scholarly journals Effect of the Silvopastoral System on the Thermal Comfort of Lambs in a Subtropical Climate: A Preliminary Study

Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 790
Author(s):  
Frederico Márcio C. Vieira ◽  
Jaqueline Agnes Pilatti ◽  
Zilmara Maria Welfer Czekoski ◽  
Vinicius F. C. Fonsêca ◽  
Piotr Herbut ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Heat Load ◽  
Thermal Environment ◽  
Ground Surface ◽  
Radiant Heat ◽  
Silvopastoral System ◽  
Hair Coat ◽  
Ground Surface Temperature ◽  
Preliminary Study

The silvopastoral system has the potential to alleviate the negative impacts of heat stress on livestock. Through a preliminary study, we assessed the thermal environment experienced by hair coat lambs, as well as the impacts on their bio-thermal and behavioural responses, when either kept in either the silvopastoral system, or exposed to full sun. Twelve hair coat lambs (Dorper × Santa Ines) were randomly assigned to a silvopastoral system or full sun exposure during the summer (from January to February 2017). Parameters, including air temperature, black globe temperature, relative humidity, wind speed, and ground surface temperature, were measured daily for both thermal environments. From 14:00 to 16:00, lambs kept in silvopastoral areas experienced lower levels of air temperature, radiant heat load, and ground surface temperature. Consequently, they had a lower hair coat surface and lower body rectal temperatures. Lambs exposed to a shaded environment spent more time grazing and walking, and less time standing at rest. In conclusion, lambs kept in a silvopastoral system experienced lower levels of radiant heat load and ground surface temperature. In addition, the animals showed a reduced requirement for evaporative cooling and expressed behaviours that indicated a comfortable thermal environment.

scholarly journals Thermoregulatory and Behaviour Responses of Dairy Heifers Raised on a Silvopastoral System in a Subtropical Climate

2020 ◽  
Vol 20 (2) ◽  
pp. 613-627 ◽  
Author(s):  
Frederico Márcio C. Vieira ◽  
Matheus Deniz ◽  
Edgar S. Vismara ◽  
Piotr Herbut ◽  
Jaqueline A. Pilatti ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Water Intake ◽  
Time Of Day ◽  
Subtropical Climate ◽  
Silvopastoral System ◽  
Hair Coat ◽  
Dairy Heifers ◽  
Temperature Humidity Index ◽  
Humidity Index

AbstractIn this study, we investigated the influence of a silvopastoral system on the thermal environment, behaviour and thermoregulation of dairy heifers in a subtropical climate. The experiment was conducted on a dairy farm in Southwest Paraná, Brazil, during the summer of 2014. Crossbred Holstein × Jersey dairy heifers (n = 10) were used in a split-plot design. The fixed effects in this study include time of day (9:00–10:00, 13:00–14:00, and 17:00–18:00 h) under silvopastoral or open pastures conditions, which were the main-plot and split-plot factors, respectively. To assess the environmental conditions in both systems, air temperature, relative humidity and wind speed were recorded. In addition, the temperature-humidity index was calculated based on the microcli-mate measurements. Respiratory rate and hair coat surface temperature of heifers were measured in both groups during time of day (30 days). Diurnal behaviour using focal observations with 0/1 sampling was observed. Data were analysed using Bayesian inference with a mixed effects model. The air temperature was higher (P<0.05) in open pasture conditions than the silvopasture system. Temperature-humidity index values for the silvopasture system were lower than open pasture during the hottest hours of the day. Regarding thermoregulation responses, there was an interaction between time of day and pasture environment (P<0.05). Heifers showed lower respiratory rates and hair coat surface temperature values (P<0.05) when access to shade was provided, mainly during the hottest periods in the afternoon. In addition, there was also an interaction between rumination and water intake (P<0.05), which indicates a higher rumination frequency for animals in the silvopasture system during the hottest period, as well as a higher water intake frequency for heifers in open pasture during midday. These findings imply that the arrangement of trees in a silvopasture system provides better thermal comfort conditions for dairy heifers raised in a subtropical climate.

scholarly journals Large area land surface simulations in heterogeneous terrain driven by global datasets: application to mountain permafrost

2013 ◽  
Vol 7 (6) ◽  
pp. 5853-5887 ◽  
Author(s):  
J. Fiddes ◽  
S. Endrizzi ◽  
S. Gruber
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface ◽  
Snow Depth ◽  
Ground Surface ◽  
Swiss Alps ◽  
Large Area ◽  
Heterogeneous Terrain ◽  
Ground Surface Temperature ◽  
Mountain Permafrost

Abstract. Numerical simulations of land-surface processes are important in order to perform landscape-scale assessments of earth-systems. This task is problematic in complex terrain due to: (i) high resolution grids required to capture strong lateral variability, (ii) lack of meteorological forcing data where it is required. In this study we test a topography and climate processor, which is designed for use with large area land surface simulation, in complex and remote terrain. The scheme is driven entirely by globally available datasets. We simulate air temperature, ground surface temperature, snow depth and test the model with a large network of measurements in the Swiss Alps. We obtain RMSE values of 0.64 °C for air temperature, 0.67–1.34 °C for non-bedrock ground surface temperature, and 44.5 mm for snow depth, which is likely affected by poor input precipitation field. Due to this we trial a simple winter precipitation correction method based on melt-dates of the snow-pack. We present a test application of the scheme in the context of simulating mountain permafrost. The scheme produces a permafrost estimate of 2000 km2 which compares well to published estimates. We suggest that this scheme represents a good first effort in application of numerical models over large areas in heterogeneous terrain.

scholarly journals Large-area land surface simulations in heterogeneous terrain driven by global data sets: application to mountain permafrost

2015 ◽  
Vol 9 (1) ◽  
pp. 411-426 ◽  
Author(s):  
J. Fiddes ◽  
S. Endrizzi ◽  
S. Gruber
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface ◽  
Snow Depth ◽  
Ground Surface ◽  
Data Sets ◽  
Large Area ◽  
Heterogeneous Terrain ◽  
Ground Surface Temperature ◽  
Mountain Permafrost

Abstract. Numerical simulations of land surface processes are important in order to perform landscape-scale assessments of earth systems. This task is problematic in complex terrain due to (i) high-resolution grids required to capture strong lateral variability, and (ii) lack of meteorological forcing data where they are required. In this study we test a topography and climate processor, which is designed for use with large-area land surface simulation, in complex and remote terrain. The scheme is driven entirely by globally available data sets. We simulate air temperature, ground surface temperature and snow depth and test the model with a large network of measurements in the Swiss Alps. We obtain root-mean-squared error (RMSE) values of 0.64 °C for air temperature, 0.67–1.34 °C for non-bedrock ground surface temperature, and 44.5 mm for snow depth, which is likely affected by poor input precipitation field. Due to this we trial a simple winter precipitation correction method based on melt dates of the snowpack. We present a test application of the scheme in the context of simulating mountain permafrost. The scheme produces a permafrost estimate of 2000 km2, which compares well to published estimates. We suggest that this scheme represents a useful step in application of numerical models over large areas in heterogeneous terrain.

scholarly journals Spatio-Temporal Variations of Soil Active Layer Thickness in Chinese Boreal Forests from 2000 to 2015

2018 ◽  
Vol 10 (8) ◽  
pp. 1225 ◽  
Author(s):  
Xiongxiong Bai ◽  
Jian Yang ◽  
Bo Tao ◽  
Wei Ren
Keyword(s):  
Surface Temperature ◽  
Layer Thickness ◽  
Active Layer ◽  
Air Temperature ◽  
Climate Warming ◽  
Boreal Forests ◽  
Ground Surface ◽  
Active Layer Thickness ◽  
Ground Surface Temperature ◽  
Spatio Temporal

The soil active layer in boreal forests is sensitive to climate warming. Climate-induced changes in the active layer may greatly affect the global carbon budget and planetary climatic system by releasing large quantities of greenhouse gases that currently are stored in permafrost. Ground surface temperature is an immediate driver of active layer thickness (ALT) dynamics. In this study, we mapped ALT distribution in Chinese boreal larch forests from 2000 to 2015 by integrating remote sensing data with the Stefan equation. We then examined the changes of the ALT in response to changes in ground surface temperature and identified drivers of the spatio-temporal patterns of ALT. Active layer thickness varied from 1.18 to 1.3 m in the study area. Areas of nonforested land and low elevation or with increased air temperature had a relatively high ALT, whereas ALT was lower at relatively high elevation and with decreased air temperatures. Interannual variations of ALT had no obvious trend, however, and the ALT changed at a rate of only −0.01 and 0.01 m year−1. In a mega-fire patch of 79,000 ha burned in 2003, ΔALT (ALTi − ALT2002, where 2003 ≤ i ≤ 2015) was significantly higher than in the unburned area, with the influence of the wildfire persisting 10 years. Under the high emission scenario (RCP8.5), an increase of 2.6–4.8 °C in mean air temperature would increase ALT into 1.46–1.55 m by 2100, which in turn would produce a significant positive feedback to climate warming.

scholarly journals Trends in the differences between homogenized ground surface temperature and surface air temperature in China during 1961–2016 and its possible causes

2021 ◽  
Author(s):  
Xiaohui Shi ◽  
Jinqiu Chen
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Causal Effect ◽  
Ground Surface ◽  
Surface Air Temperature ◽  
Ground Surface Temperature ◽  
Temporal Complexity ◽  
Northern Regions ◽  
Increasing Trends ◽  
Linear Trends

AbstractBased on the latest series of homogenized ground surface temperature (GST) and surface air temperature (SAT) data for China, this study performed a detailed analysis of the trend of the differences between the two homogenized series in 1961–2016. The differences, referred to as surface–air temperature differences (SATDs) in this study, were separately averaged by month, season, and year. The long-term and spatial changes in the trends of SATDs were investigated. Moreover, interdecadal trend breakpoints were identified to understand the characteristics of trends in fluctuation. The possible influences of precipitation, Pacific Decadal Oscillation (PDO), and global warming on SATDs were also analyzed. The results showed that during the 12 months of a year, only three months, March, April, and May, exhibited increasing trends of station-averaged, monthly mean SATDs while the other nine months exhibited decreasing trends. In addition, the station-averaged annual and seasonal mean SATDs of summer, autumn, and winter all showed significant decreasing trends, while the spring mean SATDs showed a significant increasing trend. The spatial distribution pattern of the linear trends of monthly, seasonal, and annual SATDs in meteorological stations indicated that SATDs had more obviously increasing trends in the northern regions than the southern regions of China. The trends of station-averaged monthly mean SATDs (except for April) and station-averaged seasonal and annual mean SATDs experienced interdecadal breakpoints, fully indicative of obvious interdecadal fluctuations with temporal complexity among China’s SATD trends. By the regression analysis of monthly STADs against simultaneous precipitation, as well as the comparative analysis of their linear trends, we found that both amount of precipitation and the change of precipitation type have important influences on SATDs. The results of convergent cross mapping analysis also revealed the causal effect of precipitation on SATDs.

scholarly journals Modeling the Temperature Field in the Ground with an Installed Slinky-Coil Heat Exchanger

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4010
Author(s):  
Monika Gwadera ◽  
Krzysztof Kupiec
Keyword(s):  
Temperature Field ◽  
Heat Exchanger ◽  
Surface Temperature ◽  
Ground Surface ◽  
Heat Sources ◽  
Ground Surface Temperature ◽  
Coil Heat Exchanger ◽  
The Relationship ◽  
Temperature Responses ◽  
Coil Heat

In order to find the temperature field in the ground with a heat exchanger, it is necessary to determine temperature responses of the ground caused by heat sources and the influence of the environment. To determine the latter, a new model of heat transfer in the ground under natural conditions was developed. The heat flux of the evaporation of moisture from the ground was described by the relationship taking into account the annual amount of rainfall. The analytical solution for the equations of this model is presented. Under the conditions for which the calculations were performed, the following data were obtained: the average ground surface temperature Tsm = 10.67 °C, the ground surface temperature amplitude As = 13.88 K, and the phase angle Ps = 0.202 rad. This method makes it possible to easily determine the undisturbed ground temperature at any depth and at any time. This solution was used to find the temperature field in the ground with an installed slinky-coil heat exchanger that consisted of 63 coils. The results of calculations according to the presented model were compared with the results of measurements from the literature. The 3D model for the ground with an installed heat exchanger enables the analysis of the influence of miscellaneous parameters of the process of extracting or supplying heat from/to the ground on its temperature field.

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