Analysis of Water Vapor Fluxes Over a Seasonal Snowpack Using the Maximum Entropy Production Model
Analysis of Water Vapor Fluxes Over a Seasonal Snowpack Using the Maximum Entropy Production Model
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DOI：
10.1029/2020jd033049
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发表时间：
2020-12
期刊：
影响因子：
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通讯作者：
I. Hajji;D. Nadeau;B. Music;F. Anctil;Jingfeng Wang
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文献类型：
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作者：
I. Hajji;D. Nadeau;B. Music;F. Anctil;Jingfeng Wang
积雪在寒冷地区的水和能量收支中起着关键作用。在水文模型中了解和参数化雪表面的水和热交换仍然是一个重大挑战。开发了一种基于最大熵产生（MEP）理论的创新方法，用于模拟积雪覆盖表面的能量预算。这项研究概括了MEP模型来模拟地表水蒸气（潜热）通量在整个积雪的生命周期，包括积雪积累和融化在生长季节的早期。扩展MEP模型结合土壤蒸发，冠层蒸腾，和雪升华，以评估积雪的生命周期中的雪水损失。检验了两个假设：（1）当积雪是等温的（0°C）时，在融雪期间升华变得可忽略不计;（2）在植被苏醒期间，蒸腾作用作为空气温度的函数逐渐被激活。所提出的方法被证明是有效的模拟积雪的生命周期的总表面水汽通量。这两种假设都得到了实地观察的支持。
Snow cover plays a key role in the water and energy budgets over cold regions. Understanding and parameterizing water and heat exchange over snow surfaces in hydrologic models remains a major challenge. An innovative approach based on the theory of maximum entropy production (MEP) was developed for modeling energy budgets for snow‐covered surfaces. This study generalizes the MEP model to simulate surface water vapor (latent heat) fluxes over an entire snowpack lifecycle, including snow accumulation and melting during the early growing season. The expanded MEP model combines soil evaporation, canopy transpiration, and snow sublimation to evaluate snow water loss during the lifecycle of the snowpack. Two hypotheses are tested: (1) sublimation becomes negligible during snowmelt when snowpack is isothermal (0°C) and (2) transpiration is progressively activated as a function of the air temperature during vegetation awakening. The proposed approach is shown to be effective for modeling the total surface water vapor fluxes over the snowpack's lifecycle. Both the hypotheses are supported by field observations.