Variations of trace gases over the Bay of Bengal during the summer monsoon     

I A Girach  Narendra Ojha  Prabha R Nair  Yogesh K Tiwari  K Ravi Kumar 《Journal of Earth System Science》2018,127(1):15

In situ measurements of near-surface ozone (\(\hbox {O}_{3})\), carbon monoxide (CO), and methane (\(\hbox {CH}_{4})\) were carried out over the Bay of Bengal (BoB) as a part of the Continental Tropical Convergence Zone (CTCZ) campaign during the summer monsoon season of 2009. \(\hbox {O}_{3}\), CO and \(\hbox {CH}_{4}\) mixing ratios varied in the ranges of 8–54 ppbv, 50–200 ppbv and 1.57–2.15 ppmv, respectively during 16 July–17 August 2009. The spatial distribution of mean tropospheric \(\hbox {O}_{3}\) from satellite retrievals is found to be similar to that in surface \(\hbox {O}_{3}\) observations, with higher levels over coastal and northern BoB as compared to central BoB. The comparison of in situ measurements with the Monitoring Atmospheric Composition & Climate (MACC) global reanalysis shows that MACC simulations reproduce the observations with small mean biases of 1.6 ppbv, –2.6 ppbv and 0.07 ppmv for \(\hbox {O}_{3}\), CO and \(\hbox {CH}_{4}\), respectively. The analysis of diurnal variation of \(\hbox {O}_{3}\) based on observations and the simulations from Weather Research and Forecasting coupled with Chemistry (WRF-Chem) at a stationary point over the BoB did not show a net photochemical build up during daytime. Satellite retrievals show limitations in capturing \(\hbox {CH}_{4}\) variations as measured by in situ sample analysis highlighting the need of more shipborne in situ measurements of trace gases over this region during monsoon.  相似文献   

Improvement in Prediction of Slope Stability & Relative Importance Factors Using ANN     

Marrapu  Balendra M.  Kukunuri  Anjana  Jakka  Ravi S. 《Geotechnical and Geological Engineering》2021,39(8):5879-5894

Geotechnical and Geological Engineering - Evaluation of slope stability using conventional limit equilibrium methods is very time consuming and repetitive, while the use of simplified approaches...  相似文献   

Implementing climate change adaptation: lessons from India’s national adaptation fund on climate change (NAFCC)     

Ravi S. Prasad 《Climate Policy》2019,19(3):354-366

With poverty alleviation and sustainable development as key imperatives for a developing economy like India, what drives the resource-constrained state governments to prioritize actions that address climate change impacts? We examine this question and argue that without access to additional earmarked financial resources, climate action would get overshadowed by developmental priorities and effective mainstreaming might not be possible. A systematic literature review was carried out to draw insights from the current state of implementation of adaptation projects, programmes and schemes at the subnational levels, along with barriers to mainstreaming climate change adaptation. The findings from a literature review were supplemented with lessons emerging from the implementation of India’s National Adaptation Fund on Climate Change (NAFCC). The results of this study underscore the scheme’s relevance.

Key policy insights

• Experience with NAFCC implementation reveals that states require sustained ‘handholding’ in terms of financial, technical and capacity support until climate change issues are fully understood and embedded in the policy landscape.

• Domestic sources of finance are critically important in the absence of predictable and adequate adaptation finance from international sources.

• The dedicated window for climate finance fosters a spirit of competitive federalism among states and encourages enhanced climate action.

• Enhanced budgetary allocation to NAFCC to strengthen the state-level adaptation response and create capacity to mainstream climate change concerns in state planning frames, is urgently needed.

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Iterative methods for non-classically damped dynamic systems     

Firdaus E. Udwadia  Ravi Kumar 《地震工程与结构动力学》1994,23(2):137-152

Non-classically damped structural systems do not easily lend themselves to the modal superposition method because these systems yield coupled second-order differential equations. In this paper, a variety of new computationally efficient iterative methods for determining the response of such systems are developed. The iterative approaches presented here differ from those presented earlier in that they are computationally superior and/or are applicable to the determination of the responses of broader classes of structural systems. Numerical examples, which are designed to evaluate the efficacy of these schemes, show the vastly improved rates of convergence when compared to earlier iterative schemes.  相似文献   

Homogeneous zones of heavy rainfall of 1-day duration over India     

P. R. Rakhecha  A. K. Kulkarni  B. N. Mandal  N. R. Deshpande 《Theoretical and Applied Climatology》1990,41(4):213-219

Summary The highest recorded 24-hour rainfall totals from 1875 to 1982 for about 300 stations were plotted and isohyets drawn to delineate the homogeneous zones of heavy rainfall. The isohyetal pattern indicated an unsteady increase from less than 20 cm in the far west and far north to over 50 cm on or near the coasts. At a few inland stations outstanding amounts have been recorded but these are randomly distributed in space and time. Besides these, there existed a densely gauged area in the Central Peninsula between latitudes 8 °N to 21 °N within which more than 20 cm of rain in 24 hours have never been recorded. The areas of heavy rainfall of one day duration include the entire Indian region except the far western extremity, the northern area bordered by the Himalayas and the central peninsula. The correlation coefficient between the highest rainfall and elevation indicated no significant relationship.With 2 Figures  相似文献   

Low latitude airglow     

P. V. Kulkarni 《Journal of Earth System Science》1983,92(3):247-253

Tropical airglow work during the last few years is reviewed. Airglow instrumentation is becoming more complex. Some of these sophisticated airglow experiments giving important information about the upper atmosphere such as ionospheric F region electron density, height of maximum electron density, dynamics of and irregularities in the F region, mesospheric neutral temperature and its variation, dynamics of mesospheric, etc. are mentioned. At the end some problems which could be tackled in near future with airglow techniques have been suggested. Invited Review paper, Commission 21, IAU, Patras, Greece, August, 1982.  相似文献   

Upper mantle beneath foothills of the western Himalaya: subducted lithospheric slab or a keel of the Indian shield?   总被引：1，自引：0，他引：1  

L. Vinnik  A. Singh  S. Kiselev  M. Ravi Kumar 《Geophysical Journal International》2007,171(3):1162-1171

  相似文献   

Delineation of shallow Deccan basaltic aquifers from Maharashtra using aerial photointerpretation     

Himanshu Kulkarni 《Journal of the Indian Society of Remote Sensing》1992,20(2-3):129-138

The Deccan basaltic lava flows form shallow unconfined aquifers tapped for irrigation by large diameter dugwells. Aerial photographs form an important utility in the hydrogeological mapping of these shallow basaltic aquifers. Aerial photographs provide extensive information regarding the agricultural landuse in the agricultural sector from the Deccan basaltic terrain of Maharashtra. A zonation based on the cultivation, patterns brings out, quite clearly, the relationship between the agriculture in the area and the irrigation potential of the aquifer(s). This, relationship itself points to the inherent heterogeneity of the Deccan basaltic aquifers. Cultivation patterns/signatures that emerge through aerial photointerpretation can form the basis for a systematic hydrogeological mapping leading to aquifer characterisation of Deccan basalts, especially in regions where rock surfaces are not, directly exposed (such as is evident in many agricultural belts of Maharashtra state).  相似文献   

Ozone and airglow in the mesosphere region     

Rao  V. R.  Kulkarni  P. V.  Ramanathan  K. R. 《Pure and Applied Geophysics》1973,106(1):1318-1324

The paper presents the results of a photometric study of the hydroxyl bands (7–2) and (8–3) in the night airglow spectrum at Mt. Abu in the winter and spring of 1966–1972. The observed nocturnal variation differs from the variation expected from the theoretical studies of Hesstvedt, Hunt, Shimazaki and others. Instead of a gradual fall in intensity after sunset to shortly before sunrise, a peak in intensity is found at a time which changes from month to month and roughly coincides with the transit times of the X-ray star TAU (XR-1)-Crab Nebula. Anexplanation of the observed phenomenon is offered in terms of the increased energy output into the D and E regions of the atmospheres, increased eddy diffusion, and production, of additional O(³P) and O₃ in the region 80–95 km. O₃ reacting with H gives rise to OH^*.  相似文献   

A measurement of the cosmic microwave background temperature 1280 MHz     

A. Raghunathan  Ravi Subrahmanyan 《Journal of Astrophysics and Astronomy》2000,21(1-2):1-17

The absolute temperature of the cosmic microwave background (CMB) has been measured at a frequency of 1280 MHz. The observation was made with a modified version of the L-band receiver used in the Giant Metre wavelength Radio Telescope (GMRT): the feed horn was replaced by a corrugated plate and the receiver was placed on the ground, directed at zenith, and shielded from ground radiation by an aluminium screen with corrugated edges. Novel techniques have been adopted for

?reducing and cancelling unwanted contributions to the system temperature of the receiver and

?calibrating the contributions from the feed assembly and receiver.

The thermodynamic temperature of the CMB is estimated to be 3.45 ± 0.78 K.  相似文献