Detection of regional scale sea-to-air oxygen emission related to spring bloom near Japan by using in-situ measurements of the atmospheric oxygen/nitrogen ratio

Abstract

Abstract. We have been carrying out in-situ monitoring of atmospheric O2/N2 ratio at Cape Ochi-ishi (COI; 43°10' N, 145°30' E) in the northern part of Japan since March 2005 by using a modified gas chromatography/thermal conductivity detector (GC/TCD). The standard deviation of the O2/N2 ratio is estimated to be about ±14 per meg (≈3 ppm) with intervals of 10 minutes. Thus, the in-situ measurement system has a 1σ precision of ± 6 per meg (≈1.2 ppm) for one-hour mean O2/N2 ratio. Atmospheric potential oxygen (APO≈O2+1.1 CO2), which is conserved with respect to terrestrial photosynthesis and respiration but reflects changes in air-sea O2 and CO2 fluxes, shows large variabilities from April to early July 2005. Distribution of satellite-derived marine primary production indicates occurrences of strong bloom in the Japan Sea and the latitudinal band between 30° and 40° N in the western North Pacific in April and in the Okhotsk Sea and northeastern region near Hokkaido Island in the North Pacific in June. Back trajectory analysis of air masses indicates that high values of APO, which last for several hours or several days, can be attributed to the oxygen emission associated with the spring bloom of active primary production.

Studies of Recent Changes in Atmospheric O2 Content

“…Gas chromatographic, electrochemical fuel cell, and vacuum ultraviolet absorption (VUV) techniques have also been introduced (Steinbach, 2010;Stephens et al, 2003Stephens et al, , 2007Tohjima, 2000). The gas chromatographic technique has seen extensive use for analyzing flasks from a shipboard sampling program over the western Pacific starting in 2002 (Tohjima et al, 2005b) and for land-stations in Japan (Minejima et al, 2012;Yamagishi et al, 2008). The fuel cell method has been used for both land and shipboard measurements (Patecki and Manning, 2007;Popa et al, 2010;Thompson et al, 2007Thompson et al, , 2009van der Laan-Luijkx et al, 2010b).…”

Analysis of ΔO<sub>2</sub>/ΔCO<sub>2</sub> ratios for the pollution events observed at Hateruma Island, Japan

“…The collected air sample is dried by passing through cold traps, and then introduced into the O 2 /N 2 measurement system that includes a gas chromatograph equipped with a thermal conductivity detector (GC/TCD). Details of the sampling, analyzing and data processing methods are described elsewhere (Tohjima, 2000;Yamagishi et al, 2008). The CO 2 mixing ratios are continuously measured by a nondispersive infrared analyzer (NDIR) (Mukai et al, 2001).…”

Observation of atmospheric oxygen/nitrogen ratio aboard a cargo ship using gas chromatography/thermal conductivity detector

“…[8] Yamagishi et al [2008] found that there was a bias of $8 per meg in the on-site measurements of the O 2 /N 2 ratio at Cape Ochi-ishi compared with the values obtained from the flask sampling at the same site. In that paper, we speculated on the possibility of the bias resulting from the short tubing ($30 cm length) between the spherical flask and the back pressure regulator.…”

“…YAMAGISHI ET AL. : SHIPBOARD O 2 /N 2 MEASUREMENTS USING GC D04309 D04309 Yamagishi et al [2008] for details). Therefore, the value of d{(O 2 + Ar)/N 2 } GL measured by GC-323 is corrected using the following equation:…”

“…[5] In this paper we present a new shipboard measurement system for measuring atmospheric O 2 /N 2 ratio using the GC/ TCD technique that was developed by Tohjima [2000] for flask sampling and modified for on-site measurements by Yamagishi et al [2008]. Unfortunately, we have found that the gas-chromatographic O 2 /N 2 measurement systems that have been developed for use at land stations are sensitive to motion and thus not readily suitable for shipboard use.…”