Evidence for Nearly Complete Decoupling of Very Stable Nocturnal Boundary Layer Overland
- 105 Downloads
Concentrations of 222Rn at 0.1 m and 6.5 m height above ground level and 222Rn flux density were measured during nights characterized by strong cooling, light winds and clear sky conditions in the Carpathian Basin in Hungary. A very stable boundary layer (vSBL) formed on 14 nights between 15 August and 3 September 2009. On 12 nights, an estimated 72% (s.d. 20%) of 222Rn emitted from the surface since sunset was retained within the lowest 6.5 m above the ground until sunrise the following morning. On two nights an intermittent increase in wind speed at 9.4 m height was followed by a rise in temperature at 2.0 m height, indicating a larger atmospheric motion that resulted in 222Rn at 0.1 m around sunrise being the same as around the preceding sunset. It does not seem to be rare in a large continental basin for a vSBL to be nearly completely decoupled from the atmosphere above for the entire period from sunset to sunrise.
KeywordsDecoupling Radon Tracer experiment Very stable nocturnal boundary layer
Unable to display preview. Download preview PDF.
- Beyrich F (1994) Sodar observations of the stable boundary layer height in relation to the nocturnal low-level jet. Meteorol Z 3: 29–34Google Scholar
- Conen F, Neftel A, Schmid M, Lehmann BE (2002) N2O/Rn-222—soil flux calibration in the stable nocturnal surface layer. Geophys Res Lett. doi:10.1029/2001GL013429
- Haszpra L (1998) Atmospheric CO2 record from in situ measurements at K-puszta, Hungary. In: Trends: a compendium of data on global change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, TN, USAGoogle Scholar
- Stull RB (1988) An introduction to boundary layer meteorology. Kluwer, Dordrecht, p 666Google Scholar