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Construction of Vertical Wind Profile from Satellite-Derived Winds for Objective Analysis of Wind Field

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Advances in Atmospheric Sciences 1992年第2期9卷 237-246页

作者： P.N.Mahajan D.R.Talwalkar S.Nair S.Rajamani Indian Institute of Tropical Meteorology Pune-411008Indian Institute of Tropical Meteorology Pune-411008Indian Institute of Tropical Meteorology Pune-411008Indian Institute of Tropical Meteorology Pune-411008

During summer Monex-79, a variety of observing systems viz. research ships, research aircrafts, constant pressure balloons and geostationary satellite etc. were deployed, besides the regular conventional observations. The purpose of these additional systems was to make the best possible data for the studies on various aspects of monsoon circulation. The present study is aimed at the construction of vertical wind profile using cloud motion vectors obtained from GOES (I-O) satellite and to examine whether the constructed wind profiles improves the representation of the monsoon system, flow pattern etc. in the objective analysis. For this purpose, climatological normals of the wind field are considered as the initial guess and the objective analyses of the wind field are made with, first using only data from conventional observations over land areas, subsequently including the constructed winds from cloud motion vectors. These analyses are then compared with the standard analyses of wind field obtained from Quick Look Atlas by T. N. Krishnamurti et al. (1979).It is inferred that satellite estimated mean wind profiles show good agreement with the mean wind profiles of the research ships with RMS errors less than 5 mps below 500 hPa and less than 8 mps above 500 hPa. It is further inferred that the inclusion of constructed winds shows a positive impact on the objective analysis and improvement is seen to be more marked in the data-sparse region of the Arabian sea. Analyses which include the constructed winds show better agreement with the standard analysis, than the analyses obtained using only conventional winds. Thus, results of our study suggest that the wind profiles constructed using cloud motion vectors are of potential use in objective analysis to depict the major circulation features over the Indian region.

关键词： Construction of Vertical Wind Profile from Satellite-Derived Winds for Objective Analysis of Wind Field Wind

Toluene Alkylation to Selective Formation of p-Xylene over Co-Crystalline ZSM-12/ZSM-5 Catalyst

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Journal of Natural Gas Chemistry 2007年第1期16卷 37-41页

作者： P.N.Joshi P.S.Niphadkar P.A.Desai R.Patil V.V.Bokade Catalysis Division National Chemical LaboratoryPune-411008India

The alkylation of toluene with methanol to selective formation of p-xylene has been systematically studied. ZSM-12 （MTW）/ZSM-5 co-crystalline zeolite in 40：60 proportions have been synthesized by the same molar gel composition, but at different temperatures and periods than that of ZSM-12 and ZSM-5, separately. All the prepared samples are characterized by XRD, SEM, BET, and XRF. The activity of toluene alkylation was investigated with a mixture of toluene and methanol as a feed over the ZSM-12, ZSM-12/ZSM-5 co-crystalline, ZSM-5, and physical mixture of ZSM-12/ZSM-5. From characterization, it is observed that the ZSM-12/ZSM-5 co-crystalline material is different from that of ZSM-12, ZSM-5, and their physical mixture. Further, the ZSM-12/ZSM-5 co-crystalline zeolite produces the highest content of xylene and has better selectivity for p-xylene than ZSM-12, ZSM-5, and their physical mixture.

关键词： ZSM-12 ZSM-5 co-crystalline toluene alkylation p-xylene

Use of Surface Observations to Estimate Upper Air Humidity for the Objective Analysis of Relative Humidity over Indian Region

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Advances in Atmospheric Sciences 1990年第4期7卷 491-501页

作者： S.K.Sinha D.R.Talwalkar S.G.Narkhedkar P.L.Kulkarni S.Nair S.Rajamani Indian Institute of Tropical Meteorology pune-411008 India Indian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 India

In the present study objective analyses of relative humidity (RH) at surface and at the levels of 850, 700 and 500 hPa have been made using Gandin's (1963) optimum interpolation scheme. As the horizontal resolution of the radiosonde stations is rather inadequate for upper air humidity analysis, a scheme has been developed, following Rasmussen (1982) to estimate the upper air RH from the surface observations like surface RH, present weather and cloud cover. The relative humidities at the levels 850, 700 and 500 hPa were related to the surface observations through three separate regression relations. The RH values at 850, 700 and 500 hPa levels were estimated from the surface RH, cloud coverage and present weather using the above regression relations and subsequently the objective analyses at 00 GMT for the period from 4 July to 8 July 1979, were made using these estimated data along with the observed radiosonde data. Objective analyses were also made for the same period using only the radiosonde data for comparison to study the impact of those estimated data. Root mean square errors were computed for all the five days by interpolating RH at the observing stations from the objectively analysed field and comparing them with the actually observed RH to examine how best the analyses (with and without estimated data) fitted the observations. Lastly they were compared with satellite cloud pictures. This study shows that the estimated upper air RH values have positive impact on the analysis of upper air RH and could be used over radiosonde data sparse region and even over oceanic regions.

关键词： In RH over

A Hydrometeorological Analysis of the Severe Rainstorm of 20-22 September 1900 over the Gangetic West Bengal

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Advances in Atmospheric Sciences 1993年第1期10卷 113-120页

作者： P. R. Rakhecha B. N. Mandal A. K. Kulkarni R. B. Sangam Indian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

A hydrometeorological study is made of the September, 1900 severe rainstorm which led up to the record rainfalls over Gangetic West Bengal with subsequent disastrous flooding in the Damodar and the Hooghly rivers. The spatial extent of the rainstorm for different durations has been examined by constructing the isohyetal patterns based on rainfall records of stations affected by the storm. Areal rainfalls for 1,2 and 3-day periods are calculated and the values have been compared with similar values from other major rainstorms of the region. The comparison revealed that the September, 1900 rainstorm was the heaviest for 1,2 and 3-day durations for all the areas. The storm contributed rainfalls of 33.0 cm, 52.0 cm and 62.0 cm over an area of 10,000 km2 in 1,2 and 3 days respectively. This rainstorm could, therefore, be considered as an important input in flood and design storm studies in the Gangetic West Bengal region. A relationship between point to areal rainfall has also been developed with a view to evaluate areal PMP estimates.

关键词： A Hydrometeorological Analysis of the Severe Rainstorm of 20-22 September 1900 over the Gangetic West Bengal over West

Analysis-Prediction Experiments over Indian Region Using Primitive Equation Barotropic Model

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Advances in Atmospheric Sciences 1992年第4期9卷 477-482页

作者： M.Y.Totagi D.R.Talwalkar S.Rajamani S.S.Singh Indain Institute of Tropical Meteorology Pune-411008 IndiaIndain Institute of Tropical Meteorology Pune-411008 IndiaIndain Institute of Tropical Meteorology Pune-411008 IndiaIndain Institute of Tropical Meteorology Pune-411008 India

The impact of initial guess and grid resolutions on the analysis and prediction has been investigated over the Indian region. For this purpose, an univariate objective analysis scheme and a primitive equation barotrop... 详细信息

关键词： over Analysis-Prediction Experiments over Indian Region Using Primitive Equation Barotropic Model

Aircraft Observations of Electrical Conductivity in Warm Clouds

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Advances in Atmospheric Sciences 1993年第1期10卷 95-102页

作者： P.Ernest Raj P. C. S. Devara A. M. Selvam A. S. R. Murty Indian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

Aircraft observations of electrical conductivity and cloud microphsical, dynamical and other electrical parameters were made in warm stratocumulus and cumulus clouds forming during the summer monsoon seasons (June-September) of 1983 and 1985 in the Deccan Plateau region, India. A Gerdien type cylindrical condenser was used for the measurement of electrical conductivity. The variations in the electrical conductivity are observed to be closely associated with the updrafts and downdrafts in the cloud, liquid water content, cloud droplet charge and corona discharge current. The value of electrical conductivity in warm clouds is found to be in the order of 10-12 ohm-1 m-1 which is two orders higher than that observed in clear-air at cloud-base levels in some regions by other *** static electricity concepts predict reduced conductivity values inside clouds. Cloud electrical conductivity measurements, particularly in warm clouds are few and the results are contradictory. The recently identified mechanism of vertical mixing in clouds lends support to convective charge separation mechanism with inherent larger than clear-air values for cloud electrical conductivity and therefore consistent with the measurements reported herein.

关键词： Aircraft Observations of Electrical Conductivity in Warm Clouds

Synthesis of ethyl acetate by esterification of acetic acid with ethanol over a heteropolyacid on montmorillonite K10

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Journal of Natural Gas Chemistry 2010年第2期19卷 161-164页

作者： Hanumant Gurav Vijay V.Bokade Catalysis Division National Chemical LaboratoryPune-411008India

In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid （DTPA） supported on K10 montmorillonite was systematically studied and optimization of process parameters was carried *** 20% m/m DTPA/K10 was found to be the optimum catalyst with 90% acetic acid conversion and 100% ethyl acetate *** study was also explored to see the feasibility of 20% m/m DTPA/K10 as a catalyst for the alkylation of acetic acid with other alcohols like methanol,iso-propanol and *** 20% m/m DTPA/K10 has shown increased activity with the increase in carbon number,at the same alcohol *** results are novel.

关键词： acetic acid ethanol heteropolyacid montmorillonite K10 ethyl acetate

Some Experiments with Multivariate Objective Analysis Scheme of Heights and Winds Using Optimum Interpolation

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Advances in Atmospheric Sciences 1992年第4期9卷 431-440页

作者： S.K.Sinha S.G.Narkhedkar D.R.Talwalkar S.Rajamani Indian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

A two-dimensional, multitvariate objective analysis scheme for simultaneous analysis of geopotential height and wind fields has been developed over Indian and adjoining region for use in numerical weather prediction. The height-height correlations calculated using daily data of four July months (1976-1979), are used to derive the other autocorrelations and cross-correlations assuming geostropic relationship. A Gaussian function is used to model the autocorrelation function. Since the scheme is multivariate the regression coefficients (weights) are *** the equator, the geostrophic approximation relating mass and wind is decoupled in a way similar to Bergman (1979). The objective analyses were made over Indian and adjoining region for 850, 700, 500, 300 and 200 hPa levels for the period from 4 July to 8 July 1979, 12 GMT. The analyses obtained using multivariate optimum interpolation scheme depict the synoptic situations satisfactorily. The analyses were also compared with the FGGE analyses (from ECMWF) and also with the station observations by computing the root mean square (RMS) errors and the RMS errors are comparable with those obtained in other similar studies.

关键词： In Some Experiments with Multivariate Objective Analysis Scheme of Heights and Winds Using Optimum Interpolation

Tropical Stratospheric Circulation and Monsoon Rainfall

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Advances in Atmospheric Sciences 1993年第3期10卷 379-385页

作者： A.B.Sikder S.K.Patwardhan H.N.Bhalme Indian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

Interannual variability of both SW monsoon (June-September) and NE monsoon (October-December) rainfall over subdivisions of Coastal Andhra Pradesh, Rayalaseema and Tamil Nadu have been examined in relation to monthly zonal wind anomaly for 10 hPa, 30 hPa and 50 hPa at Balboa (9°N, 80°W) for the 29 year period (1958-1986). Correlations of zonal wind anomalies to SW monsoon rainfall (r = 0.57, significant at 1% level) is highest with the longer lead time (August of the previous year) at 10 hPa level suggesting some predictive value for Coastal Andhra Pradesh. The probabilities estimated from the contingency table reveal non-occurrence of flood during easterly wind anomalies and near non-occurrence of drought during westerly anomalies for August of the previous year at 10 hPa which provides information for forecasting of performance of SW monsoon over Coastal Andhra Pradesh. However, NE monsoon has a weak relationship with zonal wind anomalies of 10 hPa, 30 hPa and 50 hPa for Coastal Andhra Pradesh, Rayalaseema and Tamil *** of the SW monsoon storms and depressions in association with the stratospheric wind were also examined to couple with the fluctuations in SW monsoon rainfall. It is noted that easterly / westerly wind at 10 hPa, in some manner, suppresses / enhances monsoon storms and depressions activity affecting their tracks.

关键词： QBO Stratospheric wind and monsoon rainfall Interannual variability of SW monsoon Probability forecasts of droughts / floods