Investigation of the Planetary Boundary Layer in the Swiss Alps Using Remote Sensing and In Situ Measurements
2014 (English)In: Boundary-layer Meteorology, ISSN 0006-8314, E-ISSN 1573-1472, Vol. 151, no 2, 317-334 p.Article in journal (Refereed) Published
The development of the planetary boundary layer (PBL) has been studied in a complex terrain using various remote sensing and in situ techniques. The high-altitude research station at Jungfraujoch (3,580 m a.s.l.) in the Swiss Alps lies for most of the time in the free troposphere except when it is influenced by the PBL reaching the station, especially during the summer season. A ceilometer and a wind profiler were installed at Kleine Scheidegg, a mountain pass close to Jungfraujoch, located at an altitude of 2,061 m a.s.l. Data from the ceilometer were analyzed using two different algorithms, while the signal-to-noise ratio of the wind profiler was studied to compare the retrieved PBL heights. The retrieved values from the ceilometer and wind profiler agreed well during daytime and cloud-free conditions. The results were additionally compared with the PBL height estimated by the numerical weather prediction model COSMO-2, which showed a clear underestimation of the PBL height for most of the cases but occasionally also a slight overestimation especially around noon, when the PBL showed its maximum extent. Air parcels were transported upwards by slope winds towards Jungfraujoch when the PBL was higher than 2,800 m a.s.l. during cloud-free cases. This was confirmed by the in situ aerosol measurements at Jungfraujoch with a significant increase in particle number concentration, particle light absorption and scattering coefficients when PBL-influenced air masses reached the station in the afternoon hours. The continuous aerosol in situ measurements at Jungfraujoch were clearly influenced by the local PBL development but also by long-range transport phenomena such as Saharan dust or pollution from the south.
Place, publisher, year, edition, pages
2014. Vol. 151, no 2, 317-334 p.
Boundary layer, Ceilometer, Complex topography, In situ measurements, Jungfraujoch, Remote sensing, Switzerland, Wind profiler
Meteorology and Atmospheric Sciences
IdentifiersURN: urn:nbn:se:su:diva-102945DOI: 10.1007/s10546-013-9897-8ISI: 000333334600007OAI: oai:DiVA.org:su-102945DiVA: diva2:715034