Ya 'an is a prefecture-level city under the jurisdiction of Sichuan Province, so Ya 'an belongs to Sichuan Province, not Chengdu.
in p>195, ya' an was liberated, and ya' an area was established, with ya' an as the capital of Xikang province.
In p>1951, Ya 'an Special Area was renamed Ya 'an Special Agency, and Shimian County was built in Hanyuan, Yuexi and Mianning.
in p>1955, Xikang province was abolished, Ya 'an area was merged into Sichuan province, and Mingshan County and Luding County were divided into regions.
in p>1956, Luding county was placed under the jurisdiction of Ganzi prefecture.
in p>1981, ya' an area was renamed ya' an area, under the jurisdiction of Yucheng, Mingshan, Yingjing, Hanyuan, Shimian, Tianquan, Lushan and Baoxing, 42 towns and 16 townships (including 18 ethnic townships).
in December p>2, the establishment of Ya 'an City (prefecture-level city) was abolished in Ya 'an area.
Ya 'an City is located on the western edge of Sichuan Basin, and its northeast edge is adjacent to Chengdu. East of Meishan City; The southeast is connected with Leshan City; Liangshan Yi Autonomous Prefecture in the south; West Ganzi Tibetan Autonomous Prefecture; Northern Aba Tibetan and Qiang Autonomous Prefecture.
ya' an city belongs to the mountainous area on the western edge of Sichuan basin, which spans the Sichuan basin and the Qinghai-Tibet Plateau. It is a transitional zone from the basin to the Qinghai-Tibet Plateau. The terrain is higher in the north, west and south, and lower in the middle and east. The highest point is Shenxianliangzi at the junction of Shimian, Kangding and Jiulong counties in the southwest, with the main peak at an altitude of 5,793 meters and the lowest point at the exit of Qingyi River in Caoba, with an altitude of 515.97 meters. The city has vertical and horizontal mountains, rugged surface, complex and diverse landform types, many mountains and few hills and flat dams. The hilly flat dams are mostly distributed on both sides of the river valley, accounting for only 6% of the city area, and the low mountains (5 to 1 meters) are located in Yucheng District and Mingshan County in the middle, accounting for 4% of the city area. Zhongshan (15-35 meters) is the most widely distributed, accounting for more than 6% of the total land. The high mountains (3,5-5,m) account for 6% of the total area of the city, which are mostly distributed in Baoxing County, the northwest of tianquan county, the southwest of Shimian County and the northern end of Lushan County, with a relative height difference of 1,m-2,m. The main mountainous areas in the territory belong to Qionglai Mountain and Daxue Mountain, and the southeast edge is mainly the north section of Xiaoxiangling Mountain in the north-south direction. Daxiangling is not only the main watershed of Dadu River and Qingyi River, but also an important dividing line of the city's physical geography.
the climate type of ya' an city is subtropical monsoon humid climate, mostly in low latitudes. Where the monthly temperature is below ℃, there are only a few hills with an altitude of more than 2 meters. The average annual temperature is above 14℃, and the average annual temperature in Zhougong Mountain, which is 1744 meters above sea level, is also 13℃. In terms of precipitation, although it is located inland, it is located in the western corner of the Sichuan Basin. When the mountains in the northeast and south-north directions are windward of the trumpet mouth, it is backed by the cold high pressure of the Qinghai-Tibet Plateau and faces the warm and humid airflow of the southeast monsoon. Therefore, there are many orographic precipitation and frontal rains in summer. In winter, it belongs to the northern boundary of quasi-static front in Kunming. When the dry and warm westerly wind along the north of Hengduan Mountain is blocked and weakened in Daxiangling and Erlang Mountain, it meets the south winter wind in Yingjing, Ya 'an and Tianquan, forming a quasi-static front hovering between heaven, elegance and Xingying, so it is rainy in autumn. Because the cold and warm air flows meet for a long time, resulting in a lot of clouds, and the water vapor in mountain valleys is not easy to distribute, so the relative humidity is high and the sunshine is less. High humidity increases the heat capacity of air and regulates the temperature, so the daily temperature difference is not large. Ya 'an has more precipitation, more clouds, less sunshine and lower temperature in annual range. Compared with the cities in subtropical monsoon region with the same latitude in China, Ya 'an is the city with the farthest distance from the sea, the smallest temperature difference and the most precipitation.