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D.M.CHATE R.T.WAGHMARE C.K.JENA V.GOPALAKRISHNAN P.MURUGAVEL Sachin D.GHUDE Rachana KULKARNI P.C.S.DEVARA 《大气科学进展》2018,35(2):218-223
The first measurements of cloud condensation nuclei(CCN) at five supersaturations were carried out onboard the research vessel "Sagar Kanya"(cruise SK-296) from the south to the head-bay of the Bay of Bengal as part of the Continental Tropical Convergence Zone(CTCZ) Project during the Indian summer monsoon of 2012. In this paper, we assess the diurnal variation in CCN distributions at supersaturations from 0.2% to 1%(in steps of 0.2%) and the power-law fit at supersaturation of 1%.The diurnal pattern shows peaks in CCN concentration(NCCN) at supersaturations from 0.2% to 1% between 0600 and 0700 LST(local standard time, UTC+0530), with relatively low concentrations between 1200 and 1400 LST, followed by a peak at around 1800 LST. The power-law fit for the CCN distribution at different supersaturation levels relates the empirical exponent(k) of supersaturation(%) and the NCCNat a supersaturation of 1%. The NCCNat a supersaturation of 0.4% is observed to vary from 702 cm~(-3) to 1289 cm~(-3), with a mean of 961 ± 161 cm~(-3)(95% confidence interval), representing the CCN activity of marine air masses. Whereas, the mean NCCNof 1628 ± 193 cm~(-3) at a supersaturation of 1% is higher than anticipated for the marine background. When the number of CCN spectra is 1293, the value of k is 0.57 ± 0.03(99% confidence interval)and its probability distribution shows cumulative counts significant at k ≈ 0.55 ± 0.25. The results are found to be better at representing the features of the marine environment(103 cm~(-3) and k ≈ 0.5) and useful for validating CCN closure studies for Indian sea regions. 相似文献
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A case of new particle formation observed during dissipation stage of a thunderstorm at a tropical station, Pune, India on
3 June 2008 is reported. The flash rate and rainfall intensity increased as high as 110 flashes per 5 minutes and 150 mm hour − 1 respectively during the active stage of thunderstorm, and then gradually decreased during the dissipation stage. The number
concentration of particles in the size range of 10–100 nm sharply increased from 350 particles cm − 3 to ∼8000 particles cm − 3 during the dissipation stage of a thunderstorm and grew to larger diameter subsequently. Observations suggest that the atmospheric
conditions such as (i) reduced background aerosol concentration after heavy rain, (ii) high humidity condition, and (iii)
increased ion concentration during the dissipation stage by corona discharges, favoured generation of new particles by ion-induced
nucleation (IIN). Observations also suggest that generation of unipolar ions by corona discharges may be more favourable for
IIN and subsequent growth of the particles. 相似文献
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GOPALAKRISHNAN Ayyaru RAJKUMAR Mayalagu 孙军 PARIDA Ajay VENMATHI MARAN Balu Alagar 《中国海洋湖沼学报》2011,29(1)
The efficacy of grass carp Ctenopharyngodon idella (Cyprinidae) and weevils Neochetina spp. (Curculionidae) to control the aquatic weed, water hyacinth, is investigated in a square net cage (happas) setting at a farm in Cuddalore District, South India. This novel combination of insects and fish is found to be superior to individual treatments for controlling the weed growth within 110 d. The biomass of the weed, number of plants, percentage of flowered plants and chlorophyll contents were studied. The weed ... 相似文献
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孙军 《中国海洋湖沼学报》2011,29(1):162-166
The efficacy of grass carp Ctenopharyngodon idella (Cyprinidae) and weevils Neochetina spp. (Curculionidae) to control the aquatic weed, water hyacinth, is investigated in a square net cage (happas) setting at a farm in Cuddalore District, South India. This novel combination of insects and fish is found to be superior to individual treatments for controlling the weed growth within 110 d. The biomass of the weed, number of plants, percentage of flowered plants and chlorophyll contents were studied. The weed biomass is reduced from 5 kg (day 1) to 0.33 kg (day 110) when exposed to grass carp and weevils. The number of plants is reduced to 0.75 in grass carp and weevil exposed happas, while it is 741.5 in the control. The mean number of leaves per plant is also reduced. In addition, the chlorophyll a and b are significantly reduced in happas exposed to the combination of fish and insects when compared to the other treatments. Based on the results of this study, we consider the combined use of grass carp and weevils to be more efficient and sustainable for managing water hyacinths than the use of these organisms individually. 相似文献
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