近年、我が国は大規模なにみまわれ断水被害が発生する傾向にある。2016年１月において福岡県を中心に大規模な断水が発生した。本研究は、2016年１月で断水した福岡県大牟田市、桂川町、大野城市を対象に、水道事業者の災害対応及び事前事後対策について調査し、が水道事業者に与えた影響と教訓を３事業者で比較しながら明らかにするとともに、対策で検討すべき事項について考察を加えた。その結果、水道事業者のによる断水被害を想定した対策計画の必要性を示唆した。今後の対策として、①被害想定、②広報活動、③空き家対策、④道路・交通面の対策、⑤応急給水の５つの事項に考慮する必要性を指摘した。

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近年、我が国は大規模なに見舞われ断水被害が発生しており、による断水被害を最小限にする対策や対応が求められる。本報は、自治体広報紙による家庭内水道管の凍結対策に関する情報提供のあり方に資する基礎資料の提供を目的に、2016年１月前後の福岡県内60自治体の広報紙における水道管凍結対策記事を調査・分析した。その結果、①自治体の断水被害に関係なく、2016年１月を契機に記事数が増加し、その後も継続して掲載されていた。②記事内容は屋外管の保温対策や破損した場合に自治体指定の給水装置工事事業者に修理を依頼するなどの項目が多かった。③記事内のイラストは断水被害を経験した自治体の方が掲載する傾向にあった。

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中華人民共和国の雲南省全域におけるの時空間構造を,28年間 (1958～1987) の冬 (12, 1, 2月)の月平均気温偏差に主成分分析の手法を適用することにより調べた。また,卓越するのモードが,中国全域に影響を及ぼすの卓越モードと,どのような関係にあるかを,中国全土160地点の同じデータの主成分分析の結果と比較することにより,考察した。その結果,雲南省全域で最も卓越するの型は,より巨視的にみると,チベット高原から雲貴高原,さらに華南南部にかけての山岳・丘陵地にのみ集中して襲来する(雲南モード)に対応していること,これに対し,長江の中・下流を中心として中国平原部全域に最も卓越する(平原モード)の影響は,雲南省では比較的小さく,よりローカルであることがわかった。雲南モードのは,チベット高原から吹き降りて来る寒気団と,高原北(東)縁を地形に沿って流れ降りて来る沿岸ケルヴィン波的な寒気団の振舞いが重要であることも示唆された。
これら二つののモードに対応する大規模循環場を,北半球全域の500mb高度偏差と,地上気圧偏差の合成図手法により,調べた。その結果,雲南モードは,偏西風の遙か風上側である,ユーラシア大陸西部と北大西洋からグリーンランド付近での循環場の偏差と密接に関連していること,これに対し,平原モードは,中国北東方のシベリア中・東部での低指数型循環と寒気団の南下に,より直接的に対応していることが明かとなった。

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The purpose of this paper is to bring out, largely by means of observational material, outstanding features concerning the formation of hurricanes in the south Pacific. Because these data were few, fairly marked hurricanes had to be chosen for study, so that a sufficient number of observations might be obtained within one and the same hurricane. While the conclusions reached may have been influenced by this particular selection of cases, it is believed that the results are generally applicable.
Now take up the storminess of the south pacific, longitude 160°E to 140°W, by island groups. It will be seen that the hurricane season⁽¹⁾extends from December to April, inclusive. During this five month period about 90-95 per cent of the recorded storms have occurred. After making conservative allowance for the incompleteness of the record, and counting all gale-producing storms, not only true hurricanes, it appears that on the average fully a dozen tropical cyclones occur annually in the south Pacific.
Tropical storms form most frequently in the south Pacific when the thermal equator is farthest south. The season when they are most frequent occurs during the winter and the early spring of the northern Hemisphere. The outbreaks of the cold air from the morth polar region move southward and surge against the Equatorial Front in the southern Hemisphere. But it is the opinion of the author that the hurricane in the south Pacific do not show any warm sector at the surface to the south of the hurricane. On account of the distribution of land and sea over the surface of the earth, both northern and southern air masses generally arrive at the Equatorial Front after a long journey over water. Both masses are there fore warm and humid in the surface layer.
The occurrence of the outbreak of cold waves in the north Pacific from China to Kamtchatka inclusive is considered in Table 1. It is based on the data obtained from the weather maps analysed by the Central Meteorological Observatory, Tokyo, Japan.
Table 1. Annual Frequency of Cold Waves in the North Pacific 1933-1939. The cold wave season extends from December to April, inclusive. During this five-month period about 20 cold waves have occured. After making allowance for the imcompleteness of the record of hurricanes in the south Pacific and the completeness of the record of cold waves in the north Pacific, it appears probable that the formation of hurrjcanes in the south Pacific is somewhat related to the outbreak of cold waves in Siberia.
Utilizing this method for the hurricane in the south Pacific of the 8th to the 12th February, 1932, in which⁽²⁾ there are appropriate data, a marked outbreak of cold air from the north polar region which moved southward and surged against the Equatorial Front in the southern Hemisphere is proved. The results are generally applicable for the hurricane of the 27th December, 1932, to 5th January, 1933, ⁽¹⁾and the hurricane of the 28th January to the 3rd February, 1936.⁽²⁾
The work of S. Li⁽³⁾shows that the formation of typhoons in the North Pacific is somewhat related to the outbreak of cold waves in Australia. The conclusions stated above agree with that Li had to say regarding the formation of tropical cyclones in 1936.

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東アジアの冬季地上気温に,広域にわたり著しく大きなアノマリーをもたらすような大規模の総観的なモデル化を行なった.
大規模とば,太平洋と大西洋のブロッキングリッジが発達して極渦を切離し,寒気が大規模に南下する現象である.大規模が起こると,大気の大規模な南北交換によって,高緯度に正アノマリーが,また中・低緯度に負アノマリーが出現する.東アジアにおいては,北東太平洋のブロッキングリッジの有無およびその位置の変動によって,気温アノマリー分布が三つの型に分類される.
極ブロッキング型は,大西洋と太平洋のブロッキングリッジが極で連結するのが特徴で,中緯度を中心に寒気が流出する.北太平洋ブロッキング型は,太平洋のブロッキングリッジがカムチャツカ半島にのび,トラフが南偏して寒気が低緯度まで達する.また,北太平洋のブロッキング活動が弱く,リッジが発達しないときには,極渦が分裂せずに持続するため,中・低緯度に大規模が欠如する.このような場合を,特に極渦型としてとりあげ,前二者と比較した.

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本研究では,冬季東アジアおよび東南アジアにおけるについて,初めに回転主成分分析を用いて五っの低温偏差分布の型として抽出し,次に各型の総観場と出現傾向を調べた結果,以下のような特徴が明らかになった.1型は中国全土,豆型は中国東北地方に卓越するで,ともに出現の年々変動が大きい.丑1型は日本の気圧配置型の西高東低型に対応し,1型・II型に続いて出現する.IV型は華南地方に卓越するで・15～30日周期の変動をしている.V型は日本の気圧配置型の北高型に対応し,1型の約2日後に出現する.さらに各型が出現する時の低緯度地方における雲活動を調べた結果,III型とIV型のとき,トラフ前面に伴う雲帯とその南西端で南西進する熱帯積雲がみられた.とくにIV型出現時に,赤道付近の積雲域が通常の東進ではなく西進をする傾向があり,大気の中緯度一熱帯相互作用の存在が考えられる.

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Distribution of winter precipitation in Japan was compared for the cases of warm and cold win-ters. In winter, the Japan Sea coast area has a great deal of precipitation brought by the NW mon-soon, whereas the Pacific coast area is dominated by dry weather because the mountains have a “rain shadow” effect against the NW monsoon. Precipitation along the Pacific coast is ordinarily brought by extratropical cyclones passing through off the coast of the Pacific Ocean. Sometimes cyclones emerge in the Japan Sea and bring some precipitation in the area of the Japan Sea coast.
In cold winters the contrast in distribution of precipitation between the Japan Sea coast and the Pacific coast becomes more marked because of the more persistent and severe NW monsoon. In warm winters, however, such contrast becomes obscure and cyclone precipitation dominates the whole country (Fig. 5).
Six winters were selected as warm and cold winters from 27 winters (1953/54-1979/80) by the following method. A winter surface temperature (three months: Dec. -Feb.) was represented by nine 10-day mean values. When the 10-day value was higher (lower) than the normal by one standard deviation, it was counted as a warm (cold) 10-day period. The numbers of warm and cold 10-day periods were counted for ten meteorological stations (see Fig. 1-c). The winters that had a large number of warm (cold) periods and a very small number of cold (warm) periods were selected as warm (cold) winters (Fig. 2).
Figure 4 shows the average precipitation rate and its ratio to normal values for the periods. In a warm winter relatively heavy precipitation (above normal) was observed over a broad area except the Japan Sea coast area, whereas in a cold winter the distribution showed the reverse pattern.
Synoptic factors bringing precipitation were classified by using daily synoptic charts (Table 1). Figure 6 shows these factors: 1) M-type, in which the pressure patterns are “West-high East-low” type and NW monsoon is strong, 2) L-type, in which extratropical cyclones are situated in the vicinity of Japan and the NW monsoon is very weak or absent, 3) ML-type, which means a transi-tional pattern from L-type to M-type, and 4) 0-type, which means “others” The occurrence fre-quency for the six winters (Table 2) shows that about 70% of total days were classified as days with M- and L-type precipitation.
Figures 7 and 8 show the precipitation amounts and percentage of total amount for each factor, respectively. M-type precipitation dominated the Japan Sea coast area, especially in the central part of Honshu Island; the percentage value exceeded 50% in cold winters, whereas it was about 20% in warm winters. L-type is the only main factor in the Pacific coast area, so this type showed about 80% in either warm or cold winters. In addition, L-type precipitation is fairly abundant in warm winters even in the Japan Sea coast area, and this became the dominant factor in warm winters almost all over Japan except in the central part of Honshu Island.
In sum, during warm winters most precipitation in the whole country was caused by extratro-pical cyclones, whereas in cold winters the NW monsoon caused a great deal of much precipitation and dominated in the Japan Sea coast area. The only area with above (below) normal precipitation in cold (warm) winters was the central part of the Japan Sea coast of Honshu, Island, because of the greater increase (decrease) in M-type precipitation than the decrease (increase) in L-type precipitation.

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