scholarly journals Measurement of Light absorbing particles in surface snow of central and western Himalayan glaciers: spatial variability, radiative impacts, and potential source regions

2021 ◽  
Author(s):  
Chaman Gul ◽  
Shichang Kang ◽  
Siva Praveen Puppala ◽  
Xiaokang Wu ◽  
Cenlin He ◽  
...  
Keyword(s):  
Spatial Variability ◽  
South Asia ◽  
Radiative Forcing ◽  
Western Himalayas ◽  
Source Regions ◽  
Potential Source ◽  
Himalayan Glaciers ◽  
Radiative Impacts ◽  
Surface Snow ◽  
The Difference

Abstract. We collected surface snow samples from three different glaciers: Yala, Thana, and Sachin in the central and western Himalayas to understand the spatial variability and radiative impacts of light-absorbing particles. The Yala and Thana glaciers in Nepal and Bhutan, respectively, were selected to represent the central Himalayas. The Sachin glacier in Pakistan was selected to represent the western Himalayas. The samples were collected during the pre-and post-monsoon seasons of the year 2016. The samples were analysed for black carbon (BC) and water-insoluble organic carbon (OC) through the thermal optical method. The average mass concentrations (BC 2381.39 ng g−1; OC 3896.00 ng g−1; dust 101.05 µg g−1) in the western Himalaya (Sachin glacier) were quite higher compared to the mass concentrations (BC 357.93 ng g−1, OC 903.86 ng g−1, dust 21.95 µg g−1) at the central Himalaya (Yala glacier). The difference in mass concentration may be due to the difference in elevation, snow age, local pollution sources, and difference in meteorological conditions. BC in surface snow was also estimated through WRF-Chem simulations at the three glacier sites during the sampling periods. Simulations reasonably capture the spatial and seasonal patterns of the observed BC in snow but with a relatively smaller magnitude. Absolute snow albedo was estimated through the Snow, Ice, and Aerosol Radiation (SNICAR) model. The absolute snow albedo reduction was ranging between 0.48 % (Thana glacier during September) to 24 % (Sachin glacier during May) due to BC and 0.13 % (Yala glacier during September) to 5 % (Sachin glacier during May) due to dust. The instantaneous radiative forcing due to BC and dust was estimated in the range of 0 to 96.48 W m−2 and 0 to 25 W m−2 respectively. The lowest and highest albedo reduction and radiative forcing were observed in central and western Himalayan glaciers, respectively. The potential source regions of the deposited pollutants were inferred using WRF-Chem tagged-tracer simulations. Selected glaciers in the western Himalayas were mostly affected by long-range transport from the Middle East and Central Asia; however, the central Himalayan glaciers were mainly affected by local and South Asia emissions (from Nepal, India, and China) especially during the pre-monsoon season. Overall, South Asia and West Asia were the main contributing source regions of pollutants.

Investigation of potential source regions of atmospheric Black Carbon in the data deficit region of the western Himalayas and its foothills

2019 ◽  
Vol 10 (6) ◽  
pp. 1832-1842 ◽  
Author(s):  
Ashish Soni ◽  
Stefano Decesari ◽  
Vijay Shridhar ◽  
Vignesh Prabhu ◽  
Pooja Panwar ◽  
...  
Keyword(s):  
Black Carbon ◽  
Western Himalayas ◽  
Source Regions ◽  
Potential Source

scholarly journals Why do the dark and light ogives of Forbes bands have similar surface mass balances?

2018 ◽  
Vol 64 (244) ◽  
pp. 236-246 ◽  
Author(s):  
C. VINCENT ◽  
M. DUMONT ◽  
D. SIX ◽  
F. BRUN ◽  
G. PICARD ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Short Wave ◽  
Wave Radiation ◽  
Mass Balances ◽  
Surface Mass ◽  
Significant Difference ◽  
Radiative Impacts ◽  
The Difference ◽  
Glacier Flow

ABSTRACTBand ogives are a striking and enigmatic feature of Mer de Glace glacier flow. The surface mass balances (SMBs) of these ogives have been thoroughly investigated over a period of 12 years. We find similar cumulative SMBs over this period, ranging between −64.1 and −66.2 m w.e., on the dark and light ogives even though the dark ogive albedo is ~40% lower than that of the light ogives. We, therefore, looked for another process that could compensate for the large difference of absorbed short-wave radiation between dark and light ogives. Based on in situ roughness measurements, our numerical modeling experiments demonstrate that a significant difference in turbulent flux over the dark and light ogives due to different surface roughnesses could compensate for the difference in radiative forcing. Our results discard theories for the genesis of band ogives that are based on the assumption of a strong ice ablation contrast between dark and light ogives. More generally, our study demonstrates that future roughness changes are as important to analyze as the radiative impacts of a potential increase of aerosols or debris at the surface of glaciers.

scholarly journals Uncertainty in modeling dust mass balance and radiative forcing from size parameterization

2013 ◽  
Vol 13 (7) ◽  
pp. 19649-19700 ◽  
Author(s):  
C. Zhao ◽  
S. Chen ◽  
L. R. Leung ◽  
Y. Qian ◽  
J. Kok ◽  
...  
Keyword(s):  
Mass Balance ◽  
Radiative Forcing ◽  
Dust Emission ◽  
Dust Particles ◽  
Mass Loading ◽  
Dust Source ◽  
Deposition Fluxes ◽  
Source Regions ◽  
Dust Mass ◽  
The Difference

Abstract. This study examines the uncertainties in simulating mass balance and radiative forcing of mineral dust due to biases in the dust size parameterization. Simulations are conducted quasi-globally (180° W–180° E and 60° S–70° N) using the WRF-Chem model with three different approaches to represent dust size distribution (8-bin, 4-bin, and 3-mode). The biases in the 3-mode or 4-bin approaches against a relatively more accurate 8-bin approach in simulating dust mass balance and radiative forcing are identified. Compared to the 8-bin approach, the 4-bin approach simulates similar but coarser size distributions of dust particles in the atmosphere, while the 3-mode approach retains more fine dust particles but fewer coarse dust particles due to its prescribed σg of each mode. Although the 3-mode approach yields up to 10 days longer dust mass lifetime over the remote oceanic regions than the 8-bin approach, the three size approaches produce similar dust mass lifetime (3.2 days to 3.5 days) on quasi-global average, reflecting that the global dust mass lifetime is mainly determined by the dust mass lifetime near the dust source regions. With the same global dust emission (∼6000 Tg yr-1), the 8-bin approach produces a dust mass loading of 39 Tg, while the 4-bin and 3-mode approaches produce 3% (40.2 Tg) and 25% (49.1 Tg) higher dust mass loading, respectively. The difference in dust mass loading between the 8-bin approach and the 4-bin or 3-mode approaches has large spatial variations, with generally smaller relative difference (<10%) near the surface over the dust source regions. The three size approaches also result in significantly different dry and wet deposition fluxes and number concentrations of dust. The difference in dust aerosol optical depth (AOD) (a factor of 3) among the three size approaches is much larger than their difference (25%) in dust mass loading. Compared to the 8-bin approach, the 4-bin approach yields stronger dust absorptivity, while the 3-mode approach yields weaker dust absorptivity. Overall, on quasi-global average, the three size parameterizations result in a significant difference of a factor of 2∼3 in dust surface cooling (-1.02∼-2.87 W m-2) and atmospheric warming (0.39∼0.96 W m-2) and in a tremendous difference of a factor of ∼10 in dust TOA cooling (-0.24∼-2.20 W m-2). An uncertainty of a factor of 2 is quantified in dust emission estimation due to the different size parameterizations. This study also highlights the uncertainties in modeling dust mass and number loading, deposition fluxes, and radiative forcing resulting from different size parameterizations, and motivates further investigation of the impact of size parameterizations on modeling dust impacts on air quality, climate, and ecosystem.

scholarly journals Uncertainty in modeling dust mass balance and radiative forcing from size parameterization

2013 ◽  
Vol 13 (21) ◽  
pp. 10733-10753 ◽  
Author(s):  
C. Zhao ◽  
S. Chen ◽  
L. R. Leung ◽  
Y. Qian ◽  
J. F. Kok ◽  
...  
Keyword(s):  
Mass Balance ◽  
Radiative Forcing ◽  
Dust Emission ◽  
Dust Particles ◽  
Mass Loading ◽  
Dust Source ◽  
Source Regions ◽  
Dust Mass ◽  
The Difference ◽  
The Impact

Abstract. This study examines the uncertainties in simulating mass balance and radiative forcing of mineral dust due to biases in the dust size parameterization. Simulations are conducted quasi-globally (180° W–180° E and 60° S–70° N) using the WRF-Chem model with three different approaches to represent dust size distribution (8-bin, 4-bin, and 3-mode). The biases in the 3-mode or 4-bin approaches against a relatively more accurate 8-bin approach in simulating dust mass balance and radiative forcing are identified. Compared to the 8-bin approach, the 4-bin approach simulates similar but coarser size distributions of dust particles in the atmosphere, while the 3-mode approach retains more fine dust particles but fewer coarse dust particles due to its prescribed σg of each mode. Although the 3-mode approach yields up to 10 days of longer dust mass lifetime over the remote oceanic regions than the 8-bin approach, the three size approaches produce a similar dust mass lifetime (3.2 days to 3.5 days) on quasi-global average, reflecting that the global dust mass lifetime is mainly determined by the dust mass lifetime near the dust source regions. With the same global dust emission (~4600 Tg yr−1), the 8-bin approach produces a dust mass loading of 39 Tg, while the 4-bin and 3-mode approaches produce 3% (40.2 Tg) and 25% (49.1 Tg) higher dust mass loading, respectively. The difference in dust mass loading between the 8-bin approach and the 4-bin or 3-mode approaches has large spatial variations, with generally smaller relative difference (<10%) near the surface over the dust source regions. The three size approaches also result in significantly different dry and wet deposition fluxes and number concentrations of dust. The difference in dust aerosol optical depth (AOD) (a factor of 3) among the three size approaches is much larger than their difference (25%) in dust mass loading. Compared to the 8-bin approach, the 4-bin approach yields stronger dust absorptivity, while the 3-mode approach yields weaker dust absorptivity. Overall, on quasi-global average, the three size parameterizations result in a significant difference of a factor of 2~3 in dust surface cooling (−1.02~−2.87 W m−2) and atmospheric warming (0.39~0.96 W m−2) and in a tremendous difference of a factor of ~10 in dust TOA (top of atmosphere) cooling (−0.24~−2.20 W m−2). The impact of different size representations on dust radiative forcing efficiency is smaller. An uncertainty of a factor of 2 is quantified in dust emission estimation due to the different size parameterizations. This study also highlights the uncertainties in modeling dust mass and number loading, deposition fluxes, and radiative forcing resulting from different size parameterizations, and motivates further investigation of the impact of size parameterizations on modeling dust impacts on air quality, climate, and ecosystems.

scholarly journals Carbonaceous aerosols recorded in a southeastern Tibetan glacier: analysis of temporal variations and model estimates of sources and radiative forcing

2015 ◽  
Vol 15 (3) ◽  
pp. 1191-1204 ◽  
Author(s):  
M. Wang ◽  
B. Xu ◽  
J. Cao ◽  
X. Tie ◽  
H. Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
South Asia ◽  
Radiative Forcing ◽  
Monsoon Season ◽  
Ice Core ◽  
High Temporal Resolution ◽  
Carbonaceous Aerosols ◽  
Southeastern Tibetan Plateau ◽  
Source Regions ◽  
Ice Core Record

Abstract. High temporal resolution measurements of black carbon (BC) and organic carbon (OC) covering the time period of 1956–2006 in an ice core over the southeastern Tibetan Plateau show a distinct seasonal dependence of BC and OC with higher respective concentrations but a lower OC / BC ratio in the non-monsoon season than during the summer monsoon. We use a global aerosol-climate model, in which BC emitted from different source regions can be explicitly tracked, to quantify BC source–receptor relationships between four Asian source regions and the southeastern Tibetan Plateau as a receptor. The model results show that South Asia has the largest contribution to the present-day (1996–2005) mean BC deposition at the ice-core drilling site during the non-monsoon season (October to May) (81%) and all year round (74%), followed by East Asia (14% to the non-monsoon mean and 21% to the annual mean). The ice-core record also indicates stable and relatively low BC and OC deposition fluxes from the late 1950s to 1980, followed by an overall increase to recent years. This trend is consistent with the BC and OC emission inventories and the fuel consumption of South Asia (as the primary contributor to annual mean BC deposition). Moreover, the increasing trend of the OC / BC ratio since the early 1990s indicates a growing contribution of coal combustion and/or biomass burning to the emissions. The estimated radiative forcing induced by BC and OC impurities in snow has increased since 1980, suggesting an increasing potential influence of carbonaceous aerosols on the Tibetan glacier melting and the availability of water resources in the surrounding regions. Our study indicates that more attention to OC is merited because of its non-negligible light absorption and the recent rapid increases evident in the ice-core record.

scholarly journals Carbonaceous aerosols recorded in a Southeastern Tibetan glacier: variations, sources and radiative forcing

2014 ◽  
Vol 14 (13) ◽  
pp. 19719-19746 ◽  
Author(s):  
M. Wang ◽  
B. Xu ◽  
J. Cao ◽  
X. Tie ◽  
H. Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
South Asia ◽  
Radiative Forcing ◽  
Monsoon Season ◽  
Ice Core ◽  
High Temporal Resolution ◽  
Carbonaceous Aerosols ◽  
Southeastern Tibetan Plateau ◽  
Source Regions ◽  
Ice Core Record

Abstract. High temporal resolution measurements of black carbon (BC) and organic carbon (OC) covering the time period of 1956–2006 in an ice core over the southeastern Tibetan Plateau show a distinct seasonal dependence of OC / BC ratio with higher values in the non-monsoon season than during the summer monsoon. We use a global aerosol-climate model, in which BC emitted from different source regions can be explicitly tracked, to quantify BC source-receptor relationships between four Asian source regions and the southeastern Tibetan Plateau as a receptor. The model results show that South Asia is a primary contributor during the non-monsoon season (October to May) (81%) and on an annual basis (74%), followed by East Asia (14% and 21%, respectively). The ice-core record also indicates stable and relatively low BC and OC deposition fluxes from late 1950s to 1980, followed by an overall increase to recent years. This trend is consistent with the BC and OC emission inventories and the fuel consumption of South Asia as the primary contributor. Moreover, the increasing trend of OC / BC ratio since the early 1990s indicates a growing contribution of coal combustion and biomass burning to the emissions. The estimated radiative forcing induced by BC and OC impurities in snow has increased since 1980, suggesting an increasing influence of carbonaceous aerosols on the Tibetan glacier melting and the availability of water resources in the surrounding regions. Our study indicates that more attention to OC is merited because of its non-negligible light absorption and the recent rapid increases evident in the ice core record.

«Имперский синдром»: концепция османского халифата на Ближнем Востоке и в Южной Азии (первая четверть XX в.)

2019 ◽  
Author(s):  
S.A. Kirillina ◽  
A.L. Safronova ◽  
V.V. Orlov
Keyword(s):  
Middle East ◽  
South Asia ◽  
South Asian ◽  
Political Role ◽  
The Social ◽  
The Difference ◽  
Aspect Interaction ◽  
Muhammad Rashid Rida ◽  
Political Actions

Аннотация В статье изучены общие и специфические черты идейных воззрений, пропагандистской риторики и политических действий представителей халифатистского движения на Ближнем Востоке и в Южной Азии. В ретроспективном ключе прослеживается эволюция представлений о сущности и необходимости возрождения института халифата в трудах исламских идеологов, реформаторов и политиков Джамал ад-Дина ал-Афгани, Абд ар-Рахмана ал-Кавакиби, Мухаммада Рашида Риды, Абул Калама Азада. Внимание авторов сосредоточено на общественно-политических дискуссиях 2030-х годов XX столетия, а также на повестке дня халифатистских конгрессов и конференций этого периода. На них вырабатывались первые представления современников о пост-османском формате мусульманского единства и идейно-политической роли будущего халифата. Авторы демонстрируют различие между моделями реакции мусульман Ближнего Востока и Южной Азии на упразднение османского халифата республиканским руководством Турции. Установлена многоаспектная взаимосвязь между халифатистскими ценностями, проосманскими настроениями и формами самоотождествления, которые сложились в арабских и южноазиатских обществах. Отдельно намечено соотношение между подъемом халифатистских настроений и радикализацией антиколониальных действий мусульман Индостана.Abstract The article deals with analysis of common and specific features of ideas, propaganda, rhetoric and political actions taken by representatives of the movement for defense of the Caliphate in the Middle East and South Asia. The retrospection showing the transformation of conception of the Caliphate and the necessity of its revival in the works of eminent ideologists and politicians of the Muslim world Jamal al-Din al-Afghani, Abd al-Rahman al-Kawakibi, Muhammad Rashid Rida and Abul Kalam Azad, is also given in the article. The authors also focus on the social and political discussions of the 1920s 1930s, as well as on the agenda of Caliphatist congresses and conferences of this period. They helped to elaborate the early representations of post-Ottoman pattern of the Muslim unity and the ideological and political role of the future Caliphate. The authors demonstrate the difference between the forms of reaction of Muslims in the Middle East and South Asia to the repudiation of the Caliphate by the Republican leaders of Turkey. The article establishes a multi-aspect interaction between the Caliphatist values and forms of self-identification, emerged in Arab and South Asian societies. The correlation between the rise of Caliphatist attitudes and radicalization of anti-colonial actions of South Asian Muslims is also outlined.

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