北京石花洞空气环境主要因子季节性变化特征研究

洞穴大气CO2浓度不仅是影响洞穴沉积物沉积（或者溶蚀）的重要因素之一,而且在旅游洞穴,它关系到沉积物景观的稳定性以及旅游环境的舒适性。本文通过对石花洞洞穴大气温度、湿度及CO2浓度近4个水文年的观测,结果表明：（1）洞穴温度在15℃上下波动,夏季约高1℃,主要与洞内外温差的季节性变化和旅游活动有关;（2）洞穴CO2浓度随着大气温度上升而缓慢升高,至每年的7月上旬雨季来临时,气温、降水及土壤中CO2大幅提高,降水溶解大量的土壤CO2并渗入洞穴中,导致洞穴CO2浓度迅速上升,8月观测到的最高浓度可达到4 334ppm,在雨季结束后,随着大气温度降低,CO2浓度缓慢下降,2月份平均值达到最低,为360~458 ppm。另外,在5月份和10月份的旅游黄金周,旅游人数的增加,洞穴CO2浓度异常增高。在进行洞穴管理与规划时,应综合考虑自然和人为因素对洞穴的影响。

Research on seasonal variations of the air's main environmental factors in the Shihua Cave,Beijing

The CO2 concentration in cave air is an important factor not only controlling the deposition or corrosion of carbonate in caves but also affecting the stability of carbonate landscape and comfort of tourist in show cave.The CO2 concentration,temperature and relative humidity（RH） are monitored for near 4 hydrologic years in the Shihua Cave,Beijing.The results show that（1） cave temperature fluctuates around 15 ℃and is about 1 ℃higher in summer,which is related to tourism activities and the seasonal variation of temperature difference between inside and outside of the cave;（2） the CO2 concentration of cave air increases slowly with the air temperature until July,when it can increase quickly due to a large quantity of groundwater coming into the cave after the every strong rain.In August the highest CO2 concentration of cave air can reach 4 334 ppmv.After the rainy season,the CO2 concentration of cave air also attenuates slowly with the decreasing of the air temperature to reach minimum value（360~458 ppmv） in February.In addition,it has two small CO2 concentration peaks in May and October with the increasing in tourists.The analyzed results indicate that high concentration CO2 in soil environment dissolved in drip water makes a greater contribution to CO2 concentration in cave air during rainy period.Respiration of tourists is another contributor during the busy traveling season.Therefore,both natural and anthropogenic factors can be considered when planning and management is carried out for show cave.