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Analysis of Water Vapor Fluxes Over a Seasonal Snowpack Using the Maximum Entropy Production Model
Author(s) -
Hajji Islem,
Nadeau Daniel F.,
Music Biljana,
Anctil François,
Wang Jingfeng
Publication year - 2021
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2020jd033049
Subject(s) - snowpack , snowmelt , snow , environmental science , transpiration , latent heat , sublimation (psychology) , atmospheric sciences , water vapor , entropy production , sensible heat , hydrology (agriculture) , meteorology , thermodynamics , geology , chemistry , geography , psychology , biochemistry , photosynthesis , geotechnical engineering , psychotherapist , physics
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.