Hydrochemistry and dissolved solute load of meltwater in a catchment of a cold-arid trans-Himalayan region of Ladakh over an entire melting period

2016 ◽  
Vol 47 (6) ◽  
pp. 1224-1238 ◽  
Author(s):  
Namrata Priya ◽  
Renoj J. Thayyen ◽  
AL. Ramanathan ◽  
Virendra Bahadur Singh
Keyword(s):  
Atmospheric Aerosols ◽  
Himalayan Region ◽  
Ion Chemistry ◽  
Anthropogenic Aerosols ◽  
Ice Melt ◽  
Hydrochemical Study ◽  
Alkaline Dust ◽  
Melting Period ◽  
Early Peak ◽  
Dominant Process

The hydrochemical study of meltwater draining from a catchment dominated by snowmelt in a cold-arid trans-Himalayan region of Ladakh, India, was carried out for an entire melting season (May–September) during the year of 2010. Cation concentration in the meltwater shows a consistent trend of Ca > >Mg > Na > K for this period. Carbonate weathering has been identified as the dominant process controlling the dissolved ion chemistry of meltwater in the study area. There are indications that atmospheric aerosols contain alkaline dust, sea salt and anthropogenic aerosols like NO3 and SO4 that might have also added some solute to the system. Meltwater chemistry has been showing an intra-annual variation with highest concentration for most of the dissolved solutes during the late melt period, pointing towards the contribution of ground ice melt to the catchment runoff. The lowest concentration during the peak melt period is due to higher contribution from snow melt which has less residence time to interact with rock. Cationic denudation rate for this catchment has been estimated as 778 meq m−2 a−1, while the average total dissolved solids flux for early, peak and late melt period is 0.64 t day−1, 3.02 t day−1, 1.31 t day−1, respectively.

The Long Term Spatial-temporal Distribution of Aerosol Optical Depth and Its Associated Atmospheric Circulation Over Southeast Africa.

2021 ◽  
Author(s):  
Matthews Nyasulu ◽  
Md. Mozammel Haque ◽  
Bathsheba Musonda ◽  
Cao Fang
Keyword(s):  
Human Health ◽  
Atmospheric Circulation ◽  
Atmospheric Aerosols ◽  
Crop Residues ◽  
Temporal Distribution ◽  
Western Coast ◽  
High Concentration ◽  
Anthropogenic Aerosols ◽  
Anthropogenic Aerosol

Abstract Recent studies have revealed significant impacts of increased concentration of anthropogenic aerosols in the atmosphere to both climate and human health. Southeast Africa is one of the regions where studies related to atmospheric aerosols remain scant, causing high uncertainty in predicting and understanding the impacts of these aerosols to both climate and human health. The present study therefore has investigated the long term spatial-temporal distribution of atmospheric aerosols, trends, its relationship with cloud properties and the associated atmospheric circulation over the region. High concentration of aerosol has been detected during the dry months of September to November (SON) while low during March to May (MAM) and June-July (JJA) seasons in most areas. Highest 550 was recorded in areas with low elevation such as over Lake Malawi, Zambezi valley and along the western coast of the Indian Ocean. The average of the detected concentration is however low as compared to highly polluted regions of the globe. Statistical analyses revealed insignificant change of AOD550 in most areas between 2002 and 2020 time period. The study has also revealed seasonality of aerosol distribution highly influenced by changes in atmospheric circulation. Burning of biomass during dry months such bush fires and burning of crop residues remain the major source of anthropogenic aerosol concentration over Southeast Africa hence needs to be controlled.

Trend of atmospheric aerosols over the north western Himalayan region, India

2005 ◽  
Vol 39 (27) ◽  
pp. 4817-4825 ◽  
Author(s):  
K GAJANANDA ◽  
J KUNIYAL ◽  
G MOMIN ◽  
P RAO ◽  
P SAFAI ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Himalayan Region ◽  
The North ◽  
Western Himalayan Region ◽  
North Western

scholarly journals Estimation of Biomass Burning Influence on Air Pollution around Beijing from an Aerosol Retrieval Model

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sonoyo Mukai ◽  
Masayoshi Yasumoto ◽  
Makiko Nakata
Keyword(s):  
Air Pollution ◽  
Radiative Transfer ◽  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Transfer Problem ◽  
Carbonaceous Aerosols ◽  
Retrieval Model ◽  
Anthropogenic Aerosols ◽  
Radiative Transfer Problem ◽  
Aerosol Retrieval

We investigate heavy haze episodes (with dense concentrations of atmospheric aerosols) occurring around Beijing in June, when serious air pollution was detected by both satellite and ground measurements. Aerosol retrieval is achieved by radiative transfer simulation in an Earth atmosphere model. We solve the radiative transfer problem in the case of haze episodes by successive order of scattering. We conclude that air pollution around Beijing in June is mainly due to increased emissions of anthropogenic aerosols and that carbonaceous aerosols from agriculture biomass burning in Southeast Asia also contribute to pollution.

scholarly journals Physical and optical properties of atmospheric aerosol by in-situ and radiometric measurements

2009 ◽  
Vol 9 (6) ◽  
pp. 25565-25597
Author(s):  
M. Calvello ◽  
F. Esposito ◽  
G. Pavese ◽  
C. Serio
Keyword(s):  
Optical Properties ◽  
Atmospheric Aerosols ◽  
Saharan Dust ◽  
Dust Particles ◽  
Rural Site ◽  
Size Distributions ◽  
Anthropogenic Aerosols ◽  
Anthropogenic Aerosol ◽  
Observation Methods

Abstract. Physical and optical properties of atmospheric aerosols collected by using a high resolution (1.5 nm) spectroradiometer (spectral range 400–800 nm), a 13 stages Dekati Low Pressure Impactor (size range 30 nm–10 μm), and an AE31 Aethalometer (7 wavelenghts from 370 nm to 950 nm), have been examined in a semi-rural site in Southwest Italy (Tito Scalo, 40°35´ N, 15°41´ E, 750 m a.s.l.). In particular, daily averaged values of AOD and Ångström turbidity parameters from radiometric data together with mass-size distributions from impactor data and Black Carbon (BC) concentrations have been analyzed from May to October 2008. Furthermore, by inverting direct solar radiances, aerosol columnar number and volume size distributions have been obtained for the same period. Comparison of different observation methods, allowed to verify if, and in what conditions, changes in aerosol properties measured at ground are representative of columnar properties variations. Agreement between columnar and in-situ measurements has been obtained in case of anthropogenic aerosol loading, while in case of Saharan dust intrusions some discrepancies have been found when dust particles were located at high layers in the atmosphere (4–8 km) thus affecting columnar properties more than surface ones. For anthropogenic aerosols, a good correlation has been confirmed through the comparison of fine aerosol fraction contribution as measured by radiometer, impactor and aethalometer, suggesting that in this case particles are more homogeneously distributed over the lower layers of atmosphere and columnar aerosol optical properties are dominated by surface measured component.

scholarly journals Ice Melt-Induced Variations of Structural and Functional Traits of the Aquatic Microbial Community along an Arctic River (Pasvik River, Norway)

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2297
Author(s):  
Maria Papale ◽  
Carmen Rizzo ◽  
Gabriella Caruso ◽  
Stefano Amalfitano ◽  
Giovanna Maimone ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Functional Traits ◽  
Microbial Community Composition ◽  
The Arctic ◽  
Ice Melting ◽  
Ice Melt ◽  
Variation Patterns ◽  
Melting Period ◽  
Spatial Diversification

The effects of climate change-induced ice melting on the microbial communities in different glacial-fed aquatic systems have been reported, but seasonal dynamics remain poorly investigated. In this study, the structural and functional traits of the aquatic microbial community were assessed along with the hydrological and biogeochemical variation patterns of the Arctic Pasvik River under riverine and brackish conditions at the beginning (May = Ice-melt (−)) and during the ice-melting season (July = Ice-melt (+)). The microbial abundance and morphometric analysis showed a spatial diversification between the riverine and brackish stations. Results highlighted different levels of microbial respiration and activities with different carbon and phosphorous utilization pathways, thus suggesting an active biogeochemical cycling along the river especially at the beginning of the ice-melting period. At Ice-melt (−), Gammaproteobacteria and Alphaproteobacteria were dominant in riverine and brackish stations, respectively. Conversely, at Ice-melt (+), the microbial community composition was more homogeneously distributed along the river (Gammaproteobacteria > Alphaproteobacteria > Bacteroidetes). Our findings provide evidence on how riverine microbial communities adapt and respond to seasonal ice melting in glacial-fed aquatic ecosystems.

scholarly journals Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

2012 ◽  
Vol 12 (11) ◽  
pp. 5129-5145 ◽  
Author(s):  
O. E. García ◽  
J. P. Díaz ◽  
F. J. Expósito ◽  
A. M. Díaz ◽  
O. Dubovik ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Radiative Forcing ◽  
Mineral Dust ◽  
High Surface ◽  
Global Scale ◽  
Free Troposphere ◽  
Anthropogenic Aerosols ◽  
Radiative Balance ◽  
Absorbing Aerosols

Abstract. The shortwave radiative forcing (ΔF) and the radiative forcing efficiency (ΔFeff) of natural and anthropogenic aerosols have been analyzed using estimates of radiation both at the Top (TOA) and at the Bottom Of Atmosphere (BOA) modeled based on AERONET aerosol retrievals. Six main types of atmospheric aerosols have been compared (desert mineral dust, biomass burning, urban-industrial, continental background, oceanic and free troposphere) in similar observational conditions (i.e., for solar zenith angles between 55° and 65°) in order to compare the nearly same solar geometry. The instantaneous ΔF averages obtained vary from −122 ± 37 Wm−2 (aerosol optical depth, AOD, at 0.55 μm, 0.85 ± 0.45) at the BOA for the mixture of desert mineral dust and biomass burning aerosols in West Africa and −42 ± 22 Wm−2 (AOD = 0.9 ± 0.5) at the TOA for the pure mineral dust also in this region up to −6 ± 3 Wm−2 and −4 ± 2 Wm−2 (AOD = 0.03 ± 0.02) at the BOA and the TOA, respectively, for free troposphere conditions. This last result may be taken as reference on a global scale. Furthermore, we observe that the more absorbing aerosols are overall more efficient at the BOA in contrast to at the TOA, where they backscatter less solar energy into the space. The analysis of the radiative balance at the TOA shows that, together with the amount of aerosols and their absorptive capacity, it is essential to consider the surface albedo of the region on which they are. Thus, we document that in regions with high surface reflectivity (deserts and snow conditions) atmospheric aerosols lead to a warming of the Earth-atmosphere system.

scholarly journals Microalgae community of the Huaytire wetland, an Andean high-altitude wetland in Peru

2012 ◽  
Vol 24 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Gian Salazar-Torres ◽  
Vera Lúcia de Moraes Huszar
Keyword(s):  
High Altitude ◽  
Light Exposure ◽  
Floristic Composition ◽  
Alpha Diversity ◽  
Urban Land Use ◽  
Ice Melting ◽  
Low Light ◽  
Taxa Richness ◽  
Ice Melt ◽  
Melting Period

AIM: The diversity and distribution of microalgae communities in a high-altitude (3,000 to 4,500 m a.s.l) Andean wetland, regionally known as bofedal, were examined to assess seasonal and spatial patterns. METHODS: Samples were taken monthly from June to December, 2008 at 13 stations in the Huaytire wetland (16° 54’ S and 70° 20’ W), covering three areas (impacted by urban land use, impacted by camelid pasture, and non-impacted) and three climatologically induced periods (ice-covered, ice-melt and ice-free). RESULTS: A total of 52 genera of algae were recorded. Diatoms were the predominant group in abundance and richness. We found a significantly higher abundance during the ice-melting period, when light exposure and runoff were intermediate, in comparison to the ice-covered (low light and flushing) and ice-free (high light and low runoff) periods. Microalgae abundance was significantly lower in the non-impacted area compared to the sites close to the urban area and to the camelid pastures. Alpha diversity ranged from 8 to 29 genera per sample. High genera exchange was observed throughout the wetland, showing a similar floristic composition (beta diversity = 4%). CONCLUSIONS: We found that diatoms were dominant and adapted to the extreme conditions of the Andean wetland, showing higher abundance during the ice-melt period and in the livestock area. Also, taxa richness was higher in the ice-melt period and in the most-impacted areas.

scholarly journals Natural aerosols explain seasonal and spatial patterns of Southern Ocean cloud albedo

2015 ◽  
Vol 1 (6) ◽  
pp. e1500157 ◽  
Author(s):  
Daniel T. McCoy ◽  
Susannah M. Burrows ◽  
Robert Wood ◽  
Daniel P. Grosvenor ◽  
Scott M. Elliott ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Atmospheric Aerosols ◽  
Suspended Solid ◽  
Spatiotemporal Variability ◽  
Anthropogenic Aerosols ◽  
Spatially Correlated ◽  
Cloud Properties ◽  
Planetary Albedo ◽  
High Concentrations ◽  
Natural Aerosols

Atmospheric aerosols, suspended solid and liquid particles, act as nucleation sites for cloud drop formation, affecting clouds and cloud properties—ultimately influencing the cloud dynamics, lifetime, water path, and areal extent that determine the reflectivity (albedo) of clouds. The concentration Nd of droplets in clouds that influences planetary albedo is sensitive to the availability of aerosol particles on which the droplets form. Natural aerosol concentrations affect not only cloud properties themselves but also modulate the sensitivity of clouds to changes in anthropogenic aerosols. It is shown that modeled natural aerosols, principally marine biogenic primary and secondary aerosol sources, explain more than half of the spatiotemporal variability in satellite-observed Nd. Enhanced Nd is spatially correlated with regions of high chlorophyll a, and the spatiotemporal variability in Nd is found to be driven primarily by high concentrations of sulfate aerosol at lower Southern Ocean latitudes (35o to 45oS) and by organic matter in sea spray aerosol at higher latitudes (45o to 55oS). Biogenic sources are estimated to increase the summertime mean reflected solar radiation in excess of 10 W m–2 over parts of the Southern Ocean, which is comparable to the annual mean increases expected from anthropogenic aerosols over heavily polluted regions of the Northern Hemisphere.

scholarly journals A Heat-Balance Study on Mccall Glacier, Brooks Range, Alaska: A Contribution to the International Hydrological Decade

1974 ◽  
Vol 13 (67) ◽  
pp. 13-26 ◽  
Author(s):  
Gerd Wendler ◽  
Gunter Weller
Keyword(s):  
Heat Balance ◽  
Brooks Range ◽  
Balance Study ◽  
Ice Melt ◽  
Melting Period ◽  
Precipitation Area ◽  
The Individual ◽  
Northern Alaska ◽  
Arctic Glacier ◽  
The Relationship

On the McCall Glacier, an Arctic glacier in the eastern Brooks Range, northern Alaska, a heat balance study was carried out during the summer of 1970 to investigate quantitatively the relationship between energy transfer, climatic parameters and melting processes. Considering the individual energy balance terms, it was found that radiation is the most important heat source for snow and ice melt. The melting period itself is only 11 weeks long, which is quite short. The evaporation overcompensates for what little condensation occurs, and amounts to about 2% of the total ablation. Evaporation is more important in the spring, but becomes decreasingly so during the summer. The melt water which percolates into the snow-pack and refreezes at a lower level is a more effective way of transporting energy into the ground than conduction, and is of importance during the beginning of the melt period. The summer balance is considerably less energetic than over the tundra north of the Brooks Range. The main difference is a higher surface albedo, and to a lesser extent the protected nature of the glacier in a deep valley on a N–S axis, which reduces the duration of possible sunshine by 39% in summer. These are the important factors in maintaining the McCall Glacier and other similar glaciers in an otherwise low precipitation area.

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