Modeling air pressure propagation through Wind Cave and Jewel Cave

Recent speleoclimatological research has shed new light on air pressure dynamics inside barometric caves by identifying pressure-modifying processes and resulting systematic differences between cave and surface air pressure. Based on these new findings, a multi- step quantitative model is developed and explored to predict air pressure inside Wind Cave and Jewel Cave – two major barometric cave systems in the Black Hills of South Dakota, USA – from external surface measurements. Therefore, each identified speleoclimatological pressure process is translated into a mathematical operation. Model evaluation based on Pearson correlation and mean (absolute) deviation between model outputs and control measurements yields good to excellent results: Depending on the location, the presented model predicts 99.2% to 99.7% of measured air pressure inside Wind Cave compared to 90.3% and 99.4% inside Jewel Cave, thus proving that the previously identified and now modeled processes adequately and comprehensively describe the speleoclimatological pressure dynamics inside barometric caves. Slightly weaker model performance is observed at the lower elevator level inside Wind Cave and at Deep Camp inside Jewel Cave due to irregular pressure disturbances caused by elevator operation and unique morphological features in the deeper parts of Jewel Cave, respectively. Comparative spatial analyses of model constants and model accuracies at all investigated locations reveal significant differences in pressure patterns between the caves, thus demonstrating the effect of morphological characteristics on air pressure propagation and resulting modifications. The findings also support earlier research in Wind Cave and Jewel Cave as they provide speleoclimatological background for previously observed differences in airflow dynamics between both caves. Therefore, this study presents an important contribution to understanding the complex speleoclimatology of barometric caves

Airflow dynamics in Wind Cave and Jewel Cave

Recent research on air pressure propagation through barometric caves has revealed various speleoclimatological processes, which cause a more complex relationship between surface air pressure changes and resulting pressure gradients between cave and surface air than previously assumed. So far, however, studies on barometric cave airflow have only been based on surface air pressure measurements. Thus, this study investigates and compares airflow at the openings of Wind Cave and Jewel Cave – two major barometric cave systems in South Dakota, USA – as a response to surface air pressure changes and air pressure gradients. Based on high-resolution long-term air pressure measurements from the surfaces and several locations inside the caves, as well as ultra-sonic airflow measurements at the openings, the analysis proves that for both caves, cave airflow velocity can be predicted more accurately by air pressure gradients than by previous surface air pressure changes. An inter-cave comparison also reveals substantial differences in cave airflow dynamics between Wind Cave and Jewel Cave, with the relevant period of surface air pressure variations for cave airflow velocity and the cave reaction times being significantly longer at Jewel Cave compared to Wind Cave. Therefore, the findings of this study demonstrate the effects of cave morphology on airflow and significantly contribute to a better understanding of the speleoclimatological mechanisms and dynamics of compensating airflow at the openings of barometric caves

The influence of subway climatology on gas dispersion and the effectiveness of guided evacuations in a complex subway station

This paper discusses a strategy that integrates data from tracer gas experiments with results from pedestrian simulation software in the evaluation of different evacuation procedures for subway stations in response to a fire or a terrorist attack with chemical, biological, radiological, nuclear and enhanced conventional weapons (CBRNE). The study demonstrates that by combining the two data sets a greater understanding of the impact of different evacuations routes on an evacuee’s health is gained. It is shown that by controlling the routes pedestrians would use to exit a subway station, the number of fatalities and evacuees with long term health issues can be reduced. It is highlighted that a dynamic evacuation guiding system based on subway climatology would take into account the source of the toxin, the resulting dispersal of gas, smoke, etc. and the subway climatology at the time. In doing so, it would be possible to identify the most endangered areas and guide passengers via an adaptive escape route using audio and visual techniques. Information on the evolution of the emergency situation could also simultaneously be relayed back to the rescue forces to help to plan the rescue and evacuation procedures and optimise the deployment of the search and rescue teams

Reports on ice caves in literature from the twelfth to the middle of the twentieth century

The main goal of this paper is to summarize the history and the progress of ice cave research in the northern hemisphere as an introduction to the following papers about modern research in the U.S. We focus on the earliest descriptions of ice caves starting from the twelfth century, a cave with ice in India, as well as the beginning of modern ice cave research in the nineteenth and twentieth centuries. Moreover, we give a short overview of the different theories about ice caves over the course of time. The article is an introduction to the much younger ice cave research in the U.S., which will be the topic of a second paper in this journal

Temperature sensing in underground facilities by Raman optical frequency domain reflectometry using fiber-optic communication cables

Gaining information on climatic conditions in subway tunnels is the key to predicting the propagation of smoke or toxic gases in these infrastructures in the case of a fire or a terrorist attack. As anemometer measurements are not economically suitable, the employment of alternative monitoring methods is necessary. High-resolution temperature sensing with Raman optical frequency domain reflectometry (OFDR) using optical communication fiber cables shows great potential as it allows the surveillance of several kilometers of underground transport facilities without the need for installing sensing equipment in the tunnels. This paper presents first results of a study using this approach for monitoring subway tunnels. In the Berlin subway, temperature data gathered from newly installed as well as pre-installed communication cables were evaluated and compared to reference data from temperature loggers. Results are very promising as high correlations between all data can be achieved showing the potential of this approach

Talus-and-gorge ice caves in the northeastern United States past to present

The focus of this article is both a region and a type of cave not typically associated with ice caves. Nevertheless, both the region and the type play an important role in American ice-cave research. Talus-and-gorge ice caves in the northeastern United States can be used as climate indicators for a whole region; and therefore, they are the target of this young field of research. Ice caves, in general, are sensitive climatopes that can serve as excellent indicators for short and long term changes in the climate of a region, principally because of shifts between phases of increasing ice growth and melting during a year and over time. This research started with an investigation of known talus-and-gorge ice caves, followed by environmental monitoring of selected caves with perennial ice that were equipped with temperature sensors recorded over four years. This is one of the world’s longest high-resolution climatologic monitoring record of such caves. In addition, the height of the ice was surveyed annually at a time when ice would most likely be at its minimum, the start of November. This allowed for investigation of the annual changes and the influence of the temperature over the previous year. Some predictions for the future of the ice caves and the whole region could be deduced from the data. At the moment, there is no sign of either a renewed increase in the number of talus-and-gorge ice caves or an increase in ice accumulation within the existing ones

Ice cave research of the United States

Natural and anthropogenic ice caves are spread out on the North American continent, especially in the United States. Many of these climate archives are already forgotten, no longer contain ice due to climatic changes, or are expected to lose their ice soon. However, sources from the nineteenth and twentieth centuries suggest the former density of ice caves in this nation. A synopsis of the American ice cave research from its beginnings in the early nineteenth century to the present is the focus of this article. A priori, basic terms and problems of ice cave research are addressed and elucidated. Subsequently, climatic conditions that facilitate or counteract the buildup of cave ice over the course of a year are presented. On the basis of an ice cave classification, different ice cave types are outlined and analyzed in their distribution in the United States. The accompanying map illustrating the geographic locations of caves in the mainland United States represents the first version of an American ice cave distribution

The importance of air temperature as a key parameter to identify climatic processes inside Carlsbad Cavern, New Mexico, USA

The meteorological and climatic conditions in Carlsbad Cavern are very complex. The huge rooms and the large entrance area, in combination with smaller connection tunnels and remote chambers, cause a complexity of different microclimates side by side. As in the case of most others, Carlsbad Cavern is not easy to classify as a barometric or a convective cave system. The objective of this paper is to explain the climate at different positions inside Carlsbad Cavern by evaluating a series of measurements taken during the year 2013. The air temperature will be used as a key parameter for the analysis. We will identify the thermal- or convection-driven influences, as well as some clear barometric effects and underline the importance of air temperature for cave climate research. We will also investigate the influence of the tourist use of the cave, which means the visitors themselves, as well as the elevators, the cafeteria, and the electrical system and lights. Because the analyzed time period includes the time of the government shutdown in 2013, the artificial effects can be identified very easily

Climatologic studies inside Sandy Glacier at Mount Hood Volcano in Oregon, USA

Previous investigations of climatic conditions of glaciers primarily focused on the glacier’s surface or on the moulin as the entrance to the glacier’s interior. Many glaciers, however, contain far-reaching cave systems inside the ice that have been understood and investigated as drainage systems for meltwater. Until now, there have been no comprehensive climate studies inside a glacier cave. Thus, the climatic conditions, as well as their effects on the glacier, are unknown. The first climatologic investigations inside the cave system of Sandy Glacier on Mt. Hood in Oregon (USA) in June 2015 have shown that both thermic activity of the volcanic subsurface and chimney effects between the glacier snout at the base of the glacier and higher opening of the moulin can cause drastic melting inside the glacier. Those processes lead to considerably stronger melting from the inside than observations at the surface suggest and can cause an unexpected collapse over a distance of several hundred meters. We will present and assess the first measuring results of both the thermic and flow conditions inside Sandy Glacier

Climatologic studies inside Sandy Glacier at Mount Hood Volcano in Oregon, USA

Previous investigations of climatic conditions of glaciers primarily focused on the glacier’s surface or on the moulin as the entrance to the glacier’s interior. Many glaciers, however, contain far-reaching cave systems inside the ice that have been understood and investigated as drainage systems for meltwater. Until now, there have been no comprehensive climate studies inside a glacier cave. Thus, the climatic conditions, as well as their effects on the glacier, are unknown. The first climatologic investigations inside the cave system of Sandy Glacier on Mt. Hood in Oregon (USA) in June 2015 have shown that both thermic activity of the volcanic subsurface and chimney effects between the glacier snout at the base of the glacier and higher opening of the moulin can cause drastic melting inside the glacier. Those processes lead to considerably stronger melting from the inside than observations at the surface suggest and can cause an unexpected collapse over a distance of several hundred meters. We will present and assess the first measuring results of both the thermic and flow conditions inside Sandy Glacier