Long Range Transport and Wet Deposition Fluxes of Major Chemical Species in Snow at Gulmarg in North Western Himalayas (India)

Abstract

The study reports snow chemistry and long range transport of pollutants at Gulmarg in north-western Himalayan region of India during winters of 2012-2013. The pH of snowmelt varied between 5.16 and 7.68 with an average of 5.90. The frequency distribution of pH of snowmelt showed that the maximum number of samples (31%) had pH between 6.81 and 7.20. However, 12% samples were observed to be acidic (below 5.6 respectively. Both local emissions as well as long range transport (LRT) of pollutants were found to be the sources of these ionic species. Backward airmass trajectory calculations showed that this site received airmasses from six major sectors i.e., i) North Atlantic Ocean origin (NAO), ii) African origin (Af), iii) Middle East origin (ME), iv) European origin (Eu), v) Western India origin (InW), vi) Pakistan origin (Pk). The highest average pH (7.58) of the snowfall was noticed during InW airmasses which had the lowest ratios of nssSO 4 2-/nssCa 2+ and NO 3 -/nssCa 2+ . Very high pH has been observed in precipitation samples at Indian sites due to buffering of acidic components by atmospheric dust rich in CaCO 3 . The lowest pH (4.94) was noticed for ME airmasses which had the highest nssSO 4 2-/nssCa 2+ and NO 3 -/nssCa 2+ ratios. Data of present study was compared with a study reported almost three decades ago. We noticed a drastic increase in the concentrations of anthropogenic components such as nssSO 4 2-(114%), NO 3 -(109%) and NH 4 + (90%). This is probably due to increase in LRT of pollutants as well as local activities during past three decades.

Chemical Characteristics of Rainwater in Sumatera, Indonesia, during 2001–2010

“…However, sodium to chloride molar ratios measured along the entire profile (Cl − /Na + mean value = 1.137, = 0.008) is very close to the bulk sea water value of 1.16 [17]. Average, Cl − /Na + ratio was very close to sea water value (1.16) indicating that Cl − was completely contributed by marine sources [18]. The average ratio values of Cl − /Na + in Medan, Lampung, Palembang, and Kototabang during 2001-2010 were 1.49, 1.16, 1.30, and 1.15, respectively.…”

“…We used a web based system called READY (real-time environmental applications and display) system developed by the Air Resources Laboratory (ARL) [27]. READY is also used to run trajectory (for multiple source locations or one source location) and dispersion model assessment and display for meteorological data [18,28]. The HYSPLIT is the most widely used model and particulate matter is the kind of pollutant most frequently investigated.…”

Annual and decadal variation in chemical composition of rain water at all the ten GAW stations in India

“…High concentration of Ca +2 can also be attributed to long range transport (LRT) of calcium carbonate rich dust in the air masses originated from North Atlantic Ocean, Africa, Northwest India and Pakistan (Kumar et al 2016). Similarly incorporation of SO 4 −2 and NO 3 − ions in the air masses originated from Middle East and Europe due to fossil fuel combustion and industrial activities was responsible for higher levels of NO 3 − and SO 4 −2 (Kumar et al 2016). Therefore NO 3 from local cement and brick industries as well as LRT from Middle East and Europe and HCO 3 formation from the transported and local suspended dust were responsible for anion sequence of NO 3 > HCO 3 > SO 4 > Cl at Srinagar (Fig.…”

“…As explained above, LRT of soil dust from Thar as well as Saharan deserts at both the stations and contribution of dust from the cement factory in the southeast direction at Srinagar made Ca the most abundant ion among the cations. Transportation of seal salt components from the air masses originated from North Atlantic Ocean (Kumar et al 2016) might be responsible for abundance of Na next to Ca. Kodaikanal at an altitude of 2343 m in tropics on top of Nilgiri hills is also free from local boundary layer pollution and therefore had lowest concentrations of the chemical species among all the GAW stations.…”

Revisiting the observed correlation between weekly averaged Indian monsoon precipitation and Arabian Sea aerosol optical depth

“…The role of aerosols in the seasonal and subseasonal modulation of summertime rainfall over India has long been the subject of scientific investigation [ Chung et al ., ; Menon et al ., ; Ramanathan et al ., ; Chung and Ramanathan , ; Lau et al ., ; Nigam and Bollasina , ; Das et al ., ; Solmon et al ., , Kulshrestha and Sharma , ]. Dust is one of the major contributors to the aerosol load over the Indian subcontinent due to long‐range transport from North Africa and west Asia (including the Arabian Peninsula), with the Great Indian Thar Desert as a local source [ Prospero et al ., ; Dey et al ., ; Gautam et al ., ; Sharma and Kulshrestha , ; Kumar et al ., ]. This highlights the role of the atmospheric circulation in aerosol loading from distant sources [ Kaskaoutis et al ., ], where phenomena local to the Indian Ocean like tropical cyclones raise dust far upwind [ Ramaswamy , ].…”