Physical geography of Xinxing County

The county is located in the south of the Tropic of Cancer, and the nearest point to the ocean is 100 km. It belongs to subtropical monsoon climate, with the characteristics of mild climate, abundant heat, abundant sunshine, abundant rainfall and short frost period.

(A) the characteristics of the four seasons

The natural seasons in Guangdong are divided into winter when the average temperature is lower than 14℃, summer when the average temperature is higher than or equal to 24℃, and spring and autumn climate in between. The climatic characteristics of four seasons in Xinxing County are as follows:

Spring (March-May): In spring, the temperature rises slowly, and the temperature, sunshine and rain change frequently. The annual average temperature is 65438 08.4℃ in March, 22.2℃ in April and 25.8℃ in May. There are few sunshine hours, with the lowest value in March, with an average of 76.2 hours over the years. The lowest sunshine hours in March are 1975, only 10.2 hours. The strongest wind direction is the north wind. The rainy season begins in March, and the average annual precipitation is 62mm in March, 16 1.4mm in April and 233.5mm in May. This season, the front is active, rainy and sunny, and the total radiation is less. Occasionally, cold air invades, and the temperature drops sharply, resulting in low temperature and rainy weather and "late spring cold". 1958- 1985 During these 28 years, 14 experienced severe low temperature and rainy days, with seven years of late spring cold. But there is also the opposite situation, which is controlled by a single heating group and the air is dry, which is prone to spring drought. During the 23 years from 1958 to 1980, there were spring droughts in 1960, 1962, 1963 and 1977.

Summer (June-August): In summer, rainfall is concentrated, precipitation intensity is high, and the weather is hot and sunny. The average annual precipitation is 260.3mm in June, 202.2mm in July and 267.4mm in August. The rainy days are the most, reaching 58 days, accounting for 36% of the whole year. June is the most rainy month in the whole year, reaching 20 days, accounting for 12% of the annual rainfall, and it is the wettest period of the year. During the period from Xiaoman to Mangzhong from May to June every year, rain and flood disasters often occur, commonly known as "dragon boat water". The temperature in this season is relatively stable, with little change. The annual average temperature is 27.65438 0℃ in June, 28.3℃ in July and 27.3℃ in August. In the hottest July, the extreme maximum temperature was 1980, and in July 10 reached 38.2℃. The sunshine is abundant and the sunshine hours are long, with 532.5 hours from June to August; The most in July, with an average of 206.8 hours; The extreme maximum month is1July 964, reaching 274.5 hours, accounting for 66.5% of the available hours. The maximum average solar radiation in a year appears in July, which is 0.5962 kilocalories per square centimeter. The maximum wind direction is south wind and east wind, with a frequency of 4%. From July to September, the chances of being affected by typhoons are the most, accounting for 7855; It reached its peak in August, accounting for 34% of the whole year. Due to the influence of typhoon or tropical depression, it often brings heavy rain or heavy rain, which is easy to cause floods.

Autumn (September ~165438+1October): The temperature drops rapidly in this season, with a large daily range. The annual average temperature is 26.4℃ in September, 65438+22.9℃ in1October and 165438+ 18.4℃ in1October. The range of daily average temperature in each month is: 8℃ in September,165438+9. 1℃, 10/65438+9.9℃. The climate is dry with little rain, and the average annual precipitation in September is [92.3mm,1October 65438+83.3mm,1October 165438+38mm]. 165438+1October has the least rainy days, only 6 days. In the 23 years from 1958 to 1980. The drought years in autumn are: 1966, 1968, 1969, 197 1. There are many north winds in autumn. Before and after the "cold dew wind" festival, the strong cold air in the north went south, resulting in low temperature, dry and windy weather, sometimes accompanied by rainy weather, and sometimes met with typhoons, forming a wet and cold cold cold dew wind. The cold dew wind that affected our county first appeared on September 22nd 1976, and the latest was June 65438+1October19,968, with an average date of June 65438+1October1June. During the 23 years from 1958 to 1980, the cold dew wind has seriously affected 1970, 197 1, 1975, 1976 and/.

Winter (12 ~ February): sunny, cold, rainy, frosty and northerly. When the strong cold air in the north invaded the county seat, the weather turned fine, the wind weakened, and the advection and radiation cooled sharply at night, forming a low-temperature frost. In this county, the average first frost date is in late February of 65438+,the final frost date is in late October of 65438+/kloc-0, and the average frost date is 65438+February 2.2 and 65438+1October 2.8. The annual average temperature is 65438 04.7℃ in February, 65438 02.9℃ in October and 65438 04.4℃ in February. The annual minimum temperature is 65438+ 10 month, the monthly average minimum temperature is 9. 1℃, and the extreme minimum temperature is -2.3℃ (appearing in 1967, 1.07). During the 23 years from 1958 to 1980, the frost was severe: 1962 ~ 1963, 1966 ~ 1967,1967. The rainy days in winter are the least, only 27 days, accounting for 16.8% of the whole year. During the 28 years from 1958 to 1985, the average annual precipitation was 128.4 mm, accounting for 12.96% of the annual rainfall, including 66 mm in February. The surface water resources in Xinxing County mainly come from precipitation. The distribution of precipitation in different regions and months is extremely uneven, with great interannual variation, with more in summer and autumn, less in winter and spring, more in southern mountainous areas and less in northwest China. The flood season (April-September) accounts for 80-83% of the whole year, and the non-flood season (10-March of the following year) accounts for17-20% of the whole year. The maximum monthly rainfall occurs in August, accounting for 16.7% of the annual average rainfall, and May and June of the following year each account for about 15% of the annual average rainfall. Xinxing county is rich in mineral resources, including 3 categories and more than 20 kinds of * * *. Non-ferrous metals include: tungsten, tin, molybdenum, copper, aluminum, zinc, lead, gold and so on. Non-ferrous metals include granite, limestone, potash feldspar, kaolin, crystal stone, barite, quartzite, calcite and pyrite. Rare metals include monazite, uranium, beryl, tantalum-niobium, ilmenite and so on.

Granite is distributed all over the county, with a reserve of over 7.5 billion cubic meters. The colors are jade red, peach red, tiger pattern, emerging green, multicolored, black, black sesame, black rose, striped black, coarse pattern, big spot, cold night snowflake, black-and-white spotted crystal, grayish green, jadeite and so on. After drilling by the geological department and identification by the central laboratory of the Provincial Bureau of Geology and Mineral Resources, the hardness is 6 Mohs, the compressive strength is strong, the physical and chemical indexes are excellent, and the rejection rate is over 50%, which is rich in mining value. Kaolin (white mud) is distributed in Shangsha, Chegang, Rencun, Hetou, bamboo and other places, with excellent quality and abundant reserves. Quartz stone is distributed in gold mines in Chengdu, Hetou, Lidong, Paradise, Hetou and Bamu. Inferred by provincial geological experts, Xinxing County is located in the middle of Wuchuan and Sihui faults, which is a place with gold-forming conditions. Biological resources The plant resources in Xinxing County are: cereals (including miscellaneous grains), hemp, melons and vegetables, fungi, fruits, wood, bamboo, flowers, spices, medicinal materials, grasses (including vines) and dyes.

Animal resources are: birds, mammals, fish scales, snakes and insects.