The effect of grass transpiration on the air temperature

Biologia ◽  
2014 ◽  
Vol 69 (11) ◽  
Author(s):  
Miloslav Šír ◽  
Miroslav Tesař ◽  
Ľubomír Lichner ◽  
Henryk Czachor
Keyword(s):  
Air Temperature ◽  
Root Zone ◽  
Sunshine Duration ◽  
Global Radiation ◽  
Maximum Intensity ◽  
Vegetative Cover ◽  
Brown Forest Soil ◽  
Large Area ◽  
Avenella Flexuosa ◽  
Daily Total

AbstractOscillations of the air temperature and tensiometric pressure of the soil water were measured in the experimental slope Tomšovka (Czech Republic, Jizera Mts, 822 m a.s.l.). The brown forest soil (Dystric Cambisols) is covered with Calamagrostis villosa, Avenella flexuosa and Vaccinium myrtilus. Thermometers were placed at a height of 5 and 200 cm above the grassland. The tensiometer was installed in the root zone of grass at a depth of 15 cm. Oscillations in a cloudless day, August 24, 2001, (sunshine duration 12.1 hour/day, daily total of global radiation 22.4 MJ/m2/day, maximum intensity of global radiation 1008 W/m2, transpiration 13.7 MJ/m2/day) were analysed in detail. The oscillations with a period of about 30 to 60 minutes were recorded in the air temperature course taken from 11 am to 5 pm. At the height of 200 cm oscillations ranged from 24 to 28°C. Concurrently, in the depth of 15 cm, the oscillations of tensiometric pressure in the range of −6 to −11 kPa were recorded from 8 am to 4 pm. It was concluded that the oscillations in the air temperature resulted from autonomous and self-regulated oscillations in the intensity of transpiration. It is evident that the 2-m air temperature was significantly influenced by transpiration of plants around the large area. The fact that the air temperature oscillated sharply confirms that the rate of transpiration was synchronized in this area. Vegetative cover thus created a self-regulated superorganism that substantially affected the temperature of the near-ground atmosphere layer.

scholarly journals Hydrophytometeorological indexes of Virginia type tobacco

2008 ◽  
Vol 53 (2) ◽  
pp. 91-97 ◽  
Author(s):  
Miroljub Aksic ◽  
Nebojsa Deletic ◽  
Nebojsa Gudzic ◽  
Slavisa Gudzic ◽  
Slavisa Stojkovic
Keyword(s):  
Air Temperature ◽  
Water Consumption ◽  
Potential Evapotranspiration ◽  
Sunshine Duration ◽  
Global Radiation ◽  
Precipitation Amount ◽  
Soil Layer ◽  
Vegetation Period ◽  
Air Humidity ◽  
Type Water

The field trial of Virginia type tobacco (Hevesi-9) was set in irrigation conditions, in the vicinity of Brzi Brod village, Nisava River's valley, on the alluvium soil type. Water consumption for evapotranspiration, at the irrigated variant and the control one, was calculated for each month and the whole vegetation period, by making the balance between water consumption from the soil layer to 2m under the ground, total precipitation amount in the vegetation and water added by irrigation. Hydro-phyto-meteorological indexes of Virginia type tobacco were calculated in regard to air temperature, relative air humidity, air humidity deficiency, sunshine duration and global radiation. Among the six meteorological elements (the above mentioned five and wind speed) analyzed in the studied period, the highest level of correlation with tobacco ETP was shown by air temperature (r=0.88), so the use of hydro-phytotermic index could be recommended for calculation of potential evapotranspiration in irrigation practice.

Interval of days required for determining efficient relations between climatic factors and cotton flower and boll production

2002 ◽  
Vol 82 (3) ◽  
pp. 499-506 ◽  
Author(s):  
Zakaria M Sawan ◽  
Louis I Hanna ◽  
Willis L McCuistion
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Surface Soil ◽  
Cultural Practices ◽  
Agricultural Research ◽  
Climatic Factors ◽  
Sunshine Duration ◽  
Field Trials ◽  
Cotton Production ◽  
Surface Soil Temperature

The cotton plant (Gossypium spp.) is sensitive to numerous environmental factors. This study was aimed at predicting effects of climatic factors grouped into convenient intervals (in days) on cotton flower and boll production compared with daily observations. Two uniformity field trials using the cotton (G. barbadense L.) cv. Giza 75 were conducted in 1992 and 1993 at the Agricultural Research Center, Giza, Egypt. Randomly chosen plants were used to record daily numbers of flowers and bolls during the reproductive stage (60 days). During this period, daily air temperature, temperature magnitude, evaporation, surface soil temperature, sunshine duration, humidity, and wind speed were recorded. Data, grouped into intervals of 2, 3, 4, 5, 6, and 10 d, were correlated with cotton production variables using regression analysis. Evaporation was found to be the most important climatic variable affecting flower and boll production, followed by humidity and sunshine duration. The least important variables were surface soil temperature at 0600 and minimum air temperature. The 5-d interval was found to provide the best correlation with yield parameters. Applying appropriate cultural practices that minimize the deleterious effects of evaporation and humidity could lead to an important improvement in cotton yield in Egypt. Key words: Cotton, flower production, boll production, boll retention

Empirical Equations to Estimate Evapotranspiration in Mosul City

2020 ◽  
Vol 27 (4) ◽  
pp. 98-102
Author(s):  
Haqqi Yasin ◽  
Luma Abdullah
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Reference Evapotranspiration ◽  
Sunshine Duration ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Daily Data ◽  
Daily Sunshine ◽  
Measured Wind Speed

Average daily data of solar radiation, relative humidity, wind speed and air temperature from 1980 to 2008 are used to estimate the daily reference evapotranspiration in the Mosul City, North of Iraq. ETo calculator software with the Penman Monteith method standardized by the Food and Agriculture Organization is used for calculations. Further, a nonlinear regression approach using SPSS Statistics is utilized to drive the daily reference evapotranspiration relationships in which ETo is function to one or more of the average daily air temperature, actual daily sunshine duration, measured wind speed at 2m height and relative humidity

scholarly journals Ground-based “Pot-in-Pot” system and its effectiveness in growing Thuja occidentalis “Smaragd” planting material in a nursery

2021 ◽  
Vol 875 (1) ◽  
pp. 012092
Author(s):  
A N Tseplyaev ◽  
A A Tseplyaeva
Keyword(s):  
New Technologies ◽  
Root Zone ◽  
Effect Of Temperature ◽  
Forest Steppe ◽  
High Survival ◽  
Large Area ◽  
Thuja Occidentalis ◽  
Planting Material ◽  
Favorable Temperature ◽  
Intensive Growth

Abstract For the sparsely wooded regions of Russia, and in particular, the Central forest-steppe, new technologies for growing seedlings and seedlings of tree species are extremely important. It provids rapid growth and high survival rate, which is compared to classic technologies. The purpose of our experiment was to establish the effect of temperature screens from pots of various sizes on the temperature in the root zone of the substrate, and, as a consequence, on the growth and productivity of Thuja occidentalis “Smaragd” in plastic pots for three seasons. The most favorable temperature conditions for plants are formed in large pots, which is facilitated by smooth temperature drops in the substrate and a large area of contact between the substrate and the root system. Agrotechnical methods of growing plants have shown the main advantages of “Pot-in-Pot” technology. This is accelerated plant growth due to more efficient use of water and fertilizers on a specially prepared substrate under conditions of minimal temperature fluctuations. Plants, especially large ones, will have a favorable presentation due to better leafing, a well-developed crown, and a large crown diameter. High safety during wintering also increases the efficiency of the technology providing a higher yield and subsequent more intensive growth.

scholarly journals Comparison of Pyranometric and Pyrheliometric Methods for the Determination of Sunshine Duration

2007 ◽  
Vol 24 (5) ◽  
pp. 835-846 ◽  
Author(s):  
Yvonne B. L. Hinssen ◽  
Wouter H. Knap
Keyword(s):  
Solar Irradiance ◽  
Extreme Values ◽  
Sunshine Duration ◽  
Global Radiation ◽  
Surface Radiation ◽  
Global Irradiance ◽  
Correlation Algorithm ◽  
Mean Differences ◽  
Radiation Measurements

Abstract Two pyranometric methods for the determination of sunshine duration (SD) from global irradiance measurements are evaluated by means of summated sunshine seconds derived from pyrheliometric measurements in combination with the WMO threshold of 120 W m−2 for the direct solar irradiance. The evaluation is performed using direct and global radiation measurements made at the Cabauw Baseline Surface Radiation Network (BSRN) site in the Netherlands for the period March 2005–February 2006. The “Slob algorithm” uses 10-min mean and extreme values of the measured global irradiance and parameterized estimates of the direct and diffuse irradiance. The “correlation algorithm” directly relates SD to 10-min mean measurements of global irradiance. The cumulative pyrheliometric SD for the mentioned period is 1429 h. Relative to this value, the Slob algorithm and correlation algorithm give −72 h (−5%) and +8 h (+0.6%). On a daily mean basis, the values are −0.22 ± 0.05 h day−1 and 0.03 ± 0.03 h day−1, respectively. By means of tuning the irradiance parameterizations of the Slob algorithm, the yearly cumulative and daily mean differences can be reduced to +7 h (+0.5%) and 0.02 ± 0.04 h day−1, respectively. It is concluded that, by use of either algorithm, it is possible to estimate daily sums of SD from 10-min mean measurements of global irradiance with a typical uncertainty of 0.5–0.7 h day−1. For yearly sums, the uncertainty typically amounts to 0.5%.

scholarly journals The effect of the total solar eclipse of 29 March 2006 on meteorological variables in Greece

2007 ◽  
Vol 7 (21) ◽  
pp. 5543-5553 ◽  
Author(s):  
D. Founda ◽  
D. Melas ◽  
S. Lykoudis ◽  
I. Lisaridis ◽  
E. Gerasopoulos ◽  
...  
Keyword(s):  
Air Temperature ◽  
Solar Eclipse ◽  
Global Radiation ◽  
Surface Wind ◽  
Temperature Drop ◽  
Surface Air Temperature ◽  
Total Solar Eclipse ◽  
Meteorological Variables ◽  
Small Island ◽  
Meteorological Model

Abstract. This paper examines the effect of the total solar eclipse of 29 March 2006 on meteorological variables across Greece. Integrated micrometeorological measurements were conducted at Kastelorizo, a small island within the path of totality, and other sites within the Greek domain, with various degrees of solar obscuration. The observations showed a dramatic reduction in the incoming global radiation and subsequent, pronounced changes in surface air temperature with the lowest temperature values occurring about 15 min after the full phase. The amplitude of the air temperature drop was not analogous to the obscuration percentage but was principally determined by the surrounding environment (mainly the sea influence), the background meteorological conditions and local cloudiness. Surface wind-speed decreased in most sites as a result of the cooling and stabilization of the atmospheric boundary layer. This perturbation provided a unique opportunity to apply a sensitivity analysis on the effect of the eclipse to the Weather Research and Forecast (WRF) numerical mesoscale meteorological model. Strong anomalies, not associated with a dynamic response, were simulated over land especially in surface air temperature. The simulated temperature drop pattern was consistent with the observations.

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