scholarly journals Comparative studies on energy balance components and their inter relations on soybean crop and bare soil in kharif season at Pune situated in semi-arid tract

MAUSAM ◽  
2022 ◽  
Vol 53 (3) ◽  
pp. 319-328
Author(s):  
R. P. SAMUI ◽  
S. S. MONDAL ◽  
A. K. DHOTRE
Keyword(s):  
Comparative Studies ◽  
Bare Soil ◽  
Global Solar Radiation ◽  
Short Wave ◽  
Radiation Balance ◽  
Growth Stages ◽  
Soybean Crop ◽  
Kharif Season ◽  
Long Wave ◽  
The Mean

Comparative studies of radiation balance components at different growth stages on soybean crop and bare soil were made at Central Agrometeorological  Observatory  (CAgMO), Pune.  Continuous measurements of net, reflected and global solar radiations were made over cropped field as well as over bare soil all throughout the growth phases in kharif season of 1995.  Net and reflected radiations and albedo over canopy were higher by 7, 26 and 25 per cent respectively than bare soil.  The net short wave (absorbed) radiation and net long wave (out-going) radiation evaluated over the canopy  were less than those over bare soil by 5 and 20 per cent respectively.                 The mean daily net, reflected, net short wave and net long wave (out-going)  radiation were 9.86, 3.86, 15.35 and 5.49 MJm-2 respectively and the albedo was 20 per cent over soybean canopy whereas for bare soil they were 9.23, 3.07, 16.15 and 6.91 MJm-2  and 16 per cent respectively.  The mean daily global  solar radiation during the crop growing  season was 19.20 MJm-2. The highest albedo (26 per cent) of the crop recorded in the 10th  week after sowing  (WAS) was in correspondence to maximum LAI (5.9) observed at pod formation stage.

scholarly journals Evaluating the Effects of Façade Greening on Human Bioclimate in a Complex Urban Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Britta Jänicke ◽  
Fred Meier ◽  
Marie-Therese Hoelscher ◽  
Dieter Scherer
Keyword(s):  
Heat Stress ◽  
Short Wave ◽  
Wave Radiation ◽  
Short Wave Radiation ◽  
Long Wave ◽  
Building Facades ◽  
Urban Heat ◽  
The Mean ◽  
Human Bioclimate ◽  
Radiant Temperature

The evaluation of the effectiveness of countermeasures for a reduction of urban heat stress, such as façade greening, is challenging due to lacking transferability of results from one location to another. Furthermore, complex variables such as the mean radiant temperature(Tmrt)are necessary to assess outdoor human bioclimate. We observedTmrtin front of a building façade in Berlin, Germany, which is half-greened while the other part is bare.Tmrtwas reduced (mean 2 K) in front of the greened compared to the bare façade. To overcome observational shortcomings, we applied the microscale models ENVI-met, RayMan, and SOLWEIG. We evaluated these models based on observations. Our results show thatTmrt(MD = −1.93 K) and downward short-wave radiation (MD = 14.39 W/m2) were sufficiently simulated in contrast to upward short-wave and long-wave radiation. Finally, we compare the simulated reduction ofTmrtwith the observed one in front of the façade greening, showing that the models were not able to simulate the effects of façade greening with the applied settings. Our results reveal that façade greening contributes only slightly to a reduction of heat stress in front of building façades.

scholarly journals The Influence of Cloudiness on The Net Radiation Balance of A Snow Surface with High Albedo

1974 ◽  
Vol 13 (67) ◽  
pp. 73-84 ◽  
Author(s):  
W. Ambach
Keyword(s):  
Greenland Ice Sheet ◽  
Short Wave ◽  
Mean Value ◽  
Wave Radiation ◽  
Radiation Balance ◽  
Net Radiation ◽  
Long Wave ◽  
Energy Excess ◽  
Overcast Sky ◽  
Long Wave Radiation

The short-wave and long-wave radiant fluxes measured in the accumulation area of the Greenland ice sheet during a mid-summer period are discussed with respect to their dependence on cloudiness. At a cloudiness of 10/10, a mean value of 270 J/cm2 d is obtained for the daily totals of net radiation balance, whereas a mean value of only 75 J/cm2 d is observed at 0/10. The energy excess of the net radiation balance with overcast sky is due to the significant influence of the incoming long-wave radiation and the high albedo of the surface (average of 84%). High values of net radiation balance are therefore correlated with high values of long-wave radiation balance and low values of short-wave radiation balance.

Cloud effects on surface radiation balance at Helheim and Jakobshavn Glaciers (Greenland) using ground-based observations 

2021 ◽  
Author(s):  
Georges Djoumna ◽  
Sebastian H. Mernild ◽  
David Holland
Keyword(s):  
Short Wave ◽  
Surface Radiation ◽  
Radiation Budget ◽  
Wave Radiation ◽  
Radiation Balance ◽  
Short Wave Radiation ◽  
Radiative Fluxes ◽  
Long Wave ◽  
Transmittance Factor ◽  
Cloud Metrics

<p>The surface radiation budget is an essential component of the total energy exchange between the atmosphere and the Earth’s surface. Measurements of radiative fluxes near/on ice surfaces are sparse in the polar regions, including on the Greenland Ice Sheet (GrIS), and the effects of cloud on radiative fluxes are still poorly studied. In this work, we assess the impacts of cloud on radiative fluxes using two metrics: the longwave-equivalent cloudiness, derived from long-wave radiation measurements, and the cloud transmittance factor, obtained from short-wave radiation. The metrics are applied to radiation data from two automatic weather stations located over the bare ground near the ice front of Helheim (HG) and Jakobshavn Isbræ (JI) on the GrIS. Comparisons of meteorological parameters, surface radiation fluxes, and cloud metrics show significant differences between the two sites. The cloud transmittance factor is higher at HG than at JI, and the incoming short-wave radiation in the summer at HG is 50.0 W m−2 larger than at JI. Cloud metrics derived at the two sites reveal   a high dependency on the wind direction. The total cloud radiative effect (CREnet) generally increases during melt season at the two stations due to long-wave CRE enhancement by cloud fraction.  CREnet decreases from May to June and increases afterward, due to the strengthened short-wave CRE. The annually averaged CREnet were 3.0 ± 7.4 W m-2 and 1.9 ± 15.1 W m−2 at JI and HG.  CREnet estimated from AWS indicates that clouds cool the JI and HG during melt season at different rates.</p>

scholarly journals The Radiation Budget At Mizuho Station, Antarctica, 1979

1982 ◽  
Vol 3 ◽  
pp. 327-332
Author(s):  
Takashi Yamanouchi ◽  
Makoto Wada ◽  
Shinji Mae ◽  
Sadao Kawaguchi ◽  
Kou Kusunoki
Keyword(s):  
Seasonal Variations ◽  
Daily Variation ◽  
Short Wave ◽  
Radiation Budget ◽  
Wave Radiation ◽  
Radiation Balance ◽  
Snow Surface ◽  
Net Radiation ◽  
Long Wave ◽  
Meteorological Elements

Radiation budget measurements were made at Mizuho station (70°42'S, 44"20'E, 2 230 m a. s.1.), East Antarctica, in 1979, within the framework of the Japanese POLEX-South programme. Global, and reflected short-wave and downward and upward long-wave radiat i on fluxes were measured at the snow surface and at the top of a 30 m tower. Direct solar radiation was also measured at the snow surface.Seasonal variations of net radiation and net short-wave and net long-wave radiation are presented. Daily variation of net radiation is also presented with the daily value of meteorological elements. The monthly amounts of net radiation in winter months had very large negative values of about -80 MJ m−2 month−1. (-2 kly month−1). Daily totals of net radiation for clear skies were negative even i n summer, and were always smaller than those for cloudy skies. Monthly amounts of net radiation in summer months (about -1 MJ m−2 month−1 in December) were the smallest among the several Antarctic stations compared, and whether the balance was negative or positive depended on the ratio of clear and cloudy days. Comparison of seasonal variations of radiation components was made and the dominant cause of the radiation balance was discussed.

Radiation and Crops

1965 ◽  
Vol 1 (4) ◽  
pp. 241-251 ◽  
Author(s):  
J. L. Monteith
Keyword(s):  
Cloud Amount ◽  
Short Wave ◽  
Net Radiation ◽  
Direct Sunlight ◽  
Area Index ◽  
Long Wave ◽  
Unit Energy ◽  
The Mean ◽  
South East England ◽  
Agricultural Meteorology

SummaryThe analysis of radiation climate is a central problem of agricultural meteorology because rates of photosynthesis depend on the receipt of visible light and rates of transpiration depend on the net exchange of radiation by a crop canopy. Both short-wave (solar) and long-wave (terrestrial) radiation are correlated with cloud amount, and in south-east England the income of net radiation in summer is proportional to the income of solar radiation.In principle, the fraction of total radiation in the visible waveband depends on cloud cover and on the amount of absorption and scattering in the atmosphere, but in practice the fraction is often between 0·40 and 0·45. The calculation of photosynthetic efficiency needs a figure for the number of quanta (or Einsteins) per unit energy, and this figure can be calculated from the mean wavelength of the radiation weighted by energy, about 0·55μ for direct sunlight.The reflection of radiation by vegetation changes with solar elevation, and at angles between 40° and 60° it ranges between 0·15 for a rough crop (e.g. pineapple) to 0·26 for smoother crops (e.g. sugar beet, kale). The transmission of radiation through the canopy can be expressed as a function of the leaf area index and a parameter that depends on the distribution and orientation of leaves.

scholarly journals New Spectral Observations of the Variable Galaxy Kaz 163

2013 ◽  
Vol 9 (S304) ◽  
pp. 39-40
Author(s):  
Emilia L. Karapetyan
Keyword(s):  
Elliptical Galaxy ◽  
Short Wave ◽  
Mean Value ◽  
Emission Lines ◽  
Byurakan Astrophysical Observatory ◽  
X Ray ◽  
Long Wave ◽  
The Galaxy ◽  
The Mean ◽  
Active Processes

AbstractKaz 163 is a close double galaxy. Its southern component S is compact, with a very blue nucleus, in which heated active processes take place. From time to time gas formations are ejected from it, which behave themselves like emission components around the main emission lines Hα and Hβ, around both from their long-wave and short-wave sides. This paper presents the spectral data of new observations, which were carried out with the 2.6m telescope at the Byurakan Astrophysical Observatory in September 2011. During the former observation in October 1981, lines [NII] λλ 6584,6548 were not visible in the spectrum of the component S. In 2001 they were already visible on the spectrum, and on the spectrum obtained in 2011 they already surpassed the intensity of Hα. The magnitude of the component S is also changing: its nucleus is very blue and its U-B = −0m.63. In the soft X-ray spectral range (0.1–2 keV) the flux of the radiation changed by 45% during 55,000 sec, and in the hard one (2–10keV) it changed up to 3.4 times. Photoindices Γ for the soft and hard ranges in the spectrum of galaxy S, unlike other objects, do not so much differ from each other. The mean value for the first interval is approximately 2.5 and is equal −2.0 for the second one. On the histogram of redshifts Kaz 163 corresponds to the first big peak of the distribution. It is concluded that the component S of the galaxy Kaz 163 is a NLS1 galaxy, with the development of their evolution, is in the preliminary stage. Component N is a normal elliptical galaxy with no activity.

A stochastic model of sea-surface roughness. II

1991 ◽  
Vol 435 (1894) ◽  
pp. 405-422 ◽  
Keyword(s):  
Wave Energy ◽  
Short Wave ◽  
Long Waves ◽  
Scale Model ◽  
Short Waves ◽  
Long Wave ◽  
Proportional Rate ◽  
The Mean ◽  
Sheltering Effect ◽  
Increasing Function

A two-scale model of a wind-ruffled surface is developed which includes (1) modulation of the short waves by orbital straining in the long waves, (2) dissipation of short-wave energy by breaking, and (3) regeneration of the short-wave energy by the wind. For simplicity the long waves are at first assumed to be uniform. It is shown that the character of the surface is governed by the parameter Ω = (β/σγKA ), where β is the proportional rate of short-wave growth due to the wind, σ , K and A are the long-wave frequency wavenumber and amplitude, and γ = 2.08. When Ω < 1 the short waves break over only part of the long-wave surface. When Ω ≽ 1 they break everywhere. The mean-square steepness s 2 ¯ of the short waves is an increasing function of β/σ , but a decreasing function of the long-wave steepness AK . The phase angle between s 2 ¯ and the long-wave elevation η is an increasing function of Ω . The correlation between s 2 ¯ and η is largest when Ω ≪1, but tends to 0 as Ω → 1. The simple model is extended to the case when the long-wave amplitude A has a Rayleigh probability density. To take account of the ‘sheltering ’ effect of high waves we compute the case when any two successive waves have a bivariate Rayleigh density. The application of the model to laboratory and field data is discussed.

Modulation of the growth rate of short surface capillary–gravity wind waves by a long wave

1994 ◽  
Vol 273 ◽  
pp. 169-187 ◽  
Author(s):  
Yu. I. Troitskaya
Keyword(s):  
Growth Rate ◽  
Wind Velocity ◽  
Velocity Gradient ◽  
Wind Waves ◽  
Viscous Sublayer ◽  
Short Wave ◽  
Main Process ◽  
Modulation Amplitude ◽  
Long Wave ◽  
The Mean

Modulation of the growth rate of short capillary–gravity surface wind waves in the presence of a long wave with steepness much smaller than the maximum is studied theoretically. The Miles (1962) mechanism taking into account the viscous wave stresses in the air flow is considered to be the main process of short-wave generation. The short-wave growth rate is defined by the wind velocity gradient in the viscous sublayer of the logarithmic boundary layer. The long wave propagating on the wave surface induces an additional component of the wind velocity gradient oscillating with the length and time periods of the long wave, which results in modulation, with the same period, of the growth rate of the short wave riding on the long one. The growthrate modulation amplitude depends on the parameter M being of the order of the relation between the oscillating and the mean wind velocity gradients in the viscous sublayer \[M=\frac{2kac}{u^2_*}(ckv_{\alpha})^{1/2} \] (where c, k, a are the phase velocity, the wavenumber and the elevation amplitude of the long wave; va is the viscosity coefficient in the air; u* is the wind friction velocity). When M = O(1) (weak winds and long waves) the oscillating component of the shortwave growth rate is of the same order as the mean one. If M is much smaller than unity, then the relative amplitude of the growth rate is of the same order as the steepness of the long wave.

The radiation balance of an apple tree

1972 ◽  
Vol 50 (8) ◽  
pp. 1731-1740 ◽  
Author(s):  
J. T. A. Proctor ◽  
W. J. Kyle ◽  
J. A. Davies
Keyword(s):  
Reflection Coefficient ◽  
Apple Tree ◽  
Short Wave ◽  
Wave Radiation ◽  
Radiation Balance ◽  
Net Radiation ◽  
Short Wave Radiation ◽  
Radiative Processes ◽  
Long Wave ◽  
Long Wave Radiation

Measurements of radiation balance components over an apple tree on 7 days during the growing season showed that 17% of the short-wave radiation was reflected, 17% was lost as long-wave radiation and net radiation amounted to 66%. The reflection coefficient exhibited a characteristic diurnal variation, demonstrating its dependence on solar zenith angle, and varied little over the season. Within the orchard, surfaces ranked in order of increasing reflection coefficient as tree, dry orchard grass, and intertree space.Correlation coefficients relating hourly values of net radiation to incoming short-wave radiation and net short-wave radiation, and net long-wave radiation to net short-wave radiation were highly significant. The heating coefficient was positive and decreased slightly at the end of the season. The long-wave exchange coefficient was negative and exhibited no seasonal trend. This coefficient was closely correlated with screen temperature and may provide a basis for interpretation of surface radiative processes.

scholarly journals The Radiation Budget At Mizuho Station, Antarctica, 1979

1982 ◽  
Vol 3 ◽  
pp. 327-332 ◽  
Author(s):  
Takashi Yamanouchi ◽  
Makoto Wada ◽  
Shinji Mae ◽  
Sadao Kawaguchi ◽  
Kou Kusunoki
Keyword(s):  
Seasonal Variations ◽  
Daily Variation ◽  
Short Wave ◽  
Radiation Budget ◽  
Wave Radiation ◽  
Radiation Balance ◽  
Snow Surface ◽  
Net Radiation ◽  
Long Wave ◽  
Meteorological Elements

Radiation budget measurements were made at Mizuho station (70°42'S, 44"20'E, 2 230 m a. s.1.), East Antarctica, in 1979, within the framework of the Japanese POLEX-South programme. Global, and reflected short-wave and downward and upward long-wave radiat i on fluxes were measured at the snow surface and at the top of a 30 m tower. Direct solar radiation was also measured at the snow surface. Seasonal variations of net radiation and net short-wave and net long-wave radiation are presented. Daily variation of net radiation is also presented with the daily value of meteorological elements. The monthly amounts of net radiation in winter months had very large negative values of about -80 MJ m−2 month−1. (-2 kly month−1). Daily totals of net radiation for clear skies were negative even i n summer, and were always smaller than those for cloudy skies. Monthly amounts of net radiation in summer months (about -1 MJ m−2 month−1 in December) were the smallest among the several Antarctic stations compared, and whether the balance was negative or positive depended on the ratio of clear and cloudy days. Comparison of seasonal variations of radiation components was made and the dominant cause of the radiation balance was discussed.

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