Aspects of the convective boundary layer structure over complex terrain

Koßmann, M.; Vögtlin, R.; Corsmeier, U.; Vogel, Bernhard; Fiedler, F.; Binder, H.-J.; Kalthoff, Norbert; Beyrich, Frank

doi:10.1016/s1352-2310(97)00271-9

Cited by 91 publications

(70 citation statements)

References 39 publications

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“…However, there are examples that show very good agreement with a standard PBL description as e.g. described in Stull (1988) (Kossmann et al 1998;Wekker et al 2004;Weigel 2005). The typical diurnal cycle of the PBL is characterized by specific daytime and nighttime profiles of the virtual potential temperature, wind speed, water vapour mixing ratio and aerosol concentration.…”

Section: Introductionmentioning

confidence: 82%

“…The literature describes the convective boundary layer as a PBL that follows the terrain (Wekker et al 2004) or as a layer that is decoupled from the terrain (Kossmann et al 1998). On the other hand, an aerosol layer is nearly uniform in height and generally does not follow the underlying terrain on a scale up to tens of km (Nyeki et al 2000;Wekker 2002).…”

Section: Ceilometer Versus Wind Profiler Pbl Determinationmentioning

confidence: 99%

“…The few available studies are based on highly simplified and idealized parametrizations of mountains, undulating areas or valleys (Stull 1988;Whiteman 2000;Wekker et al 2004;Weigel 2005). However, mountain ranges enable exchange processes, also called handover processes (Kossmann et al 1998), i.e. mixing of PBL air masses into the free troposphere by cloud and mountain venting.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the Planetary Boundary Layer in the Swiss Alps Using Remote Sensing and In Situ Measurements

Ketterer

Zieger

Bukowiecki

et al. 2014

Boundary-Layer Meteorol

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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.

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Section: Introductionmentioning

confidence: 82%

Section: Ceilometer Versus Wind Profiler Pbl Determinationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the Planetary Boundary Layer in the Swiss Alps Using Remote Sensing and In Situ Measurements

Ketterer

Zieger

Bukowiecki

et al. 2014

Boundary-Layer Meteorol

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“…In contrast, precipitation in the COPS region covering low-mountain regions in southwestern Germany/eastern France is due to a complex interaction between large-scale instabilities, modification of mesoscale flow by orography, and thermally induced orographic flow. COPS benefitted from previous campaigns in the region such as TRACT in 1992 (Kossmann et al, 1998), VERTIKATOR in 2002 (Barthlott et al, 2006;Schwitalla et al, 2008), and PRINCE in 2006 (Groenemeijer et al, 2009;Trentmann et al, 2009), which focused mainly on the understanding of surface processes, secondary circulation systems, and initiation of convection. However, the relationship between these processes and QPF had not been studied in detail before it was addressed by COPS.…”

Section: Introductionmentioning

confidence: 99%

The Convective and Orographically‐induced Precipitation Study (COPS): the scientific strategy, the field phase, and research highlights

Wulfmeyer

Behrendt

Kottmeier

et al. 2011

Quart J Royal Meteoro Soc

196

136

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Within the framework of the international field campaign COPS (Convective and Orographically-induced Precipitation Study), a large suite of state-of-the-art meteorological instrumentation was operated, partially combined for the first time. This includes networks of in situ and remote-sensing systems such as the Global Positioning System as well as a synergy of multi-wavelength passive and active remote-sensing instruments such as advanced radar and lidar systems. The COPS field phase was performed from 01 June to 31 August 2007 in a low-mountain area in southwestern Germany/eastern France covering the Vosges mountains, the Rhine valley and the Black Forest mountains. The collected data set covers the entire evolution of convective precipitation events in complex terrain from their initiation, to their development and mature phase until their decay. Eighteen Intensive Observation Periods with 37 operation days and eight additional Special Observation Periods were performed, providing a comprehensive data set covering different forcing conditions. In this article, an overview of the COPS scientific strategy, the field phase, and its first accomplishments is given. Highlights of the campaign are illustrated with several measurement examples. It is demonstrated that COPS research provides new insight into key processes leading to convection initiation and to the modification of precipitation by orography, in the improvement of quantitative precipitation forecasting by the assimilation of new observations, and in the performance of ensembles of convection-permitting models in complex terrain.

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“…South-western Germany and eastern France, meaning the upper Rhine valley, enclosed by the Black Forest and Vosges mountains, is well known as a favourable area for the triggering of convection (Bertram et al, 2004;Barthlott et al, 2006;Meißner et al, 2007;Groenemeijer et al, 2009). Additionally, considerable information about the spatial distribution of the energy balance (Kalthoff et al, 1999) as well as about the spatial and temporal variability of the CBL height is available (Kalthoff et al, , 2000Koßmann et al, 1998). Therefore, this region was chosen in summer 2007 to perform the field campaign 'Convective and Orographically-induced Precipitation Study' (COPS: Wulfmeyer et al, 2008) within the framework of the priority programme 'Quantitative Precipitation Forecast' of the German Research Foundation.…”

Section: Introductionmentioning

confidence: 99%

The dependence of convection‐related parameters on surface and boundary‐layer conditions over complex terrain

Kalthoff

Köhler

Barthlott

et al. 2010

Quart J Royal Meteoro Soc

Self Cite

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The field campaign 'Convective and Orographically-induced Precipitation Study' (COPS) was performed in south-western Germany and eastern France in summer 2007. Within the COPS context this study focused on the process chain of soil moisture, surface fluxes, conditions of the convective boundary layer (CBL), and convection-related parameters.The results were different for valley and mountain sites. Only in the Rhine valley did the ratios of sensible and latent heat to the net radiation at the surface, H 0 /Q 0 and E 0 /Q 0 respectively, reveal a weak dependence on soil moisture. H 0 /Q 0 was lower and E 0 /Q 0 was higher at higher soil moisture. The correlation of the diurnal increase of the equivalent potential temperature, e , with the energy supplied by H 0 and E 0 was found to be lower for higher surface inhomogeneity. Furthermore, only a weak dependence of the CBL depth on the sensible surface heat flux was found for valley sites and was non-existent for the mountain crest.The convective indices in the whole COPS domain were found to depend on e in the CBL. The absolute values of conditional and potential instability are not necessarily the decisive parameters for convection to occur, because highest instability was observed in the Rhine valley while convection was preferably initiated over the mountains. Convective inhibition (CIN) was positively correlated with the capping strength and negatively with the CBL height: the higher the CBL, the lower the upper threshold of CIN. The frequency of low CIN was higher in the Black Forest mountains than in the Rhine valley, which facilitates convection initiation over the mountain sites.

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Aspects of the convective boundary layer structure over complex terrain

Cited by 91 publications

References 39 publications

Investigation of the Planetary Boundary Layer in the Swiss Alps Using Remote Sensing and In Situ Measurements

Investigation of the Planetary Boundary Layer in the Swiss Alps Using Remote Sensing and In Situ Measurements

The Convective and Orographically‐induced Precipitation Study (COPS): the scientific strategy, the field phase, and research highlights

The dependence of convection‐related parameters on surface and boundary‐layer conditions over complex terrain

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