Hongtao Zhan's research while affiliated with Chinese Academy Of Cultural Heritage and other places

Publications (19)

Article
Monitoring experiments of soil air in column show that relative humidity (RH) of air in the soil of the Loess Plateau fluctuates with atmospheric pressure (AP), which is barometric pumping resulting in the vertical movement of soil air and the change of its RH. When AP increases, soil air is compressed and atmospheric air enters the soil, causing R...
Article
Full-text available
Dust storms bring a large quantity of dust aerosols from arid and semi-arid regions of the Earth. However, real-time dust concentration data for dust storms in arid regions, important for wind erosion studies, are still limited. Here, temporal variation of airborne dust concentrations in the Mogao Grottoes, Northwest China, during the monitoring pe...
Article
The dynamic process of dust emission from gobi is a largely un-solved scientific question while it is essential for minimizing the dust hazards. In this study, field wind tunnel experiments have been performed to reveal the processes of dust emission from gobi on the top of the Mogao Grottoes. We found that the dust content of gobi is the dominant...
Article
In extremely arid regions, deeply‐buried phreatic water evaporates during the daytime from March to November in the northern hemisphere. It has been found that the earth‐air undergoes ‘autonomous breathing’ and ‘passive breathing’, respectively caused by the changes of temperature and atmospheric pressure. In this paper, the effects of these breath...
Article
Full-text available
The variable climatic and environmental conditions associated with dryland regions can cause rapid erosion to both natural and man‐made earthen structures. Whilst there is a long history of research into the evolution of erosional landforms such as yardangs, little research has investigated how dryland processes influence the erosion of built struc...
Article
Full-text available
The mirage is a unique optical phenomenon in the desert. This paper investigates the mechanism by which they form. Optical experiments in the Gobi show that the refractive index decreases about 20 to 40cm above the ground causing a total reflection of ground surface light. Thus, ground light cannot get through and a ‘water surface’ mirage is formed—...
Article
Full-text available
The term earth-air refers to the air inside the vadose zone. The observation of earth-air was called hou-qi, which was used to enact meter calendar in ancient China. Currently, however, as a detailed knowledge of hou-qi has been lost for a long time, it has been denounced as a pseudoscience, as earth-air is not scientifically and systematically mon...
Poster
Full-text available
Ruins of Ancient Suoyang City located in western Hexi Corridor and were an important strategic site on ancient Silk Road, added to UNESCO's list of World Cultural Heritages in 2014. The border town were built in Han Dynasty (202BC-220AD) and prospered in Tang Dynasty (618-907). Along with close of Jiayuguan Pass of the Ming Dynasty Great Wall in 15...
Article
Full-text available
Water scarcity is the primary cause of land deterioration, so finding new available water resources is crucial to ecological restoration. We investigated a hyper-arid Gobi location in the Dunhuang Mogao Grottoes in this work wherein the burial depth of phreatic water is over 200 m. An air-conditioner was used in a closed greenhouse to condense and...
Article
Past research has shown that evaporation of deeply buried phreatic water occurs in extra-arid areas where the soil surface is very dry. A dry surface layer can suppress the evaporation of capillary water, but it is not clear whether it suppresses deeply buried phreatic evaporation (PE). We deduced that the PE could be suppressed by a dry surface so...
Article
Full-text available
The aim of this paper is to study the influence of atmospheric humidity and temperature on the mural paintings in the Mogao Grottoes of Dunhuang by measuring the weight of a simulated mural block. Under open conditions, the daily changes in the atmospheric humidity and temperature have an apparent effect on the water content of these murals. There...
Article
Full-text available
The Dunhuang Mogao Grottoes in China was designated as a world heritage site by UNESCO in 1987 and is famous for its cultural relics. Water is the most active factor that harms the relics in the caves as it damages the grotto murals and painted sculptures. Thus, determining the water sources and driving forces of water movement is a key issue for p...
Article
Full-text available
The aeolian processes of erosion, transport and deposition are threatening the Mogao Grottoes, a world culture heritage site. A field wind tunnel experiment was conducted atop the Mogao Grottoes using weighing sensors to quantify aeolian processes over protective gravel beds. Results reveal that aeolian erosion and deposition over gravel beds are b...
Article
A survey found that sand wedges are widely distributed in the extremely extra-arid Gobi region of Dunhuang, China. The sand wedges are still developing. Well-developed sand wedges are surrounded by polygonal areas showing fractal structures. The depth of a well-developed sand wedge is 50–60 cm and its maximum width is 50–60 cm, so the depth/width r...
Article
Full-text available
There is always a relatively high moisture content in the shallow soil layer in Gobi area on the top of the Mogao Grottoes in the extremely dry zone. This paper gives out a new judgement on soil water source through field experiments using the isolated water method, simulated rainfall method and greenhouse method. Under the condition of typical hyp...

Citations

... Field wind-tunnel tests are a valuable tool to close data gaps and gain information about local dust entrainment and flux, particularly in remote areas. They have been increasingly applied for various research aims such as dust emissions due to anthropogenic activity [20], investigation of fine dust development from desert regions [21], wind erosion related to specific crops [22] and the diffusion of salt particles from a dry lake site [23]. ...
... The Loess Plateau is a semi-arid region with a thick coverage of loess (100-200 m), limited by the amount of precipitation, and the ecological environment is relatively fragile (Li et al., 2021c). There is serious soil erosion Wen and Zhen, 2020) and the soil layer frequently dries out . ...
... In this case, probabilistic hazard modelling for strong winds has also been tackled by past research [63][64][65], but only a few studies have addressed the behaviour and vulnerability of built heritage to this type of hazard [66][67][68][69]. Given the damaging effects of strong winds to cultural heritage [70][71][72], further research is needed to expand existing knowledge to other types of vulnerable heritage structures and/or involving other wind-related heritage-damaging phenomena [73]. Likewise, limited research has also addressed the development of risk assessment methods for cultural heritage subjected to freeze-thaw cycles [74,75], despite the existing research analysing the damage they can cause to different materials (e.g. ...
... Furthermore, the latest research findings of the present author proved the 'autonomous breathing' on daily and yearly timescales because of the earth's motion and periodic fluctuations in the temperature of the soil (Li 2018). Therefore, earth-air breathing is a universal phenomenon that occurs globally (Li and Zhan 2018). The movement of earth-air has a significant impact on evaporation, which increases the phreatic evaporation by three orders of magnitude (Li et al. 2021). ...
... When the air pressure reached to a certain threshold, the membrane that seals the pipe would break open. Thus, when the seasons changed, the membranes break according to their burial depth and this could be used to enact a calendar (Wang, 2016) However, the hou-qi is regarded as pseudoscience in the Science and Civilization in China (Needham, 1962), and current scholars believe that hou-qi is the biggest hoax in the history of Chinese science and technology for two thousand years (Li et al., 2017;Li and Zhan, 2018;Li et al., 2021). ...
... However, monitoring carried out in the Gobi soil suggested that RH and AH in the soil changed with temperature rather than AP (Li et al., 2014). Our explanation is that the soil has a very strong water absorption/ release function and can control the RH and AH of earth-air in the vertical fluctuation in time (Li, 2018;Li et al., 2016). So, even if there is earth-air movement in soil, the variations of RH and AH cannot be detected (Li, Zhan, et al., 2021). ...
... The occurrence and development of mural salt damage is a slow and cumulative process, which is highly susceptible to activation due to environmental changes [19,20] . Rainfall leads to increasing and highly uctuating humidity in caves, and high humidity provides su cient moisture for the deliquescence of soluble salts [15] , while humidity uctuations cause repeated deliquescence-recrystallization or deliquescence-hydration changes of labile salts, which triggers salt diseases on murals in turn [5] . ...
... Previous studies indicated that water is one of the main causes of weathering to the grottoes and the phenomena such as swelling, disintegration and softening occurred after the water penetrated and interacted with the rock, resulting in the reduction of stability. The various forms of occurrence and special action of slight seepage produced a cyclical effect to the Grotto rock mass, and turned to be a dominant factor, accelerating the deterioration and weathering destruction of rock mass [7][8][9][10][11]. The existence of fracture network usually functions as an underground water flow path, thus posing a serious threat to safety of grotto relics. ...
... It is a regional name of desert pavement in Asia and mainly distributed in areas that experience strong winds in northwest China and Mongolia (Livingstone & Warren, 1996;Feng et al., 2014). Gobi is a major source area for dust storms in northern China (Wang et al., 2004Zhang et al., 2017), and the intense sediment flux causes serious damage, such as impeding traffic (Cheng et al., 2015;Huang et al., 2019), damaging electrical power system (Zhao et al., 2013), and burying cultural relics (Qu et al., 1997;Zhang et al., 2014). ...
... Sand wedges are special sedimentary structures in extreme cold windy environments of periglacial regions (Murton 2013). They are unique arid landmarks and have important value in the palaeoclimatic reconstruction and research on polygon structures on other planets (Fábián et al. 2014;Li et al. 2014). Sand wedges are V-shaped cracks in the ground filled with primary debris, especially sand, that extend downwards into the ground to a maximum of several metres. ...