Latent and sensible heat flux predictions from a uniform pine forest using surface renewal and flux variance methods

1996 ◽  
Vol 80 (3) ◽  
pp. 249-282 ◽  
Author(s):  
Gabriel Katul ◽  
Cheng-I Hsieh ◽  
Ram Oren ◽  
David Ellsworth ◽  
Nathan Phillips
Keyword(s):  
Heat Flux ◽  
Sensible Heat Flux ◽  
Pine Forest ◽  
Sensible Heat ◽  
Surface Renewal

<i>Estimating sensible heat flux from Camellia sinensis using the Surface renewal method</i>

2019 ◽  
Author(s):  
Noman Ali Buttar ◽  
Yongguang Hu ◽  
Imran Ali Lakhiar ◽  
Ahmad Azeem ◽  
Muhammad Zaman ◽  
...  
Keyword(s):  
Heat Flux ◽  
Camellia Sinensis ◽  
Sensible Heat Flux ◽  
Sensible Heat ◽  
Surface Renewal ◽  
Renewal Method

scholarly journals Seasonal and inter annual variability of energy exchange above a boreal Scots pine forest

2010 ◽  
Vol 7 (4) ◽  
pp. 6441-6494 ◽  
Author(s):  
S. Launiainen
Keyword(s):  
Heat Flux ◽  
Scots Pine ◽  
Seasonal Cycle ◽  
Sensible Heat Flux ◽  
Bowen Ratio ◽  
Pine Forest ◽  
Surface Conductance ◽  
Sensible Heat ◽  
Annual Variability ◽  
Scots Pine Forest

Abstract. Twelve-years of eddy-covariance measurements conducted above a boreal Scots pine forest in Hyytiälä, Southern Finland, were analyzed to assess the seasonal and inter-annual variability of surface conductance (gs) and energy partitioning. The gs had distinct annual course, driven by the seasonal cycle of the Scots pine. Low gs (2–3 mm s−1 in April) restricted transpiration in springtime and caused the sensible heat flux to peak in May–June while evapotranspiration takes over later in July–August when gs is typically 5–7 mm s−1. Hence, during normal years Bowen ratio decreases from 4–6 in April to 0.7–0.9 in August. Sensitivity of gs to ambient vapor pressure deficit (D) was relatively constant but the reference value at D=1 kPa varied seasonally and between years. Only two drought episodes when volumetric soil moisture content in upper mineral soil decreased below 0.15 m3 m−3 occurred during the period. Below this threshold value transpiration was strongly reduced, which promoted sensible heat exchange increasing Bowen ratio to 3–4. Annual evapotranspiration varied between 218 and 361 mm and accounted between 50% and 90% of equilibrium evaporation. The forest floor contributed between 16 and 25% of the total evapotranspiration on annual scale. The fraction stayed similar over the observed range of environmental conditions including drought. The inter-annual variability of evapotranspiration could not be linked to any mean climate parameter while the summertime sensible heat flux and net radiation were well explained by global radiation. The energy balance closure varied annually between 0.66 and 0.95 and had a distinct seasonal cycle with worse closure in spring when large proportion of available energy is partitioned into sensible heat.

scholarly journals Estimation of the Latent Heat Flux over Irrigated Short Fescue Grass for Different Fetches

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 322
Author(s):  
Francesc Castellví ◽  
Pedro Gavilán
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Sensible Heat Flux ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
The Other ◽  
Sensible Heat ◽  
Surface Renewal ◽  
Residual Method ◽  
Flux Footprints

Often in agrometeorology the instrumentation required to estimate turbulent surface fluxes must be installed at sites where fetch is not sufficient for a sector of wind directions. For different integrated flux-footprints (IFFP) thresholds and taking as a reference the half-hourly latent heat fluxes (LE) measured with a large weighing lysimeter (LELys), the eddy covariance (EC) method and two methods based on surface renewal (SR) analysis to estimate LE were tested over short fescue grass. One method combined SR with the flux-gradient (profile) relationship, SR-P method, and the other with the dissipation method, SR-D method. When LE was estimated using traces of air moisture, good performances were obtained using the EC and the SR-P methods for samples with IFFP higher than 85%. However, the closest LE estimates were obtained using the residual method. For IFFP higher than 50%, the residual method combined with the sensible heat flux estimates determined using the SR-P method performed close to LELys and using the SR-D method good estimates were obtained for accumulated LELys. To estimate the sensible heat flux, the SR-D method can be recommended for day-to-day use by farmers because it is friendly and affordable.

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