Meso-Climatological Study of the Strong Winds in the Shonai Plain, Northeastern Honshu, Japan : on the Local Wind Kiyokawadashi and the NW Monsoon
Meso-Climatological Study of the Strong Winds in the Shonai Plain, Northeastern Honshu, Japan : on the Local Wind Kiyokawadashi and the NW Monsoon
复制标题
日本本州东北部庄内平原强风的中气候研究：局地风清川大石和西北季风
DOI：
10.5026/jgeography.95.6_397
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发表时间：
1986
影响因子：
3.1
通讯作者：
T. Aoyama
中科院分区：
文献类型：
--
作者：
T. Aoyama
在本州东北部的庄内平原的最上川沿着地区，主要是从东南和东南方向吹来的强东风和主要是从西北和西北偏西方向吹来的强西风（表1）。强烈的东风是庄内平原的地方风，称为“清川风”。这些西风带大部分与东亚的冬季季候风相对应。这些风的一些特性可以通过Karikawa AMeDAS站的日平均风速来证明（38° 48 'N，139° 59' E）和酒田气象站（北纬38° 54 '，东经139° 51'）（图三）;这两个车站都位于庄内平原上，狩川位于最上川流入平原的东侧，而坂田位于西侧，在日本海的海岸。本文在统计比较这些风的中尺度气候特征的基础上，研究了地形的影响，并利用仙台（38° 16 'N，140° 54' E）的高空气象资料，分析了嘉利川东风和西风时高空风的垂直结构。在北方本州东北地区，在最高层（约800毫巴）以下的S风向条件下，东风发展（图4（a））。此外，狩川的风速与峰顶以下的风速呈正相关，与更高层的风速呈负相关（表2）。另一方面，西风带的速度取决于W或NW方向的高空风速（图4（B），表2）。在狩川，海平面气压分布也显示出东风带和西风带各自的特征。东风带出现时，日本列岛日本海一侧的低压和太平洋一侧的高压明显，气压分布的等值线几乎呈南北走向。这种压力分布模式与上述东风出现时东北地区山顶以下低层发展的南风相对应。特别是在强东风的情况下，日本海一侧的低压加强，日本海一侧的东西气压梯度变大（图5，图6（a），（B））。这种气压模式显示了ATKINSON（1981）和巴里（1981）解释的逆风中高压和背风中低压;这也表明低层的南风是由东北地区的地形影响引起的。在西风带的情况下，地形的影响也很容易在气压分布图上看到;背风低压和逆风高压发展，太平洋一侧的气压梯度特别大（图7，图8（a），（B））。等压线的走向为西北-东南方向，与总风向基本一致。为了评价地形在不同尺度上的影响，本文还研究了风速与气压梯度的关系。关于气压梯度，计算了东北地区和日本海一侧地区的空间平均值以及新庄和酒田之间的差异。在Karikawa的风速和这些压力梯度是相互关联的，具有很强的线性相关性（图9，表3）。特别是在日本海一侧的气压梯度的空间平均值与嘉利川的东风密切相关，而在东北地区的西风相对较好地相关。另外，值得注意的是，新庄-酒田之间的气压梯度与东风的相关性强于西风。
In the region along the Mogami River in the Shonai Plain, Northeastern Honshu, the strong easterlies which blow mainly from SE and ESE and the strong westerlies which blow mainly from NW and WNW prevail (Table 1). The strong easterlies are the local wind, called “Kiyokawa-dashi”, in the Shonai Plain. The most of this westerlies correspond to the winter monsoon winds over East Asia. Some properties of these winds can be demonstrated by the daily mean wind speed at the Karikawa AMeDAS station (38°48'N, 139°59'E) and the Sakata Meteorological Station (38°54'N, 139°51'E) (Fig. 3); Both stations are on the Shonai Plain, Karikawa is located at the eastern side, where the Mogami River comes out on the Plain, and Sakata at the westernside, on the coast of the Sea of Japan. In this report, topographic effects were investigated on the basis of the statistical comparison of the meso-climatological properties of these winds.The vertical structure of the wind aloft on the occasion of the easterlies and the wester lies at Karikawa are examined by the aerological data at Sendai (38°16'N, 140°54'E). The easterlies develop under the condition of the wind direction of S in the layer below the summit level (about 800 mb) in the Tohoku District, Northern Honshu (Fig. 4 (a)). Moreover, the wind speed at Karikawa relate to the wind speed below the summit level with positive correlation and that on the heigher levels with negative correlation (Table 2). On the other hand, the velocity of the westerlies depend on the upper wind speed with the direction of W or NW (Fig. 4 (b), Table 2).The sea level pressure distribution shows also respective characteristic features in each case of the easterlies and the westerlies at Karikawa. On the occasion of the easterlies, the low on the Japan Sea side of the Japanese Islands and the high on the Pacific side appear clearly and the contours run almost in north-south direction on the pressure distribution pattern. This pattern of pressure distribution corresponds with the southerlies which develop in the lower layer below the summit level in the Tohoku District on the occasion of the easterlies as described above. In particular, the low pressure on the Japan Sea side strengthen in the case of the strong easterlies ; the east to west pressure gradient in the region of the Japan Sea side become large (Fig. 5, Fig. 6 (a), (b)). This pressure pattern suggests the upwind meso-high and the Lee meso-low explained by ATKINSON (1981) and BARRY (1981); this also indicates that the southerlies in the lower layer are induced by the topographic effects of the Tohoku District. On the occasion of the westerlies, the topographic effects are also readily seen on the pressure distribution maps ; the lee low and the upwind high develop and the pressure gradients are particularly large in the region of the Pacific side (Fig. 7, Fig. 8 (a), (b)). The trend of the isobars are northwest-southeast direction, which almost equivalents to the general wind direction.In order to evaluate the topographic effects in various dimensions, the relationships between the wind speed and the pressure gradient are examined. In regard to the pressure gradients, the space means of the Tohoku District and of the Japan Sea side region and the difference between Shinjo and Sakata are calculated. The wind speed at Karikawa and these pressure gradients are related to each other with strong linear correlation (Fig. 9, Table 3). In particular, the easterlies at Karikawa are related closely to the space mean of the pressure gradient in the Japan Sea side region and the westerlies are related relatively well to that in the Tohoku District. In addition, it is atracted special attention that the pressure gradient between Shinjo and Sakata strongly correlate with the easterlies than with the westerlies.