Home > Guidance > Journal of the Aerological Observatory > Vol.73
In Tateno (Aerological Observatory of Japan Meteorological Agency), the Vaisala RS92-SGP GPS sondes were replaced by the Meisei RS-11G GPS sondes in July 2013. We carried out comparison observations of these 2 types of radiosonde for four seasons to investigate any differences in performance. The results of comparison showed that the recorded temperature difference is 0.5 K above the 100 hPa layer and pressure difference is between 0.2 and 0.5 hPa above the 300 hPa layer in day time observations. Furthermore, humidity measurements of the RS-11G are higher than those of the RS92-SGP values in both day and night time observations. These differences between two radiosonde values have a negligible impact on the daily weather forecasts, however, they should be taken into consideration when the observation data is used for climate monitoring.
The altitudinal increasing rates of the UV radiations were elucidated by the observations with Brewer spectrophotometers at Norikura (2,772 ma.s.l) locating in the Northern Japanese Alps, and at Tsukuba (39 m a.s.l.), every summer season for six years from 2009 to 2014, and the same observation at Suzuran (1,455 m a.s.l.) in summer season, 2014. Results of those observations are summarized below.
(1) By the comparative data of "Norikura to Tsukuba", locating at almost same latitude for six years, the altitudinal increasing rate of the UV radiation (CIE) in clear day was calculated as the value of about +14.4%/1,000 m. Accuracy of the rate was verified by the observation data at Suzuran that is locating very close to the Norikura site, in particular the comparative data of "Norikura to Suzuran". (2) The altitudinal increasing rates of the UV irradiances at every wavelength could be calculated by the comparative data of "Norikura to Tsukuba". As a result, it was clarified that the altitudinal increasing rates of the UV irradiances could be classified to 3 elements of the GLUV (global UV), the DFUV (diffused UV) and the DHUV (direct (horizontal) UV) at every wavelength, and could be calculated by the simple approximate expressions such as Y = 0.0204 X2 - 13.169 X + 2134.7 (Y: increasing rate of GLUV (%/1,000 m), X: wavelength (nm), 295≤X≤325 nm). (3) The irradiance rates of the integrated UV radiations of TUV, UVB, DUV and CIE, and of the UV irradiances at every wavelength by the comparative data of "Norikura to Suzuran" in clear day did not show the daily variation. Therefore, the altitudinal increasing rates are estimated to indicate constant rates in all the day.
In this paper, the altitudinal increasing rates of the integrated UV radiations and the UV irradiances at every wavelength could be elucidated. And the increasing rates at every wavelength could be calculated briefly by using the approximate expressions. However, observations by using high accurate instruments of Brewer MKIII type at those sites are necessary in the future. Moreover the study of seasonal variation of the increasing rate is also very important.