Effect of abnormal weather on the microenvironment of Mogao Cave 285, Dunhuang

Abstract

Cultural heritage is directly affected by the conservation environment, and climate change is already having an impact on the conservation of cultural heritage. The Mogao Caves murals, one of China’s most prestigious cultural heritages, have been affected by extreme rainfall. The aim of this study was therefore to assess the impact of abnormal weather on the microenvironment within the caves and on the preservation of the murals. First, the 30-year meteorological data of the Dunhuang area and the one-year cycle of Cave 285’s monitoring data are collated. The results show that for Cave 285, summer is the most noteworthy period. Then, a heat and moisture transfer model is established, and the accuracy of the model is verified. Finally, the model is used to evaluate the effect of different abnormal weather factors on the hygrothermal environment in the cave. The simulation results indicate that for Cave 285, abnormally high temperatures in summer do not make the situation worse, but both abnormally low temperatures and abnormally high humidity can cause the relative humidity in the cave to exceed safety critical value. In particular, when high humidity persists for a week, the relative humidity inside the cave can exceed 80% and take about 4 days to fall back to a safe value. In such cases, dehumidification measures are recommended.