开放参观对莫高窟洞窟微环境的影响

洞窟微环境相对湿度是影响壁画保存的关键因素,为了解开放参观对莫高窟洞窟相对湿度的影响,本研究选择莫高窟南区四个相似洞窟进行长达10年(2004~2013年)的定期监测,对比分析了开放洞窟和关闭洞窟其相对湿度的变化情况。结果表明:开放洞窟相对湿度在开放时段波动频率与游客参观频次正相关,发生降雨时开放洞窟相对湿度迅速上升,关闭洞窟可有效阻隔窟外相对湿度波动的影响。开放洞窟在参观量大的旅游旺季,其相对湿度月极大值、日较差月均值以及日极大值超过60%的频次均明显高于关闭洞窟。将开放洞窟关闭,关闭洞窟开放后,其相对湿度呈相反规律变化。开放参观会导致洞窟相对湿度水平显著升高,日波动幅度明显增大,从而增加壁画劣化风险。这些结论可为洞窟的预防性管理和风险评估提供科学依据。

The impact of visitation on the microenvironment of the Mogao Caves

Relative humidity of microenvironment in Mogao Caves is a key factor for conservation of wall paintings. In order to realize the impact of visitation on relative humidity in Mogao Caves, the relative humidity of four relatively similar test caves in the southern area of the Mogao Grottoes were monitored regularly for ten years during 2004~2013. The relative humidity of open caves was compared to that of closed caves. The results indicated that the relative humidity fluctuation frequency in open caves was proportional to tourist numbers and that the relative humidity of open caves increased rapidly due to rain. Closing the cave could lower the impact of outdoor relative humidity significantly. Visited caves showed much higher monthly maximum relative humidity, monthly mean diurnal range of relative humidity and number of days that daily the maximum relative humidity exceeded 60%, compared with unvisited caves during high season. The changes in relative humidity were reversed when open caves were closed and closed caves were opened. Visitation would lead to higher relative humidity and higher daily fluctuations of relative humidity and thus massively elevate the risk of deterioration of wall paintings. These achievements have provided a scientific basis for preventive management and assessment of risk to the wall paintings.