Seasonal to sub-seasonal variations of the Asian Tropopause Aerosols Layer affected by the deep convection, surface pollutants and precipitation

Wu, Dongyou; Shi, Tenglong; Niu, Xiaoying; Chen, Ziqi; Cui, Jiecan; Chun-xia, Yang; Zhang, Xueying; Li, Jun; Ji, Mingxia; Wang, Xin; Pu, Weihua

doi:10.1016/j.jes.2021.07.022

Cited by 4 publications

(6 citation statements)

References 51 publications

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“…In this study, we applied a multiple linear regression method comparable to that of Chen et al (2019a) to derive the fractional contribution of each WSOC component to light absorption. Despite this method having been used elsewhere (Wu et al, 2022;, it remains a highly innovative approach to evaluating the light absorption of snowpack WSOC.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

Niu

Pu²,

Fu³

et al. 2022

Atmos. Chem. Phys.

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Abstract. Water-soluble organic carbon (WSOC) in the cryosphere can significantly influence the global carbon cycle and radiation budget. However, WSOC in the snowpack has received little scientific attention to date. This study reports the fluorescence characteristics, absorption properties, and radiative effects of WSOC based on 34 snow samples collected from sites in northeastern China. A significant degree of regional WSOC variability is found, with concentrations ranging from 0.5±0.2 to 5.7±3.7 µg g−1 (average concentration: 3.6±3.2 µg g−1). The three principal fluorescent components of WSOC are identified as (1) the high-oxygenated humic-like substances (HULIS-1) of terrestrial origin, (2) the low-oxygenated humic-like substances (HULIS-2) of mixed origin, and (3) the protein-like substances (PRLIS) derived from autochthonous microbial activity. In southeastern Inner Mongolia (SEIM), a region dominated by desert and exposed soils, the WSOC exhibits the highest humification index (HIX) but the lowest fluorescence (FI) and biological (BIX) indices; the fluorescence signal is mainly attributed to HULIS-1 and thus implicates soil as the primary source. By contrast, the HIX (FI and BIX) value is the lowest (highest), and the percentage of PRLIS is the highest in the remote area of northeastern Inner Mongolia (NEIM), suggesting a primarily biological source. For south and north of northeastern China (SNC and NNC), both of which are characterized by intensive agriculture and industrial activity, the fluorescence signal is dominated by HULIS-2, and the HIX, FI, and BIX values are all moderate, indicating the mixed origins for WSOC (anthropogenic activity, microbial activity, and soil). We also observe that, throughout northeastern China, the light absorption of WSOC is dominated by HULIS-1, followed by HULIS-2 and PRLIS. The contribution of WSOC to albedo reduction (average concentration: 3.6 µg g−1) in the ultraviolet–visible (UV–Vis) band is approximately half that of black carbon (BC average concentration: 0.6 µg g−1). Radiative forcing is 3.8 (0.8) W m−2 in old (fresh) snow, equating to 19 % (17 %) of the radiative forcing of BC. These results indicate that WSOC has a profound impact on snow albedo and the solar radiation balance.

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Section: Introductionmentioning

confidence: 99%

Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

Niu

Pu²,

Fu³

et al. 2022

Atmos. Chem. Phys.

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“…Aerosol and ozone products have proved very helpful in the study of global air pollution, from the troposphere to the stratosphere (Che et al 2019. Moreover, the tropopause aerosol layer phenomenon has been revealed by several studies utilizing MERRA2 reanalysis (Yuan et al 2019a, Lau and Kim 2022, Wu et al 2022b, Bresciani et al 2024. The MERRA2 has been employed to recognize CAs trend in the upper troposphere and lower stratosphere linked to the anticyclone, and the aerosol components including CAs, dust and sulfate have also been widely utilized to explore the formation, source, transport, and variability of tropopause aerosol layer with the validation of observation including CALIPSO and in-situ measurements (Yuan et al 2019a, Lau and Kim 2022, Wu et al 2022b.…”

Section: Reanalysismentioning

confidence: 99%

“…The ATAL is formed by the joint effects of atmospheric dynamics (deep convection activities and anticyclonic system) and surface pollutant emission (Yu et al 2017, Lau et al 2018, Lelieveld et al 2018. Specifically, local emissions and long-range transport by prevailing southwesterly winds lead to high concentrations of surface pollutants over South and East Asia (Neely et al 2014, Zhang et al 2019, Wu et al 2022b. During the Asian summer monsoon period, deep convection and strong updrafts occur, forcing surface pollutants to penetrate into the stratosphere (Bucci et al 2020, Lau andKim 2022).…”

Section: Introductionmentioning

confidence: 99%

Divergent features of the upper-tropospheric carbonaceous aerosol layer: effects of atmospheric dynamics and pollution emissions in Asia, South America, and Africa

Wu,

Yan,

Zhang

et al. 2024

Environ. Res. Lett.

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The upper-tropospheric carbonaceous aerosol layer (TCAL) represents the increase of aerosols in the upper-troposphere. It was first discovered over Asia but was found in this study to also occur over South America and Africa. The TCALs over three regions typically exist during the strong deep convection season, with the Asian, South American, and African TCALs showing peak intensity during July–August, October–December, and November–December, respectively. Over Asia, the TCAL has the highest altitude and widest spread due to strongest deep convection and upper-troposphere anticyclonic system. TCAL intensity is highest in South America maybe due to heaviest pollutant emissions. Anthropogenic pollution from India and western China produces two Asian TCAL centers, whereas widespread wildfires result in single centers over South America and Africa. TCAL radiative effect at the top of the atmosphere has warming effects over Asia (+0.23 W m−2), whereas cooling effects perform over South America (−0.54 W m−2) and Africa (−0.20 W m−2) owing to its altitude and the divergent strengths of black-carbon absorption and organic-carbon scattering.

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“…We note that, despite this method having been used elsewhere (Wu et al, 2022;Wu et al, 2021), it remains a highly innovative approach to evaluating the light absorption of snowpack WSOC.…”

Section: Fractional Contributions Of Different Wsoc Components To Lig...mentioning

confidence: 99%

Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

Niu

et al. 2022

Preprint

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Abstract. Although water-soluble organic carbon (WSOC) in the cryosphere can significantly influence the global carbon cycle and radiation budget, WSOC in the snowpack has received little scientific attention to date. This study reports the fluorescence characteristics, absorption properties, and radiative effects of WSOC based on 34 snow samples collected from sites in northeastern China. Sampling sites were divided into five groups, comprising southeastern Inner Mongolia (SEIM), northeastern Inner Mongolia (NEIM), the south of northeastern China (SNC), the north of northeastern China (NNC), and the Changbai Mountain area (CBM). Together, these groups represent a significant degree of regional WSOC variability, with concentrations ranging from 0.50 ± 0.19 to 5.70 ± 3.68 μg g−1 (mean = 3.59 ± 3.19 μg g−1). We then identified the three principal fluorescent components of WSOC as (1) a high‑oxygen humic-like component (HULIS-1) of terrestrial origin, (2) a low‑oxygen humic-like component (HULIS-2) of mixed origin, (3) and a protein-like component (PRLIS) derived from autochthonous microbial activity. In SEIM, a region dominated by desert and exposed soils, the WSOC content exhibits the highest humification index (HIX) but the lowest fluorescence (FI) and biological (BIX) indices; the fluorescence signal is mainly attributed to HULIS-1, and thus implicates soil as the primary source. By contrast, the HIX (FI and BIX) value was the lowest (highest) and PRLIS most intense in the remote grasslands and forested areas of NEIM, suggesting a primarily biological source. For SNC and NNC, both of which are characterized by intensive agriculture and industrial activity, the fluorescence signal is dominated by HULIS-2 and the HIX, FI, and BIX values are all moderate, indicating mixed origins for WSOC (anthropogenic activity, microbial activity, and soil). We also observed that, throughout northeastern China, the light absorption of WSOC is dominated by HULIS-1, followed by HULIS-2 and PRLIS. The contribution of WSOC to albedo reduction (average concentration 3.6 μg g−1) in the ultraviolet–visible (UV–vis) band is approximately half that of black carbon (BC: average concentration 0.6 μg g−1); radiative forcing is 3.8 (0.8) W m−2 in old (fresh) snow, equating to 19 % (17 %) of the radiative forcing of BC. These results indicate that WSOC has a profound impact on snow albedo and the solar radiation balance.

show abstract

Seasonal to sub-seasonal variations of the Asian Tropopause Aerosols Layer affected by the deep convection, surface pollutants and precipitation

Cited by 4 publications

References 51 publications

Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

Divergent features of the upper-tropospheric carbonaceous aerosol layer: effects of atmospheric dynamics and pollution emissions in Asia, South America, and Africa

Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

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