Home > Guidance > Journal of the Aerological Observatory > Vol.69
| Title | Author | |
|---|---|---|
| Foreword | in Japanese | Yoshitomo KOJOH |
| Two remote sensing instruments for upper-air observations installed in theAerologicalObservatory in 2009 | in Japanese | Yoshiyuki NOTO |
| Long-term trends of downward longwave radiation at Tateno | [Abstract] | Nozomu OHKAWARA and Matsumi TAKANO |
| Characteristics of Spectral UV in Twilight at the Syowa Station in the Antarctica | in Japanese | Tetsuya SHIMAMURA |
| Annual Changes on the Atmospheric Temperature observed from 1969 to 2007 at the Syowa Station in the Antarctica | in Japanese | Noriaki OSHIKI |
| The Optical Characteristics of the Fore-Optics and the Calibration for Direct-Sun UV Observation with Brewer Spectrophotometers | in Japanese | Mahito ITO |
| Intercomparison of Brewer Spectrophotometers between the Meteorological Service of Canada and the Japan Meteorological Agency at Toronto, Canada in 2010 | [Abstract] | Mahito ITO, Tom GRAJNAR, Michael BROHART and Vladimir SAVASTIOUK |
| Observations of Total Ozone and UV Solar Radiation with Brewer Spectrophotometers on the Norikura Mountains in 2009 | [Abstract] | Mahito ITO, Matsumi TAKANO, Hideyuki OGURI, Masato TAKITA, Hideaki SHIMODAIRA and Hideki ISHITSUKA |
| The test to transfer Observation of Aerosol Optical Depth into the Precision Filter Radiometer (PFR) - Ensuring the reliability of observation data and decision of the instrument necessary for comparison of current instrument - | in Japanese | Matsumi TAKANO and Nozomu OHKAWARA |
| Comparison for Aerosol Optical Depth Observation between PFR(Precision FilterRadiometer) and MS110 (Filter Sunphotometer) | in Japanese | Itaru UESATO |
| Notes | in Japanese | Masahito ISHIHARA |
Long-term trends of downward longwave radiation at the earth's surface from 1979 to 2004 at Tateno are analyzed after applying bias correction by using radiative transfer calculation. Downward longwave radiation decreases from 1979 to the middle of the 1980's, and then it increases to 2004. From a long-term viewpoint, the trends are similar to those of downward shortwave radiation at the Earth's surface except for a turning point from decreasing to increasing. The turning point for downward longwave radiation is around the early 1980's while that of downward shortwave radiation is around the early 1990's. The trends of total downward radiation are almost same as those of downward longwave radiation including the turning point. The main causes of change in downward longwave radiation are air temperature change near the surface and change of greenhouse gases concentration in the atmosphere and they affect itto the same extent.
Experimental studies using the NIST standard lamps and the intercomparison of Brewer spectrophotometers for UV and Ozone observations between the Canadian standard (MKIII BR#145) and the Japanese standards (JMA standard MKIII BR#174 and travelling standard MKII BR#113) were conducted from March 31 to April 13, 2010, at the Meteorological Service of Canada (MSC). These studies and intercomparisons were carried out as the MSC-JMA joint project ''Cooperation on the Advanced System for Hazardous Solar Ultraviolet Radiation Spectrum Monitoring with Brewer Spectrophotometer'' in the framework of the Canada-Japan Cooperative Agreement on Science and Technology. The results were as follows.
1) The difference of instrument responsivity ratios determined by several NIST lamp calibration methods using three systems, MSC, IOS (International Ozone Services Inc.), and JMA, exhibited the following various ratios as "S_D" (S system and D distance between lamp filament to diffuser). (a) IOS_50/MSC_40 = 1.013. (b) IOS_50/JMA_50 = 0.979. (c) JMA_50/MSC_40 = 1.0347. The difference of 3.5 % between MSC and JMA systems confirmed an estimated difference of 3.3 % from the last comparison and test at MSC in 2006.
2) 9 days comparison between BR#145 and BR#174 (and BR#113 for 4 days) revealed the following ratios of solar UV irradiances measurement results. (a) Ir#174/Ir#145: from 0.971 to 0.977. (b) Ir#113/Ir#145: from 0.958 to 0.969. Those ratios changed after the consideration of the correction of the difference of 3.3 % between MSC and JMA NIST lamp calibration systems. These ratios changed as follows; (a) Ir#174/Ir#145: from 1.003 to 1.009. (b) Ir#113/Ir#145: from 0.990 to 1.001. After the correction, the irradiance ratios between BR#145 and BR#174 (BR#113) agreed within approx. 1 %. Based on the fact that these comparison results were almost the same as the results from the previous comparisons in 1994, 1998, 2002 and 2006, and that the JMA system has not changed since 1989, we concluded that the irradiance level (standard irradiance) of the NIST lamp calibration for the Brewer Spectrophotometers at Aerological Observatory, JMA, has been kept 3.3 % lower than MSC's lamp calibration for the past 22 years.
3) 8 days comparison between BR#145 and BR#174 revealed the following ratios of total ozone (ds O3) and total sulfur dioxide (ds SO2) measurement results. (a) O3 difference, (BR#174-BR#145)/BR#145: 0.002 (+0.2 %). (b) SO2 difference, (BR#174-BR#145): -2.0 m atm-cm. The O3 difference between BR#145 and BR#174 agreed within about 1 %.
These experimental studies of NIST lamp calibration and intercomparisons between MSC and JMA had been carried out at MSC since 1994. This has been very useful for the highly accurate observations of UV and O3 in Japanese Brewer Networks, JMA, NIES (National Institute for Environmental Studies) and others, and also useful for the construction planning of RBCC-A (Regional Brewer Calibration Centre in Asia).
"Observations of Total Ozone and UV Solar Radiation with Brewer Spectrophotometer on the Norikura Mountains in 2009" as the joint project between Aerological Observatory of the Japan Meteorological Agency (JMA) and the Institute for Cosmic Ray Research (ICRR), the University of Tokyo, was obtained at the Norikura Observatory of ICRR (Brewer site: 36.112 N, 137.555 E, 2,772 m a.s.l) in summer, 2009. The summary of their observation results and some test results using Brewer MKIII #174 (BR#174), Brewer MKII #113 (BR#113), pyranometer CM21 and pyrheliometer CH1 are given below.
(1) Comparative data of ds O3 and ds SO2, measured with BR#174 and BR#113.
Compare to the value in Tsukuba (36.058 N, 140.126 E, 39 m a.s.l.), daily mean of ds O3 at Norikura was 2 to 3 % lower. Daily variation and day-to-day variation (against Tsukuba) were also small. ds SO2 values were not recognized at Norikura station. The absolute calibration of Brewers for ds O3 and ds SO2 observations could be carried out within the range of air mass from 7.264 (maximum) to 1.055 (minimum) in clear day. The Extra-Terrestrial Coefficients (=ETC) of BR#174 and BR#113 at Norikura mountains were identical (within 1 %) to the currently used coefficients.
(2) Comparative data of UV range of solar radiation, measured with BR#174 and BR#113.
In comparison to the data acquired at Tsukuba, average of daily total GLUV (global UV radiation) indicated higher intensity of +18 to +25 % (+44 to +55 % in the clear day), and the daily total DFUV (diffuse UV radiation) indicated slightly higher value of +2 to +11 % (+1 to +8 % in the clear day). Average of daily RDFUV (diffusivity of UV radiation) indicated lower ratio than the ratio measured at Tsukuba. RDFUV was 0.72 (0.54 in the clear day) where the RDFUV at Tsukuba was 0.83 (0.74 in the clear day). Daily total GLUV increased in the short wavelength range. For example, increase in; 325 nm was +15 % (+39 % in the clear day), 315 nm was +18% (43 % in the clear day), and 305 nm was +2 5 % (+55 % in the clear day), against the daily total at Tsukuba. The altitudinal increasing rate of GLUV indicated the calculated amounts from +7 to +9 % (+16 to +20 % in clear day) per 1,000 m.
(3) Solar radiation measurement results with CM21 and CH1.
Average of daily total GLSL (global solar radiation) indicated the higher intensity of +14 % (+23 % in clear day) and the daily total DFSL (diffuse solar radiation) did the lower intensity of -5 % (-56 % in clear day), against the values at Tsukuba. Average of daily RDFSL (diffusivity of solar radiation) indicated the lower ratio of 0.60 (0.13 in clear day), relative to the ratio of 0.67 (0.35 in clear day) at Tsukuba.
(4) Some tests relating to Brewers
Some tests of the dispersion tests, the spectral tests, the NIST lamp calibrations and the external lamp tests had been carried out at Norikura. Those tests could be successfully completed except for the NIST lamp calibrations with the low outputs from the power supply due to the low-air-pressure on high mountains. The O3 absn coefficients from the results of the dispersion tests indicated the trends within 0.5 % in the observation period.
Those environmental conditions at the Norikura station were useful for the O3 and UV observations, intercomparison of the unit, and also useful for the absolute calibrations with Brewers.