Environmental monitoring
1、 Meteorological and soil characteristics
1. Meteorology
a. Temperature
According to the data of nearby weather stations, the monthly average temperature is as follows:
From January to March, it was - 2 ℃
5 ℃ from April to June
13 ℃ from July to September
It is 1.8 ℃ from October to December
b. Precipitation
According to many years' observation, the rainfall distribution of Siguniang mountain is as follows
38mm from January to March
1 mm from April to June
546 mm from July to September
4 mm from October to December
Precipitation is mainly concentrated from May to October, accounting for more than 80% of the annual precipitation.
The annual precipitation days are about 150 days; the daily rainfall of rainfall intensity is more than or equal to 10 mm, and the annual average is no more than 20 days; the average number of days with daily rainfall ≥ 20 mm is only about 1 week in the whole year; the daily rainfall ≥ 50 mm rarely occurs.
The annual average relative humidity of Siguniang mountain is about 40%, and the lowest relative humidity is no less than 20% from November to January of the next year. The humidity is relatively low and the climate is relatively dry; the highest relative humidity is more than 70% from June to August, which gives people a comfortable feeling.
c. Fog and sunshine
The average total cloud cover of Siguniang mountain is close to 60% and more than 70% in summer. There are more foggy days in summer than in other seasons.
The sunshine hours of Siguniang mountain are about 2265 hours a year, 900 hours more than 1400 hours in Sichuan Basin. The sunshine percentage is about 53%, and the sunshine in autumn, winter and spring is much more than that in summer.
d. Wind
In Siguniang mountain, the river valley is deep. Generally, the wind force is moderate, and the annual average wind speed is only about 1-3 M / S; the wind is slightly stronger in spring, which is more than 4 m / S; the breeze in summer half year is northward, and the light wind in winter half year is south. The wind in summer is warm and sunny, and there is no strong wind in winter.
2. Soil
Due to the influence of geographical factors, the distribution of soil in Siguniang mountain is characterized by vertical distribution and regional cross distribution.
a. Brown soil
Brown soil is one of the main soil groups in the gully, which is distributed in the altitude range of 2900-3400m, accounting for about 30% of the area. The parent material of the soil is the residual slope deposit of Paleozoic Sandstone and granite. The vegetation is composed of Hippophae rhamnoides, Sichuan Redwood, spruce, soap willow and birch.
b. Alpine meadow soil
It is distributed in the original area of gentle slope land in the elevation range of 4200-4600m above sea level. It is developed in residual slope and loess parent material, and liushitan is embedded in alpine meadow soil.
c. Subalpine meadow soil
As long as it is distributed in the range of 3800-4400m above sea level. It is mainly shrub growing area, and the forest on shady slope is distributed to 4200m above sea level.
d. Brown soil
It is mainly distributed between 3200-3800m above sea level, and is one of the most concentrated areas of biodiversity in the reserve.
2、 Hydrological characteristics
Siguniangshan belongs to the upper reaches of Dadu River in the Yangtze River system. The Siguniangshan river flows into xiaojinchuan from north to south. Xiaojinchuan and dajinchuan converge in Danba county and are called Dadu River, which flows through Ganzi and Leshan, and finally flows into the Yangtze River in Yibin. The Siguniangshan river originates from the Siguniang mountain peak of Qionglai mountain range, with a drainage area of 487.56km2, a drainage density of 0.65km/km2, and a maximum width depth ratio of 23:1 and an average of 5.2:1. The main tributaries are shuangqiaogou (daniuchang ditch, dianzigou, Dagou, muerzhai ditch, liushapo gully, Baihai ditch), Changping ditch (chongchongchongjiao ditch, lverguang ditch, lianghegou, Chiwen ditch, Chibu Gou, Changgou), Haizigou (Lufang ditch, banjiegou, chuyugou, xiaogoushuanghaizi ditch), Xiangyanggou, shitigou, shuangdiaogou, tiaoshuigou, balangshan gully, Changheba, etc, The average gradient is 42 ‰. There are many lakes in the area, including 26 bingdou lakes, the largest of which is yangmantaihaizi, with an area of 2053800m2, while the smallest is only a few square meters; there are 8 dammed lakes, with the largest area of sigonacuo, with an area of 2510120 m2; and 7 swamp lakes, of which the largest is huahaizi, with an area of 1902090m2. The distribution of lakes in Siguniangshan has the following characteristics: bingdou lake is mainly distributed in the alpine cold desert area with an altitude of 4600m; the dammed lake is mainly distributed in the area below 3700m; and the swamp lake is mainly in the area of 3500m-4000m. Modern glaciers are well developed in the area, mainly distributed in the shady slope area with an altitude of 4600 m and the rock area with an altitude of 5700 M. among them, there are Potala peak glacier, a'yan mountain glacier, Redwood glacier, yutufeng glacier in shuangqiaogou, Sanfeng glacier, Sifeng glacier, xiageluo glacier, yangbazi glacier, Changgou glacier, yangmantai glacier and Luotuofeng glacier in changpinggou And Chibu glacier; the two peak glacier, three peak glacier and Xiaogou glacier in Haizigou; the four peak glacier with an area of about 12 km2 and water storage capacity of 72 million tons.