Near-surface soil carbon detection for monitoring CO<Subscript>2</Subscript> seepage from a geological reservoir     

Lucian Wielopolski  Sudeep Mitra 《Environmental Earth Sciences》2010,60(2):307-312

The promise of the Brookhaven National Laboratory (BNL) Inelastic Neutron Scattering (INS) System was evaluated for use as a long-term, in-field monitor to detect cumulative changes in belowground carbon resulting from the leakage of CO₂ stored in deep geological reservoirs. This system underwent tests at a facility constructed specifically for testing, under controlled conditions, various detection systems for monitoring near-surface transport and accumulations of CO₂ fluxes emanating from a shallow buried, slotted horizontal well. The INS System was assessed by comparing the results from placing it above the horizontal well at a spot with a known high CO₂ leak identified and quantified the previous years, with those obtained from background readings adjacent to the well. At two different “Hot Spots”, a suppression of about 14% in 2008 and about 7% in 2009 in carbon content above the well in comparison to the background signal was observed. An overview of these results is presented.  相似文献   

Study of cloud liquid water path and total precipitable water from irs-p4/msmr and numerical weather prediction model output     

S.?Das  A.?S.?K.?A.?V.?Prasad?Rao  U.?C.?MohantyEmail author  A.?K.?Mitra  D.?Rajan 《Journal of the Indian Society of Remote Sensing》2004,32(2):175-184

A global weather analysis-forecast system is used to produce six hourly analysis of meteorological fields at roughly 150 km × 150 km resolution at the National Center for Medium Range Weather Forecast (NCMRWF). In this paper, we have studied the Total Precipitable Water Content (TPWC) and Cloud Liquid Water Path (CLWP) derived from the Indian Remote Sensing (IRS-P4) Satellite over the Indian Ocean region in relation to operational numerical weather prediction (NWP) model analysis and short-range forecasts. An objective analysis was carried out by introducing the observations of CLWP, TPWC and their values (six hour forecasts) from the T80 model as the first guess, for a 20 days period of August 1999 using the standard Cressman’s technique. The reanalysis could capture the signature of TPWC and CLWP data from IRS-P4 satellite. In general the observed values of TPWC and CLWP from IRS-P4 have a positive bias compared to NCMRWF analysis over the region where the satellite passed. The CLWP values have been compared with Special Sensor Microwave/Imager (SSM/I) products from the Defense Meteorological Satellite Program (DMSP) satellites. Results indicate that the model derived CLWP values were within acceptable limits, whereas the observations from the Multi-channel Scanning Microwave Radiometer (MSMR) showed slightly larger values.  相似文献   

Variation of Rayleigh wave group velocity dispersion and seismic heterogeneity of the Indian crust and uppermost mantle     

S. Mitra  K. Priestley  V. K. Gaur  S. S. Rai  J. Haines 《Geophysical Journal International》2006,164(1):88-98

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Observations of trace gases and aerosols over the Indian Ocean during the monsoon transition period     

T. K. Manual  Ateef Khan  Y. Nazeer Ahammed  R. S. Tanwar  R. S. Parmar  K. S. Zalpuri  Prabhat K. Gupta  S. L. Jain  Risal Singh  A. P. Mitra  S. C. Garg  A. Suryanarayana  V. S. N. Murty  M. Dileep Kumar  Andrew J. Shepherd 《Journal of Earth System Science》2006,115(4):473-484

Characteristics of trace gases (O₃, CO, CO₂, CH₄ and N₂O) and aerosols (particle size of 2.5 micron) were studied over the Arabian Sea, equatorial Indian Ocean and southwest part of the Bay of Bengal during the monsoon transition period (October–November, 2004). Flow of pollutants is expected from south and southeast Asia during the monsoonal transition period due to the patterns of wind flow which are different from the monsoon period. This is the first detailed report on aerosols and trace gases during the sampled period as the earlier Bay of Bengal Experiment (BOBMEX), Arabian Sea Monsoon Experiment (ARMEX) and Indian Ocean Experiments (INDOEX) were during monsoon seasons. The significant observations during the transition period include: (i) low ozone concentration of the order of 5 ppbv around the equator, (ii) high concentrations of CO₂, CH₄ and N₂O and (iii) variations in PM2.5 of 5–20μg/m³.  相似文献   

The ice nucleating ability of pollen: Part III: New laboratory studies in immersion and contact freezing modes including more pollen types     

Nadine von Blohn  Subir K. Mitra  Karoline Diehl  Stephan Borrmann   《Atmospheric Research》2005,78(3-4):182-189

Based on earlier experimental studies, the ice nucleating abilities of further pollen types were investigated in the immersion and contact freezing modes. The studies were carried out at the Mainz vertical wind tunnel with freely floating supercooled droplets down to − 28 °C. The pollen had diameters between 26 and 28 μm and correspondingly low sink velocities around 2.5 cm s^{− 1}. The radii of the studied drops were calculated from the recorded wind velocity and for both freezing modes the radii of the observed droplets varied between 315 and 380 μm. Immersion freezing experiments were conducted with pollen particles added to the droplets while in contact freezing experiments supercooled droplets were subjected to a burst of pollen particles. The median freezing temperatures found in the immersion freezing mode were: − 13.5 °C (alder), − 21.5 °C (lombardy poplar), − 21.0 °C (redtop grass) and − 19.8 °C (kentucky blue). The median freezing temperatures in the contact freezing mode were found as: − 12.6 °C (alder), − 17.9 °C (lombardy poplar), − 18.7 °C (redtop grass) and − 16.1 °C (kentucky blue). The results show that the ice nucleating ability of pollen is not restricted to single pollen types but seems to be a general pollen property.  相似文献   

New Bathonian (Middle Jurassic) ammonite assemblages from Kutch, India     

Pinaki Roy  Subhendu Bardhan  Aparajita Mitra  Sudipta K. Jana 《Journal of Asian Earth Sciences》2007,30(5-6):629-651

The Bathonian ammonite assemblages have been previously poorly recorded in Kutch. The present study has unearthed a rich array of ammonite taxa ranging from the Middle to Upper Bathonian. While Oxycerites Rollier (1909) is a new record from Kutch, the oldest occurrence of Choffatia Siemiradzki (1898) has been found from the Middle Bathonian horizon. Oxycerites cf. orbis (Giebel) is a zonal index of the Late Bathonian in other areas and thus facilitates interprovincial correlation. Besides, palaeobiogeographic and stratigraphic distribution of many species have been modified based on new information. For example, macrocephalitin species, i.e., Kamptokephalites cf. etheridgei Spath (1928), Macrocephalites bifurcatus transient intermedius Spath (1928), M. cf. mantataranus Boehm (1912) were previously known from West Pacific, Indonesia have been now found in Kutch. Gracilisphinctes Buckman (1920) has been previously known to occur during the Middle Bathonian time, the present work extends its stratigraphic distribution up to the definite Upper Bathonian horizon. Procerites hians (Waagen) an endemic species in Kutch previously known from the Upper Bathonian beds, its stratigraphic range has been extended down to the Middle Bathonian.Detail taxonomy of the newly obtained taxa has been done and in many cases sexual dimorphism has been recognized.  相似文献   

Formation of solar nebula and mass distribution in the planetary system     

Ved Mitra 《Astrophysics and Space Science》1976,39(2):387-396

The formation of the solar nebula and the distribution of mass in its planetary system is studied. The underlying idea is that the protosun, fragmented out from an interstellar cloud as a result of cluster formation, gathered the planetary material and, hence, spin angular momentum by gravitational accretion during its orbital motion around the centre of the Galaxy. The study gives the initial angular momentum of the solar nebula nearly equal to the present value of the solar system.  相似文献   

RAYLEIGH WAVES IN A MULTI-LAYERED MEDIUM WITH APPLICATIONS TO MICROSEISMS     

M. Mitra 《Geophysical Journal International》1957,7(6):324-331

Summary. An analysis is presented for the propagation of Rayleigh waves in a multi-layered medium with water as the uppermost layer from which it is possible to obtain the group velocity as well as the phase velocity for the Rayleigh waves in an oceanic path with the ocean bed consisting of two upper layers each of uniform composition and finite thickness, underlain by ultrabasic rock extended to large depths. The results have been applied in the analysis of microseisms associated with cyclones and "norwesters". It has been shown that the period of the microseisms recorded at different stations depends critically on the structure of the continental shelf. The results obtained in the present paper, when compared with the nature of the recorded microseisms associated with cyclones, and their variations, give useful information about the depth and structure of the ocean beds.  相似文献   

Reclamation of mining-generated wastelands at Alkusha–Gopalpur abandoned open cast project, Raniganj Coalfield, eastern India   总被引：4，自引：0，他引：4  

Sahadeb De  Arup K. Mitra 《Environmental Geology》2002,43(1-2):39-47

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On the impact of divergent part of the wind computed from INSAT OLR data on global analysis and forecast fields     

P. L. Kulkarni  A. K. Mitra  S. G. Narkhedkar  A. K. Bohra  S. Rajamani 《Meteorology and Atmospheric Physics》1997,64(1-2):61-82

Summary In this paper, a procedure for the computation of the divergent part of wind from Outgoing Longwave Radiation (OLR) data is described. This divergent part is included in the global analysis scheme and its impact is studied by computing the vertical velocity, velocity potential etc., using the analysed fields with and without modifying the divergent part and also making 24 hr and 48 hr rainfall forecasts.Results show that magnitudes of vertical velocity were increased when the divergent part was modified in the wind analysis. There were also changes observed in the analysed wind field over convective regions and the changes over the oceanic regions were higher, suggesting that the impact of divergent part is more pronounced over data sparse regions. Marginal increase was observed in 24 hr and 48 hr rainfall forecast over the Indian region. The area averaged rainfall forecast at each time step in the first 6 hours of model integration was also higher in the case when the wind field contained the divergent part.To sum up, it can be stated that the inclusion of the divergent part from OLR data in the initial wind field has brought out positive impact on the wind analyses and rainfall forecast.With 12 Figures  相似文献