The soil heat flux sensor functioning checks, imbalances' origins, and forgotten energies

[摘要] Soil heat flux is an important component of the surface energybalance (SEB) equation. Measuring it requires an indirect measurement. Everyused technique may present some possible errors tied with the utilizedspecific technique, soil inhomogeneities, or physical phenomena such aslatent heat conversion beneath the plates, especially in desiccation crackingsoil or vertisol. The installation place may also induce imbalances.Finally, some errors resulting from the physical sensor presence, vegetationpresence, or soil inhomogeneities may occur and are not avoidable. For allthese reasons it is important to check the validity of the measurements. Aquick and easy way is to integrate results over 1 year. By considerationof the inert core internal energy conservation law, it is shown that thecorresponding integration should be close to zero after a necessarygeothermal heat efflux subtraction. However, below-plate evaporation andvegetation-absorbed water or rainwater infiltration may also contributeto the observed short-scale and/or long-scale imbalance generatingconvective heat fluxes not sensed by the heat flux sensors. Another energysource is usually not included in the SEB equation: rainfall or irrigation.Yet its importance for short- and long-term integration is notable. As anexample, the most used sensor, soil heat flux plates (SHFPs), is given.

[学科分类] 再生能源与代替技术