Air circulation and its impact on microclimatic variables in the Císařská Cave (Moravian Karst, Czech Republic)

FAIMON, Jiří, Dana TROPPOVÁ, Vít BALDÍK and Roman NOVOTNÝ. Air circulation and its impact on microclimatic variables in the Císařská Cave (Moravian Karst, Czech Republic). International Journal of Climatology. Chichester: John Wiley & Sons, 2012, vol. 32, No 4, p. 599-623. ISSN 0899-8418. Available from: https://dx.doi.org/10.1002/joc.2298.

Basic information

• Original name: Air circulation and its impact on microclimatic variables in the Císařská Cave (Moravian Karst, Czech Republic)
• Name in Czech: Air circulation and its impact on microclimatic variables in the Císařská Cave (Moravian Karst, Czech Republic)
• Authors: FAIMON, Jiří (203 Czech Republic, guarantor), Dana TROPPOVÁ (203 Czech Republic, belonging to the institution), Vít BALDÍK (203 Czech Republic, belonging to the institution) and Roman NOVOTNÝ (203 Czech Republic, belonging to the institution).
• Edition: International Journal of Climatology, Chichester, John Wiley & Sons, 2012, 0899-8418.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: Geochemistry
• Country of publisher: United States of America
• Confidentiality degree: is not subject to a state or trade secret
• Impact factor: Impact factor: 2.886
• RIV identification code: RIV/00216224:14310/12:00057194
• Organization unit: Faculty of Science
• Doi: http://dx.doi.org/10.1002/joc.2298
• UT WoS: 000301494600010
• Keywords (in Czech): airflow; cave; CO2; humidity; oscillations; temperature; ventilation mode; ventilation period
• Keywords in English: airflow; cave; CO2; humidity; oscillations; temperature; ventilation mode; ventilation period
• Tags: AKR, rivok
• Tags: International impact, Reviewed

Abstract

Airflows and their impact on microclimatic parameters were studied in the two entranced Císařská Cave (Moravian Karst, Czech Republic). Basing on the airflow direction with respect to the upper entrance (UE) and lower entrance (LE), three ventilation modes were distinguished: upward airflow one (UAF mode), downward airflow one (DAF mode), and transitional mode. A switching between the UAF and DAF happens in the transitional mode, in the range of external temperatures from 9.5 to 11.1 C. Basing on the extent of cave ventilation, a period of active ventilation and period of stagnant ventilation were recognised. The cave air is intensively exchanged with external airs during the active ventilation period when the cave persists in either the DAF or UAF mode. During the stagnant ventilation period, the single airflow modes switch during diurnal cycle and only cave entering passages are vented (impacted). The airflows were found to depend (i) linearly on the differences in cave-outdoor air densities, (ii) nonlinearly on the external temperature, and (iii) both linearly (LE) and non-linearly (UE) on the temperature gradient. Majority of the airflows showed high frequency oscillations with the period from tens of seconds to minutes and with the amplitude up to 0.1 m3/s. Different airflow spectra were found at the individual entrances. The highest spectral densities were registered at low driving forces. The air circulation changed the pattern of temperature distribution depending on the ventilation mode and ventilation period. The cave relaxation length varied in the extreme range from 1 to 69.6 m. The asymptotic temperature and asymptotic specific humidity varied from 7.5 to 11.8 C, and from 5.47 to 7.15 kg/kg, respectively. The impact of airflows on the cave CO2 levels is discussed based on a dynamic model.

Abstract (in Czech)

Airflows and their impact on microclimatic parameters were studied in the two entranced Císařská Cave (Moravian Karst, Czech Republic). Basing on the airflow direction with respect to the upper entrance (UE) and lower entrance (LE), three ventilation modes were distinguished: upward airflow one (UAF mode), downward airflow one (DAF mode), and transitional mode. A switching between the UAF and DAF happens in the transitional mode, in the range of external temperatures from 9.5 to 11.1 C. Basing on the extent of cave ventilation, a period of active ventilation and period of stagnant ventilation were recognised. The cave air is intensively exchanged with external airs during the active ventilation period when the cave persists in either the DAF or UAF mode. During the stagnant ventilation period, the single airflow modes switch during diurnal cycle and only cave entering passages are vented (impacted). The airflows were found to depend (i) linearly on the differences in cave-outdoor air densities, (ii) nonlinearly on the external temperature, and (iii) both linearly (LE) and non-linearly (UE) on the temperature gradient. Majority of the airflows showed high frequency oscillations with the period from tens of seconds to minutes and with the amplitude up to 0.1 m3/s. Different airflow spectra were found at the individual entrances. The highest spectral densities were registered at low driving forces. The air circulation changed the pattern of temperature distribution depending on the ventilation mode and ventilation period. The cave relaxation length varied in the extreme range from 1 to 69.6 m. The asymptotic temperature and asymptotic specific humidity varied from 7.5 to 11.8 C, and from 5.47 to 7.15 kg/kg, respectively. The impact of airflows on the cave CO2 levels is discussed based on a dynamic model.

Links

• GA205/03/1128, research and development project: Name: Recentní krasové procesy: destrukce speleotém

Investor: Czech Science Foundation, Recent karst processes: speleothem destruction

• MSM 143100004, plan (intention): Name: Geologické procesy a jejich environmentální vyústění - styk variscid a alpid

Investor: Ministry of Education, Youth and Sports of the CR, Geological Processes and their Environmental Impact - Contact of the Variscides and Alpides

• MSM0021622412, plan (intention): Name: Interakce mezi chemickými látkami, prostředím a biologickými systémy a jejich důsledky na globální, regionální a lokální úrovni (INCHEMBIOL) (Acronym: INCHEMBIOL)

Investor: Ministry of Education, Youth and Sports of the CR, Interactions among the chemicals, environment and biological systems and their consequences on the global, regional and local scales (INCHEMBIOL)