Long term variation in chemical composition of precipitation and wet deposition of major ions at Minicoy and Portblair : Islands in Arabian Sea and Bay of Bengal

Lkkj & bl ’kks/k Ik= esa vjc lkxj ds feuhdkW; rFkk caxky dh [kkM+h ds iksVZCys;j }hi ds nks LFkkuksa ds o"kZ 1981 ls 2002 rd ds 22 o"kkZsa ds jklk;fud feJ.k ds dsoy vknzZ&o"kZ.k vk¡dM+kas dk fo’ys"k.k fd;k x;k gSA fofo/k vk;fud ldsUnzh;dj.k ds chp ds lglaca/kksa dks Li"V djus dk iz;kl fd;k x;k gSA ’kjn_rq ds nkSjku gqbZ o"kkZ ds ty esa lYQsV] ukbVªsV vkSj gkbMªkstu vk;uksa dh vf/kdre lkUnzrk ikbZ xbZ gS A _rq okj oxhZdj.k ds nkSjku ekWulwu _rq esa lHkh vk;uksa ds vknZz o"kZ.k vfHkokg ds vf/kdre gksus dk irk pyk gS A nksuksa gh LFkkuksa ij vEyh; fu{ksi.k esa c<+ksrjh dh izo`fr ns[kh xbZ gS A futZu}hi ij Tokykeq[kh dh fØ;k’khyrk iksVZCys;j ds o"kkZty esa jklk;fud feJ.k dks izHkkfor djrh gS A lYQsV vk;u ¼½ dk okf"kZd vknzZ o"kZ.k feuhdkW; esa 15-6 fd-xzk- izfr gsDVs;j izfr o"kZ rFkk iksVZCys;j es 25-5 fd-xzk- izfr gsDVsvj izfr o"kZ ik;k x;k gS rFkk ukbVªsV vk;u ¼½ dh fu{ksfir ek=k feuhdkW; esa 38-0 fd-xzk- izfr gsDVs;j izfr o"kZ vkSj iksVZCys;j esa 74-6 fd-xzk- izfr gsDVs;j izfr o"kZ rd ikbZ xbZ gS A /kuk;u vk;uksa esa lksfM;e vk;u ¼Na+½ rFkk dSfY’k;e vk;u ¼Ca2+½ ds rRo vf/kd ek=k esa tek gksrs gSa ftuesa eSXusf’k;e vk;u ¼Mg2+½ds lkFk&lkFk iksVkf’k;e vk;u ¼K+½ Hkh feys gksrs gSa A The data on chemical composition of wet only precipitation from two island stations Minicoy in Arabian Sea and Portblair in Bay of Bengal, representing 22 year period, 1981-2002 have been analyzed. An attempt has been made to explain the correlation between various ionic concentrations. The maximum concentrations of sulfate, nitrate and hydrogen ions in rainwater are observed during winter season. When classified by season the wet deposition flux for all the ions is greatest in the monsoon season during which precipitation is substantially high. A tendency for increase in acidic deposition is observed at both the stations. The volcanic activity at Barren island appears to influence the chemical composition of rainwater at Portblair. The annual wet deposition of SO42- ranged from 15.6 kg ha-1 yr-1 at Minicoy to 25.5 kg ha-1 yr-1 at Portblair, and the corresponding amounts of NO3- deposited ranged from 38.0 kg ha-1 yr-1 at Minicoy to 74.6 kg ha-1 yr-1 at Portblair. Of the cations Na+ and Ca2+ are the elements deposited in largest quantities followed by Mg2+ and K+.

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Wet Deposition Fluxes of Nitrate and Ammonium at a Rural Agricultural Site in north India

10.5194/egusphere-egu21-9103 ◽

2021 ◽

Author(s):

Sudesh Yadav ◽

Umesh Kulshrestha

Keyword(s):

Wet Deposition ◽

Major Ions ◽

Monsoon Season ◽

North India ◽

Reactive Nitrogen ◽

Deposition Flux ◽

Deposition Fluxes ◽

Average Value ◽

Wet Deposition Flux ◽

Agricultural Site

The chemical composition of rainwater is an indicator of the air quality and sources of influence. In this study, pH and ionic concentrations were measured in rain samples collected during monsoon season of 2018 at a rural agricultural site located in northern part of India. Wet deposition fluxes of reactive nitrogen species NH4+ over NO3- were calculated to estimate their annual deposition. The pH of samples varied between 5.2 and 6.14, with an average value of 5.72 which is in alkaline range considering 5.6 as the neutral pH of cloud water with atmospheric CO2 equilibrium. These relatively high pH values indicate the neutralisation of acidity in precipitation. Samples were analysed for their cationic and anionic content using ion chromatography. The results showed that NH4+ concentrations were higher than NO3- with the VWM concentrations of 187.23 &#956;eql-1 and 26.79 &#956;eql-1 respectively. Furthermore, wet deposition flux of NH4+-N was calculated as 4.25 kg ha-1 yr-1 while that of NO3--N was as 2.10 kg ha-1 yr-1. VWM concentrations of major ions decreased in the following order NH4+ > Ca2+ > SO42- > NO3- > K+ > Cl- > Na+ > Mg2+. In this study, relatively high NH4+ concentrations in rainwater can be attributed to nearby agricultural activities, excreta and biomass burning.Keywords: Rainwater, Neutralisation, VWM concentration, Agricultural site, Reactive Nitrogen.

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Impacts of Anthropogenic Emissions and Meteorological Variation on Hg Wet Deposition in Chongming, China

Atmosphere ◽

10.3390/atmos11121301 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1301

Author(s):

Yi Tang ◽

Qingru Wu ◽

Wei Gao ◽

Shuxiao Wang ◽

Zhijian Li ◽

...

Keyword(s):

Wet Deposition ◽

Warm Season ◽

Meteorological Condition ◽

Anthropogenic Emissions ◽

Deposition Flux ◽

Wet Deposition Flux ◽

Meteorological Variation ◽

Global Concern ◽

The Impact

Mercury (Hg) is a ubiquitous environmental toxicant that has caused global concern due to its persistence and bioaccumulation in the environment. Wet deposition is a crucial Hg input for both terrestrial and aquatic environments and is a significant indicator for evaluating the effectiveness of anthropogenic Hg control. Rainwater samples were collected from May 2014 to October 2018 in Chongming Island to understand the multi-year Hg wet deposition characteristics. The annual Hg wet deposition flux ranged from 2.6 to 9.8 μg m−2 yr−1 (mean: 4.9 μg m−2 yr−1). Hg wet deposition flux in Chongming was comparable to the observations at temperate and subtropical background sites (2.0–10.2 μg m−2 yr−1) in the northern hemisphere. Hg wet deposition flux decreased from 8.6 μg m−2 yr−1 in 2014–2015 to 3.8 μg m−2 yr−1 in 2016 and was attributed to a decrease in the volume-weighted mean (VWM) Hg concentration (−4.1 ng L−1 yr−1). The reduced VWM Hg was explained by the decreasing atmospheric Hg and anthropogenic emissions reductions. The annual Hg wet deposition flux further decreased from 3.8 μg m−2 in 2016 to 2.6 μg m−2 in 2018. The reduction of warm season (April–September) rainfall amounts (356–845 mm) mainly contributed to the Hg wet deposition flux reduction during 2016–2018. The multi-year monitoring results suggest that long-term measurements are necessary when using wet deposition as an indicator to reflect the impact of anthropogenic efforts on mercury pollution control and meteorological condition variations.

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Biodiversity of butterflies in endosulfan-affected areas of Kerala, India

The Journal of Basic and Applied Zoology ◽

10.1186/s41936-020-00192-w ◽

2020 ◽

Vol 81 (1) ◽

Author(s):

K. N. Raghavendra ◽

Kumar Arvind ◽

G. K. Anushree ◽

Tony Grace

Keyword(s):

Monsoon Season ◽

Winter Season ◽

Wiener Index ◽

Long Term Effects ◽

Affected Area ◽

Butterfly Assemblages ◽

Abundance And Diversity ◽

The One ◽

One Way Anova

Abstract Background Butterflies are considered as bio-indicators of a healthy and diversified ecosystem. Endosulfan was sprayed indiscriminately in large plantations of Kasaragod district, Kerala which had caused serious threats to the ecosystem. In this study, we surveyed the butterflies for their abundance and diversity in three differentially endosulfan-affected areas viz., Enmakaje—highly affected area, Periye—moderately affected area, Padanakkad—unaffected area, carried out between the end of the monsoon season and the start of the winter season, lasting approximately 100 days. Seven variables viz., butterfly abundance (N), species richness (S), Simpson’s reciprocal index (D), the Shannon–Wiener index (H′), the exponential of the Shannon–Wiener index (expH′), Pielou’s evenness (J) and species evenness (D/S), related to species diversity were estimated, followed by the one-way ANOVA (F = 25.01, p < 0.001) and the Kruskal-Wallis test (H = 22.59, p < 0.001). Results A population of three different butterfly assemblages comprised of 2300 butterflies which represented 61 species were encountered. Our results showed that Enmakaje displayed significantly lower butterfly diversity and abundance, compared to the other two communities. Conclusion So far, this is the first study concerning the effect of endosulfan on the biodiversity of butterfly in the affected areas of Kasaragod, Kerala, India. This study may present an indirect assessment of the persisting effects of endosulfan in the affected areas, suggesting its long-term effects on the ecosystem.

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Long term precipitation chemistry and wet deposition in a remote dry savanna site in Africa (Niger)

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-1579-2009 ◽

2009 ◽

Vol 9 (5) ◽

pp. 1579-1595 ◽

Cited By ~ 50

Author(s):

C. Galy-Lacaux ◽

D. Laouali ◽

L. Descroix ◽

N. Gobron ◽

C. Liousse

Keyword(s):

Wet Deposition ◽

Ph Value ◽

Precipitation Chemistry ◽

Annual Rainfall ◽

Deposition Flux ◽

Air Concentration ◽

Ionic Charge ◽

Rainfall Gradient ◽

The Mean

Abstract. Long-term precipitation chemistry have been recorded in the rural area of Banizoumbou (Niger), representative of a semi-arid savanna ecosystem. A total of 305 rainfall samples ~90% of the total annual rainfall) were collected from June 1994 to September 2005. From ionic chromatography, pH major inorganic and organic ions were detected. Rainwater chemistry is controlled by soil/dust emissions associated with terrigeneous elements represented by SO42−, Ca2+, Carbonates, K+ and Mg2+. It is found that calcium and carbonates represent ~40% of the total ionic charge. The second highest contribution is nitrogenous, with annual Volume Weighed Mean (VWM) for NO3− and NH4+ concentrations of 11.6 and 18.1 μeq.l−1, respectively. This is the signature of ammonia sources from animals and NOx emissions from savannas soil-particles rain-induced. The mean annual NH3 and NO2 air concentration are of 6 ppbv and 2.6 ppbv, respectively. The annual VWM precipitation concentration of sodium and chloride are both of 8.7 μeq.l−1 which reflects the marine signature of monsoonal and humid air masses. The median pH value is of 6.05. Acidity is neutralized by mineral dust, mainly carbonates, and/or dissolved gases such NH3. High level of organic acidity with 8μeq.l−1 and 5.2 μeq.l−1 of formate and acetate were also found. The analysis of monthly Black Carbon emissions and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) values show that both biogenic emission from vegetation and biomass burning could explain the rainfall organic acidity content. The interannual variability of the VWM concentrations around the mean (1994–2005) is between ±5% and ±30% and mainly due to variations of sources strength and rainfall spatio-temporal distribution. From 1994 to 2005, the total mean wet deposition flux in the Sahelian region is of 60.1 mmol.m−2.yr−1 ±25%. Finally, Banizoumbou measurements are compared to other long-term measurements of precipitation chemistry in the wet savanna of Lamto (Côte d'Ivoire) and in the forested zone of Zoétélé (Cameroon). The total chemical loading presents a maximum in the dry savanna and a minimum in the forest (from 143.7, 100.2 to 86.6 μeq.l−1), associated with the gradient of terrigeneous sources. The wet deposition fluxes present an opposite trend, with 60.0 mmol.m−2.yr−1 in Banizoumbou, 108.6 mmol.m−2.yr−1 in Lamto and 162.9 mmol.m−2.yr−1 in Zoétélé, controlled by rainfall gradient along the ecosystems transect.

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Seven year satellite observations of the mean structures and variabilities in the regional aerosol distribution over the oceanic areas around the Indian subcontinent

Annales Geophysicae ◽

10.5194/angeo-23-2011-2005 ◽

2005 ◽

Vol 23 (6) ◽

pp. 2011-2030 ◽

Cited By ~ 24

Author(s):

S. K. Nair ◽

K. Parameswaran ◽

K. Rajeev

Keyword(s):

Indian Ocean ◽

Southern Hemisphere ◽

Bay Of Bengal ◽

Arabian Sea ◽

Indian Subcontinent ◽

Monsoon Season ◽

Dry Season ◽

Aerosol Transport ◽

Summer Monsoon Season ◽

Aerosol Distribution

Abstract. Aerosol distribution over the oceanic regions around the Indian subcontinent and its seasonal and interannual variabilities are studied using the aerosol optical depth (AOD) derived from NOAA-14 and NOAA-16 AVHRR data for the period of November 1995–December 2003. The air-mass types over this region during the Asian summer monsoon season (June–September) are significantly different from those during the Asian dry season (November–April). Hence, the aerosol loading and its properties over these oceanic regions are also distinctly different in these two periods. During the Asian dry season, the Arabian Sea and Bay of Bengal are dominated by the transport of aerosols from Northern Hemispheric landmasses, mainly the Indian subcontinent, Southeast Asia and Arabia. This aerosol transport is rather weak in the early part of the dry season (November–January) compared to that in the later period (February–April). Large-scale transport of mineral dust from Arabia and the production of sea-salt aerosols, due to high surface wind speeds, contribute to the high aerosol loading over the Arabian Sea region during the summer monsoon season. As a result, the monthly mean AOD over the Arabian Sea shows a clear annual cycle with the highest values occurring in July. The AOD over the Bay of Bengal and the Southern Hemisphere Indian Ocean also displays an annual cycle with maxima during March and October, respectively. The amplitude of the annual variation is the largest in coastal Arabia and the least in the Southern Hemisphere Indian Ocean. The interannual variability in AOD is the largest over the Southeast Arabian Sea (seasonal mean AOD varies from 0.19 to 0.42) and the northern Bay of Bengal (seasonal mean AOD varies from 0.24 to 0.39) during the February–April period and is the least over the Southern Hemisphere Indian Ocean. This study also investigates the altitude regions and pathways of dominant aerosol transport by combining the AOD distribution with the atmospheric circulation. Keywords. Atmospheric composition and structure (Aerosols and particles) – Meteorology and atmospheric dynamics (Climatology) – Oceanography: physical (Ocean fog and aerosols)

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Satellite-based study of physico-optical properties of aerosols over a westernmost location of Brahmaputra valley

Satellite Oceanography and Meteorology ◽

10.18063/som.v3i2.699 ◽

2018 ◽

Vol 3 (2) ◽

Author(s):

Jhuma Biswas 1

Keyword(s):

Atmospheric Aerosols ◽

Monsoon Season ◽

Cloud Condensation Nuclei ◽

Winter Season ◽

Earth Observing System ◽

Brahmaputra Valley ◽

Increasing Trend ◽

Long Term Trend ◽

Term Analysis

This study examines the long term trend of the radiatively active atmospheric aerosols which can influence the Earth’s energy budget directly by scattering and absorbing radiation and indirectly by acting as cloud condensation nuclei. MODIS sensor on board the NASA Earth Observing System Terra and Aqua satellite based Aerosol Optical Depth (AOD) data are used for long term analysis of aerosols over Bongaigaon, Assam for the period August, 2002 to March, 2017. Highest AOD values are observed in pre-monsoon (March-May) season due to long range transportation as well as intense biomass burning activities especially as a part of Jhum cultivation. In general, AOD values are low in post-monsoon (October-November) season which may be due to wash out of aerosols by rain in the preceding months without enough replacement. The monthly AOD values vary from its highest value 0.949 in April, 2016 to its lowest value 0.107 in November, 2002 for the study period. From the comparison of MODIS Terra and Aqua AOD at 550 nm, it is clearly seen that generally Terra AOD at 10:30 hr is higher than the Aqua AOD at 13:30hr. A slowly increasing trend of both Aqua and Terra AOD at 550 nm is observed over the study location. The observed Ångström exponent value varies from its minimum value in monsoon season to its maximum value in winter season. With increasing AOD values, horizontal visibility decreases over Bongaigaon.

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Subtropical subsidence and surface deposition of oxidized mercury produced in the free troposphere

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-8999-2017 ◽

2017 ◽

Vol 17 (14) ◽

pp. 8999-9017 ◽

Cited By ~ 9

Author(s):

Viral Shah ◽

Lyatt Jaeglé

Keyword(s):

Boundary Layer ◽

Dry Deposition ◽

Wet Deposition ◽

Transport Model ◽

Lower Troposphere ◽

Deposition Flux ◽

Surface Deposition ◽

Middle Troposphere ◽

Western Us ◽

Wet Deposition Flux

Abstract. Oxidized mercury (Hg(II)) is chemically produced in the atmosphere by oxidation of elemental mercury and is directly emitted by anthropogenic activities. We use the GEOS-Chem global chemical transport model with gaseous oxidation driven by Br atoms to quantify how surface deposition of Hg(II) is influenced by Hg(II) production at different atmospheric heights. We tag Hg(II) chemically produced in the lower (surface–750 hPa), middle (750–400 hPa), and upper troposphere (400 hPa–tropopause), in the stratosphere, as well as directly emitted Hg(II). We evaluate our 2-year simulation (2013–2014) against observations of Hg(II) wet deposition as well as surface and free-tropospheric observations of Hg(II), finding reasonable agreement. We find that Hg(II) produced in the upper and middle troposphere constitutes 91 % of the tropospheric mass of Hg(II) and 91 % of the annual Hg(II) wet deposition flux. This large global influence from the upper and middle troposphere is the result of strong chemical production coupled with a long lifetime of Hg(II) in these regions. Annually, 77–84 % of surface-level Hg(II) over the western US, South America, South Africa, and Australia is produced in the upper and middle troposphere, whereas 26–66 % of surface Hg(II) over the eastern US, Europe, and East Asia, and South Asia is directly emitted. The influence of directly emitted Hg(II) near emission sources is likely higher but cannot be quantified by our coarse-resolution global model (2° latitude  ×  2.5° longitude). Over the oceans, 72 % of surface Hg(II) is produced in the lower troposphere because of higher Br concentrations in the marine boundary layer. The global contribution of the upper and middle troposphere to the Hg(II) dry deposition flux is 52 %. It is lower compared to the contribution to wet deposition because dry deposition of Hg(II) produced aloft requires its entrainment into the boundary layer, while rain can scavenge Hg(II) from higher altitudes more readily. We find that 55 % of the spatial variation of Hg wet deposition flux observed at the Mercury Deposition Network sites is explained by the combined variation of precipitation and Hg(II) produced in the upper and middle troposphere. Our simulation points to a large role of the dry subtropical subsidence regions. Hg(II) present in these regions accounts for 74 % of Hg(II) at 500 hPa over the continental US and more than 60 % of the surface Hg(II) over high-altitude areas of the western US. Globally, it accounts for 78 % of the tropospheric Hg(II) mass and 61 % of the total Hg(II) deposition. During the Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) aircraft campaign, the contribution of Hg(II) from the dry subtropical regions was found to be 75 % when measured Hg(II) exceeded 250 pg m−3. Hg(II) produced in the upper and middle troposphere subsides in the anticyclones, where the dry conditions inhibit the loss of Hg(II). Our results highlight the importance the subtropical anticyclones as the primary conduits for the production and export of Hg(II) to the global atmosphere.

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Chemical composition of precipitation and wet deposition of major ions on the Korean peninsula

Atmospheric Environment ◽

10.1016/s1352-2310(99)00225-3 ◽

2000 ◽

Vol 34 (4) ◽

pp. 563-575 ◽

Cited By ~ 109

Author(s):

Bo Kyoung Lee ◽

Seung Hee Hong ◽

Dong Soo Lee

Keyword(s):

Chemical Composition ◽

Korean Peninsula ◽

Wet Deposition ◽

Major Ions

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Study of wet precipitation and its chemical composition in South of Brazil

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652008000200016 ◽

2008 ◽

Vol 80 (2) ◽

pp. 381-395 ◽

Cited By ~ 17

Author(s):

Elba C. Teixeira ◽

Daniela Migliavacca ◽

Sadi Pereira Filho ◽

Andréa C.M. Machado ◽

Juliana B. Dallarosa

Keyword(s):

Chemical Composition ◽

Wet Deposition ◽

Major Ions ◽

Rio Grande ◽

Anthropogenic Sources ◽

Anthropogenic Influence ◽

Rio Grande Do Sul ◽

Soil Dust ◽

Wet Precipitation ◽

South Of Brazil

The purpose of this study is to analyze the chemical composition of wet precipitation in samples collected at three stations in the Candiota region in the Brazilian state of Rio Grande do Sul (RS). Samples were collected in 2004. Variables analyzed in wet precipitation were pH, conductivity, and concentration of Cl-, NO3-, SO4(2-) F-, Na+, Ca2+, Mg2+, K+, NH4+, Cu, Zn, Fe, Mn, Pb, Ni, Cd, Co, and Cr. SO2 and NO2 distribution over the time were also evaluated. Results have showed that pH < 5.6 are found mostly at Candiota airport (85%), followed by Aceguá (72%) and Três Lagoas (65%). Enrichment Factor of the studied ions in wet deposition revealed higher Ca2+ and SO4(2-) enrichment in Três Lagoas. Factor Analysis applied to metals and major ions allowed identifying the major sources. While Cl-, Na+, Mg2+ are of marine origin, SO4(2-), NO3-, NH4+ ,F- come from anthropogenic sources. Except for Fe and Mn originating from the soil dust, the metals studied showed to have anthropogenic influence The average SO2 and NO2 concentration, as well as SO4(2-) and NO3- in wet precipitation in the Candiota region showed higher concentrations during the warmer months.

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