scholarly journals Effect of Phyisco-chemical Parameters on the Thermal Diffusivity and Soil Heat Flux over Ayadi, Ondo State, Nigeria

2020 ◽  
Vol 9 (1) ◽  
pp. 1-5
Author(s):  
K. D. Adedayo Adedayo
Keyword(s):  
Heat Flux ◽  
Thermal Diffusivity ◽  
Physical Properties ◽  
Soil Temperature ◽  
Air Temperature ◽  
Soil Heat Flux ◽  
Dry Season ◽  
Wet Season ◽  
Different Depths ◽  
Ondo State

This study assesses the effect of some soil physical properties on the thermal diffusivity and soil heat flux over Ayadi in Ondo State, Nigeria. Physical properties of the soil at different depths were determined using laboratory techniques. In-situ measurement of air temperature and surface soil temperature were carried out. The phase lag method was used to determine the thermal diffusivity of the soil, while the subsoil heat flux was determined from values obtained for the thermal diffusivity. The result showed that the subsoil heat flux values during the dry season ranged between 0.58 and 52.84 W/m2, while that of the wet season ranged between -0.77 and 98.50 W/m2. The average thermal diffusivity values at the different depths had values between 0.74 × 10-7 and 238.7 × 10-7 m2/s for the dry season, while the wet season had a range of 1.97 × 10-7 to 238.7 × 10-7 m2/s. Keywords: soil moisture content, air temperature, soil temperature, soil heat flux, thermal diffusivity.

scholarly journals Análise Comparativa do Fluxo de Calor no Solo em Profundidade e na Superfície (Brazil Comparative Analysis of Soil Heat Flux in Depth and Surface)

2013 ◽  
Vol 6 (4) ◽  
pp. 665
Author(s):  
Willames Albuquerque Soares
Keyword(s):  
Heat Flux ◽  
Comparative Analysis ◽  
Thermal Diffusivity ◽  
Heat Flow ◽  
Soil Temperature ◽  
Soil Surface ◽  
Soil Heat Flux ◽  
Clear Sky ◽  
Harmonic Method ◽  
Sky Conditions

O objetivo deste estudo é comparar os resultados do fluxo de calor no solo, na superfície e em profundidade, encontrados por sensores de fluxo de calor no solo e pelo método harmônico, em cultivo de mamoneira. No dia sem chuvas, a pouca quantidade de água no solo diminuiu a sua difusividade térmica, provocando um maior acúmulo de energia no solo, e, consequentemente, a elevação na temperatura nas camadas mais próximas à superfície. As principais diferenças entre os valores medidos e estimados aconteceram nos horários de maior insolação, principalmente nos dias em que o céu estava encoberto por nuvens. A presença da vegetação cobrindo o solo influenciou diretamente nos valores medidos e modelados. As estimativas tanto em profundidade como para a superfície do solo se mostraram bastante satisfatórias, tanto em dias de céu claro como para dias de céu encoberto.     A B S T R A C T The aim of this study was to compare the results of soil heat flow, in the surface and depth, found by sensors soil heat flux and by harmonic method, in castor  crop . On days without rainfall, the small amounts of water in the soil decreased its thermal diffusivity, causing a higher energy accumulation in the soil and consequently an increase at a temperature on the layers nearest the surface. The main differences between the measured and estimated values occurred at times of intense sunlight, especially on days when the sky was obscured by clouds. The presence of vegetation covering the soil directly influenced the values measured and modeled. Estimates both in depth and to the soil surface proved very satisfactory, both in clear sky conditions as for overcast days.   Key-Words: Harmonic Method, Soil temperature, soil heat flux plates.

scholarly journals Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 319
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann
Keyword(s):  
Air Temperature ◽  
Daily Rainfall ◽  
Climatic Conditions ◽  
Dry Season ◽  
Climate Impacts ◽  
Calling Behavior ◽  
Wet Season ◽  
Focal Species ◽  
Calling Activity ◽  
Vocal Activity

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

scholarly journals Analysing surface energy balance closure and partitioning over a semi-arid savanna FLUXNET site in Skukuza, Kruger National Park, South Africa

2017 ◽  
Vol 21 (7) ◽  
pp. 3401-3415 ◽  
Author(s):  
Nobuhle P. Majozi ◽  
Chris M. Mannaerts ◽  
Abel Ramoelo ◽  
Renaud Mathieu ◽  
Alecia Nickless ◽  
...  
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Surface Energy ◽  
Latent Heat ◽  
Surface Energy Balance ◽  
Sensible Heat Flux ◽  
Dry Season ◽  
Energy Balance Closure ◽  
Net Radiation ◽  
Wet Season

Abstract. Flux towers provide essential terrestrial climate, water, and radiation budget information needed for environmental monitoring and evaluation of climate change impacts on ecosystems and society in general. They are also intended for calibration and validation of satellite-based Earth observation and monitoring efforts, such as assessment of evapotranspiration from land and vegetation surfaces using surface energy balance approaches. In this paper, 15 years of Skukuza eddy covariance data, i.e. from 2000 to 2014, were analysed for surface energy balance closure (EBC) and partitioning. The surface energy balance closure was evaluated using the ordinary least squares regression (OLS) of turbulent energy fluxes (sensible (H) and latent heat (LE)) against available energy (net radiation (Rn) less soil heat (G)), and the energy balance ratio (EBR). Partitioning of the surface energy during the wet and dry seasons was also investigated, as well as how it is affected by atmospheric vapour pressure deficit (VPD), and net radiation. After filtering years with low-quality data (2004–2008), our results show an overall mean EBR of 0.93. Seasonal variations of EBR also showed the wet season with 1.17 and spring (1.02) being closest to unity, with the dry season (0.70) having the highest imbalance. Nocturnal surface energy closure was very low at 0.26, and this was linked to low friction velocity during night-time, with results showing an increase in closure with increase in friction velocity. The energy partition analysis showed that sensible heat flux is the dominant portion of net radiation, especially between March and October, followed by latent heat flux, and lastly the soil heat flux, and during the wet season where latent heat flux dominated sensible heat flux. An increase in net radiation was characterized by an increase in both LE and H, with LE showing a higher rate of increase than H in the wet season, and the reverse happening during the dry season. An increase in VPD is correlated with a decrease in LE and increase in H during the wet season, and an increase in both fluxes during the dry season.

Corrigendum to: Seasonal patterns of soil carbon dioxide efflux from a wet¿dry tropical savanna of northern Australia

2002 ◽  
Vol 50 (3) ◽  
pp. 373
Author(s):  
Xiaoyong Chen ◽  
Derek Eamus ◽  
Lindsay B. Hutley
Keyword(s):  
Root Growth ◽  
Soil Temperature ◽  
Dry Season ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Tropical Savanna ◽  
Northern Australia ◽  
Soil Co2 ◽  
Wet Season ◽  
Closed Chamber

Soil CO2 efflux rates were measured in a eucalypt open forest in a tropical savanna of northern Australia, with a portable closed chamber and CO2 gas analyser. Both abiotic (soil temperature and water content) and biotic (litterfall and fine-root growth) factors that may influence soil CO2 efflux were examined. Daytime rates of soil CO2 efflux rate were consistently higher than nocturnal values. Maximal rates occurred during late afternoons when soil temperatures were also maximal and minimum values were recorded during the early morning (0400–0800 hours). Average soil CO2 efflux was 5.37 mol m–2 s–1 (range 3.5–6.7 mol m–2 s–1 during the wet season and declined to 2.20 mol m–2 s–1 (range 1.2–3.6 mol m–2 s–1) during the dry season. The amount of carbon released from soil was 14.3 t ha–1 year–1, with approximately 70% released during the wet season and 30% during the dry season. The rate of efflux was correlated with soil moisture content and soil temperature only during the wet season, when root growth and respiration were high. During the dry season there was no correlation with soil temperature. These results are discussed in relation to the carbon balance of tropical savannas.

scholarly journals Fluxo de calor no solo modelado a partir de dados de temperatura em dois níveis de profundidade em uma floresta tropical na Amazônia Ocidental

2018 ◽  
Vol 40 ◽  
pp. 138
Author(s):  
Antônio Vinicius do Prado Rodrigues ◽  
Nelma Tavares Dias Soares ◽  
Renata Gonçalves Aguiar ◽  
Alberto Dresch Webler ◽  
Bruno Soares de Castro
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Soil Temperature ◽  
Tropical Forest ◽  
Large Scale ◽  
Energy Exchange ◽  
Global Climate ◽  
Soil Heat Flux ◽  
Measured Data ◽  
Biological Reserve

The global climate is dependent of ecological balance of forests, especially tropical. The heat flux in the soil is an important factor in studies of energy balance representing the main form of energy exchange between soil and atmosphere. The aim of the present work was to estimate soil heat flux using soil temperature measurements at two depth levels in a tropical forest in the Western Amazon, in order to obtain coherent data for both the use of the values and for the filling of failures in database. Had been used data on temperature and soil heat flux collected in a micrometeorological tower belonging to the towers network of the Large Scale Biosphere-Atmosphere Program in the Amazon, located in the Jaru Biological Reserve. The estimated data presented 94% agreement with the measured data, the two have similar behaviors that allow the use in filling of failures in a demonstrative way. However, there is a delay in the estimated values of the heat flux in the soil in relation to the measured one, which interferes in the result of the model, provoking more studies to improve it.

scholarly journals Sub-soil temperature variation and estimation of soil heat flux at Pune

MAUSAM ◽  
2021 ◽  
Vol 42 (4) ◽  
pp. 357-360
Author(s):  
A. CHOWDHURY ◽  
H. P. DAS ◽  
A. D. PUJARI
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Soil Temperature ◽  
Temperature Variation ◽  
Heat Balance ◽  
Thermal Wave ◽  
Heat Storage ◽  
Soil Heat Flux ◽  
Temperature Ranges ◽  
Maximum Minimum

Utilising experimental data from 23 November to 8.December 1989. temperature and heat storage variations at Pune have been studied, based on 3 hourly observations.. pattern of penetration of .thermal wave within the soil has been examined and time of occurrence of maximum/minimum temperatures discussed for various depths. Temperature ranges in different layers have been theoretically computed and compared with those based on actual observations. Heat balance at various depths has also been presented and discussed.

scholarly journals Hydrometeorological dataset of West Siberian boreal peatland: a 10-year record from the Mukhrino field station

2021 ◽  
Vol 13 (6) ◽  
pp. 2595-2605
Author(s):  
Egor Dyukarev ◽  
Nina Filippova ◽  
Dmitriy Karpov ◽  
Nikolay Shnyrev ◽  
Evgeny Zarov ◽  
...  
Keyword(s):  
Heat Flux ◽  
Air Temperature ◽  
Gaussian Process Regression ◽  
Soil Heat Flux ◽  
Net Radiation ◽  
Field Station ◽  
Local Climate ◽  
Ombrotrophic Peatland ◽  
Meteorological Observations ◽  
Northern Peatlands

Abstract. Northern peatlands represent one of the largest carbon pools in the biosphere, but the carbon they store is increasingly vulnerable to perturbations from climate and land-use change. Meteorological observations taken directly at peatland areas in Siberia are unique and rare, while peatlands are characterized by a specific local climate. This paper presents a hydrological and meteorological dataset collected at the Mukhrino peatland, Khanty-Mansi Autonomous Okrug – Yugra, Russia, over the period of 8 May 2010 to 31 December 2019. Hydrometeorological data were collected from stations located at a small pine–shrub–Sphagnum ridge and Scheuchzeria–Sphagnum hollow at ridge–hollow complexes of ombrotrophic peatland. The monitored meteorological variables include air temperature, air humidity, atmospheric pressure, wind speed and direction, incoming and reflected photosynthetically active radiation, net radiation, soil heat flux, precipitation (rain), and snow depth. A gap-filling procedure based on the Gaussian process regression model with an exponential kernel was developed to obtain continuous time series. For the record from 2010 to 2019, the average mean annual air temperature at the site was −1.0 ∘C, with the mean monthly temperature of the warmest month (July) recorded as 17.4 ∘C and for the coldest month (January) −21.5 ∘C. The average net radiation was about 35.0 W m−2, and the soil heat flux was 2.4 and 1.2 W m−2 for the hollow and the ridge sites, respectively. The presented data are freely available through Zenodo (https://doi.org/10.5281/zenodo.4323024, Dyukarev et al., 2020), last access: 15 December 2020) and can be used in coordination with other hydrological and meteorological datasets to examine the spatiotemporal effects of meteorological conditions on local hydrological responses across cold regions.

scholarly journals Estimating hourly reference evapotranspiration from limited weather data by sequentially adaptive RBF network

2011 ◽  
Vol 9 (3) ◽  
pp. 473-480 ◽  
Author(s):  
Slavisa Trajkovic
Keyword(s):  
Heat Flux ◽  
Air Temperature ◽  
Reference Evapotranspiration ◽  
Soil Heat Flux ◽  
Weather Data ◽  
Canopy Resistance ◽  
Net Radiation ◽  
Rbf Networks ◽  
Rbf Network ◽  
Two Parameters

This study investigates the utility of adaptive Radial Basis Function (RBF) networks for estimating hourly grass reference evapotranspiration (ET0) from limited weather data. Nineteen days of micrometeorological and lysimeter data collected at half-hour intervals during 1962-63 and 1966-67 in the Campbell Tract research site in Davis, California were used in this study. Ten randomly chosen days (234 patterns) were selected for the RBF networks training. Two sequentially adaptive RBF networks with different number of inputs (ANNTR and ANNTHR) and two Penman-Monteith equations with different canopy resistance values (PM42 and PM70) were tested against hourly lysimeter data from remaining nine days (200 patterns). The ANNTR requires only two parameters (air temperature and net radiation) as inputs. Air temperature, humidity, net radiation and soil heat flux were used as inputs in the ANNTHR. PM equations use air temperature, humidity, wind speed, net radiation and soil heat flux density as inputs. The results reveal that ANNTR and PM42 were generally the best in estimating hourly ET0. The ANNTHR performed less well, but the results were acceptable for estimating ET0. These results are of significant practical use because the RBF network with air temperature and net radiation as inputs could be used to estimate hourly ET0 at Davis, California.

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