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1.
Kusuma G. Rao V. N. Lykossov A. Prabhu S. Sridhar E. Tonkacheyev 《Journal of Earth System Science》1996,105(3):227-260
An attempt has been made here to study the sensitivity of the mean and the turbulence structure of the monsoon trough boundary
layer to the choice of the constants in the dissipation equation for two stations Delhi and Calcutta, using one-dimensional
atmospheric boundary layer model withe-ε turbulence closure. An analytical discussion of the problems associated with the constants of the dissipation equation is
presented. It is shown here that the choice of the constants in the dissipation equation is quite crucial and the turbulence
structure is very sensitive to these constants. The modification of the dissipation equation adopted by earlier studies, that
is, approximating the Tke generation (due to shear and buoyancy production) in theε-equation by max (shear production, shear + buoyancy production), can be avoided by a suitable choice of the constants suggested
here. The observed turbulence structure is better simulated with these constants. The turbulence structure simulation with
the constants recommended by Aupoixet al (1989) (which are interactive in time) for the monsoon region is shown to be qualitatively similar to the simulation obtained
with the constants suggested here, thus implying that no universal constants exist to regulate dissipation rate.
Simulations of the mean structure show little sensitivity to the type of the closure parameterization betweene-l ande-ε closures. However the turbulence structure simulation withe-ε. closure is far better compared to thee-l model simulations. The model simulations of temperature profiles compare quite well with the observations whenever the boundary
layer is well mixed (neutral) or unstable. However the models are not able to simulate the nocturnal boundary layer (stable)
temperature profiles. Moisture profiles are simulated reasonably better. With one-dimensional models, capturing observed wind
variations is not up to the mark. 相似文献
2.
Yoichi Fukuda Toshihiro Higashi Shuzo Takemoto Maiko Abe Sjafra Dwipa Dendi Surya Kusuma Achmad Andan Koichiro Doi Yuichi Imanishi Giuseppe Arduino 《Journal of Geodynamics》2004,38(3-5):489
For the purposes of the calibration of the superconducting gravimeter (SG) in Bandung and the establishment of the absolute gravity (AG) points, we carried out AG measurements for the first time in Indonesia in November 2002. The measurements in Bandung were conducted between November 15th and 20th by means of a FG5 (#210), and 14,520 effective drops were obtained. The gravity value newly determined at the AG point in Bandung is 977976701.2 μgal (1 μgal = 10−8 ms−2) and the scale factor for the SG is −52.22 μgal/V. We also established another AG point in Yogyakarta near Merapi volcano and carried out AG measurements in Yogyakarta between November 22nd and 26th. The gravity value determined for this station is 978203093.5 μgal. 相似文献
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5.
Barik Tapan K. Swain Surya N. Sahu Bijayalaxmi Tripathy Bibarani Acharya Usha R. 《海洋学报(英文版)》2020,39(6):26-35
Marine ecosystems provide a wide variety of diverse habitats that frequently promote migration and ecological adaptation. The extent to which the geographic distribution of marine organism has reshaped by human activities remains underappreciated. The limitations intrinsic to morphology-based identification systems have engendered an urgent need for reliable genetic methods that enable the unequivocal recognition of fish species,particularly those that are prone to overexploitation and/or market substitution. In the present study, however, an attempt has been taken to identify two locally adapted fish species, Siganus sutor(Valenciennes, 1835) and Seriolina nigrofasciata(Rüppell, 1829) of order Perciformes, which happens to be the first record in Odisha coast,Bay of Bengal. The diagnostic characteristics of Siganus sutor are: dorsal fin XIII-10, anal fin VII-9, pectoral fin 15,pelvic fin II-3, while that of Seriolina nigrofasciata dorsal fin VI-I-35, anal fin I-17, pectoral fin 16, pelvic fin 5. All COI barcodes generated in this study were matched with reference sequences of expected species, according to morphological identification. Bayesian and likelihood phylogenetic trees were drawn based on DNA barcodes and all the specimens clustered in agreement with their taxonomic classification at the species level. The phylogeographic studies based on haplotype network and migration rates suggest that both the species were not panmitic and the high-frequency population distribution indicates successful migration. The result of this study provides an important validation of the use of DNA barcode sequences for monitoring species diversity and changes within a complex marine ecosystem. 相似文献
6.
R. Pandiyan S. V. Subbarao T. Nagamani Chaitra Rao N. Hari Prasad Rao Harish Joglekar Naresh Kumar Surya Ratna Prakash Dumpa Anshu Chauhan B. P. Dakshayani 《Journal of Astrophysics and Astronomy》2017,38(2):35
On 28th September 2015, India launched its first astronomical space observatory AstroSat, successfully. AstroSat carried five astronomy payloads, namely, (i) Cadmium Zinc Telluride Imager (CZTI), (ii) Large Area X-ray Proportional Counter (LAXPC), (iii) Soft X-ray Telescope (SXT), (iv) Ultra Violet Imaging Telescope (UVIT) and (v) Scanning Sky Monitor (SSM) and therefore, has the capability to observe celestial objects in multi-wavelength. Four of the payloads are co-aligned along the positive roll axis of the spacecraft and the remaining one is placed along the positive yaw axis direction. All the payloads are sensitive to bright objects and specifically, require avoiding bright Sun within a safe zone of their bore axes in orbit. Further, there are other operational constraints both from spacecraft side and payloads side which are to be strictly enforced during operations. Even on-orbit spacecraft manoeuvres are constrained to about two of the axes in order to avoid bright Sun within this safe zone and a special constrained manoeuvre is exercised during manoeuvres. The planning and scheduling of the payloads during the Performance Verification (PV) phase was carried out in semi-autonomous/manual mode and a complete automation is exercised for normal phase/Guaranteed Time Observation (GuTO) operations. The process is found to be labour intensive and several operational software tools, encompassing spacecraft sub-systems, on-orbit, domain and environmental constraints, were built-in and interacted with the scheduling tool for appropriate decision-making and science scheduling. The procedural details of the complex scheduling of a multi-wavelength astronomy space observatory and their working in PV phase and in normal/GuTO phases are presented in this paper. 相似文献
7.
This paper reports the occurrence of thorite and confirms the earlier find of radioactive zircon by Subbarao, Murali and others
from syenite pegmatite in the Vinayakapuram-Kunavaram alkaline belt in the Khammam district of Andhra Pradesh, India. Thorite
has also been found as residual concentrations in soil overlying the pegmatite. 相似文献
8.
S. Anbazhagan T. K. Biswal T. Roy K. N. Kusuma 《Journal of the Indian Society of Remote Sensing》2006,34(4):331-341
The geology of northwestern part of Indian peninsula is considered to be important due to complete preservation of rocks from Archaean to Upper Proterozoic. Further, these rocks have served as ideal host of varieties of economic minerals. The present work is an attempt to study the structurally deformed granulitic terrain in parts of Gujarat and Rajasthan in light of remote sensing. The study area falls under Sirohi, Banas Kantha and Sabar Kantha districts of Rajasthan and Gujarat. Remote sensing technique is utilized for the understanding of structural geology and deciphering the shear pattern. The methods adopted in this study include generation of False Color Composite (FCC) of satellite data, interpretation of lineaments from FCC and study the drainage pattern, structural basin delineation, profiling, and field mapping. It is observed that the area has undergone extensive deformation. There are two major sets of lineaments interpreted in the granulitic terrain such as WNW-ESE and NE-SW directions. Majority of the WNW-ESE lineaments are brittle in nature and N-S, NE-SW trending lineaments are ductile in nature. Overall the study area bifurcated into seven structural basins comprises of basic granulites, calc granulites and pelitic granulites. 相似文献
9.
N. Subba Rao K. V. Srinivasa Rao P. Surya Rao Ch. Venkat Rao K. Arjunudu P. Madhusudhana Reddy A. Subrahmanyam 《Journal of the Geological Society of India》2009,73(5):651-656
Groundwater samples were collected from a coastal region of Andhra Pradesh to assess the possible conditions of the formation
of carbonates. The area experiences a semi-arid climate and is underlain by khondalites, over which the Quaternary sediments
occur. The study of the geochemistry of groundwater indicates that groundwater is mostly of fresh, with alkaline nature. The
study further suggest that the breakdown of feldspars as kaolinite during rock-water interaction, releases Ca2+. Soils/weathered products contribute high CO2 under the open system. The Ca2+ and CO2 are added to the groundwater through the infiltrating recharge water. They subsequently precipitate as fine-grained carbonates
in the weathering profile due to evapotranspiration under a freshwater environment. 相似文献
10.
Simulating climate change impact on soil carbon sequestration in agro-ecosystem of mid-Himalayan landscape using CENTURY model 总被引:1,自引:0,他引:1
Soils play significant roles in global carbon cycle. The increase in atmospheric CO2 due to climate change may have a significant impact on both soil organic carbon storage and management practices to sequester organic carbon in agricultural areas. The aim of the study was to simulate climate change impact on soil carbon sequestration using CENTURY model. The statistical downscaling model (SDSM) was used to downscale the climate variables (temperature and rainfall) under two scenarios A2 and B2 for three periods: 2020 (2011–2040), 2050 (2041–2070) and 2080 (2071–2099). Downscaling was better in case of temperature than precipitation, which was evident from coefficient of correlation for temperature (r 2 = 0.91–0.99) and precipitation (r 2 = 0.71–0.80). Downscaling of climate data revealed that the temperature may increase for the years 2020, 2050 and 2080 periods, whereas precipitation may increase till 2020 and then it may reduce in 2050 and 2080 as compared to 2020 in the study area. For CENTURY model, the input parameters were obtained through soil sampling and interviewing the farmers as well, whereas the climatic variables (maximum temperature, minimum temperature and precipitation) were taken from the SDSM output. The historical data of soils were collected from the literature, and six agricultural sites were selected for estimating soil carbon sequestration. After soil sampling of the same sites, it was found that the organic carbon had increased two times than historical data might be due to the addition of high organic matter in the form of farm yard manure. Therefore, the model was calibrated, considering more organic carbon in the area, and was validated using random points in the study area. Determination coefficient (r 2 = 0.95) and RMSE (538 g c/m2) were computed to assess the accuracy of the model. The organic carbon was predicted from 2011 to 2099 and was compared with the 2011 predicted data. The study revealed that the amount of soil organic carbon in Bhaitan, Kanatal, Kotdwar, Malas, Pata and Thangdhar sites may reduce by 11.6, 15.8, 17.19, 13.54, 19.2 and 12.7%, respectively, for A2 scenario and by 9.62, 15.6, 15.72, 11.45, 16.96 and 13.36% for B2 scenario up to 2099. The study provides comprehensive possible future scenarios of soil carbon sequestration in the mid-Himalaya for scientists and policy makers. 相似文献