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| Titel |
Boundary layer heights determinate from Raman multiwavelengths lidar and microwave radiometer measurements |
| VerfasserIn |
C. Talianu, D. Nicolae, E. Carstea, L. Belegante |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067648
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| Zusammenfassung |
| Planetary boundary layer (PBL) is the lowest part of the troposphere that is directly
influenced by friction and solar heating from earth’s surface. Accurate determination of the
boundary layer heights is critical in understanding the regional air quality.
Lidar systems have been widely used to examine the structure and variability of the
boundary layer (BL) heights (Brook et al 2000, Talianu et al 2006, Madonna et al, 2011).
This paper aims to develop a method of assessing the PBL heights using Raman
multi-wavelengths lidar – RALI measurements. RALI system has three elastic (1064nm,
532nm, 355nm) and two Raman (607nm, 387nm) channels. This method is based on the
vertical gradient accurate calculation of the ratio between signal collected from
elastic and inelastic channels. From 500m up to 10 km this will give information
about vertical distributions of aerosols layers. We have chosen to use as method
for validation the one described by Stull (Stull 1988) based on virtual potential
temperature. The vertical gradient of the virtual potential temperature gives also
information about the stability of stratification. Temperature, pressure and humidity
profiles provided by the microwave radiometer (collocated with the lidar system) have
been used to determine virtual potential temperature profiles. The PBL heights
calculated from virtual potential temperature have been compared with PBL heights
determinate from lidar data collected before and after sunset measurements, in Magurele
(Longitude: 26.029 E, Latitude: 44.348 N, a.s.l: 93m), near Bucharest, June to August
2011.
Results from lidar data showed the breakdown of the boundary layer after sunset and is
visible on almost every day of measurements. The height of the boundary layer has been
determined and lies between 700 and 800 meters during 2011 summer time. These results
have been similar with the outputs of the virtual potential temperature method and a good
correlation of the two methods has been found. Therefore we validated the method based on
Raman multi-wavelength lidar measurements to calculate PBL heights as a reliable and
useful tool. |
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