EFFECTS OF DIFFERENCES IN LAND USE ON CLOUDS FORMATION IN MATSUYAMA PLAIN

SWEATA SIJAPATI, Yoshifumi FUJIMORI, Ryo MORIWAKI

Abstract


The spatial and temporal variation of cloud is important to understand the concept of local climate such as prediction of torrential rainfall. There is an obvious contrast in land use between the urban and rural area along the Shigenobu River in the Matsuyama plain. Thus, the purpose of this study is to investigate the effects of differences in land use on the cloud formation. For this purpose, we analyzed the observations data of solar radiation, surface heat flux, air temperature and humidity. Here, clear sky rate was considered as an index to identify the reduction in the solar radiation due to presence of clouds. We observed that, solar radiation over urban area tends to be smaller than that over the rural area in the afternoon on days with a sunshine percentage from 50% to 80%. This was demonstrated by the development of mixing layer estimated from surface heat flux. In urban area the development of the cloud were observed even after the mixing layer reached the lifted condensation level whereas no such significant changes were observed in rural area. The obtained result would be beneficial for the study of the rainfall pattern in urban watersheds and to understand the effects of urbanization on the local climate.


Keywords


Clear sky rate, solar radiation, land use, surface heat flux, lifted condensation level, mixing layer

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References


Changnon S. A., Shealy R. T. & Scott R. W. (1991). Precipitation changes in fall, winter, and spring caused by St. Louis. Journal of Applied. Meteorology, 30, pp. 126–134.

Sakakibara Y. & Matsui E. (2005). Relation between heat island intensity and city size indices/ urban canopy characteristics in settlements of Nagano Basin, Japan, Geographical Review of Japan , 78( 12), pp.812-824.

Matsumoto J. & Takahashi K. (1999). Regional differences of daily rainfall characteristics in East Asian summer monsoon season, Geographical review of Japan, 72 (2), pp.193-201.

Saito H., Nakayama D. & Matsuyama H. (2010). Relationship between the initiation of a shallow landslide and rainfall intensity—duration thresholds in Japan. Geomorphology, 118, pp.167–175.

Fujibe F. (1988). Diurnal variations in the frequency of heavy precipitation in Japan, Journal of the Meteorological society of Japan, 77, pp.1137-1149.

Shimoju R., Nakayoshi N. & Kanda, M. (2010). Multi-case study of urban torrential rain in summer Kanto region in consideration of the urban factor, Hydraulic Engineering Proceedings, 54, pp.349-354 (in Japanese).

Bornstein R. & Lin Q. (2000). Urban heat islands and summertime convective thunderstorms in Atlanta: three case studies, Atmospheric Environment, 34(3), pp. 507-516.

Fujibe F. (2003). Long-term surface wind changes in the Tokyo Metropolitan area in the afternoon of sunny days in warm season, Journal of the Meteorological Society of Japan, 81( 1), pp. 141—149.

Inoue T. & Kimura F. (2004). Urban effects on low-level clouds around the Tokyo metropolitan area on clear summer days, Geophysical Research Letters, 31(5).

Fujimori Y., Hayashi Y. & Moriwaki R. (2010). Characteristics of urban heat island phenomenon in Matsuyama plain, Annual journal of Hydraulic Engineering, JSCE, 54, pp.313-318 (In Japanese).

Moriwaki R., Watanabe K. & Morimoto K. (2013) Urban dry island phenomenon and its impact on cloud base level, Journal of JSCE, 1, pp.521-529.

Davies F., Middleton D. R. & Pearson G. N. (2004). Observations of boundary layer depth over an urban/rural transition, AMS Fifth Conference on Urban Environment, Vancouver.

Asai T., Ke S. & Kodama Y. (1998). Diurnal Variability of Cloudiness over East Asia and the Western Pacific Ocean as Revealed by GMS during the Warm Season, Journal of the Meteorological Society of Japan, 76(5), pp.675-684.

Fujimoto M., Watanabe K. & Moriwaki R. (2012). The characters of spatio-and temporal-variation of rainfall in Matsuyama plane, Journal of Hydroscience and Hydraulic Engineering, 30(2), pp.39-47.

Sijapati S., Fujimori Y. & Moriwaki R. (2014). A study on the classification of clouds using time variation of the amount of solar radiation, Annual journal of Hydraulic Engineering, JSCE, 60 (in press).


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