|Name||Meteorological Research Institute|
|Address 1||Department of Climate and Geochemistry Research|
|Address 2||Meteorological Research Institute|
|Address 3||1-1 Nagamine, Tsukuba, 305-0052, Japan|
|Organization name||Meteorological Research Institute|
|Address 1||1-1, Nagamine|
|Address 3||Ibaraki 305-0052|
|Last updated date||2019-11-22|
9999-12-31 00:00:00 - 9999-12-31 23:59:59: Unknown(Gas chromatography (ECD))
The reference gas of 1.0 ppmv N2O was made by diluting 15 μl of pure N2O (>98%, Showa Denko) with 15 l of the air, which was passed through four U-shaped glass tubes filled with silica gel, drierite, ascarite and molecular sieve 5A (1/16” pellets, 0 degrees centigrade). In 1982, the purity of N2O was checked by a “standard gas” (99.5%, Gasukuro Kogyo), and those values previously reported were corrected.
Correction factor for N2O in each fiscal year are shown in Table 1.
Errors in the measurements of the sample air are summarized in Table 2 of Hirota et al(1984). The precision of measurements of the concentrations of these three gases were all estimated at about 4-5%.
In 1983, the preparation method of a reference gas for N2O was changed, and the sample size for N2O analysis was increased to 5-10 ml to obtain a large S/N ratio for N2O. A mixed gas of 970 ppmv N2O in air (Takachiho) was diluted to 0.3 ppmv with nitrogen gas (>99.9995%) using a Standard Gas Generator SGGU-72AC3 (Standard Technology). This was used as the primary reference gas. A purified and pressurized air in a 5-l stainless-steel sphere was calibrated by the primary reference gas, and was used as the secondary reference gas. The reference gas for practical use was the air sampled in a 20-l tedlar bag, which was calibrated by the secondary reference gas. This gas was used in one or two days for measurements of a series of samples.
The error in repeated measurements of the practical reference gas for N2O was 2.1%. The content of N2O in the stainless-steel sphere was almost constant, at least in two years (±0.15%). The error of the secondary reference gas for the primary one was ±1.8%.
In 1983, a pure N2O gas which had been used as the primary reference gas was compared with a new reference gas, and the mean value between December1982 and February 1983 was corrected (318 ppbv → 301ppbv)(Hirota et al., 1988).
Table 1. Correction factor for volume mixing ratio of N2O
F. Y. Correction factor
Air samples were collected by means of an air-pump into stainless-steel cylinders on an aircraft (Piper Seneca, Piper Aztec, Aerocommander 685, Cessna 404, Merlin Ⅳ, Rear Jet etc.) over Japan between February 1978 and February 1996. CF2Cl2, CFCl3 and N2O in the air sample were analyzed using a Shimadzu Gas Chromatograph GC-6AM equipped with an ECD. The sample air in the cylinder was transferred to a gas sampler (Shimadzu MGS-4) and then to the gas chromatograph. Details of the air sampling and gas chromatographic measurement are described elsewhere (Muramatsu et al., 1982; Hirota et al., 1984, 1988, 1997).
Background concentrations over Japan, and their long-term trends.
This dataset was submitted to WDCGG by Michio Hirota on 2010/2/25.
Dr. Hirota retired from Japan Meteorological Agency in 2008.
Dew point temperature:
Sea water temperature:
Sea surface water temperature:
Sea water salinity:
Sea surface water salinity:
Meteorological data may remain as first provided, even when greenhouse gas data are updated.
|Format||Text (WDCGG Data Format Table, WDCGG Meteorological Data Format Table), NetCDF|
|Relation List (Is Part Of)||
All N2O data contributed to WDCGG by GAW stations and mobiles by 2021-08-24
All N2O data contributed to WDCGG by GAW stations and mobiles by 2020-09-28
All N2O data contributed to WDCGG by GAW stations and mobiles by 2019-09-19
All N2O data contributed to WDCGG by GAW stations and mobiles by 2018-10-23
|1||Muramatsu, H., M. Hirota, and Y. Makino, 1982: Gas-chromatographic Measurements of Dinitrogen Oxide in Air, Bull. Chem. Soc. Japan, 55, 117-120.|
|2||Hirota, M., H. Muramatsu, Y. Makino, T. Sasaki, and Y. Toyama, 1984: The Vertical Distributiobs of Atmospheric CF2Cl2, CFCl3 and N2O over Japan, J. Meteor. Soc. Japan, 62, 158-164.|
|3||Hirota, M., H. Muramatsu, T. Sasaki, Y. Makino and M. Asahi, 1988: Atmospheric Concentrations and Distributions of CF2Cl2, CFCl3 and N2O over Japan between 1979 and 1986, J. Meteor. Soc. Japan, 66, 703-708.|
|4||Hirota, M., Y. Makino, T. Sasaki, Y. Tsutsumi, Y. Zaizen and M. Ikegami, 1997: Tropospheric Concentrations and Distributions of CF2Cl2 and CFCl3 over Japan since 1978, Papers Meteor. Geophys., 48, 19-24.|
|5||The flights of 20 Oct. 1982, 20 Feb. 1983, 14 Feb. and 7 and 8 Aug. 1984, and 16 and 17 Dec. 1985 were carried out in the Middle Atmosphere Programme (1982-85), financially supported by the Ministry of Education, and the data are not included in the above references.|