Although Baishuitai belongs to subtropical region in latitude, its stereoscopic climate is very obvious because of the great difference between the scenic spot and the terrain: that is, in the same hillside or valley, there are warm temperate zone (2200~2500m above sea level), temperate zone (2500~3000m above sea level), cold temperate zone (3000~3500m above sea level) and cold zone (above 3500m above sea level). Due to the lack of local meteorological observation data, Zhao et al. (1998) calculated according to the meteorological records of Zhongdian meteorological station, the annual average vertical decline rate of temperature and the annual average increase rate of precipitation in this area, and concluded that the annual average temperature at the top of Baishui Station (about 2600m) was 9. 1℃, the annual average precipitation was 7 14mm, and the average rainy season began. This shows that the climate in this area is mainly controlled by the southwest monsoon of the Indian Ocean and the westerly belt of the earth.

The obvious zoning of climate has caused the obvious vertical zoning of vegetation near Baishuitai Scenic Area and the three-dimensional ecological landscape of "four seasons in one season, four seasons alternating". The primeval forests in the upper reaches of Baishui River and Shisanjiao Mountain are well preserved, and the forest coverage rate of scenic spots is as high as 80%. Primitive forest is mainly composed of fir forest at an altitude of 3,700 ~ 4100 m, spruce forest at an altitude of 3,400 ~ 3,700 m, redwood forest at an altitude of 3,200 ~ 3,700 m and Yunnan pine forest at an altitude of 2,600 ~ 3,200 m. However, the vegetation on the mountainside and foothills of Mudu Valley and the floodplain has been seriously or completely destroyed, so it is below 2,600 m.

Baishuitai is backed by a Ming Tombs (Zhao et al., 1998) composed of limestone of Triassic Beiya Formation. Since the Quaternary, due to strong tectonic movement and weathering, mountain rocks have been broken and faults and fractures have developed, providing excellent conditions for the infiltration of atmospheric precipitation and the runoff of groundwater. However, due to the barrier of a north-south fault, groundwater is exposed in the form of springs at an altitude of about 2600m, but there are only two main springs at present, namely, main spring 1 and 2. In the process of spring water exposure and flow, a large amount of CO2 is released, and abundant calcium carbonate deposits are precipitated, thus forming various travertine landscapes (figure 16.4438+0).

Figure 16. 1 Geological background map of the origin and formation of travertine in Baishuitai.

(modified by Zhao et al. 1998)

1-travertine; 2- diluvial gravel; 3- spring water; 4- limestone; 5- Fault; 6- water flow direction; 7- Monitoring point

① Baishuitai 1 and No.2 main springs; (2) the place where a large amount of travertine began to appear (about100m away from the spring); ③ ~ ⑧ are observation points in travertine pool; Pet-name ruby Baishuitai spring downstream 500 meters stream hydrochemistry automatic monitoring point.

Although the spring water temperature (about 1 1℃) is basically close to the annual average temperature at the same height (9℃), considering the influence of the cooling of snow water at high altitude at the source, the spring water temperature may be related to deep geothermal. The following evidence of hydrochemistry and carbon stable isotopes further supports this view.