What's the climate like in Xiaogan, Hubei?

Brief introduction of Xiaogan (climate, resources, history) administrative division

Xiaogan City is one of the prefecture-level cities under the jurisdiction of Hubei Province. It now governs Xiaonan District, Yunmeng, Dawu and Xiaochang counties, and Hanchuan, Yingcheng and Anlu county-level cities. The existing land area is 89 10 square kilometers with a total population of 5.06 million.

Climatic characteristics

Xiaogan city is located in the mid-latitude zone and belongs to the subtropical monsoon climate. There are four distinct seasons in the territory, with northerly winds prevailing in winter, southerly winds prevailing in summer, short-lived hot and cold in summer, and mild climate in spring, autumn and early summer for a long time. Abundant rainfall, with annual average precipitation1133.8mm; Sufficient light and heat, annual average sunshine hours 1, 996.7 hours, annual average temperature 16.0℃, accumulated temperature ≥ 10℃ 509 1.9℃, are beneficial to the development and growth of crops. It is a zone with good coordination of light, heat and water conditions in China. However, there are frequent rainstorms in early summer and rainy season, which are prone to floods, and high temperature evaporation in midsummer often leads to summer drought. Flood and drought have become the main natural disasters in this city.

In spring (March to mid-May), the temperature rises, the rain increases, the temperature changes, and there are often low temperature and rainy days. After the spring, the temperature rises rapidly and the rainfall increases obviously, which is beneficial to the development of spring sowing crops and the growth of wintering crops. Spring is also a season of frequent alternation of cold and warm air, with an average of 7 ~ 10 days, resulting in more sunny and rainy days from mid-March to mid-April, changeable wind direction and sudden rise and fall of temperature.

In early summer (from late May to mid-July), the temperature is suitable, there is plenty of rain, and there are many rainstorms in rainy season, so floods can occur.

In midsummer (from late July to August), the weather is hot and often dry. After the summer, the cold air in the north gradually weakened, and the warm air in the south gradually strengthened, and the weather changed from cold to hot, with an average temperature of 23 ~ 28℃, which was suitable for the normal growth of crops. The rainy season is from mid-June to mid-July, and there are often heavy or continuous heavy rains, which are easy to cause flash floods in the north and floods and floods in the south. After the Meiyu ended, it entered the hot summer, and the rainfall in the territory decreased obviously, the relative humidity decreased, the sunny days increased, and the temperature increased. The average daily temperature is above 28℃. At the end of July and the beginning of July, southerly winds of 3 ~ 4 grades can appear in about one third of a year, which has certain influence on flowering and pollination of mid-season rice. During this period, high temperature weather above 35℃ often occurs, and at the same time, there is little rain and large evaporation, which is prone to drought. However, in a few years, excessive precipitation or heavy rain caused local flooding.

In autumn (September-165438+1October), there are many sunny days, few rainy days, and sometimes it is cool in autumn. In autumn, the cold air forces in the north gradually strengthened and even controlled the whole territory. The cold and warm air confrontation area moved out of Xiaogan, and the rainy weather turned into sunny and hot weather, with less rainfall, more rainy days, more sunshine hours, large daily temperature difference, high temperature during the day and cool at night. It is called "crisp autumn" climate, which is conducive to the late growth of autumn crops and autumn harvest. However, in September of some years, there were long rainy days, which made the daily average temperature lower than 20℃, resulting in autumn cold.

Winter (65438+February ~ February) is cold with little rain (snow), and there is freezing injury at the end of winter. Winter has the seasonal characteristics of low temperature and less rainfall. The average temperature in various places is mostly below 3 degrees, and the overwintering crops basically stop growing. Generally speaking, strong cold waves often attack, and the minimum temperature can drop below MINUS 5 degrees, accompanied by rain and snow and northerly winds above 5 degrees, which freeze crops and affect people's lives. But there are also a few years that are relatively warm "warm winters".

natural resource

General situation of water resources in Xiaogan city

The average annual rainfall in Xiaogan City is112mm, and the distribution of precipitation decreases from southeast to northwest, with a difference of about 250mm between north and south. The annual maximum precipitation of a single station in the city is 2420.9mm( 1954 Wanfuzha Station), and the annual minimum precipitation is 457.7mm( 1978 Tian Zi Station). The annual average temperature of the whole city is 15.8℃, the annual extreme maximum temperature is 43.1℃ (Dawu Station in1959), and the annual extreme minimum temperature is-15.7℃ (Yingcheng Station in1969).

The average total amount of water resources in Xiaogan City for many years is 3.810.40 billion m3, including 3.673 billion m3 of surface water resources and 659 million m3 of groundwater resources. There is no double counting of surface water and groundwater10.41100 million m3. The average annual inflow is 33,4851100 million m3, the average annual outflow is 55,846.2 billion m3 (excluding the Han River), the average annual water supply is 20,9321100 million m3, the average annual other water supply is 58.95 billion m3, and the average annual water consumption is 20,9321100 million m3. The average annual water consumption is 68, and the surface water quality is poor.

In 2005, the evaluated rivers in the city were Xinhe, Dafu River, Huanshui River and Fuhuan River. Of the 435.2km total evaluated rivers, the second-class river 154km in dry season accounts for 35.4% of the total evaluated river length, the fifth-class river is 4.5km, accounting for 1.0% of the total evaluated river length, the super fifth-class river is 226.7km, and the second-class river length 154km in wet season. The main pollutants are ammonia nitrogen, total phosphorus and fluoride.

General situation of forest resources in Xiaogan city

I. Forest resources

According to the second-class survey in 2000, the forestland area in Xiaogan City is 176997 hectares, and the forestland area is 13 175 1 hectare. The total standing stock is 5790634 cubic meters, and the forest stock is 45 172 19 cubic meters.

Second, wild animals

During the period of 1997, the investigation of key terrestrial wildlife resources was carried out for the first time in China. Wild animals ***4 classes, 26 orders, 58 families 138 species. Among them, amphibians 1 1 species, 2 orders and 5 families; Reptiles, 2 orders, 5 families, 14 species; 90 species in 36 families, 15 orders; There are 7 orders 12 families and 23 species of fauna. The national first-class protected wild animal is the stork; Secondary protection includes giant salamander, tiger frog, jackal, otter, leopard, civet, roe, impala, pangolin, yellow-billed egret, cygnet, crane, emu, goshawk, white-bellied harrier, kestrel, eagle and eagle. There are seven species of animals listed in Appendices I and II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, such as wolves, leopard cats and so on. Three species are listed as vulnerable by the International Union for Conservation of Nature and Natural Resources. The species named in the agreements between China, Japan and Australia on the protection of migratory birds and their habitats are: ox egret, great egret, middle egret, swan goose, bean goose, red-dot duck, mallard duck, merganser, crake, cuckoo, swallow, tiger shrike, red-tailed shrike, black-tailed wax mouth and so on. Birds are the main species of wild animals in China.

Third, wild plants.

Xiaogan woody plants can be divided into coniferous forest, broad-leaved forest and shrub, 12 vegetation types and 43 formations. Mainly includes:

(1) evergreen coniferous forest

1, masson pine community. Dominant, most widely distributed, with natural forests at an altitude of 100-600 meters. There are many types of websites. The composition structure is simple, mostly pure forests, with small shrubs or vines under the trees.

2. Pinus taiwanensis community. It is concentrated at the northern elevation of150-820m, showing a massive distribution. There are natural Pinus taiwanensis in ridges, hilltops, exposed rocks and tuyeres. The site conditions are harsh and the community structure is simple.

3. Cypress community. Originally, it was an important tree species of evergreen coniferous forest in China, but its natural regeneration ability was not as good as that of Pinus massoniana, and it was severely cut down for a long time and saved less. At the altitude of 200-300 meters from Anlufan to Xiaowulisan in Xiaochang, there are still a few remaining cypress forests and small areas of cypress and cypress groups. The soil is mostly yellow brown soil with limestone development.

(2) Evergreen broad-leaved forest

1, Cyclobalanopsis glauca community. It is a geographical indication species in China and is rarely preserved. There is a small Cyclobalanopsis microphylla forest in Liuhe Village, Xiaowu, Xiaochang, covering an area of about 10 mu, with an average DBH 10.6 cm and an average tree height of 6 meters. It is located at the edge of a valley at an altitude of180-200m, with a slope of 30 degrees. Granite develops into soil, and the bedrock is exposed. There are rhododendrons, trachelospermum, oak trees, climbing vines and so on.

2. A community consisting of Phoebe bournei, Phoebe bournei, Phoebe bournei, Phoebe bournei and Cinnamomum cassia. It is an important representative type of mixed forest in China, and its number is very limited. Scattered in Anlu, Dawu and Xiaochang, with a maximum area of 500 square meters. Living in a mountain stream or wetland at an altitude of 180-600 meters, there are many Ficus plants around.

3. Euonymus microphylla community. There is only one place in the territory, which is located on the west side of Leigong steep slope reservoir in Anlu, with an altitude of 250 meters, exposed limestone, a slope greater than 35 degrees, an area of 600 square meters, an average tree height of 3.2 meters, an average DBH 17.6 cm and a maximum DBH of 55 cm. The undergrowth plants are mainly composed of rose, rhamnus, Smilax China, Rutaceae and spiny shrubs, as well as drought-tolerant Daphne, Euphorbia, Ilex, Rhus verniciflua and Fagaceae.

(3) Deciduous broad-leaved forest. It is the second largest forest type in China after Pinus massoniana forest. Its tree species are the most abundant and widely distributed.

1, Quercus acutissima and Quercus variabilis communities. Widely distributed in northern China, it is the largest and most stable community in China. The largest is located in Tang Fu Village, Fengdian, Dawu, with an altitude of 3 10 m and an area of more than 60 mu. The average tree height is 22 meters and the average DBH is 66 cm.

2. Maple Leaf Community. Widely distributed in Dawu, Anlu and Xiaochang. Generally, it appears in the form of associated tree species or undergrowth plants, and occasionally wild sumac and beech trees can be seen in the forest.

3. Fragrant community. It is more common in the mountainous areas of China to be composed of secondary forests. Dominant tree species can be formed on sunny slopes below 700 meters above sea level. The site conditions are generally poor and the structure is simple. Excessive firewood cutting has degenerated into shrub land.

4. Liquidambar formosana community. It is the dominant tree species in deciduous mixed forest in China, and there are also scattered trees in the north.

5. Pteroceltis tatarinowii community. It is a unique single protected tree species in China and distributed in Dawu, Anlu and other places. The largest community is located in the trunk ditch of Tiedian Village, Fanyao, Dawu, with an altitude of 345 meters, an area of 1900 square meters, an average tree height of 18 meters, an average DBH of 98 cm and a maximum DBH 163 cm. Pteroceltis tatarinowii generally grows on both sides of ravines, with moist soil and running water. There are many related tree species.

(4) bamboo forest.

It is widely distributed in China and has a small area. Mainly distributed in Xiaochang Xiaowu, Dawu Lisan, Xuanhua, Anlu Bafan and other places.

(5) shrubs.

1, Quercus, Zanthoxylum bungeanum, Dalbergia odorifera, Hu Axiang and Rhus chinensis are common shrub types in China. Simple structure, many parts and generally low economic value.

2. Forsythia suspensa shrub community. Not widely distributed, in the tuyere with poor site conditions, in the middle and upper part of the mountain with an altitude of 400-700 meters, there are sparse maple trees, shell trees, walnut trees and Ulmaceae trees in the upper layer, and a small number of Rosaceae shrubs are mixed.

3. Lespedeza shrub community. It is common in barren hills and slopes, and there are no trees in the community, but there are mixed Vitex negundo and Shrub.

4. Small-diameter bamboo and shrub communities. Widely distributed in Dawu, Anlu and Xiaochang low mountainous areas, at the foot of the mountain at an altitude of 100-500 meters, scattered in small groups, and there are almost no other trees, shrubs and vines in the bamboo forest. The main bamboo species are bitter bamboo, Indocalamus, Phyllostachys pubescens and Phyllostachys bambusa.