Geography & Climate
  • Geography and Climate

    Geography Xuhui district is located in the southwest of the city, latitude 31°12′north and longitude 120°26′east. It adjoins Luwan district with Shanxi road (South) and Rihui port in the east and is separated by Huangpu River with Pudong area in the southeast and is next to Shanghai county with Dingpu River in the south and Hongmei road in the west, borders on Jing’an district and Changning district with Changle road and Huaihai road (West). It is the key way for people from some rural counties such as Qingpu, Fengxian, Songjiang and Jinshan to enter into the downtown, and also is the main drag to some other provinces such as Zhejiang, Fujian, Jiangxi and Anhui. 1. Geology The whole district lies in the east part of acetabuliform wash of Tai Lake, which is a lowland alluvial plain between Gangshen and Huangpu River. The formation time is not long after the earliest land in Shanghai area--Gangshen belt. The basement rocks are mainly formed by Paleozoic carbonatite, Mesozoic lava and intrusive rock, and red Cenozoic glutenite and basalt in local sunken basin. The basement rocks are covered by incompact deposit with different depth. The surface layer of the ground is brown yellow soil formed by sub-clay and clay. And its subsoil is gray silt-seam.. According to geologic examination, the status at Shimin Village near Hongqiao road is as the following: 10 ms to the surface is filling layer; 10 ms-50 ms to the surface is clay, sub-clay and light sub-dry soil layer; 50 ms-80 ms to the surface is mealy silt, sub-clay layer. Sap green pan is found 25 ms to the surface at Changqiao area in the south of the district. Longhua and some other places have the stratum of river floodplain light gray grit layer or gray light sub-clay layer together with mealy grit layer. The water content here is so high that quicksand is likely to occur. The depth of flat water layer is 0.5 ms in general, 0.3 ms-0.5 ms in Caohejing area and 1.3 ms-2 ms in Changqiao area. The low embedded first water bearing sand can bear the weight of 8-14 t/m². 2. Physiognomy The district is located in the middle part of Shanghai acetabuliform plateau within water meshwork zone in the south of Yangtze and is a part of lowland alluvial plain. The earth’s surface has little natural gradient, and most of the surface is below upsurge mark. Because of excessively exploitation of groundwater, the ground subsided. Some parts in the north of Zhaojiabang road have the latitude of 2.5 ms-3 ms, and its low-lying places are below 2.5 ms. Xuhui district had been one of the land and water transportation and cargo distributing centers. After the liberation, traffic construction in the district has flourished. For railway, there are Shanghai South Railway Station, Xinlonghua Organizing Railway Station and Xujiahui Railway Station. For No.1 subway, 7 subway stations of the total 13 subway stations are located here. For ground traffic, there are more than 150 roads, 38 lines of city buses run across within the district. The buses drive to southwest rural counties start in the bus station of west district. There are more than 100 rivers within the district. Huangpu river crosses the district and has many docks such as Beipiao coal load and unload dock and Kaiping dock, etc.. There are 5 ten thousand berths. The climate in the district is north semitropical monsoon climate with clear divisions of four seasons. Climate 1. Temperature Annual average temperature is 15.5℃. Average temperature of January in winter is 3℃. Average temperature of August in summer is 27.5℃. It is recorded that the lowest temperature in Xujiahui is 12.1℃ bellow zero on Jan. 19 in the 19th year of Emperor Guangxu in Qing Dynasty (1893) and the highest temperature is 40.2℃ on Jul. 12 of the 23rd year of Republic of China (1934). Xujiahui area has clear divisions of four seasons. The average temperature below 10℃ is winter and the average temperature above 22℃ is summer. The average temperature between 10℃ and 22℃ is spring and autumn. Season Distribution Sheet of Xujiahui District Season Average starting and finishing date Average number of days (about) Percentage to the whole year Spring Prophase of last ten-day period of Mar. ~ Anaphase of last ten-day period of Jun. 72 21 Summer Anaphase of first ten-day period of Jun. ~ Prophase of last ten-day period of Sep. 110 30 Autumn Prophase of last ten-day period of Sep. ~ Anaphase of last ten-day period of Nov. 60 16 Winter Anaphase of last ten-day period of Nov. ~ Prophase last ten-day period of Mar. next year. 33 2. Wind direction In winter, the district suffers the northwest monsoon from Mongolia plateau, so the weather is cold and dry with fast wind speed. In summer, it is influenced by southeaster form Pacific Ocean. It is the interim for monsoons in March, September and October with northeaster. Little southwester appears all over the year. 3. Precipitation Summer has more precipitation than winter, and spring than autumn. There is no extremely droughty season. The annual number of precipitation is 1143.1mms and the least monthly precipitation is 38.5 mms in December. There was no rain in the whole December of the 4th year of Republic of China. The number of precipitation in July of the first year of Emperor Guangxu in Qing Dynasty (1875) is 491.9 mms. The rainstorm mainly focuses in summers and autumns. The time for snowfall is short in winter here, and the snow seldom stacks thick. The time and number for hail is also so little. Record of Monthly Average Precipitation and Precipitation Days of Each Month and Day by Xujiahui Observatory Item Month Monthly average number of precipitation (mms) Number of days with more than 0.1mms precipitation in different months (days) 1 48.0 9.6 2 61.5 10.4 3 84.0 12.5 4 93.8 13.0 5 103.2 13.0 6 178.0 13.9 7 144.1 11.2 8 134.6 10.8 9 133.9 12.0 10 70.1 8.9 11 53.4 8.5 12 38.5 7.9 Whole years 1143.1 131.7 Records time 100 years(1873~1972) 100 years (1873~1972) 4. Fog and frost Because the water vapor is flush, the wind speed is slow and there is more condensation nucleus in the air within the district, there are many misty days every year. According to the data recorded by Xujiahui observatory, there are 43 fog days on average every year. The most fog days in a year are in the 19th year of Republic of China, 93 fog days all together. The fewest fog days in a year are in the 27th year of Emperor Guangxu in Qing Dynasty, 3 fog days all together. The fog day often appears at windless and cloudless night or in such morning between January and May or between October and December. Physiognomy within the district is flat, so cold wave’s influence is very visible. When cold wave comes, the temperature drops sharply and frost appears. Those will surly harm crops in early spring and late autumn. The frosty period starts on Nov. 20 and stops on Apr. 24 on average. The frosty period is about 125.4 days in a year and the period without frost is about 240 days. 5. Disastrous weathers The striking disastrous weathers are mainly tropical storm (typhoon), tornado, rainstorm, hail and so on. Typhoon always hits Shanghai in July and August, and sometimes in June and September, about twice a year. On Jul. 28, the 4th year of Republic of China, Xujiahui observatory’s dogvane was broken off by typhoon with the highest wind speed of 44 m/s. On Jul. 28, 1949, the typhoon brought a severe disaster and a rainstorm to Shanghai. According to an incomplete statistic, in the south of Zhaojia Creek within the district, 665 houses were broken down or damaged, 501 families, 2,389 people were hit by the typhoon, 85 people were killed and about 40 people were injured or went to the bed. In 1956, the 12 degree typhoon broke down the steel cross with the weight of 400 kgs on the roof of Xujiahui Catholic church. The tornado often appears between summer and autumn. A tornado hit Longhua, passed by Longhua tower and blow to the northwest on Aug. 5th, 1969. This tornado pulled up telegraph poles, houses and brought huge damages to crops, people and cattle. The rainstorm usually falls in summers and autumns. On Sep. 13, 1963, Longhua was hit by a rainstorm with the rainfall of 246.7 mms. On Aug. 5, 1969, Longhua was hit by a rainstorm with the rainfall of 204.4 mms, and one hour of this rainstorm had reached the highest rainfall of 71.2 mms. It is recorded that a record rainfall was 47 mms in 15 minutes and some places were flooded. The hail seldom appears in the district and with a small quantity. According to the Records of Songjiang Government Office, on the Apr. 8, of the first year of Emperor Yongzheng in Qing Dynasty (1723), the hail hit the area between Longhua and Zhagang. A man was killed and uncountable people were injured. Some big hails were even 25 kgs.