A Hybrid Bulk Algorithm to Predict Turbulent Fluxes over Dry and Wet Bare Soils
A Hybrid Bulk Algorithm to Predict Turbulent Fluxes over Dry and Wet Bare Soils
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DOI：
10.1175/jamc-d-20-0232.1
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发表时间：
2022-04-01
影响因子：
3
通讯作者：
McCaffrey, Katherine L.
中科院分区：
文献类型：
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作者：
Grachev, Andrey A.;Fairall, Christopher W.;McCaffrey, Katherine L.
在哥伦比亚河流域（俄勒冈州）在第二个风预报改进项目（WFIP 2）现场活动的不规则地形的区域进行的测量被用来开发一个优化的混合散装算法，预测表面湍流通量从容易测量或模拟的数量在干燥和潮湿的裸露或轻度植被土壤表面。混合（合成）算法结合了（i）湍流的空气动力学方法，该方法基于传递系数（阻力系数和斯坦顿数）、粗糙度长度和Monin-Obukhov相似性;以及（ii）具有基于物理的生态生理约束的改进的Priestley-Taylor（P-T）算法，该算法基本上基于表面能量收支（SEB）方程。在后一种情况下，土壤热通量估计从土壤温度和土壤湿度的测量。在混合算法的框架内，批量估计的动量通量和感热通量来自传统的空气动力学方法，而潜热通量（或水分通量）的评估从修改后的P-T模型。直接测量的表面通量（湍流和辐射）和其他辅助大气/土壤参数在WFIP 2不同的土壤条件（干和湿）进行优化和调整的混合散装算法。批量通量估计验证对测得的涡度协方差通量。我们还讨论了SEB关闭在不同的时间尺度的基础上模拟和测量通量的干和湿表面。尽管该批量通量算法针对WFIP 2期间收集的数据进行了优化，但混合方法可用于类似的通量塔站点和现场活动。
Measurements made in the Columbia River basin (Oregon) in an area of irregular terrain during the second Wind Forecast Improvement Project (WFIP2) field campaign are used to develop an optimized hybrid bulk algorithm to predict the surface turbulent fluxes from readily measured or modeled quantities over dry and wet bare or lightly vegetated soil surfaces. The hybrid (synthetic) algorithm combines (i) an aerodynamic method for turbulent flow, which is based on the transfer coefficients (drag coefficient and Stanton number), roughness lengths, and Monin-Obukhov similarity; and (ii) a modified Priestley-Taylor (P-T) algorithm with physically based ecophysiological constraints, which is essentially based on the surface energy budget (SEB) equation. Soil heat flux in the latter case was estimated from measurements of soil temperature and soil moisture. In the framework of the hybrid algorithm, bulk estimates of the momentum flux and the sensible heat flux are derived from a traditional aerodynamic approach, whereas the latent heat flux (or moisture flux) is evaluated from a modified P-T model. Direct measurements of the surface fluxes (turbulent and radiative) and other ancillary atmospheric/soil parameters made during WFIP2 for different soil conditions (dry and wet) are used to optimize and tune the hybrid bulk algorithm. The bulk flux estimates are validated against the measured eddy-covariance fluxes. We also discuss the SEB closure over dry and wet surfaces at various time scales based on the modeled and measured fluxes. Although this bulk flux algorithm is optimized for the data collected during the WFIP2, a hybrid approach can be used for similar flux-tower sites and field campaigns.