RT Journal Article
T1 Impacts of afternoon and evening sea-breeze fronts on local turbulence, and on CO2 and radon-222 transport
A1 Arrillaga Mitxelena, Jon Ander
A1 Vilà-Guerau de Arellano, Jordi
A1 Bosveld, Fred
A1 Klein Baltink, Henk
A1 Yagüe Anguis, Carlos
A1 Sastre Marugán, Mariano
A1 Román-Cascón, Carlos
AB We investigated sharp disruptions of local turbulence and scalar transport due to the arrival of sea-breeze fronts (SBFs). To this end, we employed a comprehensive 10-year observational database from the Cabauw Experimental Site for Atmospheric Research (CESAR, the Netherlands). Sea-breeze (SB) days were selected using a five-filter algorithm, which accounts for large-scale conditions and a clear mesoscale-frontal signal associated with the land-sea contrast. Among those days (102 in all, 8.3%), based on the value of the sensible-heat flux at the onset of SB, we identified three atmospheric boundary-layer (ABL) regimes: convective, transition and stable. In the convective regime, the thermally driven convective boundary layer is only slightly altered by a small enhancement of the shear when the SBF arrives. Regarding the transition regime, we found that the ABL afternoon transition is accelerated. This was quantified by estimating the contributions of shear and buoyancy to the turbulent kinetic energy. Other relevant disruptions are the sharp reduction in ABL depth (similar to 250 m/hr) and the sudden increase in average wind speed (> 2 m/s). In the stable regime, the arrival of the SB leads to disturbances in the wind profile at the surface layer. We observed a deviation of more than 1 m/s in the observed surface-layer wind profile compared with the profile calculated using Monin-Obukhov Similarity Theory (MOST). Our findings furthermore reveal the determinant role of the SB direction in the transport of water vapour, CO2 and Rn-222. The return of continental air masses driven by the SB circulation generates sharp CO2 increases (up to 14 ppm in half an hour) in a few SB events. We suggest that the variability in Rn-222 evolution may also be influenced by other non-local processes such as the large-scale footprint from more remote sources.
PB Wiley
SN 0035-9009
YR 2018
FD 2018-08-06
LK https://hdl.handle.net/20.500.14352/12276
UL https://hdl.handle.net/20.500.14352/12276
LA eng
NO ©2018 WileyThis project was funded by the Spanish government project CGL2015-65627-C3-3-R (MINECO/FEDER). Jon A. Arrillaga is supported by the Predoctoral Training Program for Non-Doctorate Researchers of the Department of Education of the Basque government (PRE_2016_2_0160, MOD = B). The first author developed part of the research during a visit to Wageningen University, supported by a EGONLABUR mobility grant from the Basque government (EP_2016_1_0048). We thank the Royal Netherlands Meteorological Institute (KNMI) for the meteorological data from Cabauw. We are also grateful to the Energy Research Centre of the Netherlands (ECN) for the CO2 and 222Rn data and we also thank OSI-SAF for the satellite full-resolution Metop data provided.
NO Ministerio de Economía y Competitividad (MINECO)/FEDER
NO Department of Education of the Basque government
NO Basque government
DS Docta Complutense
RD 9 abr 2025