Modeling air pressure propagation through Wind Cave and Jewel Cave: How can air pressure signals inside barometric caves be predicted from surface pressure measurements?

Abstract

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.