Climatic Disasters and Defense Countermeasures of the Oasis City
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Climatic Disasters and Defense Countermeasures of the Oasis City on Tropic of Cancer Duan Peng LingZhao JiaFengWeng (Zhaoqing Meteorological Observatory, Guangdong, China 526060) Abstract:This paper analyzes the climatic characteristics and climatic disasters of the oasis city of zhaoqing on the tropic of Cancer .The result indicates that the frequent meteorological droughts, and the frequent Geological disasters caused by heavy rain,and the high temperature,which cause energy consumption and electricity consumption, and the smog, the severe thunderstorms and short-term strong winds which effect on urban transport. And the impact of dominant winds on industrial layout, and some defense countermeasures have been put forward:Ecological city planning should consider meteorological risk areas according to meteorological conditions; Climate demonstration must be conducted for major urban projects;Strengthen the relevant research of meteorological planning for eco-city construction and other countermeasures. These efforts will provide scientific data for the government departments to plan for the sustainable development of ecological cities. Key words: Oasis City; Climate characteristics; Climate disasters;Countermeasure 1.Introduction Zhaoqing City, Guangdong Province is located in the central and western part of Guangdong Province. It is located in the south of Nanling, with high mountains in the Northwest and low in the Southeast. The mountains, hilly basins, river valleys, and plains criss-cross each other. The topography is complex and diverse. The entire territory of Zhaoqing is between 22 ° 47 ′ and 24 ° 24 ′ north latitude, and the Tropic of Cancer runs through it. Due to the subtropical monsoon and monsoon humid climate and the high and low terrain in the Northwest and Southeast, the climate is hot and rainy. Zhaoqing has a forest coverage rate of 69.8 %. It has 104 forest parks and 3 wetland parks. The city has a total of 15,82,400 acres of forest land. It also has the world's closest tropical virgin forest with a history of more than 400 years from the city-Dinghu Mountain. Known as the "oasis on the Tropic of Cancer." What causes such a unique oasis city? What are the climate characteristics? What about climate disasters? How do you defend yourself? 1 As a huge man-made ecosystem, the chain reaction of urban disasters has obviously changed the original material energy cycle in nature. Cities rely heavily on the lifeline systems, and the links between industries and departments are closely and complex. Moreover, most cities have developed and utilized resources with long-term excessive intensity, discharged large amounts of exhaust gas, wastewater, and waste residue, resulting in resource destruction and environmental degradation[ 1-2] And ... In this case, the city is not only faced with natural disasters such as floods, internal floods, typhoons, landslides, mudslides, and cold hazards[ 3-5] , It is also faced with a variety of "man-made" disasters that are closely related to urban development, such as land subsidence, ground cracks, seawater intrusion, and water resources crisis. Once a certain disaster occurs, it often produces a chain reaction, resulting in a series of secondary disasters. And derivative disasters. In recent years, many scholars have paid attention to the occurrence law of urban meteorological disasters and put forward prevention and control measures. Wuyaling [6] Analysed the meteorological disasters in Shenzhen since 2000 and conducted a risk assessment. Linjisheng[ 7] The effects of meteorological disasters in Guangzhou were evaluated and predicted by expert evaluation method. At present, the future development plan of the Zhaoqing City People's Government is to build a new ecological city in Zhaoqing near Dinghu Mountain, a natural ecological area on the Tropic of Cancer. Therefore, the climatic characteristics of the oasis city and the laws governing the occurrence of climate disasters are analyzed in detail, and the meteorological problems caused by the catastrophic impact of the development of ecological cities are analyzed. It also expounds the meteorological factors that need special attention in the industrial layout of ecological cities, puts forward corresponding countermeasures, and provides scientific data for the government departments to do a good job in the sustainable development planning of ecological cities. 2 Urban climate characteristics of oasis on the Tropic of Cancer Zhaoqing City, Guangdong Province is located in the central and western 2 part of Guangdong Province. It is affected by subtropical monsoon and monsoon humid climates and high and low terrain in the Northwest and Southeast. The climate is hot and rainy, with an average annual temperature of 22.3 °C and an average annual rainfall of 1649 mm. Zhaoqing City has a forest coverage rate of 69.8 % and is known as the "oasis on the Tropic of Cancer." What causes such a unique oasis city? What are the climate characteristics? What about climate disasters? How do you defend yourself? 2.1 Subtropical monsoon and monsoon humid climate effects In winter, the cold and dry air from the North has greatly weakened after a long journey. When it reaches the north side of the Nanling Mountains, it has become denatured. After encountering the Nanling Mountains, it is blocked. The weaker cold air may even be difficult to climb over the mountains of Vietnam., blocked in Lingbei, When the stronger cold air reaches Zhaoqing across the Nanling Mountains, the wind speed has greatly reduced and the temperature has dropped slowly. The average monthly temperature of the coldest month is as high as 13.7 °C. The total rainfall from December to February of the following year was relatively small, accounting for only about 10 % of the annual precipitation, with an average rainfall of 164.7 mm. From the spring to the early summer, with the gradual weakening of the northern and northern cold air of the subtropical high, and due to the blocking effect of the Nanling on the cold air, the frontal movement was slowed down. The Zhaoqing area often has warm humid air masses from the South and the northern cold air masses. The confrontation forms a static front. Clouds and rain have caused long rainy weather in Zhaoqing City and heavy rain weather in the previous flood season. And since March, the warm and humid air flow in the South has gradually increased. Due to the existence of the Nanling Mountains, the terrain from Zhaoqing to Nanling has been from low to high, and the ultra-low South warm and humid air flow has a topographical uplift effect on the windward slope. The convergence of air flow increases, making the wet layer thicker, Finally, it reached saturation to form cloud rainfall, and the frequency of precipitation increased from March to June. The total rainfall averaged 830.6 mm, accounting for about half of the year, of which the number of monthly 3 precipitation days from May to June was the highest. In summer and early autumn, tropical cyclones in the Western Pacific and South China Sea frequently hit Guangdong. Zhaoqing was affected by the tropical cyclone peripheral circulation cloud system and other tropical precipitation systems, resulting in heavy rainfall in the post-flood period of Zhaoqing City. The total rainfall from July to September averaged 549.2 mm. 2.2 Impact of local terrain The hills, basins, valleys, and terraces in Zhaoqing are criss-cross, and the terrain is complex, forming a diversified climate. The terrain is high in the Northwest, low in the East and South, and tilted from Northwest to Southeast. Mainly in the low and middle hills, there are fewer plains, forming mountainous landforms such as mountains, basins, hills, and alluvial plains. Mountains and hills are mainly distributed in Huaiji in the North, Guangning in the Northeast, and Fengkai and Deqing in the West. And other counties. The valley plains are distributed in the southeastern cities(districts) such as Sihui, Gaoyao, Dinghu and Duanzhou. Zhaoqing Ecological City is planned to be built in Zhaoqing New District. Zhaoqing New District is located in the west of central Guangdong Province, North of the Pearl River Delta, lower reaches of the Xijiang River, east of Sanshui and Sihui City, South of Gaoyao City, and west of Duanzhou District. It was originally the Dinghu District of Zhaoqing City. The North and South sides of Zhaoqing New District are the Luanko Mountains and the Beiling Mountains, the West is the Valley, and the middle is the river network, forming a large "U" shaped plain. There are many types of landforms in the country, including mountains, hills, plains, and water surfaces. The terrain is complex and belongs to the subtropical monsoon climate zone and monsoon humid climate with sensitive climate change. Under the influence of the summer monsoon, Zhaoqing area is relatively easy to form medium and small scale convection systems. Dinghushan and other terrains have a certain role in promoting the rising movement of the precipitation system during the rainy season, which is conducive to the maintenance of precipitation and the increase of rain intensity, bringing abundant rainfall in the flood season of Zhaoqing City.. In the combination of subtropical monsoon and terrain, the total annual 4 rainfall in Zhaoqing City is 1,649 mm. At the same time, the average annual relative humidity is 80 %. From May to June, the maximum is 85 %. From October to January, it is the smallest, and it is also close to 75 %. The humid climate and abundant rainfall have freed Zhaoqing from the influence of the dry zone of the regression line and the letter wind zone. At the same time, under the influence of the summer monsoon, the airflow humidity from the ocean is large, and the rainy season is cloudy and rain weakens the direct radiation of the sun and reduces evaporation. Therefore, Zhaoqing City is long in summer but not very hot, and the hottest month has an average temperature of 28.8 ° C.