Some Aspect of Radiation Climate of Tokyo as Observed by the Eleven Year Measurement of Spectral Global Radiation from 1961 to 1971

Abstract

Basing on data of global radiation both in total and spectral wavelengths on clear days from 1961 through 1971 the influence of pollution was discussed on the urban atmosphere of Tokyo.Decrease of radiation intensity by 10-15% during this period was noticed which may be attributed to the progress of air pollution in Tokyo.Correlations between various radiation data were calculated.Results showed a spatially homogeneous status in the central part of Tokyo. Infrared and visible data showed an extremely similar behaviour in contrast with the fact that ultraviolet radiation showed rather complex fluctuations.Correlation between radiation data and wind speed was calculated in varying wind directions. Results showed specific directional tendencies which indicated the influence of industrial areas as pollutant source.Some interpretations were given on the physics of the observed phenomena.

Solar Radiation Changes in Japan during the 20th Century: Evidence from Sunshine Duration Measurements

“…A bibliography of the published literature on global dimming, available at <http://www.rsbs. anu.edu.au/ResearchGroups/EBG/documents/ globaldimming_v2_000.pdf, includes an early account of global dimming from Japan (Sekihara 1973) reporting an 11% reduction in Eg↓ in Tokyo on cloudless days during the 1960-1970 period as measured with an actinograph; this reduction was attributed to increases in industrial air pollution. The longer and more accurate 1972-2002 thermopile measurement series from Tokyo, which included the frequent cloudy days in the annual totals analyzed, showed no evidence for a continuation of this decline, rather its reversal.…”

Progress in Urban Meteorology :A Review

“…Attenuation of K # depends on the nature and amount of the pollutants (see Oke 1982, 1988and Arnfield 2003 for reviews), but urbaninduced attenuation of K # is generally less than 10%, for example, in St. Louis, Toulouse, Vancouver, and Basel (Peterson and Stoffel 1980;Method and Carlson 1982;Estournel et al 1983;Christen and Vogt 2004). Tokyo, following rapid economic growth in the 1960s, has an urban-induced attenuation value of 10 to 15% (Sekihara 1973). Some cases of extremely large urban-induced attenuations associated with poor air quality have been reported, such as a 33% decrease in Hong Kong (Stanhill and Kalma 1995) and a 22% decrease in central Mexico City (Jauregui and Luyando 1999).…”

Letters to the Editor

“…These are now emerging as an important although hitherto neglected element in climate change. Measurements from several sites show a decrease in shortwave global irradiance, greater than the calculated increases in longwave irradiance from the atmosphere resulting from increased concentration of radiatively active gases (Abakumova 1980;Idso 1972;Ohmura and Lang 1989;Liepart et al 1994;Petrosanz 1989;Rusak 1990;Sekikara 1973;Stanhill 1995;Stanhill and Cohen 1997;Stanhill and Ianetz 1997;Stanhill and Kalma 1995;Moreshet 1992, 1994;Stief 1992).…”