Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA; Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia.
Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA.
Sci Total Environ. 2019 Sep 15;683:166-174. doi: 10.1016/j.scitotenv.2019.05.217. Epub 2019 May 20.
Tropical rainforests control the exchange of water and energy between the land surface and the atmosphere near the equator and thus play an important role in the global climate system. Measurements of latent (LE) and sensible heat exchange (H) have not been synthesized across global tropical rainforests to date, which can help place observations from individual tropical forests in a global context. We measured LE and H for four years in a tropical peat forest ecosystem in Sarawak, Malaysian Borneo using eddy covariance, and hypothesize that the study ecosystem will exhibit less seasonal variability in turbulent fluxes than other tropical ecosystems as soil water is not expected to be limiting in a tropical forested wetland. LE and H show little variability across seasons in the study ecosystem, with LE values on the order of 11 MJ m day and H on the order of 3 MJ m day. Annual evapotranspiration (ET) did not differ among years and averaged 1579 ± 47 mm year. LE exceeded characteristic values from other tropical rainforest ecosystems in the FLUXNET2015 database with the exception of GF-Guy near coastal French Guyana, which averaged 8-11 MJ m day. The Bowen ratio (Bo) in tropical rainforests in the FLUXNET2015 database either exhibited little seasonal trend, one seasonal peak, or two peaks. Volumetric water content (VWC) and VPD explained a trivial amount of the variability of LE and Bo in some of the tropical rainforests including the study ecosystem, but were strong controls in others, suggesting differences in stomatal regulation and/or the partitioning between evaporation and transpiration. Results demonstrate important differences in the seasonal patterns in water and energy exchange across different tropical rainforest ecosystems that need to be understood to quantify how ongoing changes in tropical rainforest extent will impact the global climate system.
热带雨林控制着赤道附近地表和大气之间的水分和能量交换，因此在全球气候系统中发挥着重要作用。迄今为止，尚未对全球热带雨 林的潜热（LE）和显热交换（H）进行综合测量，这有助于将个别热带森林的观测结果置于全球背景下。我们使用涡度协方差在马来西亚婆罗洲的沙捞越热带泥炭森林生态系统中进行了四年的 LE 和 H 测量，并假设研究生态系统的湍流通量季节性变化较小，因为在热带湿地中，土壤水不太可能是限制因素。在研究生态系统中，LE 和 H 在整个季节的变化都很小，LE 值约为 11 MJ m day，H 值约为 3 MJ m day。年蒸散量（ET）在各年之间没有差异，平均为 1579 ± 47 mm year。LE 超过了 FLUXNET2015 数据库中其他热带雨林生态系统的特征值，除了靠近法属圭亚那沿海的 GF-Guy，其平均值为 8-11 MJ m day。FLUXNET2015 数据库中热带雨 林的 Bowen 比（Bo）要么季节性变化很小，要么有一个季节性峰值，要么有两个峰值。在一些热带雨林中，包括研究生态系统，体积含水量（VWC）和 VPD 对 LE 和 Bo 的变异性解释微不足道，但在其他地区，VWC 和 VPD 是重要的控制因素，这表明了气孔调节和/或蒸发与蒸腾之间分配的差异。结果表明，不同热带雨林生态系统在水分和能量交换方面的季节性模式存在重要差异，需要加以理解，以量化热带雨林面积的持续变化将如何影响全球气候系统。
