Cave Microclimate: A Note on Moisture, 1969, Wigley, T. M.

The moisture budget of a cave atmosphere is examined quantitatively. The results indicate that caves can be divided into two distinct classes depending on whether the cave atmosphere is or is not saturated. A further consequence of the theory is that greater climate fluctuations are to be expected in caves in which unsaturated conditions prevail. This generalisation may have significance in studies of cavern breakdown and in ecological studies in caves.

Lethargy in the cavernicolous Chiroptera in Central Africa., 1976, De Faveaux Michel Anciaux

From his personal research undertaken in the subterranean field (natural and artificial cavities) in Shaba (ex-Katanga, in S.E. Zaire) and Rwanda, the author briefly defines the macroclimate of the prospected regions as well as the microclimate of the subterranean habitat (humidity and temperature). A reversible hypothermia has been noticed in the dry season only (from May till August) in eleven species of troglophile Chiroptera belonging to the following families: Rhinolophidae (7 species of Rhinolophus), Hipposideridae (only Hipposideros ruber) and Vespertilionidae (Miniopterus inflatus rufus, Miniopterus schreibersi arenarius & M.s. natalensis, Myotis tricolor). No sign of lethargy has been noticed in the Megachiroptera (Lissonycteris angolensis, Rousettus aegyptiacus leachi), Emballonuridae (Taphozous perforatus sudani), Hipposideridae (Cloeotis percivali australis) or Nycteridae (3 species of Nycteris). There could be correlations between lethargy and breeding if one takes into account the phenomena of late ovulation and delayed implantation. The entry into lethargy is not caused by the scarcity of food. It does not concern all the individuals of a colony or in various populations of a cave. The degree of humidity appears to be more important than the temperature as far as the conditions for hibernation are concerned.

On the meso- and microclimate of Kle?nica Valley in the vicinity of the Bear-Cave (Jaskinia Nied?wiedzia, in the ?nie?nik K?odzki massif). [in Polish], 1978, Kwiatkowski Jan, Stopka Ryszard, Szczepa?ska Zofia

Eco-ethological and parasitological data on the cavernicolous Chiroptera in Shaba (Zaire)., 1978, De Faveaux Michel Anciaux

After a brief analysis of the elements of the cavernicolous microclimate in Shaba, the author emphasizes the possibility of relations between ecology and parasitism. He then reviews the 9 species of Chiroptera that live in the subterranean field in Shaba, pointing out their environmental habitat. behaviour and parasites.

Changes in microclimatic conditions in ,,Nied?wiedzia'' Cave in 1988-1978. [in Polish], 1980, Kwiatkowski, Jan

Measurement of Small Changes in Pressure of Cave Air Using an Air Barometer, 1988, Halbert, Erik

This paper describes an extremely simple form of barometer which is capable of measuring changes in air pressure of less than five pascals. The principle of operation, construction and use are described and examples are given of its use both inside and outside the cave environment.

The Influence of Seasonal Changes of Cave Microclimate Upon the Genesis of Gypsum Formations in Caves, 1990, Maltsev, Vladimir A.

RECOGNITION OF MICROCLIMATE ZONES THROUGH RADON MAPPING, LECHUGUILLA CAVE, CARLSBAD-CAVERNS-NATIONAL-PARK, NEW-MEXICO, 1991, Cunningham Ki, Larock Ej,

Radon concentrations range from < 185 to 3,515 Bq m-3 throughout Lechuguilla Cave, Carlsbad Caverns National Park, New Mexico. Concentrations in the entrance passages and areas immediately adjacent to these passages are controlled by outside air temperature and barometric pressure, similar to other Type 2 caves. Most of the cave is developed in three geographic branches beneath the entrance passages; these areas maintain Rn levels independent of surface effects, an indication that Rn levels in deep, complex caves or mines cannot be simply estimated by outside atmospheric parameters. These deeper, more isolated areas are subject to convective ventilation driven by temperature differences along the 477-m vertical extent of the cave. Radon concentrations are used to delineate six microclimate zones (air circulation cells) throughout the cave in conjunction with observed airflow data. Suspected surface connections contribute fresh air to remote cave areas demonstrated by anomalous Rn lows surrounded by higher values, the presence of mammalian skeletal remains, CO2 concentrations and temperatures lower than the cave mean, and associated surficial karst features

Food Preparation Activities and the Microclimate within Mammoth Cave Kentucky, 1994, Trapasso L. Michael, Kaletsky Kelly

An Investigation of the Climate, Carbon Dioxide and Dust in Jenolan Caves, N.S.W., PhD Thesis, 1997, Michie, Neville

Pressure of use of Jenolan Caves as a tourist spectacle has raised concerns about the wellbeing of the caves, so three related physical subjects were reviewed and investigated; the cave microclimate, the carbon dioxide in the cave atmosphere and dustfall in the caves. The microclimate has been shown to be dominated by several physical processes: in the absence of air movement, conduction and radiation dominate; in association with air movement, convective coupled heat and mass transfer tends to dominate energy flows. A new approach using boundary conditions and qualitative characteristics of transient fronts enables accurate measurement and analysis of energy, heat and mass transfer. This technique avoids the dimensionless number and transfer coefficient methods and is not geometrically sensitive. Conditions in caves are also determined by the capillary processes of water in cave walls. Air movement in caves depends on surface weather conditions and special problems of surface weather observation arise. A series of experiments were undertaken to evaluate the cave and surface processes. The physical processes that collect, transport and release dust were measured and described. Dust in the caves was shown to be carried from the surface, mainly by visitors. The concept of the Personal Dust Ooud is developed and experimental measurements and analysis show that this process is a major threat to the caves. New techniques of measurement are described. An accurate physiological model has been developed which predicts most of the carbon dioxide measured in Jenolan Caves, derived mainly from visitors on the cave tours. This model, developed from previously published human physiological information also predicts the production of heat and water vapour by cave tourists. The effects of carbon dioxide on cave conditions has been investigated. Details of a two year program of measurements in the caves are given. The generalised approach and methods are applicable to other caves, mines and buildings.

The climate of the Marble Arch Caves, County Fermanagh, Northern Ireland, BSc thesis (Geography) , 1997, Perrin, D.

The Marble Arch cave is a high energy cave located in County Fermanagh, Northern Ireland. The first 500 metres of the system has been opened as a Showcave for approximately 13 years and has been visited by over half a million visitors since opening. Microclimatic investigations over a six month sampling period (31.7.96-10.1.97) found that the cave has a variable microclimate in response to, the surface climate, the caves hydrology and influences within the Showcave.
High positive correlation coefficient's were attained between the cave and surface air temperature. As distance increased into the cave correlation coefficients' decreased indicating a time lag. Air temperatures varied on both a temporal and spatial scale. Summer air temperature ranges of 2.1 °C were noted between sites within the cave, which increased to 7.1 °C during the winter season. The cave air temperature changed progressively from the entrance to the interior, decreasing in the summer and increasing in the winter months. During the summer months the mean surface air temperature (17.4°C) was greater than the cave mean air temperature (10.8°C). In the winter months the mean surface air temperature (1.9°C) was less than the cave mean air temperature (7.2°C). Site variability was generally greater during the summer months indicated by higher Coefficient of Variations.
The 'chimney effect' is noticeable in some parts of the cave as a result of surface and cave air temperature differences. Airflow within the cave changed direction in response to seasonal air temperature variations, flowing out of the cave during summer months and into the cave in the winter. Other processes such as the 'Entrainment Effect' were also evident. Airflow throughout the cave was generally weak, although in some parts of the cave was noticeable as a 'wind'.
The main river flowing through the cave was responsive to the seasonal cave air temperatures. During the summer months the water temperature once entering the cave decreases by approximately 2°C and increases by up to 7°C during the winter months. A relatively constant seasonal water temperature is maintained whilst travelling through the cave.
The largest air temperature variations occurred within the Showcave in which the presence of tourists and electrical lighting are believed to be partially responsible, the latter of which being the greater contributor. Results show that a tour of 18 people on average increased the surrounding air temperature by up to 1.3°C. The effect was reduced when a tour was moving past a point rather than remaining stationary in the same place.
Electronic lighting increased the overall air temperature throughout the Showcave. Each type of light used within the Showcave influenced the air temperature up to a metre away from the light source. Air temperature increases around the lighting was a result of the type of light used rather than the bulb wattage installed. In some cases the air temperature remained 2°C higher than the mean cave air temperature 1 metre away from the light source.

The Problem of Condensation in Karst Studies, 1998, Dublyansky, V. N.

Condensation in karst occurs over a wide range of natural settings, at latitudes from 25º to 70º and altitudes from sea level to 2600 m. In summer (April through September), condensation introduces a significant amount of water into the karst massifs (from 0.1% to as much as 20% of the total dry-season runoff). Contrary to common belief, in winter evaporation does not withdraw appreciable amounts of water from the massifs. Evaporating at depth, the water condenses near the surface within the epikarstic zone or on the snow cover and flows back. Condensation can sustain springs during prolonged dry periods (such as summer and winter) when there is no recharge by liquid precipitation. Condensation can play a significant role in speleogenesis, and many forms of cave macro-, meso-, and micromorphologies are attributable to condensation corrosion. It can be particularly efficient in the latter stages of hydrothermal cave development (during partial dewatering) when the temperature and the humidity gradients are highest. Coupled with evaporation, air convection, and aerosol mass transfer, condensation can play a crucial role in the formation of a number of speleothems, as well as create peculiar patterns of cave microclimate.

Microclimatic characterization of a karstic cave: human impact on microenvironmental parameters of a prehistoric rock art cave (Candamo Cave, northern Spain), 1998, Hoyos M. , Soler V. , Averas J. C. , Nchezmoral S. , Sanzrubio E. ,

Geoecological system of karst , 1998, Bá, Rá, Nykevei Ilona

The paper presents some results of the karst geo-ecological system research. The first sphere of the karst-ecological system is the karst microclimate in accordance with the microclimatic factors. Macroclimate is responsible for the quantity and intensity of precipitation while microclimatic effects modify the quantity of water infiltrating to the rocks. Microclimate affects the development of vegetation, soil temperature and humidity. Millions of microorganisms live in the soil, changing the components of soil-air through the decomposition of organic materials and through their own metabolism. They also influence the physical and chemical soil properties indirectly. The inner dynamism of soil can prevent extreme changes occurring in the system, it can change, possibly leading to disturbance in the whole system. The changes due to external effects are reversible down to the rock boundary. When they have entered the rock layer, they become irreversible. Water in the rock layer is the transport agent of materials and energy. This water reaches the surface again in karst springs. Another irreversible process, the dripstone degradation can also be due to polluted water.

Microclimate Study of Kartchner Caverns, Arizona, 1999, Buecher, R. H.

A detailed two-year study of the microclimate in Kartchner Caverns determined that the most significant problem in maintaining the microclimate of the cave is the potential for drying out due to increased airflow. Two factors—a small, hypothesized upper second entrance and a slight geothermal warming of the cave—control natural airflow and increase the amount and intensity of winter air exchange. The average amount of water reaching the cave is 7.9 mm/yr, only twice the amount lost by evaporation from cave surfaces. Kartchner Caverns has an average relative humidity (RH) of 99.4%. Useful measurement of RH required a dewpoint soil psychrometer rather than a sling psychrometer. Moisture loss from cave surfaces is proportional to relative humidity, and small changes in RH have a dramatic effect on evaporation from cave surfaces. A lowering of RH to 98.7% would double the evaporation rate and start to dry out the cave. The volume of air exchange in the cave was estimated from direct measurement, changes in CO2 concentration, and temperature profile models. All of these methods are consistent with a volume of 4,000 m³/day entering the cave during the winter. During the summer, the direction of airflow reverses and the volume of air leaving the cave is much smaller than during the winter months. Surface air is almost always drier than cave air—only during the summer months when rain occurs does outside air contain more moisture. However, the rate of air exchange is greatly reduced during the summer, which minimizes any potential effect of increased outside moisture. Radon concentrations in the cave are high enough to be of concern for long-time employees but not for the general public. Radon222 concentrations average 90 pCi/L and radon daughters average 0.77 Working Levels (WL) in the main part of the cave. During the winter, radon levels in the Echo Passage are up to six times higher than the rest of the cave due to the passage’s stable microclimate and limited air movement, which greatly reduces radon removal by plateout. Natural removal by ventilation is only a minor factor in determining radon levels in the rest of the cave.