The Japan Meteorological Agency (JMA) started monitoring the ozone layer in 1957 as part of an international scientific project, the International Geophysical Year. At that time, ozone was being monitored to better understand how ozone distribution affected stratospheric temperature as a heat source. As a tracer, ozone was expected to better determine air flow in the stratosphere.
 Beginning in the early 1980s, springtime depletions in stratospheric ozone over Antarctica were observed. These depletions were due to the catalytic destruction of ozone by atomic halogens, phenomenon called the ozone hole. This resulted, in September 1987, in an international treaty, The Montreal Protocol on Substances that Deplete the Ozone Layer, an agreement designed to protect the ozone layer by phasing out the production of numerous substances believed to be responsible for ozone depletion. Japan ratified this protocol in September 1988; it entered into force in 1989.
 In response to the international situation, the "Ozone Layer Protection Law", formally known as the Act on the Protection of the Ozone Layer through the Control of Specified Substances and Other Measures, was passed in Japan in May 1988. Article 22 of this law describes the observation and monitoring of the ozone layer. This article directs the Director-General of the JMA to monitor the state of the ozone layer and the atmospheric concentrations of specified substances and to publish the results obtained. The JMA also started monitoring ultraviolet-B (UV-B) radiation in 1990. At present, the JMA monitors the ozone layer at three domestic sites (Sapporo, Tsukuba, and Naha) and one site in Antarctica (Syowa Station),and UV-B radiation at one domestic sites (Tsukuba) and one site in Antarctica (Syowa Station).
 In this context, the JMA provides a various datasets on ozone and ultraviolet radiation to the international scientific community. Data sets include total ozone, vertical profiles of ozone from ozonesonde flights and the Umkehr technique, and ultraviolet radiation. These data sets are intended to provide further contributions to the scientific elucidation of worldwide ozone concentrations.

 The International Ozone Commission (IOC/IAMAP; 1992) recommended using new ozone absorption coefficients and molecular scattering coefficients in processing ozone data. Data on total ozone in this publication were calculated using these coefficients. Relative to values calculated using the former ozone absorption and molecular scattering coefficients, the new values are about 0.9743 times as large.
 Vertical ozone distribution determined from Umkehr observations are processed with the UMK04 algorithm.

Directory Structure and Data Files

(1) Data Files
 The contents include data on atmospheric ozone and solar UV-B radiation obtained by the JMA using the Dobson ozone spectrophotometer, ozonesonde observations, the Brewer spectrophotometer and the ultraviolet pyranometer. The files are text files (ASCII) and figures (PDF). The directory structure and contents in the data files are shown in the next section, with details provided in the document files ("readme_e.txt").

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Station        WOUDC Index No. WMO Index No.  Latitude Longitude  Elevation

Sapporo               012           47412      43°04'N  141°20'E   26.3 m(24 Sep.1998-)
                                                                   18.6 m(-23 Sep.1998)
Tsukuba (Tateno)      014           47646      36°03'N  140°08'E   31.0 m
Kagoshima             007           47827      31°33'N  130°33'E   31.7 m
(25 Feb.1994-31 Mar.2005)
Kagoshima/Yoshino     007           47827      31°38'N  130°36'E  282.6 m
(-24 Feb.1994)
Naha                  190           47936      26°12'N  127°41'E   27.5 m
(1 Mar.1987-)
Naha/Kagamizu         190           47936      26°12'N  127°40'E   29.1 m
(-28 Feb.1987)
Minamitorishima       030           47991      24°17'N  153°59'E    8.5 m
(1 Jan.1997-31 Jan.2018)
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XXX:WOUDC Index No.

 /total  Total ozone observation data
  /brewer  Observed data using Brewer spectrophotometer
   /stnXXX
  /dobson  Observed data using Dobson spectrophotometer
   /stnXXX
  /pdffiles Figures of Total ozone
   /total
    /archive
     /stnXXX

 /umkehr Umkehr observation data
  /brewer  Observed data using Brewer spectrophotometer
   /stnXXX
  /dobson  Observed data using Dobson spectrophotometer
   /stnXXX

 /sonde Ozonesonde observation data
  /stnXXX
  /pdffiles Figures of Ozonesonde
   /sonde
    /archive
     /stnXXX

 /uvb Spectral Solar ultraviolet irradiance observation data
  /uvb05nm (hourly, 0.5nm)
   /stnXXX
    /year
  /uvb50nm (hourly, 5nm)
   /stnXXX
    /year
  /uvbdly (daily accumulated values)
   /stnXXX
  /uvi (hourly, UV-index)
   /stnXXX
    /year

 /uvb_broadband Broadband Solar ultraviolet irradiance observation data
  /year Observed data in the year