开放洞穴环境变化特征及其影响因素——以桂林凉风洞为例

Characteristics of open cave environment and its influencing factors: A case study of Liangfeng cave, Guilin

通过对桂林凉风洞洞穴内、外温湿度、 p CO 2进行连续高频监测,发现洞穴温度受大气度温影响呈现出季节性变化规律。由于受到洞穴结构的阻隔作用影响,洞穴由外向里的温度变化幅度逐渐变小,并且响应的时间存在季节性差异。监测数据表明:洞穴内部温度的季节性变化幅度明显低于洞外气温变化幅度。比较洞内、外温度的时间序列发现,在季节尺度上洞穴温度升温阶段滞后时间长(与外部通风的气温流动交换慢),降温阶段滞后时间短(与外部通风的气温流动交换快,呈现突变特征),这可能与不同季节洞穴内部结构的“缓冲作用”的强弱变化有关。该洞穴空气中 p CO 2存在明显的夏季高、冬季低的季节性变化特征。并且外界大气环境季节性变化和洞穴上覆动植物的季节性活动,使得洞穴 p CO 2主控因素也存在季节性差异。

By continuous high-frequency monitoring of the internal and external temperature, humidity and p CO 2 in the Liangfeng cave of Guilin, it is found that the temperature of the cave is seasonally changed under the influence of atmosphere temperature. However, due to "buffering effect" in the cave, the range of temperature change decreases with the cave depths from the outside to the inside, and its response time varies with season. The analysis of monitoring data indicated that the seasonal variation of temperature inside the cave is significantly lower than that outside the cave. By comparing the time series of temperature inside and outside of the cave, it is found that the temperature of the cave shows a longer lag time with the increase of atmospheric temperature and a shorter lag time with the decrease of atmospheric temperature at the seasonal timescale. This difference may be affected by the "buffering effect" of the internal structure of the cave in different seasons. The p CO 2 in this cave has obvious seasonal variation characteristics of high in summer and low in winter. Moreover, seasonal changes in the external atmospheric environment and seasonal activities of the animals and plants on the caves have also caused seasonal variations in the main controlling factors of p CO 2 in the caves.