排序方式： 共有6条查询结果，搜索用时 15 毫秒
1
1.
Lekshmi S Chattopadhyay Rajib Kaur Manpreet Joseph Susmitha Phani R. Dey A. Mandal R. Sahai A. K. 《Theoretical and Applied Climatology》2022,147(1-2):205-215
Theoretical and Applied Climatology - In the seamless forecast paradigm, it is hypothesized that the reduction in initial error in the dynamical model forecast would help to reduce forecast error... 相似文献
2.
P. V. Hareesh Kumar S. Lekshmi P. S. V. Jagadeesh K. Anilkumar G. V. Krishnakumar A. D. Rao 《Marine Geodesy》2013,36(2-3):232-244
Time series of temperature and salinity collected from a station in the NE Arabian Sea during March, April, May, October, and November was utilized to explain the behavior of internal tides. Analysis revealed the existence of semi-diurnal internal tides and high frequency (HF) internal waves (IW). It was observed that the amplitudes of HF IWs were determined by the degree of stratification in the thermocline. Corresponding to an increase in the density gradient in thermocline (0.016 kg/m4 in April to 0.14 kg/m4 in October), the temperature fluctuations due to internal tides increased from <0.2°C to >1.5°C, respectively. Brunt-Vaiisala frequency also showed similar variations (～10 cph to 22 cph). Within the thermocline, semi-diurnal internal tides caused fluctuations of >10m in the isotherm depths. A linear regression equation was fitted to parameterize the amplitude of HF IWs and its upper frequency limit in terms of thermocline gradient. The IW and one-dimensional models simulated the presence of internal tides and diurnal cycling in the temperature field, respectively. Coupling of these models showed improvement in the simulation of temperature. 相似文献
3.
Lekshmi Resmi 《Journal of Astrophysics and Astronomy》2017,38(3):56
This review focuses on the physics of Gamma Ray Bursts probed through their radio afterglow emission. Even though radio band is the least explored of the afterglow spectrum, it has played an important role in the progress of GRB physics, specifically in confirming the hypothesized relativistic effects. Currently radio astronomy is in the beginning of a revolution. The high sensitive Square Kilometer Array (SKA) is being planned, its precursors and pathfinders are about to be operational, and several existing instruments are undergoing upgradation. Thus, the afterglow results from detection statistics and follow up programs are expected to improve in the coming years. We list a few avenues unique to radio band which if explored to full potential have the promise to greatly contribute to the future of GRB physics. 相似文献
4.
Fractal concepts are used to describe the irregular structures and regions of interest of solar images. The most common and
easiest way to extract regions of interest from an image is through segmentation. Segmentation techniques vary from conventional
edge-detection mechanism to fuzzy c-means clustering. In this study, the pixelwise local fractal dimension of solar images
is computed by different techniques. This is followed by different segmentation procedures including the fuzzy-based approach,
for extracting the active regions from chromospheric images and assessing their performance. These techniques have also been
applied on solar images to extract active regions from Solar Heliospheric Observatory (SOHO) Extreme Ultraviolet Telescope
(EIT) images. 相似文献
5.
J. N. Pattan G. Parthiban C. Moraes R. Rajalakshmi S. Lekshmi S. Athira S. Jai Sankar 《Journal of the Geological Society of India》2016,87(1):62-68
Pumice are explosive volcanic product, occur as uncoated or coated with ferromanganese (Fe-Mn) oxide and resides in association with ferromanganese nodules on the seabed in Central Indian Ocean Basin (CIOB). The older Fe-Mn oxide coated and younger uncoated pumice clasts were leached with 6N HCl to remove Fe-Mn oxide coatings as well as the calcium carbonate present within the vesicles. The main objective of the present study is to understand the origin of these pumice by utilizing their chemical composition. Both coated and uncoated pumice samples are rhyoliteand medium K calc-alkaline series. Major, trace, rare earth elements (∑REE) concentration and chondrite-normalized REE patterns of both coated and uncoated pumice are nearly similar to each other suggesting a same source. Tectonomagmatic discrimination diagrams (Nb vs Y: Yb vs. Ta), triangular plot (TiO2-Zr-Y) and High Field Strength Element ratios (La/Ta- 25; Ta/Hf- 0.2; Nb/Ta- 9; Zr/Nb- 22 and Ba/Ta-1084) indicate volcanic arc origin. These were probably sourced from the nearest Indonesian volcanic arc and drifted to the CIOB by currents. 相似文献
6.
A key problem of contemporary static and kinematic positioning is the problem of transformation of conformai coordinates of universal Mercator projection (UMP) type from a local datum (regional, national) to a global datum, for instance, the World Geodetic System 1984 (WGS 84) with reference to Boyle (1987). Such a problem is met if we use WGS 84 GPS‐derived ellipsoidal coordinates of a point for localization in a local chart of UMP type. In this article we derive and test the equations of a curvilinear datum transformation of ellipsoidal GPS coordinates in a global datum to conformai coordinates of UMP type in a local datum. The curvilinear datum transformation includes three parameters for translation, three parameters for rotation, one scale parameter, and two form parameters which account for a change in the semimajor axis and in the relative eccentricity of the reference ellipsoid. 相似文献
1