The geographical environment of Guang Ningxian

Guang Ningxian is located in the middle and west of Guangdong Province, the middle reaches of Suijiang River, a tributary of Beijiang River. It is adjacent to Qingxin District and Sihui City in Qingyuan City in the east, Gaoyao City and Deqing County in the south and southwest, Huaiji in the west and northwest, and Yangshan County and Huaiji County in Qingyuan City in the north. The ground span is11203' ~11243' and 23 22' ~ 23 59' north latitude.

The county is 60 kilometers wide from east to west and 68 kilometers long from north to south. In 2000, the county's total area was 2458 15 square kilometers, accounting for 1.38% of the province's land area, of which the mountainous area was 2097.80 square kilometers (equivalent to 3146,800 mu), accounting for 85.34% of the county's total area. Features of the first and fourth seasons

The Tropic of Cancer passes through the southern tip of Guangning, most of which belongs to the south subtropical monsoon climate, and the northern marginal area has the tropical climate characteristics of Central Asia. Affected by the monsoon, the climate changes greatly every year. Under normal circumstances, it is rainy in spring, hot in summer and cool in autumn, and autumn drought often occurs; It's very cold in winter, sometimes with frost. 1979 to 2000, the annual average temperature was between 20.70℃ and 22℃ (Celsius, the same below), and the annual cumulative average was 2 1℃. The annual average rainfall is 1720.20mm, the lowest in 0 years is1991391.40mm, and the highest is 1993, reaching 2083.60mm The rainfall in rainy years is only over 60% of that in rainy years. 1979 ~ 2000, the average sunshine hours were 16 13 hours, and the variation range was 1328 ~ 1820.70 hours.

In spring (March to May), the average temperature is 2 1. 10℃. The cold air is still strong in early spring, sometimes it is cold and rainy in late spring, and occasionally there is late frost and hail. As the temperature rises, thunderstorms occur frequently and rainfall increases sharply. The average seasonal rainfall is 665,438+04.90 mm ... Because the rainfall changes greatly during the year, the rainfall time distribution is uneven, and there are sometimes spring droughts or spring floods. This season is the season with the least sunshine throughout the year, with sunshine hours of 220.90 hours, with an average of 2.40 hours per day.

In summer (June-August), the average temperature is 27.70℃, and the average rainfall is 677.10mm ... In early summer, tropical cyclones are frequent. In years with many typhoons, if the rain is too concentrated, there will be floods; In years with few typhoons, there will be summer drought. This season is the most abundant sunshine season in the whole year, with sunshine hours of 557.30 hours and average daily sunshine hours of 6. 10 hours.

In autumn (September ~165438+1October), the climate turns cool, and the seasonal average temperature is 22. 10℃. There are still tropical cyclones and storms in early autumn. In the years with less tropical cyclone activity, autumn drought will occur. The cold air activity began to be active in this season, bringing cold dew and windy weather at the heading and flowering stage of late rice; Under the influence of continental cold high pressure, radiation cooling is very strong at night, and the temperature difference between day and night is mostly above 10℃, which brings cold dew wind and dry weather in autumn. In addition, this season is particularly foggy, and there may be early frost in late autumn.

In winter (65438+February to February of the following year), the climate is dry, with little rainfall and low temperature. Seasonal average temperature 13. 10℃, frequent cold waves, low temperature, frosty weather and freezing rain and snow in some years.

Second, the temperature

From 1979 to 2000, the average annual temperature in Guang Ningxian was 2 1℃. The Leng Yue is 1, and the monthly average temperature is 10℃. July is the hottest, with an average monthly temperature of 28.20℃. The extreme maximum temperature is 39. 10℃, appearing on1August/July 1990; The extreme minimum temperature was -3.20℃, which appeared on199965438+February 23rd. The county is surrounded by mountains. There are many low mountains and Zhongshan in the north, with an altitude of 700 ~ 1339 meters, which inclines from northeast to southwest; The western part is low hills, with an altitude of 200 ~ 852 meters, and it pours to the southeast. Suijiang River runs obliquely through the county from northwest to southeast, forming an oblique and concave terrain with Suijiang as the axis and high on both sides and low in the middle. The landforms are hills and mountains.

First, the mountains

(a) mountain zoning

The mountainous area of this county is divided into four districts:

Zhongshan in the north is located in Kengkou, Chikeng, Kuidong, Beishi Town and Shenkeng Township at the junction with Huaiji and Yangshan. Most of them are above 700 meters above sea level, which is the highest place in the county. Five peaks, such as Luoke Mountain, Dalingding, Lengwengding, stirrup top and Mast top, are all above 1000 meters above sea level. Among them, the highest snail shell mountain, the main peak is 1339 meters above sea level.

The eastern low mountains are located in Lianhe, Jiangtun and tanbu town, including Shipai Mountain, Daqi Mountain, Yinkengding and Shima Mountain. The main peak is over 700 meters above sea level. Among them, there are 9 low mountains with an altitude of 500-800 meters in tanbu town, which is known as the "roof of Guangning".

The low hills along the river in the middle are distributed in Shui Gu, Nanjie, Shi Jian, Paisha, Binheng, Wuhe, Hengshan and Zhouzai. There are Bijia Mountain, Lion Head, Feng Long, Wangyunding, Bailiaoding, Sanxianding, Qixingding, Maji Anti-somersault, Sankengding, Gaowangding, Chaoshan, etc., with an average elevation of more than 500 meters.

The southwest low mountain is located in the west of Muge, Shizui, Qinggui Town and Zhouzai Town. There are Susan Mountain, Lizhi Mountain, Wuzhishan Mountain, Lijiding Mountain and Shanzhai Mountain, with an average elevation of more than 500 meters. Among them, the elevation of Susan Mountain is1020m.

(2) Mountains

Guang Ningxian Mountain belongs to the residual vein of Nanling Mountains, and its intermittent winding is unclear. The mountains in the north and east are roughly northeast to southwest, slightly inclined to southwest, and the mountains in the west are low to southeast; The southern marginal mountains extend northward to the south bank of Suijiang River. In the northern part of the county, Luoke Mountain is the main peak, adjacent to the top of the cold urn in Chikeng Town, which is divided into six small peaks and extends southward to the north bank of Shui Gu River. The southern mountain range, with Huanglian Mountain in Wuhe Town as the main peak, extends to Chaoshan Mountain in Hengshan Town to the north, then passes through Zhukeng Mountain to the west and winds to Zhenshan and the south bank of Suijiang River. In the west, Susan Mountain is located at the junction of Shizui and Shui Gu Town, which is the main peak of the mountain range, passing through Pinggang to the east and reaching Suijiang. In the eastern mountainous area, Shipai Mountain in jiangtun town is the main peak, adjacent to Daqi Mountain at the junction of tanbu town, and distributed in Jiangtun and tanbu town. There is Yuanling Mountain in the middle, which is located at the junction of Nan Jiezhen and Kengkou Town. There are 99 pits around the interior wall, which span Nan Jiezhen in the southeast and extend to Shui Gu River in the northwest.

Second, Qiu Ling.

Hills below 350 meters above sea level are all over the county, especially Nanjie, Luogang, Kengkou, Shui Gu, Zhouzai, Shi Jian, Binheng, Hengshan, Wuhe and Paisha. The hilly area of the county is1895,600 mu, accounting for 5 1.38% of the total area of the county.

Third, the intermountain basin

Guang Ningxian mountain basin covers an area of 737,800 mu (including waters), accounting for 20% of the county's total area. Mainly Gu Yong River, Shui Gu River, Jinchang River, Daliang River, Lidong River, Nanjie River, Binheng River, Luo Fu River and other alluvial plains downstream of Suijiang River tributaries. Among them, Shijian Cave, Jiangjidong Cave on the bank of Suijiang River, Miaocun Cave in Binheng River, Daxin Cave in Daliangshui River, Zengcun Cave in Lidong River, Huangpen Cave and Xinlou Cave in Nanjie River are relatively open and flat. In addition, there is a strip alluvial plain on both sides of Suijiang River, which is called "Bamboo Gallery" because it is covered with green bamboo forests.