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Surface Ocean and Lower Atmosphere Study¡ªAir-Sea interactions and their climatic and environmental impacts
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The Significant Relationship between Isoprene and Monoterpenes Sea-to-air fluxes at the Tropical Air-sea Interface Wednesday 9th @ 1510-1530, Conference Room 7 Royston Uning* , The National University of Malaysia Mohd Talib Latif, The National University of Malaysia Haris Hafizal Abd Hamid, The National University of Malaysia MD Firoz Khan, The National University of Malaysia Mohd Shahrul Mohd Nadzir, The National University of Malaysia Suhaimi Suratman, Universiti Malaysia Terengganu Presenter Email: uningroyston@gmail.com |
Photochemistry of the sea surface microlayer (SML) as the air-sea interface releases biogenic volatile organic compounds (BVOCs), which affects the atmospheric chemistry, predominantly by forming tropospheric ozone (O3), modifying the oxidative capacity of the atmosphere, and contributing to secondary organic aerosol (SOA). To date, however, there is limited understanding of BVOCs sea-to-air fluxes at the air-sea interface level and next to no substantial data to be represented in the marine and atmospheric numerical models. In this study, we aim to determine BVOCs: isoprene and monoterpenes (α-pinene, β-pinene and limonene) sea-to-air fluxes at the tropical air-sea interface off the east coast of Malaysian Peninsula in the Southern China Sea. Sea-to-air fluxes were measured using a newly developed, tested and optimised technique consist of a floating flux chamber coupled with sorbent tubes. BVOCs emitted from the air-sea interface was trapped in the floating chamber and sampled into sorbent tubes before analysed using thermal desorption coupled with gas chromatography mass spectrometry (TD-GCMS) in the laboratory. This study shows mean sea-to-air fluxes of isoprene was 19.8 ± 7.3 *107 molecules cm-2 s-1 while monoterpenes (α-pinene, β-pinene, limonene) 3.6 ±2.6 *107 , 5.6 ± 2.9 *107 , 1.9 ± 0.9 *107 molecules cm-2 s-1 , respectively. The fraction of total BVOCs sea-to-air fluxes at the air-sea interface shows isoprene accounted for 64 %, which is higher compared to monoterpenes 36 % (α-pinene 12 %, β-pinene 18 %, limonene 6 %) (P-value = 0.0002). More importantly, this study observed strong and significant correlation between isoprene and monoterpenes sea-to-air fluxes at the air-sea interface (R2 = 0.54, P-value = 0.0003). The measurement of BVOCs sea-to-air fluxes at the air-sea interface is expected to improve the estimation of the ocean fluxes. |
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