TY - JOUR
T1 - Total organic carbon and the contribution from speciated organics in cloud water
T2 - Airborne data analysis from the CAMP2Ex field campaign
AU - Stahl, Connor
AU - Crosbie, Ewan
AU - Bañaga, Paola Angela
AU - Betito, Grace
AU - Braun, Rachel A.
AU - Cainglet, Zenn Marie
AU - Cambaliza, Maria Obiminda
AU - Cruz, Melliza Templonuevo
AU - Dado, Julie Mae
AU - Hilario, Miguel Ricardo A.
AU - Leung, Gabrielle Frances
AU - MacDonald, Alexander B.
AU - Magnaye, Angela Monina
AU - Reid, Jeffrey
AU - Robinson, Claire
AU - Shook, Michael A.
AU - Simpas, James Bernard
AU - Visaga, Shane Marie
AU - Winstead, Edward
AU - Ziemba, Luke
AU - Sorooshian, Armin
N1 - Funding Information:
Financial support. This research has been supported by the
Funding Information:
Acknowledgements. The authors acknowledge support from NASA (grant no. 80NSSC18K0148) in the framework of the NASA CAMP2Ex project. Rachel A. Braun acknowledges support from the ARCS Foundation, Melliza Templonuevo Cruz was supported by the Philippine Department of Science and Technology’s ASTHRD program, and Alexander B. MacDonald acknowledges support from the Mexican National Council for Science and Technology (CONACYT).
Publisher Copyright:
© Copyright:
PY - 2021/9/23
Y1 - 2021/9/23
N2 - This work focuses on total organic carbon (TOC) and contributing species in cloud water over Southeast Asia using a rare airborne dataset collected during NASA's Cloud, Aerosol and Monsoon Processes Philippines Experiment (CAMP2Ex), in which a wide variety of maritime clouds were studied, including cumulus congestus, altocumulus, altostratus, and cumulus. Knowledge of TOC masses and their contributing species is needed for improved modeling of cloud processing of organics and to understand how aerosols and gases impact and are impacted by clouds. This work relies on 159 samples collected with an axial cyclone cloud-water collector at altitudes of 0.2-6.8ĝ€¯km that had sufficient volume for both TOC and speciated organic composition analysis. Species included monocarboxylic acids (glycolate, acetate, formate, and pyruvate), dicarboxylic acids (glutarate, adipate, succinate, maleate, and oxalate), methanesulfonic acid (MSA), and dimethylamine (DMA). TOC values range between 0.018 and 13.66ĝ€¯ppmĝ€¯C with a mean of 0.902ĝ€¯ppm C. The highest TOC values are observed below 2ĝ€¯km with a general reduction aloft. An exception is samples impacted by biomass burning for which TOC remains enhanced at altitudes as high as 6.5ĝ€¯km (7.048ĝ€¯ppmĝ€¯C). Estimated total organic matter derived from TOC contributes a mean of 30.7ĝ€¯% to total measured mass (inorganics + organics). Speciated organics contribute (on a carbon mass basis) an average of 30.0ĝ€¯% to TOC in the study region and account for an average of 10.3ĝ€¯% to total measured mass. The order of the average contribution of species to TOC, in decreasing contribution of carbon mass, is as follows (±1 standard deviation): acetate (14.7ĝ€¯±ĝ€¯20.5ĝ€¯%), formate (5.4ĝ€¯±ĝ€¯9.3ĝ€¯%), oxalate (2.8ĝ€¯±ĝ€¯4.3ĝ€¯%), DMA (1.7ĝ€¯±ĝ€¯6.3ĝ€¯%), succinate (1.6ĝ€¯±ĝ€¯2.4ĝ€¯%), pyruvate (1.3ĝ€¯±ĝ€¯4.5ĝ€¯%), glycolate (1.3ĝ€¯±ĝ€¯3.7ĝ€¯%), adipate (1.0ĝ€¯±ĝ€¯3.6ĝ€¯%), MSA (0.1ĝ€¯±ĝ€¯0.1ĝ€¯%), glutarate (0.1ĝ€¯±ĝ€¯0.2ĝ€¯%), and maleate (<ĝ€¯0.1ĝ€¯±ĝ€¯0.1ĝ€¯%). Approximately 70ĝ€¯% of TOC remains unaccounted for, highlighting the complex nature of organics in the study region; in samples collected in biomass burning plumes, up to 95.6ĝ€¯% of TOC mass is unaccounted for based on the species detected. Consistent with other regions, monocarboxylic acids dominate the speciated organic mass (g1/4ĝ€¯75ĝ€¯%) and are about 4 times more abundant than dicarboxylic acids. Samples are categorized into four cases based on back-trajectory history, revealing source-independent similarity between the bulk contributions of monocarboxylic and dicarboxylic acids to TOC (16.03ĝ€¯%-23.66ĝ€¯% and 3.70ĝ€¯%-8.75ĝ€¯%, respectively). Furthermore, acetate, formate, succinate, glutarate, pyruvate, oxalate, and MSA are especially enhanced during biomass burning periods, which is attributed to peat emissions transported from Sumatra and Borneo. Lastly, dust (Ca2+) and sea salt (Na+/Cl-) tracers exhibit strong correlations with speciated organics, supporting how coarse aerosol surfaces interact with these water-soluble organics.
AB - This work focuses on total organic carbon (TOC) and contributing species in cloud water over Southeast Asia using a rare airborne dataset collected during NASA's Cloud, Aerosol and Monsoon Processes Philippines Experiment (CAMP2Ex), in which a wide variety of maritime clouds were studied, including cumulus congestus, altocumulus, altostratus, and cumulus. Knowledge of TOC masses and their contributing species is needed for improved modeling of cloud processing of organics and to understand how aerosols and gases impact and are impacted by clouds. This work relies on 159 samples collected with an axial cyclone cloud-water collector at altitudes of 0.2-6.8ĝ€¯km that had sufficient volume for both TOC and speciated organic composition analysis. Species included monocarboxylic acids (glycolate, acetate, formate, and pyruvate), dicarboxylic acids (glutarate, adipate, succinate, maleate, and oxalate), methanesulfonic acid (MSA), and dimethylamine (DMA). TOC values range between 0.018 and 13.66ĝ€¯ppmĝ€¯C with a mean of 0.902ĝ€¯ppm C. The highest TOC values are observed below 2ĝ€¯km with a general reduction aloft. An exception is samples impacted by biomass burning for which TOC remains enhanced at altitudes as high as 6.5ĝ€¯km (7.048ĝ€¯ppmĝ€¯C). Estimated total organic matter derived from TOC contributes a mean of 30.7ĝ€¯% to total measured mass (inorganics + organics). Speciated organics contribute (on a carbon mass basis) an average of 30.0ĝ€¯% to TOC in the study region and account for an average of 10.3ĝ€¯% to total measured mass. The order of the average contribution of species to TOC, in decreasing contribution of carbon mass, is as follows (±1 standard deviation): acetate (14.7ĝ€¯±ĝ€¯20.5ĝ€¯%), formate (5.4ĝ€¯±ĝ€¯9.3ĝ€¯%), oxalate (2.8ĝ€¯±ĝ€¯4.3ĝ€¯%), DMA (1.7ĝ€¯±ĝ€¯6.3ĝ€¯%), succinate (1.6ĝ€¯±ĝ€¯2.4ĝ€¯%), pyruvate (1.3ĝ€¯±ĝ€¯4.5ĝ€¯%), glycolate (1.3ĝ€¯±ĝ€¯3.7ĝ€¯%), adipate (1.0ĝ€¯±ĝ€¯3.6ĝ€¯%), MSA (0.1ĝ€¯±ĝ€¯0.1ĝ€¯%), glutarate (0.1ĝ€¯±ĝ€¯0.2ĝ€¯%), and maleate (<ĝ€¯0.1ĝ€¯±ĝ€¯0.1ĝ€¯%). Approximately 70ĝ€¯% of TOC remains unaccounted for, highlighting the complex nature of organics in the study region; in samples collected in biomass burning plumes, up to 95.6ĝ€¯% of TOC mass is unaccounted for based on the species detected. Consistent with other regions, monocarboxylic acids dominate the speciated organic mass (g1/4ĝ€¯75ĝ€¯%) and are about 4 times more abundant than dicarboxylic acids. Samples are categorized into four cases based on back-trajectory history, revealing source-independent similarity between the bulk contributions of monocarboxylic and dicarboxylic acids to TOC (16.03ĝ€¯%-23.66ĝ€¯% and 3.70ĝ€¯%-8.75ĝ€¯%, respectively). Furthermore, acetate, formate, succinate, glutarate, pyruvate, oxalate, and MSA are especially enhanced during biomass burning periods, which is attributed to peat emissions transported from Sumatra and Borneo. Lastly, dust (Ca2+) and sea salt (Na+/Cl-) tracers exhibit strong correlations with speciated organics, supporting how coarse aerosol surfaces interact with these water-soluble organics.
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U2 - 10.5194/acp-21-14109-2021
DO - 10.5194/acp-21-14109-2021
M3 - Article
AN - SCOPUS:85115999637
VL - 21
SP - 14109
EP - 14129
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
SN - 1680-7316
IS - 18
ER -