scholarly journals Carbonaceous Matter in the Atmosphere and Glaciers of the Himalayas and the Tibetan Plateau: An Investigative Review

Author(s):  
Chaoliu Li ◽  
Fangping Yan ◽  
shichang kang

<p>Carbonaceous matter, including organic carbon (OC) and black carbon (BC), is an important climate forcing agent and contributes to glacier retreat in the Himalayas and the Tibetan Plateau (HTP). The HTP - the so-called “Third Pole” – contains the most extensive glacial area outside of the polar regions. Considerable research on carbonaceous matter in the HTP has been conducted, although this research has been challenging due to the complex terrain and strong spatiotemporal heterogeneity of carbonaceous matter in the HTP. A comprehensive investigation of published atmospheric and snow data for HTP carbonaceous matter concentration, deposition and light absorption is presented, including how these factors vary with time and other parameters. Carbonaceous matter concentrations in the atmosphere and glaciers of the HTP are found to be low. Analysis of water-insoluable organic carbon and BC from snowpits reveals that concentrations of OC and BC in the atmosphere and glacier samples in arid regions of the HTP may be overestimated due to contributions from inorganic carbon in mineral dust. Due to the remote nature of the HTP, carbonaceous matter found in the HTP has generally been transported from outside the HTP (e.g., South Asia), although local HTP emissions may also be important at some sites. This study provides essential data and a synthesis of current thinking for studies on atmospheric transport modeling and radiative forcing of carbonaceous matter in the HTP.</p>

2016 ◽  
Vol 10 (6) ◽  
pp. 2611-2621 ◽  
Author(s):  
Fangping Yan ◽  
Shichang Kang ◽  
Chaoliu Li ◽  
Yulan Zhang ◽  
Xiang Qin ◽  
...  

Abstract. Light-absorbing dissolved organic carbon (DOC) constitutes a major part of the organic carbon in glacierized regions, and has important influences on the carbon cycle and radiative forcing of glaciers. However, few DOC data are currently available from the glacierized regions of the Tibetan Plateau (TP). In this study, DOC characteristics of a medium-sized valley glacier (Laohugou Glacier No. 12, LHG) on the northern TP were investigated. Generally, DOC concentrations on LHG were comparable to those in other regions around the world. DOC concentrations in snow pits, surface snow and surface ice (superimposed ice) were 332 ± 132, 229 ± 104 and 426 ± 270 µg L−1, respectively. The average discharge-weighted DOC of proglacial stream water was 238 ± 96 µg L−1, and the annual DOC flux released from this glacier was estimated to be 6949 kg C yr−1, of which 46.2 % of DOC was bioavailable and could be decomposed into CO2 within 1 month of its release. The mass absorption cross section (MAC) of DOC at 365 nm was 1.4 ± 0.4 m2 g−1 in snow and 1.3 ± 0.7 m2 g−1 in ice, similar to the values for dust transported from adjacent deserts. Moreover, there was a significant relationship between DOC and Ca2+; therefore, mineral dust transported from adjacent arid regions likely made important contributions to DOC of the glacierized regions, although contributions from autochthonous carbon and autochthonous/heterotrophic microbial activity cannot be ruled out. The radiative forcing of snow pit DOC was calculated to be 0.43 W m−2, demonstrating that DOC in snow needs to be taken into consideration in accelerating melt of glaciers on the TP.


2016 ◽  
Author(s):  
F. Yan ◽  
S. Kang ◽  
C. Li ◽  
Y. Zhang ◽  
X. Qin ◽  
...  

Abstract. Light-absorbing dissolved organic carbon (DOC) constitutes a major part of the organic carbon in the glacierized region. It has important influences on the carbon cycle and radiative forcing of glaciers. However, currently, few data are available in the glacierized region of the Tibetan Plateau (TP). In this study, DOC characteristics of a typical glacier (Laohugou glacier No. 12 (LHG glacier)) in the Northeastern TP were investigated. Generally, DOC concentrations on LHG glacier were comparable to other glacierized regions around the world. The average DOC concentrations in snowpits, surface snow, surface ice (superimposed ice) and proglacial streamwater were 332.4 ± 132.3 μg L−1, 229.3 ± 104.4 μg L−1, 425.8 ± 269.9 μg L−1, and 237.5 ± 95.6 μg L−1, respectively. It was estimated that the annual DOC flux released from this glacier was 6949.4 kg C yr−1, of which 43.2 % DOC was bioavailable and could be decomposed into CO2 within 28 days of its release. The mass absorption cross section (MAC) of DOC at 365 nm was 1.4 ± 0.4 m2 g−1 in snow and 1.3 ± 0.7 m2 g−1 in ice, similar to those of dust transported from adjacent deserts. Based on this finding and the significant relationship between DOC and Ca2+, it was proven that the main source of DOC of this glacier was mineral dust. The radiative forcing of DOC relative to black carbon (BC) was calculated to be 9.5 ± 8.4 % in snow and 0.1 ± 0.1 % in ice, respectively, implying the necessity of accounting for DOC in future radiative forcing investigations in the glacierized region on the TP, especially when these areas are covered by fresh snow.


PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0181295 ◽  
Author(s):  
Bin Qu ◽  
Mika Sillanpää ◽  
Chaoliu Li ◽  
Shichang Kang ◽  
Aron Stubbins ◽  
...  

2021 ◽  
Vol 9 ◽  
Author(s):  
Gen Wang ◽  
Yongli Wang ◽  
Zhifu Wei ◽  
Zepeng Sun ◽  
Wei He ◽  
...  

Uplift of the Tibetan Plateau plays a significant and lasting role in the variations of climate conditions and global carbon cycle. However, our knowledge is limited due to the lack of long-sequence records revealing rates of CO2 and CH4 production, hampering our understanding of the relationship between paleoclimatic conditions, carbon cycling and greenhouse gas flux. Here, we present a combination of paleoclimate records and low-temperature thermal simulation results from sediments of the Xiaolongtan Basin at the southeastern margin of the Qinghai-Tibetan Plateau, spanning the late Miocene (14.1 ∼ 11.6 Ma). The n-alkane-derived proxies suggested that the sources of organic matter were obviously different: a mixed source including lower organisms and terrestrial higher plants for the Dongshengqiao Formation from 14.1 to 12.6 Ma, and a predominant contribution from terrestrial higher plants for Xiaolongtan Formation between 12.6 and 11.6 Ma. The paleoclimate was generally warm and humid as reflected by the lipid biomarkers, consistent with previous studies. In addition, the carbon gases (including CO2 and hydrocarbon gases) generated by the low-temperature thermal simulation experiments indicated a production rate of CO2 and CH4 were as high as 88,000 ml/kg rock and 4,000 ml/kg rock, respectively, implying there were certain amounts of carbon gases generated and released into the atmosphere during their shallow burial stage. Besides, the calculated production rate of carbon gases and the estimated burial flux of organic carbon varied in response to the variations of paleoclimate conditions. Based on these observations, we propose that the climate conditions predominantly controlled the formation and accumulation of organic matter, which consequently affected the production of carbon gases and burial flux of organic carbon. The results presented here may provide a significant insight into the carbon cycle in the southeast of the Tibetan Plateau.


2020 ◽  
Vol 9 (1) ◽  
pp. 231-250
Author(s):  
Birendra Prasad Sharma ◽  
Subash Adhikari ◽  
Ganesh Paudel ◽  
Namita Paudel Adhikari

Microorganisms, as successive members of the food web, play a major role in biological processes. They are found in environments ranging from extremely hot to harsh cold temperatures. Thus, the study of bacterial communities in various ecosystems is of great concern around the world. The glacier is one of the parts of the cryosphere, which is the key component and sensitive indicator of climatic and environmental changes. A glacial ecosystem is a habitat for various microorganisms, i.e., autotrophic and heterotrophic. Different physicochemical parameters like temperature, pH, electrical conductivity, the input of nutrient concentration, precipitation, ions concentrations, etc. influence the microbial diversity in the glacial ecosystem for their metabolic processes. Successive studies of bacterial communities in the Himalayan glacial ecosystem are reliable proxies to know the relationships between microbial biodiversity and climate change since the Himalayan glaciers are free from anthropogenic activities. After the study of the relevant literature, it is clear that the researches. have been carried out in the Polar Regions, and the Tibetan plateau mainly focused on the glacial ecosystem. This review concluded that Proteobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, Verrucomicrobia, and Actinobacteria were the most dominant bacterial phyla via 16S rRNA clone libraries and Illumina MiSeq. Alter in landscapes, nutrient cycles, exposure of light, shifting on the concentration of different elements, glacier retreats were the major components for survival strength of dominant bacterial phyla. However, limited studies on the glacial ecosystem of the Himalayas have been published. Thus, the study of bacterial abundance, diversity, and community in the Himalayas will help plug this research gap.


2020 ◽  
Vol 20 (10) ◽  
pp. 5923-5943 ◽  
Author(s):  
Meixin Zhang ◽  
Chun Zhao ◽  
Zhiyuan Cong ◽  
Qiuyan Du ◽  
Mingyue Xu ◽  
...  

Abstract. Most previous modeling studies about black carbon (BC) transport and its impact over the Tibetan Plateau (TP) conducted simulations with horizontal resolutions coarser than 20 km that may not be able to resolve the complex topography of the Himalayas well. In this study, the two experiments covering all of the Himalayas with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) at the horizontal resolution of 4 km but with two different topography datasets (4 km complex topography and 20 km smooth topography) are conducted for pre-monsoon season (April 2016) to investigate the impacts of topography on modeling the transport and distribution of BC over the TP. Both experiments show the evident accumulation of aerosols near the southern Himalayas during the pre-monsoon season, consistent with the satellite retrievals. The observed episode of high surface BC concentration at the station near Mt. Everest due to heavy biomass burning near the southern Himalayas is well captured by the simulations. The simulations indicate that the prevailing upflow across the Himalayas driven by the large-scale westerly and small-scale southerly circulations during the daytime is the dominant transport mechanism of southern Asian BC into the TP, and it is much stronger than that during the nighttime. The simulation with the 4 km topography resolves more valleys and mountain ridges and shows that the BC transport across the Himalayas can overcome the majority of mountain ridges, but the valley transport is more efficient. The complex topography results in stronger overall cross-Himalayan transport during the simulation period primarily due to the strengthened efficiency of near-surface meridional transport towards the TP, enhanced wind speed at some valleys and deeper valley channels associated with larger transported BC mass volume. This results in 50 % higher transport flux of BC across the Himalayas and 30 %–50 % stronger BC radiative heating in the atmosphere up to 10 km over the TP from the simulation with the 4 km complex topography than that with the 20 km smoother topography. The different topography also leads to different distributions of snow cover and BC forcing in snow. This study implies that the relatively smooth topography used by the models with resolutions coarser than 20 km may introduce significant negative biases in estimating light-absorbing aerosol radiative forcing over the TP during the pre-monsoon season. Highlights. The black carbon (BC) transport across the Himalayas can overcome the majority of mountain ridges, but the valley transport is much more efficient during the pre-monsoon season. The complex topography results in stronger overall cross-Himalayan transport during the study period primarily due to the strengthened efficiency of near-surface meridional transport towards the TP, enhanced wind speed at some valleys and deeper valley channels associated with larger transported BC mass volume. The complex topography generates 50 % higher transport flux of BC across the Himalayas and 30 %–50 % stronger BC radiative heating in the atmosphere up to 10 km over the Tibetan Plateau (TP) than the smoother topography, which implies that the smooth topography used by the models with relatively coarse resolution may introduce significant negative biases in estimating BC radiative forcing over the TP during the pre-monsoon season. The different topography also leads to different distributions of snow cover and BC forcing in snow over the TP.


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