Open AccessDetermination of the vertical flux of dimethyl sulfide by eddy correlation and atmospheric pressure ionization mass spectrometry (APIMS)
Author(s) -
Bandy Alan R.,
Thornton Donald C.,
Tu Fang H.,
Blomquist Byron W.,
Nadler Wolfgang,
Mitchell Glenn M.,
Lenschow Donald H.
Publication year - 2002
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jd002472
Subject(s) - dimethyl sulfide , marine stratocumulus , atmospheric pressure , mass spectrometry , mixing ratio , atmospheric sciences , flux (metallurgy) , planetary boundary layer , environmental science , analytical chemistry (journal) , eddy covariance , chemistry , turbulence , meteorology , aerosol , geology , physics , environmental chemistry , ecology , sulfur , organic chemistry , chromatography , ecosystem , biology
An atmospheric pressure ionization mass spectrometer (APIMS) was developed to determine atmospheric dimethyl sulfide (DMS) with a frequency high enough (25 Hz) to compute vertical fluxes in the marine boundary by eddy correlation. High precision and immunity to sample loss, fluctuations in instrument sensitivity, etc., were achieved by adding isotopically labeled DMS ( d 3 or d 6 ) continuously to the manifold as an internal standard. Because mixing ratios are determined and not mass concentration, the vertical fluxes obtained did not suffer from “Webb effect” errors. High sensitivity at high humidities was achieved by efficient drying and by preheating the sampled air to about 400 °C. During the National Science Foundation (NSF) Dynamics and Chemistry of Marine Stratocumulus Phase II: Entrainment Studies (DYCOMS II) and Passing Efficiency of the Low Turbulence Inlet (PELTI) programs, DMS and d 3 ‐DMS (or d 6 ‐DMS) were each determined with integration times of 20 ms. From these data the ambient DMS level was computed every 40 ms. Vertical fluxes were determined with a relative precision better than 13%.