Evapotranspiration dynamics in a boreal peatland and its impact on the water and energy balance
Evapotranspiration dynamics in a boreal peatland and its impact on the water and energy balance
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DOI：
10.1029/2009jg001075
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发表时间：
2010-12
影响因子：
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通讯作者：
Jiabing Wu;Jiabing Wu;L. Kutzbach;L. Kutzbach;D. F. Jager;C. Wille;C. Wille;M. Wilmking
中科院分区：
文献类型：
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作者：
Jiabing Wu;Jiabing Wu;L. Kutzbach;L. Kutzbach;D. F. Jager;C. Wille;C. Wille;M. Wilmking
[1]水文条件在北方泥炭地的碳循环中起着关键作用。本研究探讨蒸散（ET）动态及其对水和能量平衡的影响，在不同的气象条件下，在异常干燥的2006年和正常的潮湿的2007年在芬兰的北方泥炭地。能量和水汽通量连续使用涡度相关方法确定。日蒸散率在生长季节变化很大，干年和湿年的平均值分别为2.23 ± 0.15 mm d-1和1.59 ± 0.07 mm d-1。由入射辐射和水汽压差（VPD）反映的天气条件是控制ET的关键因素。在降水模式和夏季温度的差异也占了一些观察到的差异之间的ET 2年。没有证据表明ET率和地下水位之间的关系，可能是由于相对较高的地下水位，即使在干旱的一年。潜热通量在能量平衡中占主导地位，特别是在2006年，60%的累积降水通过ET返回大气。2007年丰水年，径流是主要的水分流失，只有36%的累积降水通过ET返回大气。泥炭地的年水量平衡主要受降水模式的调节，而日蒸散量与潜在蒸发量密切相关，潜热通量可以用Penman-Monteith方法进行模拟，这为泥炭地在良好的灌溉条件下的蒸散量预测提供了两种可行的方案。
[1] Hydrological conditions play a key role in the carbon cycle of northern peatlands. This study examines the evapotranspiration (ET) dynamics and its impact on the water and energy balance in response to differing meteorological conditions during the exceptionally dry year 2006 and the normal wet year 2007 at a boreal peatland in Finland. Energy and water vapor fluxes were determined continuously using the eddy covariance approach. Daily ET rates varied considerably during the growing season and averaged 2.23 ± 0.15 mm d−1 and 1.59 ± 0.07 mm d−1 in the dry and wet year, respectively. Synoptic weather conditions as reflected by incoming radiation and water vapor pressure deficit (VPD) were the key factors controlling ET. Differences in the precipitation patterns and summer temperature also accounted for some of the observed differences in ET between the 2 years. No evidence was found for a relationship between ET rates and water table level, probably due to the relatively high water table level even in the dry year. Latent heat flux dominated the energy balance, particularly in the dry year 2006 with 60% of cumulative precipitation returned to the atmosphere through ET. In the wet year 2007, runoff dominated the water loss, and only 36% of the cumulative precipitation was returned to the atmosphere through ET. While the annual water balance regime of the peatland was mainly regulated by the precipitation pattern, daily measured ET was closely related to potential evaporation, and latent heat flux could be well modeled by the Penman-Monteith approach, suggesting two feasible schemes for ET prediction in peatlands under well watered conditions.