scholarly journals Measurement of soil-surface heat flux with a multi-needle heat-pulse probe

2017 ◽  
Vol 68 (3) ◽  
pp. 336-344 ◽  
Author(s):  
X. Peng ◽  
Y. Wang ◽  
J. Heitman ◽  
T. Ochsner ◽  
R. Horton ◽  
...  
Keyword(s):  
Heat Flux ◽  
Surface Heat Flux ◽  
Soil Surface ◽  
Heat Pulse ◽  
Surface Heat ◽  
Pulse Probe

scholarly journals Influence of wave phase difference between surface soil heat flux and soil surface temperature on land surface energy balance closure

2009 ◽  
Vol 6 (1) ◽  
pp. 1089-1110 ◽  
Author(s):  
Z. Gao ◽  
R. Horton ◽  
H. P. Liu ◽  
J. Wen ◽  
L. Wang
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Surface Energy ◽  
Phase Difference ◽  
Surface Heat Flux ◽  
Surface Energy Balance ◽  
Soil Surface ◽  
Surface Heat ◽  
Energy Balance Closure ◽  
Wave Phase

Abstract. The sensitivity of climate simulations to the diurnal variation in surface energy budget encourages enhanced inspection into the energy balance closure failure encountered in micrometeorological experiments. The diurnal wave phases of soil surface heat flux and temperature are theoretically characterized and compared for both moist soil and absolute dry soil surfaces, indicating that the diurnal wave phase difference between soil surface heat flux and temperature ranges from 0 to π/4 for natural soils. Assuming net radiation and turbulent heat fluxes have identical phase with soil surface temperature, we evaluate potential contributions of the wave phase difference on the surface energy balance closure. Results show that the sum of sensible heat flux (H) and latent heat flux (LE) is always less than surface available energy (Rn-G0) even if all energy components are accurately measured, their footprints are strictly matched, and all corrections are made. The energy balance closure ratio (ε) is extremely sensitive to the ratio of soil surface heat flux amplitude (A4) to net radiation flux amplitude (A1), and large value of A4/A1 causes a significant failure in surface energy balance closure. An experimental case study confirms the theoretical analysis.

Analysis of significant measures for thermal conductivity

2020 ◽  
pp. 35-42
Author(s):  
Yuri P. Zarichnyak ◽  
Vyacheslav P. Khodunkov
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Heat Flux Density ◽  
Measurement Method ◽  
Conductivity Measurement ◽  
Surface Heat ◽  
Measuring Instrument ◽  
New Class ◽  
Achievable Accuracy

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.

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