变化，ET将再减少4.7 km(3)，地表温度将再升高0.5℃。因此，森林在调节亚马逊地区气候方面发挥了关键作用，保护区能够减弱由土地利用变化引起的区域气候变化。我们的研究结果表明，一种主要的非温室气体强迫，在这种情况下是农业扩张，如何显著改变了亚马逊东南部的区域气候，以及受保护的森林如何缓解这种变化。
Tropical deforestation changes the surface energy balance and water cycle, but how much change occurs strongly depends on the land uses that follow deforestation. Here, we quantify how recent (2000-2010) transitions among widespread land uses (i.e., forests, croplands, and pastures) altered the water and energy balance in the Xingu region of southeast Amazonia. Spatial-temporal analyses of multiple satellite data sets revealed that forest-to-crop and forest-to-pasture transitions decreased the net surface radiation (by 18% and 12%, respectively) and latent heat flux (32% and 24%), while increasing sensible heat flux (6% and 9%). Land use transitions during the 2000s reduced contemporaneous evapotranspiration (ET) in the Xingu region by 35 km(3) and warmed the land surface temperature (LST) by 0.3 degrees C. Forest-to-pasture and forest-to-crop transitions accounted for most of the observed ET reduction (25.5 km(3) and 7 km(3), respectively) and LST increase (0.2 degrees C and 0.07 degrees C). Pasture-to-crop transitions reduced ET by an additional 2.5 km(3) and increased LST by 0.03 degrees C. If land use had changed at a similar rate within the region's protected areas, ET would have decreased by another 4.7 km(3) and the surface would have warmed an additional 0.5 degrees C. Forests thus play a key role in regulating regional climate in Amazonia, with protected areas able to attenuate regional climate change caused by land use changes. Our findings show how a major non-GHG forcing, in this case agricultural expansion, has significantly altered regional climate in southeastern Amazonia and how protected forests can mitigate such changes.