scholarly journals A gap filling method for active surface heat balance structure

2018 ◽  
Vol 23 ◽  
pp. 00023
Author(s):  
Jacek Leśny ◽  
Monika Panfil
Keyword(s):  
Latent Heat ◽  
Heat Balance ◽  
Bowen Ratio ◽  
Active Surface ◽  
Soil Heat Flux ◽  
Surface Heat ◽  
Sensible Heat ◽  
Net Radiation ◽  
Gap Filling ◽  
Balance Structure

The paper describes gap filling procedures for active surface heat balance structure data recorded for fields of rape, maize, spring and winter wheat and an apple orchard. The balance components were determined based on the Bowen ratio requiring direct measurements of net radiation, soil heat flux, temperature and water vapour pressure profiles. The latter is used to determine vertical gradients and the Bowen ratio, with sensible and latent heat fluxes calculated from the heat balance equation. Missing data are filled in from regression dependencies between individual balance components at various measurement sites. The regression data set comprised results recorded over 24 h, before the gap in measurements and after 24 h. Multiple regressions were determined from a 48-h measurement set. Regression was applied to establish missing values of net radiation (Rn), soil heat flux (G) and latent heat (LE), while sensible heat was calculated from the active surface heat balance equation. Relatively the greatest differences were found for latent heat and soil fluxes, with both estimated values deviating by 13% from the measured daily average, for net radiation the relative difference was 10% and for sensible heat – 6%. This method successfully filled gaps in measured heat balance data from April to September.

scholarly journals Ablation and Heat Balance of the Yukikabe Snow Patch in the Daisetsu Mountains, Hokkaido, Japan

1984 ◽  
Vol 5 ◽  
pp. 122-126 ◽  
Author(s):  
A. Sato ◽  
S. Takahashi ◽  
R. Naruse ◽  
G. Wakahama
Keyword(s):  
Latent Heat ◽  
Air Temperature ◽  
Heat Balance ◽  
Meteorological Parameters ◽  
Heat Sources ◽  
Sensible Heat ◽  
Net Radiation ◽  
Ice Caps ◽  
Air Temperatures ◽  
The Heat Balance

A good correlation was found between the ablation of snow and degree day index (cumulative values of positive daily mean air temperature) during the summer of 1978 on the Yukikabe snow patch in the Daisetsu mountains, central Hokkaido. The volume change of the snow patch in the ablation season of any year can hence be estimated from air temperature using this relationship. Each of the heat-balance terms controlling the ablation is evaluated separately by using empirical equations and assumed values for meteorological parameters at the snow patch. Triangular diagrams are constructed in order to illustrate the relative contributions of sensible heat, latent heat, and net radiation, the main three heat sources. A higher contribution from sensible and latent heat is found for the snow patches of Japan than for many glaciers and ice caps elsewhere. This may be due to higher mid-summer air temperatures than in other glaciated parts of the world.

Characteristics of Long-term Surface Heat Source and Its Climate Influence Factors in Central Tibetan Plateau

2021 ◽  
Author(s):  
Zeyong Hu ◽  
Xiaoqiang Yan
Keyword(s):  
Heat Flux ◽  
Heat Source ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Sensible Heat Flux ◽  
Surface Heat ◽  
Sensible Heat ◽  
Net Radiation ◽  
Maximum Value

<p>Based on multi-level AWS data during 2001 to 2015 and eddy covariance data during 2011 to 2014 at Nagqu Station of Plateau Climate and Environment, the turbulent fluxes were calculated by a surface energy balance combination (CM) and eddy covariance ( EC) method. A long-term heat fluxes and surface heat source were obtained with comparison and correction of EC and CM fluxes. The surface energy closure ratio is close to 1 in spring, summer and autumn. But it reaches to 1.34 in winter due to low net radiation observation value on snow surface. The sensible heat flux shows a ascend trend while latent heat flux shows a descend trend during 2002 to 2015. The surface heat source shows a descend trend. The analysis of the surface heat source indicates that it has a significant relationship with net radiation flux, surface temperature, soil moisture and wind speed. Particularly, the surface heat source has a significant response to net radiation flux throughout the year. There are obvious influences of surface temperature and soil moisture on the surface heat source in spring, autumn and winter. And the influence of wind speeds on surface heat source is strong only in spring. The annual variation of sensible heat flux and latent heat flux are obvious. Sensible heat flux reaches the maximum value of the year in April and the minimum value in July. however, latent heat flux shows the maximum value in July and the minimum value in January. </p>

scholarly journals Heat storage in forest biomass improves energy balance closure

2010 ◽  
Vol 7 (1) ◽  
pp. 301-313 ◽  
Author(s):  
A. Lindroth ◽  
M. Mölder ◽  
F. Lagergren
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Latent Heat ◽  
Heat Storage ◽  
Soil Heat Flux ◽  
Energy Balance Closure ◽  
Sensible Heat ◽  
Net Radiation ◽  
Tree Biomass ◽  
Stable Conditions

Abstract. Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and −35 W m−2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m−2 and the minimum was −35 W m−2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation very well. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. −0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy covariance measurements can function well during stable conditions but that the functioning under strong instabilities might be a so far unforeseen problem.

scholarly journals Heat storage in forest biomass significantly improves energy balance closure particularly during stable conditions

2009 ◽  
Vol 6 (4) ◽  
pp. 8531-8567
Author(s):  
A. Lindroth ◽  
M. Mölder ◽  
F. Lagergren
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Latent Heat ◽  
Heat Storage ◽  
Soil Heat Flux ◽  
Energy Balance Closure ◽  
Sensible Heat ◽  
Net Radiation ◽  
Tree Biomass ◽  
Stable Conditions

Abstract. Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and −35 W m−2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m−2 and the minimum was −35 W m−2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation nearly perfectly. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. −0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy covariance measurements can function well during stable conditions but that the functioning under strong instabilities might be a so far unforeseen problem.

scholarly journals DYNAMICS OF HEAT FLUXES BY BOWEN AND MATMNXFLX AND NOAH FLDAS PRODUCTS IN THE PANTANAL OF MATO GROSSO.

2019 ◽  
Vol 46 (3) ◽  
pp. 07
Author(s):  
Leilane Gomes Duarte ◽  
Kelly Souza Romera ◽  
Marlus Sabino ◽  
Leone Francisco Amorim Curado ◽  
Rafael Da Silva Palácios ◽  
...  
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Sensible Heat Flux ◽  
Bowen Ratio ◽  
Absolute Error ◽  
Soil Heat Flux ◽  
Heat Fluxes ◽  
Sensible Heat ◽  
Seasonal Behavior ◽  
Mato Grosso

This paper aimed to analyze the dynamics of the energy budget components: latent heat flux (LE), sensible heat flux (H) and soil heat flux (G), in the Mato Grosso Pantanal. The estimates of LE, H, and G were obtained by the Bowen ratio methods, using data from the micrometeorological tower located in the Baía das Pedras Park of SESC-Pantanal Ecological Resort, for the years 2011 to 2013. The normality of the variables Rn, LE, H and G, were tested by Kolmogorov-Smirnov test at 5% significance, and the seasonal differences of the fluxes were verified by the KruskalWallis test, α = 0.05. LE and H data from the remote sensing products MATMNXFLX and FLDAS_NOAH of the MERRA model was also acquired, and their comparison with the tower data was performed by the statistics of Spearman correlation (r), Mean Absolute Error (MAE), Root Mean Squared Erro (RMSE), bias, and Willmott's Concordance Index (d). It was observed that most of the available energy is used for evapotranspiration (latent heat), followed by sensible heat and soil heat flux. In the rainy season there is an increase in the partition of LE and G and reduction of H. Only the estimates of LE of MATMNXFLX and FLDAS_NOAH products correlate with the data observed in the meteorological tower. It is concluded that the energy partitions have a seasonal behavior and that the MATMNXFLX and FLDAS_NOAH products, after being calibrated, can be used to estimate LE in the Mato Grosso Pantanal.

scholarly journals Ablation and Heat Balance of the Yukikabe Snow Patch in the Daisetsu Mountains, Hokkaido, Japan

1984 ◽  
Vol 5 ◽  
pp. 122-126 ◽  
Author(s):  
A. Sato ◽  
S. Takahashi ◽  
R. Naruse ◽  
G. Wakahama
Keyword(s):  
Latent Heat ◽  
Air Temperature ◽  
Heat Balance ◽  
Meteorological Parameters ◽  
Heat Sources ◽  
Sensible Heat ◽  
Net Radiation ◽  
Ice Caps ◽  
Air Temperatures ◽  
The Heat Balance

A good correlation was found between the ablation of snow and degree day index (cumulative values of positive daily mean air temperature) during the summer of 1978 on the Yukikabe snow patch in the Daisetsu mountains, central Hokkaido. The volume change of the snow patch in the ablation season of any year can hence be estimated from air temperature using this relationship. Each of the heat-balance terms controlling the ablation is evaluated separately by using empirical equations and assumed values for meteorological parameters at the snow patch. Triangular diagrams are constructed in order to illustrate the relative contributions of sensible heat, latent heat, and net radiation, the main three heat sources. A higher contribution from sensible and latent heat is found for the snow patches of Japan than for many glaciers and ice caps elsewhere. This may be due to higher mid-summer air temperatures than in other glaciated parts of the world.

scholarly journals Summer Heat and Ice Balances on Hodges Glacier, South Georgia, Falkland Islands Dependencies

1982 ◽  
Vol 28 (99) ◽  
pp. 221-238 ◽  
Author(s):  
I. G. G. Hogg ◽  
J. G. Paren ◽  
R. J. Timmis
Keyword(s):  
Latent Heat ◽  
Heat Balance ◽  
Significant Contribution ◽  
Heat Fluxes ◽  
Falkland Islands ◽  
Mountain Range ◽  
Ablation Zone ◽  
Net Radiation ◽  
Summer Heat ◽  
The Heat Balance

AbstractThe heat and ice balances of a temperate sub-Antarctic cirque glacier were measured through the 1973–74 melt season at an altitude midway between the climatic firn limit and the snout. The melt calculated from mean daily measurements at a single level of net radiation, wind-speed, temperature, and humidity agreed with that observed at nearby budget stakes. In the central ablation zone, radiation provided (54 ± 6)% and sensible fluxes (46 ± 6)% of the heat income through the summer, which was exceptionally warm and sunny. Latent-heat fluxes made no significant contribution to the heat balance. The calculation by Smith (1960) that the radiative, sensible, and latent heat fluxes contribute about equally to ablation in this zone has not been substantiated by measurement. The measured partition of the glacier’s heat balance suggested that maritime influences on its regime are mitigated by its position in the lee of a major mountain range.

ENERGY BALANCE OVER PRAIRIE GRASS

1972 ◽  
Vol 52 (2) ◽  
pp. 215-225 ◽  
Author(s):  
LAWRENCE C. NKEMDIRIM ◽  
SHUJI YAMASHITA
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Bowen Ratio ◽  
Soil Heat Flux ◽  
Daily Basis ◽  
Net Radiation ◽  
Large Variability ◽  
Prairie Grass ◽  
Latent Flux ◽  
Evaporative Flux

The energy balance over prairie grass was computed for four cloudless days using the Bowen ratio and the Fourier heat conduction equation. For the 3 advection-free days evaporation accounted for an average of 55% of daytime net radiation. Turbulent flux of heat and soil heat flux shared the remaining portion almost equally. Hourly evaporation can be related to net radiation by the empirical equation: E = 1.2 + 0.75 R cal cm−2 hr−1, where E is the evaporative flux and R the net radiation. The patterns of the soil heat flux was fairly steady from day to day. The relation between hourly flux of sensible heat and soil heat flux was linear on a daily basis. The linearity of the two fluxes when the hourly value for the whole period of investigation was pooled was poor. The proportion of net radiation used as latent flux and sensible flux showed large variability under advection conditions.

scholarly journals Diurnal Energy Balance in a Mango Orchard in the Northeast of Pará, Brazil

2018 ◽  
Vol 33 (3) ◽  
pp. 537-546 ◽  
Author(s):  
Paulo Jorge de Oliveira Ponte de Souza ◽  
Juliana Chagas Rodrigues ◽  
Adriano Marlisom Leão de Sousa ◽  
Everaldo Barreiros de Souza
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Soil Cover ◽  
Sensible Heat Flux ◽  
Sensible Heat ◽  
Net Radiation ◽  
Growing Seasons ◽  
Available Energy

Abstract This study aimed to evaluate the diurnal energy balance during the reproductive stage of two growing seasons of a mango orchard in the northeast of Pará, Brazil. Therefore, a micrometeorological tower was installed and instrumented, in the center of the experimental area, to monitor meteorological variables, besides the phenological evaluation of the mango orchard, which was carried out during growing seasons of 2010-2011 (October 2010 to January 2011) and of 2011-2012 (September 2011 to January 2012). The energy balance was obtained by the bowen ration technique, and the available energy partitioned into heat flux to the ground, sensible heat and latent heat. The amount of rainfall was crucial to the partition of the net radiation in the energy balance components. It provided the variation in the consumption of available energy between 69% and 78% as latent heat flux, and between 23% and 32% as sensible heat flux. The heat flux to the ground was small, representing less than 1% of the net radiation, showing that the mango orchard exhibits good soil cover preventing large variations in soil heating.

Comparison of energy fluxes from eddy covariance and scintillometer over an agricultural field

2020 ◽  
Author(s):  
Matěj Orság ◽  
Milan Fischer ◽  
Josef Eitzinger ◽  
Miroslav Trnka
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Eddy Covariance ◽  
Latent Heat ◽  
Soil Heat Flux ◽  
Radiation Balance ◽  
Energy Balance Closure ◽  
Sensible Heat ◽  
Agricultural Field ◽  
Available Energy

<p>In this study we compare turbulent energy fluxes obtained from eddy covariance (EC) (LI-7500A, LI-COR + Windmaster, Gill Instruments) and large aperture scintillometer (BLS900, Scintec) over an agricultural field (wheat field, straw and bare soil). As the EC method provides direct measurements of sensible heat (H<sub>EC</sub>) and latent heat (LE<sub>EC</sub>) fluxes we use it as a reference method. The EC method enables to determine fluxes within a footprint centered around the point of measurement in the middle of the field. The scintillometer provides an estimation of sensible heat flux (H<sub>SC</sub>), derived from air refractive index fluctuation integrated over the measurement path length, in this case 570 m diagonally across whole field. The reference measurements of the radiation balance components consist of 4-component net radiometer for net radiation (Rn) (NR01, Hukseflux), three soil heat flux plates for soil heat flux (G) monitoring (HFP01, Hukseflux), including thermocouples for quantification of the heat storage above the soil heat flux plates. The scintillometer-based latent heat (LE<sub>SC</sub>) is calculated as a residuum from available energy (Rn-G) and H<sub>SC</sub>, provided by scintillometer. The measurement of radiation balance components was located at the top of 3.5 m mast with the EC system, while the soil heat flux plates were collocated around in 5 cm depth. The site is a flat, rectangular agricultural field (app. 16.5 ha), in the north-eastern Austria, Danube river lowland (48.21N, 16.622E), sown with winter wheat during growing season 2019. The measurement campaign was established in February 2019 with aim for multi-seasonal monitoring. The EC measurement height is 2.7 m, the scintillometer transmitter and receiver are fixed on 4 m masts, facing towards each other from NW and SE corners of the field.</p><p>Comparison of the EC-based turbulent fluxes (H<sub>EC</sub>+LE<sub>EC</sub>) and the available energy (Rn-G) during the period March to Mid-June showed a very good agreement, resulting in the energy balance closure of 0.96 (R<sup>2 </sup>= 0.93). This suggest high accuracy and robustness of the measurement setup together with the ability of the EC method to capture all scales of eddies responsible for energy transport at this site. The comparison of methods indicates that H<sub>SC</sub> overestimated H<sub>EC</sub> by 10 % (R<sup>2 </sup>= 0.74) and LE<sub>SC</sub> underestimated LE<sub>EC</sub> by 13 % (R<sup>2 </sup>= 0.81). Related to Rn, the H<sub>EC</sub>, LE<sub>EC</sub> and G fluxes accounted for 22 % (R<sup>2 </sup>= 0.53), 59 % (R<sup>2 </sup>= 0.70) and 15% (R<sup>2 </sup>= 0.62) of the Rn flux, respectively. We assume that the combination of EC and scintillometer method has a potential to bring deeper insight into the analysis of the energy balance closure problem.</p>

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