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1.
In this paper we consider the time-dependent diffuse reflection and transmission problems for a homogeneous anisotropically-scattering atmosphere of finite optical depth and solve it by the principle of invariance. Also we consider the time-dependent diffuse reflection and transmission of parallel rays by a slab consisting of two anisotropic homogeneous layers, whose scattering and transmission properties are known. It is shown how to express the time-dependent reflected and transmitted intensities in terms of their components. In a manner similar to that given by Tsujita (1968), we assumed that the upward-directed intensities of radiation at the boundary of the two layers are expressed by the sum of products of some auxiliary functions depending on only one argument. Then, after some analytical manipulations, three groups of systems of simultaneous integral equations governing the auxiliary functions are obtained. 相似文献
2.
The summer monsoon season of the year 2006 was highlighted by an unprecedented number of monsoon lows over the central and
the western parts of India, particularly giving widespread rainfall over Gujarat and Rajasthan. Ahmedabad had received 540.2mm
of rainfall in the month of August 2006 against the climatological mean of 219.8mm. The two spells of very heavy rainfall
of 108.4mm and 97.7mm were recorded on 8 and 12 August 2006 respectively. Due to meteorological complexities involved in replicating
the rainfall occurrences over a region, the Weather Research and Forecast (WRF-ARW version) modeling system with two different
cumulus schemes in a nested configuration is chosen for simulating these events. The spatial distributions of large-scale
circulation and moisture fields have been simulated reasonably well in this model, though there are some spatial biases in
the simulated rainfall pattern. The rainfall amount over Ahmedabad has been underestimated by both the cumulus parameterization
schemes. The quantitative validation of the simulated rainfall is done by calculating the categorical skill scores like frequency
bias, threat scores (TS) and equitable threat scores (ETS). In this case the KF scheme has outperformed the GD scheme for
the low precipitation threshold. 相似文献
3.
An approximate solution of the transfer equation for coherent scattering in stellar atmospheres with Planck's function as a nonlinear function of optical depth, viz.,
相似文献
4.
A. Chakraborty H. C. Upadhyaya O. P. Sharma S. K. Deb 《Meteorology and Atmospheric Physics》2003,83(3-4):221-236
Summary ?A newly developed ocean general circulation model has been tested and verified with some idealized experiments. Generally
two types of idealized experiments have been done here. First types are called as “symmetric experiments” and second types
are called as “transport experiments”. The first types of experiment help to correct the model core and any deficiency from
boundary conditions. The second types of experiment are the type of validation experiment. In both the experiments there are
no continents, so in the first type of experiments where symmetric forcings are provided one can expect that model should
maintain the symmetric nature. In the second type of experiments one can expect that model should respond correctly to the
wind forcings, if no wind curl is present in the wind forcing there will be no circulation in the extratropics and if there
is no wind the equator there will be no circulation. The model reproduces the possible envisaged results of these experiments
and gives the confidence for performing the realistic integration.
Received February 20, 2002; accepted July 7, 2002
Published online: February 20, 2003 相似文献
5.
We have analyzed the chemical composition and boron isotope composition of tourmaline from tourmalinites, granite and a quartz-tourmaline
vein from the Deri ore zone and from a pegmatitic band in the Rampura-Agucha ore body. These two Proterozoic massive sulfide
deposits occur in the Aravalli-Delhi orogenic belt, Rajasthan, northwest India. Tourmaline from stratiform tourmalinites closely
associated with the massive sulfides in the Deri deposit have preserved their original chemical compositions despite regional
and thermal metamorphism in the area. These tourmalines have low Fe/(Fe + Mg) ratios (0.19–0.30; mean 0.26) that suggest formation
close to the sediment-sea water interface. The δ11B values (−15.5 and −16.4‰) are compatible with boron derived from leaching of argillaceous sediments and/or felsic volcanics
underlying the original massive sulfide deposit during its formation. Boron isotope compositions measured in tourmaline from
a post-ore granite and quartz-tourmaline vein in the Deri deposit indicate that boron in these tourmalines was derived from
the tourmalinites produced during ore formation. The boron isotope systematics of a coarse brown tourmaline crystal from a
pegmatitic band on the hanging wall contact of the Rampura-Agucha deposit indicate that 45 ± 25% of the boron within the original
tourmaline was lost during upper amphibolite facies regional metamorphism.
Received: 3 April 1996 / Accepted: 11 April 1996 相似文献
6.
G. Deb Ray 《Astrophysics and Space Science》1977,47(1):229-236
Solutions for dynamical behaviour of unstable stellar models are obtained, in the special case where the velocity of a gaseous element varies asr/t. It is found that the only possible value for the constant of proportionality is 2/3 and that there are only two such stellar configurations. 相似文献
7.
Udeni Amarasinghe Asru Chaudhuri Alan S.Collins Gautam Deb Sarbani Patranabis-Deb 《地学前缘(英文版)》2015,6(3):453-463
The Pranhita-Godavari Basin in central eastern India is one of the Proterozoic "Purana" basins of cratonic India.New geochronology demonstrates that it has a vast depositional history of repeated basin reactivation from the Palaeoproterozoic to the Mesozoic.U-Pb laser ablation inductively coupled plasma mass spectrometry dating of detrital zircons from two samples of the Somanpalli Group—a member of the oldest sedimentary cycle in the valley-constrains its depositional age to ~1620 Ma and demonstrates a tripartite age provenance with peaks at ~3500 Ma,~2480 Ma and ~1620 Ma,with minor age peaks in the Eoarchaean(~3.8 Ga) and at ~2750 Ma.These ages are consistent with palaeocurrent data suggesting a southerly source from the Krishna Province and Enderby Land in East Antarctica.The similarity in the maximum depositional age with previously published authigenic glauconite ages suggest that the origin of the Pranhita-Godvari Graben originated as a rift that formed at a high angle to the coeval evolving late Meosproterozoic Krishna Province as Enderby Land collided with the Dharwar craton of India.In contrast,detrital zircons from the Cycle III Sullavai Group red sandstones yielded a maximum depositional age of 970±20 Ma and had age peaks of ~2550 Ma,~1600 Ma and then a number of Mesoproterozoic detrital zircons terminating in three analyses at ~970 Ma.The provenance of these is again consistent with a southerly source from the Eastern Ghats Orogen and Antarctica.Later cycles of deposition include the overlying Albaka/Usur Formations and finally the late Palaeozoic to Mesozoic Gondwana Supergroup. 相似文献
8.
The general equation for radiative transfer in the Milne-Eddington model is considered here. The scattering function is assumed to be quadratically anisotropic in the cosine of the scattering angle and Planck's intensity function is assumed for thermal emission. Here we have taken Planck's function as a nonlinear function of optical depth, viz.,B
v(T)=b
o+b
1
e
–. The exact solution for emergent intensity from the bounding face is obtained by the method of the Laplace transform in combination with the Wiener-Hopf technique. 相似文献
9.
S. K. Deb M. H. Manghnani K. Ross R. A. Livingston P. J. M. Monteiro 《Physics and Chemistry of Minerals》2003,30(1):31-38
A Raman scattering and X-ray diffraction study of the thermal decomposition of a naturally occurring, ettringite-group crystal
is presented. Raman spectra, recorded with increasing temperature, indicate that the thermal decomposition begins at ≈55 °C,
accompanied by dehydration of water molecules from the mineral. This is in contrast to previous studies that reported higher
temperature breakdown of ettringite. The dehydration is completed by 175 °C and this results in total collapse of the crystalline
structure and the material becomes amorphous. The Raman scattering results are supported by X-ray diffraction results obtained
at increasing temperatures.
Received: 9 July 2001 / Accepted: 14 August 2002 相似文献
10.
The accurate surface wind in the equatorial Indian Ocean is crucial for modeling ocean circulation over this region. In this study, the surface wind analysis generated at the European Center for Medium Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP) are compared with NASA QuikSCAT satellite derived Level2B (swath level) and Level3 (gridded) surface winds for the year 2005. It is observed that the ECMWF winds exhibit speed bias of 1.5 m/s with respect to QuikSCAT Level3 in the southern equatorial Indian Ocean. The NCEP winds are found to exhibit speed bias (1.0–1.5 m/s) in the southern equatorial Indian Ocean specifically during January–February 2005. The biases are also observed in the analysis when compared with Level2B product as well; however, it is less in comparison to Level3 products. The amplitude of daily variations of both ECMWF and NCEP wind speed in Bay of Bengal and parts of the Arabian Sea is about 80% of that in QuikSCAT, while in the equatorial Indian Ocean it is about 60% of that of QuikSCAT. 相似文献
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