scholarly journals Chemistry of snow deposited during the summer monsoon and in the winter season at Baishui glacier No. 1, Yulong mountain, China

2009 ◽  
Vol 55 (190) ◽  
pp. 221-228 ◽  
Author(s):  
Zongxing Li ◽  
Yuanqing He ◽  
Honxi Pang ◽  
Wenxiong Jia ◽  
Xianhong He ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Ionic Composition ◽  
Winter Season ◽  
Southwest Monsoon ◽  
Crustal Material ◽  
Marine Aerosols ◽  
Winter Climate ◽  
Air Masses ◽  
Yulong Mountain ◽  
Continental Origin

AbstractThe glaciers on Yulong mountain (5596 m a.s.l.), China, are the southernmost in mainland Eurasia. The largest is Baishui glacier No. 1. Up to 90% of the annual precipitation there falls in summer, when warm moisture-rich air masses associated with the southwest monsoon reach the area from the Indian Ocean. The winter climate is influenced by air masses with a continental origin and by the southern branch of the westerlies. The snow that accumulates on Baishui glacier No. 1 includes marine aerosols associated with the summer monsoon, and dust brought in winter from central/west Asia, Africa or the Thar Desert area. Studies in May 2006 at two sites, one in the accumulation area (4900 m) and one in the ablation area (4750 m), revealed differences between the ionic composition of the snow that had accumulated in the 2005/06 winter and that of the snow which had been deposited during the preceding summer monsoon. Differences in the chemistry of the summer-accumulated snow at the two sites probably reflected local differences in ablation and elution rates, rather than differences in ion supplies. Differences in the chemistry of the winter-accumulated snow may reflect the influence of up-valley winds, which bring more crustal material to the lower site.

scholarly journals Identification of the Aerosol Types over Athens, Greece: The Influence of Air-Mass Transport

2010 ◽  
Vol 2010 ◽  
pp. 1-15 ◽  
Author(s):  
D. G. Kaskaoutis ◽  
P. G. Kosmopoulos ◽  
H. D. Kambezidis ◽  
P. T. Nastos
Keyword(s):  
Winter Season ◽  
Saharan Dust ◽  
Dust Particles ◽  
Hysplit Model ◽  
Air Mass ◽  
Back Trajectories ◽  
Air Masses ◽  
Local Pollution ◽  
Coarse Mode ◽  
Aerosol Types

Aerosol optical depth at 550 nm () and fine-mode (FM) fraction data from Terra-MODIS were obtained over the Greater Athens Area covering the period February 2000–December 2005. Based on both and FM values three main aerosol types have been discriminated corresponding to urban/industrial aerosols, clean maritime conditions, and coarse-mode, probably desert dust, particles. Five main sectors were identified for the classification of the air-mass trajectories, which were further used in the analysis of the ( and FM data for the three aerosol types). The HYSPLIT model was used to compute back trajectories at three altitudes to investigate the relation between -FM and wind sector depending on the altitude. The accumulation of local pollution is favored in spring and corresponds to air masses at lower altitudes originating from Eastern Europe and the Balkan. Clean maritime conditions are rare over Athens, limited in the winter season and associated with air masses from the Western or Northwestern sector. The coarse-mode particles origin seems to be more complicated proportionally to the season. Thus, in summer the Northern sector dominates, while in the other seasons, and especially in spring, the air masses belong to the Southern sector enriched with Saharan dust aerosols.

scholarly journals Projected changes in winter climate in Beskids Mountains during 21st century

Beskydy ◽  
2017 ◽  
Vol 10 (1-2) ◽  
pp. 123-134
Author(s):  
Aleš Farda ◽  
Petr Štěpánek ◽  
Pavel Zahradníček ◽  
Petr Skalák ◽  
Jan Meitner
Keyword(s):  
Water Balance ◽  
21St Century ◽  
Winter Season ◽  
Winter Precipitation ◽  
Balance Budget ◽  
General Increase ◽  
Winter Climate ◽  
Climate Conditions ◽  
Winter Temperatures ◽  
Projected Changes

We have investigated the future changes of climate conditions during the winter season in the Beskids Mountains. During the 21st century mean winter temperature will increase by 2.0–6.3 °C and winter precipitation will increase by 12.5 – to 17.5 % - depending on the scenario. Higher winter temperatures will be reflected in the reduced number of frost days, the number of which may drop by 40 % according to the RCP8.5 scenario. Whilst our study expects general increase in precipitation, higher temperatures will lead to an increased evapotranspiration and also change in the form of precipitation from solid (snow, rime) to liquid (rain, drizzling). Such trends could further propel the unfavorable changes in the water balance budget.

scholarly journals Climatic influence on the composition of snow cover at Austre Okstindbreen, Norway, 1989 and 1990

1994 ◽  
Vol 19 ◽  
pp. 1-6 ◽  
Author(s):  
He Yuanqing ◽  
Wilfred H. Theakstone
Keyword(s):  
Snow Cover ◽  
North Atlantic ◽  
Early Summer ◽  
Late Winter ◽  
Crustal Material ◽  
Air Masses ◽  
The North ◽  
Air Temperatures ◽  
Winter Snow ◽  
Marine Source

Winter snow cover at Austre Okstindbreen is influenced strongly by patterns of atmospheric circulation, and by air temperatures during precipitation. Differences of circulation over the North Atlantic and Scandinavia during the winters of 1988–89 and 1989–90 were reflected in the ionic and isotopic composition of snow that accumulated at the glacier. Early summer ablation did not remove, or smooth out, all the initial stratigraphic differences. In the first half of the 1988–89 winter, most air masses took a relatively short route between a marine source and Okstindan; late winter snowfalls were from air masses which had taken a longer continental route. The snow that accumulated in the first half of the 1989–90 winter was associated with air masses which had followed longer continental routes, and so brought higher concentrations of impurities from forests, lakes and crustal material. The ablation season began earlier in 1990 than in 1989, and summer winds and rain supplied more impurities to the snowpack surface.

scholarly journals Trapping, chemistry and export of trace gases in the South Asian summer monsoon observed during CARIBIC flights in 2008

2015 ◽  
Vol 15 (5) ◽  
pp. 6967-7018 ◽  
Author(s):  
A. Rauthe-Schöch ◽  
A. K. Baker ◽  
T. J. Schuck ◽  
C. A. M. Brenninkmeijer ◽  
A. Zahn ◽  
...  
Keyword(s):  
South Asian ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Trace Gases ◽  
Particle Dispersion ◽  
Atmospheric Pollutants ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Air Masses ◽  
Asian Summer

Abstract. The CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) passenger aircraft observatory performed in situ measurements at 10–12 km altitude in the South Asian summer monsoon anticyclone between June and September 2008. These measurements enable us to investigate this atmospheric region, which so far has mostly been observed from satellites, using the broad suite of trace gases and aerosols measured by CARIBIC. Elevated levels of a range of atmospheric pollutants were recorded e.g. carbon monoxide, total reactive nitrogen oxides, aerosol particles and several volatile organic compounds. The measurements provide detailed information about the chemical composition of air in different parts of the monsoon anticyclone, particularly of ozone precursors. While covering a range of 3500 km inside the monsoon anticyclone, CARIBIC observations show remarkable consistency, i.e. with regular latitudinal patterns of trace gases during the entire monsoon period. Trajectory calculations indicate that these air masses originated mainly from South Asia and Mainland Southeast Asia. Using the CARIBIC trace gas and aerosol measurements in combination with the Lagrangian particle dispersion model FLEXPART we investigated the characteristics of monsoon outflow and the chemical evolution of air masses during transport. Estimated photochemical ages of the air were found to agree well with transport times from a source region east of 95° E. The photochemical ages of the air in the southern part of the monsoon anticyclone were consistently younger (less than 7 days) and the air masses mostly in an ozone forming chemical regime. In its northern part the air masses were older (up to 13 days) and had unclear ozone formation or destruction potential. Based on analysis of forward trajectories several receptor regions were identified. In addition to predominantly westward transport, we found evidence for efficient transport (within 10 days) to the Pacific and North America, particularly during June and September, and also of cross-tropopause exchange, which was strongest during June and July. Westward transport to Africa and further to the Mediterranean was the main pathway during July.

scholarly journals Observations of PAN and its confinement in the Asian summer monsoon anticyclone in high spatial resolution

2016 ◽  
Vol 16 (13) ◽  
pp. 8389-8403 ◽  
Author(s):  
Jörn Ungermann ◽  
Mandfred Ern ◽  
Martin Kaufmann ◽  
Rolf Müller ◽  
Reinhold Spang ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Potential Temperature ◽  
Low Earth Orbit ◽  
Transport Pathway ◽  
Air Masses ◽  
Mixing Ratios ◽  
Asian Summer ◽  
The Relationship ◽  
Eddy Shedding

Abstract. This paper presents an analysis of trace gases in the Asian summer monsoon (ASM) region on the basis of observations by the CRISTA infrared limb sounder taken in low-earth orbit in August 1997. The spatially highly resolved measurements of peroxyacetyl nitrate (PAN) and O3 allow a detailed analysis of an eddy-shedding event of the ASM anticyclone. We identify enhanced PAN volume mixing ratios (VMRs) within the main anticyclone and within the eddy, which are suitable as a tracer for polluted air originating in India and China. Plotting the retrieved PAN VMRs against potential vorticity (PV) and potential temperature reveals that the PV value at which the PAN VMRs exhibit the strongest decrease with respect to PV increases with potential temperature. These PV values might be used to identify the extent of the ASM. Using temperature values also derived from CRISTA measurements, we also computed the location of the thermal tropopause according to the WMO criterion and find that it confines the PAN anomaly vertically within the main ASM anticyclone. In contrast, the shed eddy exhibits enhanced PAN VMRs for 1 to 2 km above the thermal tropopause. Using the relationship between PAN as a tropospheric tracer and O3 as a stratospheric tracer to identify mixed air parcels, we further found the anticyclone to contain few such air parcels, whereas the region between the anticyclone and the eddy as well as the eddy itself contains many mixed air parcels. In combination, this implies that while the anticyclone confines polluted air masses well, eddy shedding provides a very rapid horizontal transport pathway of Asian pollution into the extratropical lowermost stratosphere with a timescale of only a few days.

scholarly journals Source–Receptor Relationships and Cluster Analysis of CO2, CH4, and CO Concentrations in West Africa: The Case of Lamto in Côte d’Ivoire

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 903 ◽  
Author(s):  
Dro Touré Tiemoko ◽  
Fidèle Yoroba ◽  
Jean-Daniel Paris ◽  
Adama Diawara ◽  
Antoine Berchet ◽  
...  
Keyword(s):  
Emission Sources ◽  
Air Masses ◽  
Clustering Technique ◽  
North East ◽  
Range Transport ◽  
Continental Origin ◽  
And Cluster Analysis ◽  
Combustion Processes ◽  
Co Concentrations ◽  
Source Receptor Relationships

The contribution in terms of long-range transport of CO2, CH4, and CO concentrations to measurements at Lamto (5°02′ W–6°13′ N) was analyzed for the 2014–2017 period using the FLEXPART model that calculates the retro-plumes of air masses arriving at the station. The identification of the source-receptor relationships was also studied with a clustering technique applied on those retro-plumes. This clustering technique enabled us to distinguish four categories of air mass transports arriving at Lamto site described as follows: oceanic and maritime origin (≈37% of the retro-plumes), continental origin (≈21%), and two hybrid clusters (≈42%). The results show that continental emission sources contribute significantly to the increases in concentrations of CO2, CH4, and CO and explain ≈40% of their variance. These emission sources are predominantly from north and north-east directions of the measurement point, and where densely populated and economically developed areas are located. In addition, the transport of air masses from these directions lead to the accumulation of CO2, CH4, and CO. Furthermore, the ratios ΔCO/ΔCH4 and ΔCO/ΔCO2 observed in the groups associated with Harmattan flows clearly show an influence of combustion processes on the continent. Thus, the grouping based on FLEXPART footprints shows an advantage compared to the use of simple trajectories for analyzing source–receptor relationships.

scholarly journals Atmospheric blocking induced by the strengthened Siberian High led to drying in west Asia during the 4.2 ka BP event – a hypothesis

2019 ◽  
Vol 15 (2) ◽  
pp. 781-793 ◽  
Author(s):  
Aurel Perşoiu ◽  
Monica Ionita ◽  
Harvey Weiss
Keyword(s):  
Climate Variability ◽  
Winter Season ◽  
Balkan Peninsula ◽  
Climatic Conditions ◽  
Boreal Winter ◽  
Winter Climate ◽  
Heterogeneous Distribution ◽  
Climate Conditions ◽  
Causal Explanations ◽  
Siberian High

Abstract. Causal explanations for the 4.2 ka BP event are based on the amalgamation of seasonal and annual records of climate variability that was manifest across global regions dominated by different climatic regimes. However, instrumental and paleoclimate data indicate that seasonal climate variability is not always sequential in some regions. The present study investigates the spatial manifestation of the 4.2 ka BP event during the boreal winter season in Eurasia, where climate variability is a function of the spatiotemporal dynamics of the westerly winds. We present a multi-proxy reconstruction of winter climate conditions in Europe, west Asia, and northern Africa between 4.3 and 3.8 ka. Our results show that, while winter temperatures were cold throughout the region, precipitation amounts had a heterogeneous distribution, with regionally significant low values in W Asia, SE Europe, and N Europe and local high values in the N Balkan Peninsula, the Carpathian Mountains, and E and NE Europe. Further, strong northerly winds were dominating in the Middle East and E and NE Europe. Analyzing the relationships between these climatic conditions, we hypothesize that in the extratropical Northern Hemisphere, the 4.2 ka BP event was caused by the strengthening and expansion of the Siberian High, which effectively blocked the moisture-carrying westerlies from reaching W Asia and enhanced outbreaks of cold and dry winds in that region. The behavior of the winter and summer monsoons suggests that when parts of Asia and Europe were experiencing winter droughts, SE Asia was experiencing similar summer droughts, resulting from failed and/or reduced monsoons. Thus, while in the extratropical regions of Eurasia the 4.2 ka BP event was a century-scale winter phenomenon, in the monsoon-dominated regions it may have been a feature of summer climate conditions.

scholarly journals First measurement of atmospheric mercury species in Qomolangma Natural Nature Preserve, Tibetan Plateau, and evidence oftransboundary pollutant invasion

2019 ◽  
Vol 19 (2) ◽  
pp. 1373-1391 ◽  
Author(s):  
Huiming Lin ◽  
Yindong Tong ◽  
Xiufeng Yin ◽  
Qianggong Zhang ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Transition Period ◽  
Atmospheric Pollutants ◽  
Mercury Species ◽  
The Tibetan Plateau ◽  
Monsoon Period ◽  
Air Masses ◽  
Nature Preserve

Abstract. Located in the world's “third pole” and a remote region connecting the Indian plate and the Eurasian plate, Qomolangma National Nature Preserve (QNNP) is an ideal region to study the long-range transport of atmospheric pollutants. In this study, gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM) and particle-bound mercury (PBM) were continuously measured during the Indian monsoon transition period in QNNP. A slight increase in the GEM concentration was observed from the period preceding the Indian summer monsoon (1.31±0.42 ng m−3) to the Indian summer monsoon period (1.44±0.36 ng m−3), while significant decreases were observed in the GOM and PBM concentrations, with concentrations decreasing from 35.2±18.6 to 19.3±10.9 pg m−3 (p < 0.001) for GOM and from 30.5±12.5 to 24.9±19.8 pg m−3 (p < 0.001) for PBM. A unique daily pattern was observed in QNNP with respect to the GEM concentration, with a peak value before sunrise and a low value at noon. Relative to the (low) GEM concentrations, GOM concentrations (with a mean value of 21.4±13.4 pg m−3, n=1239) in this region were relatively high compared with the measured values in some other regions of China. A cluster analysis indicated that the air masses transported to QNNP changed significantly at different stages of the monsoon, and the major potential mercury (Hg) sources shifted from northern India and western Nepal to eastern Nepal and Bangladesh. As there is a large area covered in glaciers in QNNP, local glacier winds could increase the transboundary transport of pollutants and transport polluted air masses to the Tibetan Plateau. The atmospheric Hg concentration in QNNP in the Indian summer monsoon period was influenced by transboundary Hg flows. This highlights the need for a more specific identification of Hg sources impacting QNNP and underscores the importance of international cooperation regarding global Hg controls.

scholarly journals Influence of dust and sea-salt sandwich effect on precipitation chemistry over the Western Ghats during summer monsoon

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
L. Yang ◽  
S. Mukherjee ◽  
G. Pandithurai ◽  
V. Waghmare ◽  
P. D. Safai
Keyword(s):  
Summer Monsoon ◽  
High Surface ◽  
Precipitation Chemistry ◽  
Sea Salt ◽  
Monsoon Period ◽  
Air Masses ◽  
Range Transport ◽  
Wind Regimes ◽  
High Uncertainty

AbstractAssessment of Sea Salt (SS) and Non-Sea Salt (NSS) aerosols in rainwater is important to understand the characterization of marine and continental aerosols and their source pathways. Sea salt quantification based on standard seawater ratios are primarily constrained with high uncertainty with its own limitations. Here, by the novelty of k-mean clustering and Positive Matrix Factorization (PMF) analysis, we segregate the air masses into two distinct clusters (oceanic and continental) during summer monsoon period signifying the complex intermingle of sources that act concomitantly. The rainwater composition during strong south-westerly wind regimes (cluster 2-oceanic) was profoundly linked with high sea salt and dust, whereas north-westerly low wind regimes (cluster 1-continental) showed an increase in SO42− and NO3−. However, SO42− abundance over NO3− in rain-water depicted its importance as a major acidifying ion at the region. The satellite-based observations indicate the presence of mid-tropospheric dust at the top (3–5 km) and marine sea salt at bottom acts as a “sandwich effect” for maritime clouds that leads to elevated Ca2+, Na+, Mg2+, and Cl− in rainwater. This characteristic feature is unique as sea spray generation due to high surface winds and dust aloft is only seen during this period. Furthermore, four source factors (secondary inorganic aerosol, mixed dust & sea salt, biomass burning & fertilizer use, and calcium neutralization) derived from PMF analysis showed contribution from local activities as well as long-range transport as dominant sources for the rainwater species.

SEASONAL DISTRIBUTION AND CONTAMINATION LEVELS OF TOTAL PETROLEUM HYDROCARBONS AND POLYCYCLIC AROMATIC HYDROCARBONS IN MARINE ENVIRONMENT AT ALANG[-]SOSIYA SHIP SCRAPPING YARD, GULF OF CAMBAY, INDIA

2005 ◽  
Vol 2005 (1) ◽  
pp. 149-160
Author(s):  
M. Srinivasa Reddy ◽  
Shaik Basha ◽  
H. V. Joshi ◽  
G. Ramachandraiah
Keyword(s):  
Summer Monsoon ◽  
Aromatic Hydrocarbons ◽  
Petroleum Hydrocarbons ◽  
Winter Season ◽  
Total Petroleum Hydrocarbons ◽  
Reference Station ◽  
Intertidal Sediments ◽  
Pollution Levels ◽  
Polycyclic Aromatic ◽  
Contamination Levels

ABSTRACT The present study assesses the distribution and contamination levels of total petroleum hydrocarbons (TPHCs) in surface seawaters during three successive seasons, (summer, monsoon and winter), and polyeyelie aromatic hydrocarbons (PAHs) in intertidal sediments along the worlds largest Alang-Sosiya ship-scrapping yard. The pollution levels at this coast are evaluated and compared with those at one reference station (Mahuva, 60 km away from this yard towards south) in this region and similar ship scrapping yards in Asia. The concentrations of TPHCs in seawater were high in winter season followed by summer and monsoon which were relatively, much higher, about six times in winter and five times in summer/monsoon as compared to the reference station at Mahuva. The TPHCs concentrations in the coastal waters of Alang-Sosiya region are nearly 10–100 times higher on compared with other regions. The levels of PAHs found in the Alang-Sosiya sediments are between four and nine times higher than these prescribed levels by OSPAR commission. The overall levels of PAHs show the low content in Alang-Sosiya compared to values reported from Chang Jiang in China while the concentrations were nearly three times higher than Aliaga in Turkey. The relationships between the content of PAHs and %TOM (total organic matter) in sediments are discussed.

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