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4 Fig. 2 Frequency (%) distribution of wind speed and direction at Hotaka (Ho), Matsumoto (Ma), Ina (In), and Iida (Ii)

5 Table 2 Contingency table for the frequency (days) of wind directions with southerly component in daily maximum wind speed between Matsumoto and In a stations Numbers in parentheses denote frequency of wind speed above 8m/s. The boldface values show the samples analyzed in this study.

6 Table 3 Frequency (days) of southerly winds and mean local pressure gradient (hpa/100km) at Matsumoto under the direction and strength of svnontic-scale pressure gradients over central Japan The boldface values show the maximum frequency and mean pressure gradient in each class of the synoptic scale pressure gradient.

7 Table 4 Frequency (%) of pressure pattern types for the NE and NW types Fig. 3 Monthly frequencies (%) of the NE and NW types of southerly winds

8 Table 5 Average wind direction and speed at the 850hPa and 700hPa level for the NE and NW types The values in parentheses are the standard deviation.

9 Fig. 4 Histogram (%) of wind direction at 850hPa and 700hPa under the surface southerly winds a: NE type b: NW type

10 Fig. 5 Histogram (%) of Richardson numbers Fig. 6 Histogram (%) of Scorer's parameters for the NE and NW types for the NE and NW types

12 Table 6 Correlation coeffi cients between the wind direction and speed at 850hPa and the wind speed for the NE and NW types Fig. 7 Histograms (%) of wind direction for the NE and NW types at Omachi, Suwa, and Iida

13 Table 7 Correlation coefficients between the wind direction and speed at 850hPa and the local pressure gradients for the NE and NW tvnes

14 Table 8 Correlation coefficients be tween the wind direction and speed at 850hPa and differences of potential temperature (between Ma tsumoto and Iida) for the NE and NW types

16 Kuwagata, T., Sumioka, M., Masuko, N., Kondo, J The daytime PBL heating process over complex ter rain in central Japan under fair and calm weather conditions. Part I: Meso-scale circulation and the PBL heating rate. J. Meteor. Soc. Japan 68: Queney, P The problem of air flow over moun tains, a summary of theoretical studies. Bull. Ameri can Met. Soc. 29: Smolarkiewicz, P. K., and Rotunno, R Low fro ude number flow past three-dimensional obstacles.

17 Part I: Baroclinically generated lee vortices. J. At mos. Sci. 46: Yoshino, M., and Yamakawa, S Pressure pattern calendar of East Asia, , and some climato logical discussion. Climatological Notes 34: Zangl, G., Chimani, B., and Haberli, C Numerical simulations of the Foehn in the Rhine Valley on 24 October 1999 (MAP IOP 10). Monthly Weather Re view 132: Geographical Review of Japan Orographic Effects on Local Southerly Winds in the Matsumoto Basin, Central Japan AOYAMA Takayoshi (Department of Geography, Senshu University) Orographic effects on local southerly winds developing in the area from the southern part of the Matsumoto Basin to the northern part of the ma Basin, central Japan, were analyzed statistically based on data from routine observations at meteorological stations. The development of local southerly winds is accompanied by intensification of local pressure gradients, which indicate the formation of local orographic lows in the Matsumoto Basin. The local southerly winds are classified into the NE and NW types based on the direction of the sea-level synoptic pressure gradient and occur under various pressure patterns. The typical pressure patterns for the NE type are the winter monsoon and coupled lows across Japan, and those for the NW type are stationary fronts covering Honshu (mainland Japan), lows over the Sea of Japan, and the transitional migrating high-to-trough pattern. For the NE type, winds at 850hPa are at 250 or greater in the WSW, W, and WNW directions; for the NW type, winds at 850hPa are at 250 or less in the WSW, SW, SSW and S directions. 421

18 The local southerly winds tend to increase in strength and reach the maximum value to the wind direction of 250 at 850hPa. Based on the Richardson number and Scorer's parameter (1), local southerly winds occur under stable conditions that induce the formation of leeside mountain waves. In addition, l values showed that winds of the NE type tend to have a vertical component and flow over mountains, while those of the NW type tend to split and flow around mountains. Differences in the l values between the NE and NW wind flow forms at 850hPa were investigated statistically in relation to such local meteorological phenomena as the surface wind speed, local pressure gradient, and potential temperature of local southerly winds in the Matsumoto Basin. The results showed that, for the NE type, wind direction and speed at 850hPa correlated significantly with local pressure gradient and potential temperature, suggesting intensification of the local orographic low and adiabatic heating due to air descending down the leeward side of mountains. For the NW type, wind speed at 850hPa correlated significantly with local pressure gradient but not with potential temperature, suggesting that this type splits to flow around mountains and is not significantly influenced by the descending component and adiabatic heating. The correlations between wind in the upper layer and orographic phenomena accompanying local southerly winds are in basic agreement with the wind flow forms estimated using Scorer's parameter. Key words: Matsumoto Basin, local southerly winds, mountain wave, split flow, Scorer's parameter 422

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<32322D8EA D89CD8D8797B294C E8A968388DF814589C193A1899B E5290EC8F438EA12D966B8A4393B98F5C8F9F926E95FB82CC8BC7926E F5 No.432008pp.287 302 Climatological Characteristics of Local Wind in the Tokachi District, Hokkaido, JAPAN Takashige KAWAI, Mai NAKAJYO, Hisashi KATO and Shuji YAMAKAWA Received September 30, 2007 Climatological