Estimation of Surface Fluxes from Time-Series of Temperature and Soil Moisture

根据温度和土壤湿度的时间序列估算表面通量

• 批准号: 9804996
• 负责人: Rafael Bras
• 金额: $ 30万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9804996&HistoricalAwards=false
• 关键词: Estimation; Surface; Fluxes; Time; Series

9804996 Bras A novel method is proposed for estimating ground heat flux, sensible heat flux and evaporation at the surface from time series of soil variables and atmospheric variables. The method eliminates the need of estimating gradients required by most existing algorithms to obtain surface fluxes. It achieves this objective by exploiting diffusion analogies to the vertical movement of heat and moisture in the soil and atmosphere. In such cases the vertical gradient of a scalar variable can be expressed as the half order time derivative of the variable, which in turn is a weighted integral of the time series of the variable in question at the interface between the soil and the atmosphere. Proof-of-concept has been achieved but there are many outstanding issues and need for extensive verification with field data. Some of the questions yet to be addressed include: 1. properly representing parameters that may be soil, vegetation or state dependent; 2. expanding the concept to estimating fluxes over regions, and properly handling the heterogeneity of properties in that case; 3. explore the robustness of the assumptions of the method.T'his work promises to: 1. enhance our ability to utilize remotely sensedobservations to quantify surface hydrometeorological fluxes; 2. improve ability to quantify regional energy balances; 3. suggest better parameterizations of global atmospheric and land models.

[804996]提出了一种利用土壤变量和大气变量时间序列估算地表热通量、感热通量和地表蒸发的新方法。该方法消除了大多数现有算法在获取表面通量时需要估计梯度的需要。它通过利用类似于土壤和大气中热量和水分垂直运动的扩散来实现这一目标。在这种情况下，标量变量的垂直梯度可以表示为该变量的半阶时间导数，而该导数又是该变量在土壤和大气交界面上的时间序列的加权积分。概念验证已经实现，但仍存在许多突出问题，需要用现场数据进行广泛验证。一些有待解决的问题包括：1。适当地表示可能与土壤、植被或状态相关的参数；2. 将这一概念扩展到估计各区域的通量，并在这种情况下适当处理性质的异质性；3. 探讨方法假设的稳健性。这项工作有望：1。加强利用遥感观测量化地表水文气象通量的能力；2. 提高量化区域能源平衡的能力；3. 建议对全球大气和陆地模式进行更好的参数化。