Three year observations of water vapor and energy fluxes over agricultural crops in two regional climates of Southwest Germany
Three year observations of water vapor and energy fluxes over agricultural crops in two regional climates of Southwest Germany
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DOI：
10.1127/metz/2014/0618
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发表时间：
2015-03
影响因子：
1.2
通讯作者：
H. Wizemann;J. Ingwersen;P. Högy;K. Warrach‐Sagi;T. Streck;V. Wulfmeyer
中科院分区：
文献类型：
--
作者：
H. Wizemann;J. Ingwersen;P. Högy;K. Warrach‐Sagi;T. Streck;V. Wulfmeyer
可靠的区域气候预测需要改进的陆面大气模型，其中陆面交换，特别是植被的作用，得到很好的体现。为了更好地了解陆面交换，并作为模型开发，参数化和验证的数据基础，长期的eddycovariance测量进行了农业景观在两个地区的西南德国不同的区域气候：附近的北方上莱茵河河谷气候温和，斯瓦比亚汝拉，低山脉高原的气候是寒冷和潮湿。在每个研究地点，我们安装了三个涡度协方差气象站和监测土壤水分状况以及作物的发展。我们描述了研究地点的特点，实验现场工作和数据处理。对2009 - 2011年冬小麦、冬油菜和青贮玉米的水汽和能量通量动态进行了分析。受统计学和仪器噪声误差的限制，测量的能量和物质通量的精度优于10%。能量通量和作物生长与作物生长密切相关。蒸腾速率随叶面积指数的增大而增大，随叶面积指数的减小而减小。在开花油菜上测得的反照率值高达0.28。冬季作物在较温和的气候中生长较快。潜热通量日平均值比寒冷气候高10-20 Wm b ~ 2，感热通量日平均值比寒冷气候低5-15 Wm b ~ 2。这两个区域之间的湍流通量的差异被分配主要是由于蒸汽压赤字的差异。实际的和普遍的天气条件对能量通量有很大的影响，因此，不仅在区域之间，而且在同一地点，在不同年份的同一作物中，通量动态也存在显著差异。观测到的长期通量动态方面的物候，区域气候和主要天气条件的影响进行了讨论。
Reliable regional climate projections need improved land-surface-atmosphere models in which land-surface exchange, in particular the role of the vegetation, is well represented. To get a better understanding of the landsurface exchange and as a data basis for model development, parameterization and validation, long-term eddycovariance measurements were performed over agricultural landscapes in two regions of Southwest Germany with different regional climate: near the northern Upper Rhine Valley with a mild climate and on the Swabian Jura, a low mountain range plateau where the climate is colder and wetter. At each study site we installed three eddy-covariance weather stations and monitored the soil water regime as well as the crop development. We describe the characteristics of the study sites, the experimental field work and data processing. The dynamics of water vapor and energy fluxes over winter wheat, winter oilseed rape and silage maize were evaluated for the time period from 2009 to 2011. The accuracy of the measured energy and matter fluxes limited by statistics and instrumental noise error was better than 10%. Energy fluxes and albedo were closely linked to crop development. The albedo increased and decreased with LAI. Albedo values up to 0.28 were measured over flowering oilseed rape. The winter crops developed faster in the milder climate. The daily average of latent heat flux was about 10–20 Wm b2 higher and that of sensible heat flux about 5–15 Wm b2 lower there in comparison with the colder climate. Differences between both regions with regard to the turbulent fluxes are assigned to be mainly due to differences in vapor pressure deficit. Actual and prevailing weather conditions had a large impact on energy fluxes so that notable differences of flux dynamics were observed not only between the regions but also at one site for the same crop in different years. The observed long-term flux dynamics are discussed with respect to phenology, regional climate and the impact of prevailing weather conditions.