Environmental Studies Section
Environmental Studies Section
Lugo-Fernandez A.,Environmental Studies Section |
Leben R.R.,University of Colorado at Boulder |
Hall C.A.,University of Colorado at Boulder
Dynamics of Atmospheres and Oceans | Year: 2016
We analyzed a 20-year time series (January 1st, 1993 through December 31st, 2012) of Loop Current (LC) surface area derived from satellite altimetry in the eastern Gulf of Mexico to estimate kinematical metrics of this potent flow. On average the LC intrudes to its maximum northward position about 216±126 days after the previous eddy separation; and ∼30±31 days later sheds a large anticyclonic eddy. When the northern extent of the LC intrusion following the previous eddy separation is greater than 27°N, the current retreats very quickly until it sheds another eddy with the entire separation process occurring on the order of 30 days. To first order the change in areal extent of the LC during intrusion into the Gulf occurs at an average rate of 225km2 day-1, which corresponds to an intrusion velocity of 1.7cms-1 of the LC front, and adds Caribbean water to the Gulf at a rate of 2.6±0.7Sv. © 2016.
Kumar A.,Environmental Studies Section |
Mishra M.K.,Environmental Studies Section |
Divkar J.K.,Radiation Safety Systems Division |
Rout S.,Environmental Studies Section |
And 2 more authors.
Atmospheric Research | Year: 2010
In this study, the concentration of acid and water-soluble ions (Na+, K+, Mg++, Ca++, F-, Cl-, NO3 - and SO4 - -) in different particle size range (>1.1-<2.0μm, >2.0-<3.3μm, >3.3-<4.7μm, >4.7-<5.8μm, >5.8-<9.0μm and >9μm-<10μm) of PM10 atmospheric aerosols collected by six stages Anderson Cascade Impactor were determined using conductivity suppressed ion-chromatography system. Suspended particulate matters in the form of respirable (PM10) aerosols were collected on the roof of a three storied building at a height of 20m above the ground, at Bhabha Atomic Research Centre (BARC), Mumbai using Hi-Volume Sampler (HVS) with Whatman glass fiber filter paper during the period of March-June 2009. The sequence of solubility of ions in both extractants (acid+water) of PM10 aerosols from greatest to least was found to be Na+>Ca++>K+>Cl->F->Mg++>NO3 -≈SO4 --. The average concentration of Na+, K+, Mg++, Ca++, F-, Cl-, NO3 - and SO4 -- in PM10 aerosols was estimated to be 13.36g/kg, 3.76g/kg,0.251g/kg,3.771g/kg,0.833g/kg,1.17g/kg, 81μg/kg and 290μg/kg respectively. The enrichment of particular ion in soluble components may be due to its high abundance in PM10 aerosols, less sorptivity with the tiny solid particles of atmospheric dust, high extractability and leachability, high solubility and mobility. By classifying the PM10 aerosols into two categories viz fine particle (<2.5μm) and coarse particle (>2.5μm-<10μm), it was found that generally, in the fine particle, the geometric mean concentration of total soluble ions in acid and water components was found to be higher than coarse particle. Overall, it was also observed that generally as particle size increases, the geometric mean concentration of soluble ions in both extractants of PM10 aerosols decreases. © 2010 Elsevier B.V.