The geographical environment of Hanzhong

The Qinling Mountains in the north of Hanzhong City are like a barrier, and the highest peak is in Ding Liang, Shengrenping, Yangxian County, with an altitude of 307 1 m. Other higher peaks are Guangtou Mountain in Foping County, Motianling Mountain in Yangxian County, 2603 meters, Baizi Mountain in Liuba County, 26 100 meters, and Guangtou Mountain in Mianxian County 1000 ~ 2000 meters. Micang Mountain (also known as Bashan Mountain) in the south is tall and majestic, with the highest peak at Jianggan Mountain in zhenba county, with an altitude of 2,534 meters. Compared with Gao Shanfeng, there are 2468m Tiechuan Mountain, 2367m Hongshan Mountain and 2389m Guangtou Mountain in Nanzheng County, and the general mountain elevation is1.000 ~1.500m..

Hanzhong City is located in Nangoukou, Chazhen Town, Xixiang County, with an altitude of 371.2m. The Hanjiang River passes through the middle of the basin, forming an alluvial plain. Hanzhong basin is 1 16 km long from east to west, 5-30 km wide from north to south, and 25-30 km wide near Hantai District. The Muma River and Jingyang River, a tributary of Hanshui River, meet in the northeast of Xixiang County, forming an alluvial wide valley dam named Xixiang Basin. Hanzhong basin is 500 meters above sea level, and Qinba Mountain is 500 ~ 2500 meters higher than Hanzhong basin. There are various types of landforms, but mountains account for 75.2% of the total land area (including low mountains 18.2% and high mountains/57.0%), hills 14.6% and flat dams 10.2%.

Hanzhong belongs to the subtropical climate zone, with Qinling barrier in the north, which is not easy to be attacked by cold current and has a mild and humid climate.

Temperature: The geographical distribution of temperature in this area is mainly controlled by topography. The annual average temperature is 65438 04℃. The west is slightly lower than the east, and the north and south mountainous areas are lower than the flat dams and hills. The annual average temperature in Pingba area below 600 meters above sea level is14.2 ~14.6℃; The average annual temperature in areas above1000m is lower than12℃; The annual average temperature in the western valley of Jialing River is higher than 65438 03℃.

Precipitation: Hanzhong is located in the mid-latitude of the northern hemisphere, forming a warm and humid airflow of annual precipitation, mainly from the Bay of Bengal in the Indian Ocean, followed by the western Pacific Ocean. In summer, under the influence of the subtropical high, the water vapor in the Bay of Bengal flows northward along the southwest monsoon in the lower part of the southwest vortex, passing through Tibet, Yunnan and northwest Sichuan, reaching over this area. The water vapor in the western Pacific enters this area with the southeast airflow at the edge of subtropical high. Winter is controlled by the polar continental cold air mass (mainly Mongolian high pressure), and there are many northwest monsoon, which leads to cold, dry and little rain. Spring and autumn are transitional seasons, with warm and little rain in spring, cool and rainy in autumn and humid climate. Water vapor evaporated in space by ground vegetation, reservoirs, rivers and pastoral areas. Almost no participation in precipitation. The warm and humid airflow in the southwest and southeast directions is blocked by Bashan and Qinling Mountains, which makes this area abundant in rainfall. However, due to the fact that the two mountains are on the route of southwest airflow, the convergence of water vapor system in the middle and lower clouds, and the vertical influence of topographic uplift and mountains, the water vapor in this area is not equal to the north and south, and the precipitation distribution is very different. The average precipitation for many years is between 700 ~ 1700 mm, of which Micang Mountain in the south is the most abundant and the highest in Shaanxi.

Humidity: The distribution trend of annual average relative humidity in the whole Hanzhong area is basically from the south to the north. 70-80% of Hanjiang and Bashan Pingba; Qinling 73%. It is smaller in winter and spring and larger in summer and autumn. The month of 9. 10 is the highest in the whole year, with 80% ~ 86%. In winter (12, 1, February), 75% ~ 80% is in Pingba and Bashan areas of Hanjiang River; 58%~66% of the Qinling Mountains.

Wind: the average annual wind speed in this area is between1-2.5m/s ... windy days are rarely seen, with an average of less than 2 days per year, but the surrounding suburbs are different. The rivers in Hanzhong City belong to the Yangtze River Basin. Judging from the composition of water system, it is mainly the east-west Hanjiang River system and the north-south Jialing River system. Hanjiang River, also known as Hanshui River and Mianshui River in ancient times, is the largest tributary of the Yangtze River. Hanzhong city is located in the upper reaches of Hanjiang River. The main stream of Hanjiang River flows through Ningqiang, Mianxian, Nanzheng, Hantai, Chenggu, Yangxian, Xixiang and other counties (districts) from west to east, and crosses Hanzhong Basin, which is the skeleton of Hanzhong water network. The total length of the main stream of Hanjiang River in Hanzhong City is 277.8km, accounting for 18. 1% of the total length of Hanjiang River 1532km, and the drainage area is 19692km2, accounting for1.3% of the total drainage area of Hanjiang River.

Jialing River water system is distributed in the west and south of Hanzhong City. Jialing River, which runs through the western mountainous areas of Lueyang and Ningqiang counties from north to south, is a transit river. The domestic flow is 14 1.7 km, and the basin is long and narrow, wide in the west and narrow in the east. There are 192 Jialing River rivers in the city, with a drainage area of 7554 square kilometers, accounting for 27.7% of the total land area of Hanzhong City.