Thermally Driven Flows at an Asymmetric Valley Exit: Observations and Model Studies at the Lech Valley Exit

Spengler, Thomas; Schween, Jan H.; Ablinger, Markus; Zängl, Günther; Egger, Joseph

doi:10.1175/2009mwr2779.1

Cited by 5 publications

(2 citation statements)

References 31 publications

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“…Egger et al, 2002Egger et al, , 2005Spengler et al, 2009;Reuder et al, 2011). With the availability of reasonably priced and sized autopilot systems, a considerable number of fixed and rotary-wing airframes of different size, endurance and complexity have found their way into atmospheric research during the last decade (e.g.…”

Section: Introductionmentioning

confidence: 99%

Exploring the potential of the RPA system SUMO for multipurpose boundary-layer missions during the BLLAST campaign

et al. 2016

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Abstract. In June and July 2011 the RPAS (Remotely Piloted Aircraft System) SUMO (Small Unmanned Meteorological Observer) performed a total number of 299 scientific flights during the BLLAST (Boundary Layer Late Afternoon and Sunset Turbulence) campaign in southern France. Three different types of missions were performed: vertical profiling of the mean meteorological parameters (temperature, humidity and wind), horizontal surveys of the surface temperature and horizontal transects for the estimation of turbulence. The manuscript provides an introduction to the corresponding SUMO operations, including regulatory issues and the coordination of manned and unmanned airborne operations for boundary-layer research that have been pioneered during the BLLAST campaign.The main purpose of the SUMO flight strategy was atmospheric profiling at high temporal resolution. A total of 168 profile flights were performed during the campaign with typically more than 10 flights per Intensive Observational Period (IOP) day. The collected data allow for a detailed study of boundary-layer structure and dynamics and will be used for further analysis, e.g. the determination of profiles of sensible and latent heat fluxes. First, tests of a corresponding method have shown very promising results and have provided surface-flux values in close agreement with those from ground-based eddy-covariance measurements. In addition, 74 horizontal surveys of the IR emission of the surface were performed at altitudes of around 65 m. Each of those surveys covers a typical area of around 1 km 2 and allows for an estimation of the surface-temperature variability, important information for the assessment of the heterogeneity of the surface forcing as a function of soil and vegetation properties. The comparison with other surface-temperature measurements shows that the raw data of the airborne and ground observations can differ considerably, but that even a very simple multiple regression method can reduce those differences to a large degree. Finally, 49 flight missions for the measurement of velocity variance have been realized during the BLLAST campaign. For that, SUMO has been equipped with a 5-hole probe (5HP) sensor for the determination of the flow vector at 100 Hz. In particular, for this application there is still need for further improvement, both with respect to the aircraft and sensor hard-and software, and the algorithms and methods for data analysis and interpretation. Nevertheless, the SUMO operations during the BLLAST campaign have shown the vast potential of small and lightweight RPA systems with low infrastructural demand for atmospheric boundary-layer research.

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Section: Introductionmentioning

confidence: 99%

Exploring the potential of the RPA system SUMO for multipurpose boundary-layer missions during the BLLAST campaign

et al. 2016

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“…Starting with the pioneering work of Konrad et al (1970) in the 1970s, boundary-layer researchers began to use remotely controlled aircraft for atmospheric measurements (e.g. Egger et al, 2002Egger et al, , 2005Spengler et al, 2009;Reuder et al, 2011). With the availability of reasonably priced and sized autopilot systems, a considerable number of fixed and rotary-wing airframes of different size, endurance and complexity have found their way into atmospheric research during the last decade (e.g.…”

Section: Introductionmentioning

confidence: 99%

Exploring the potential of the RPA system SUMO for multi-purpose boundary layer missions during the BLLAST campaign

Reuder¹,

Båserud²,

Jonassen³

et al. 2016

Preprint

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Abstract. In June and July 2011 the RPA system SUMO performed a total number of 299 scientific ﬂights during the BLLAST campaign in Southern France. Three different types of missions have been performed, vertical proﬁling of the mean meteorological parameters temperature, humidity and wind, horizontal surveys of the surface temperature and horizontal transects for the estimation of turbulence. The manuscript provides an introduction to the corresponding SUMO operations, including regulatory issues, and the coordination of manned and unmanned airborne operations for boundary layer research that have been pioneered during the BLLAST campaign. The main purpose of the SUMO ﬂight strategy was atmospheric proﬁling in high temporal resolution. A total of 168 proﬁle ﬂights have been performed during the campaign with typically more than 10 ﬂights per Intensive Observational Period (IOP) day. The collected data allow for a detailed study of boundary layer structure and dynamics and will in the future also be used for further analysis, e.g. the determination of proﬁles of sensible and latent heat ﬂuxes. First tests of a corresponding method have shown very promising results and have provided surface ﬂux values in close agreement with those from ground based eddy-covariance measurements. In addition 74 horizontal surveys of the IR emission of the surface have been performed at altitudes of around 65 m. Each of those surveys covers typically an area of around 1 km and allows for an estimation of the surface temperature variability, an important information for the assessment of the heterogeneity of the surface forcing as function of soil and vegetation properties. The comparison with other surface temperature measurements shows that the raw data of the airborne and ground observations can differ considerably, but that even a very simple multiple regression method can reduce those differences to a large degree. Finally also 49 ﬂight missions for the measurement of velocity variance have been realized during the BLLAST campaign. For that SUMO has been equipped with a 5 hole probe (5HP) sensor for the determination of the ﬂow vector with 100 Hz. In particular for this application there is still need for further improvement, both with respect to the aircraft and sensor hard- and software, and the algorithms and methods for data analysis and interpretation. Nevertheless have the SUMO operations during the BLLAST campaign shown the vast potential of small and light-weight RPA systems with low infrastructural demand for atmospheric boundary layer research.

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Diurnal Mountain Wind Systems

Zardi

Whiteman

2012

Springer Atmospheric Sciences

195

186

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Thermally Driven Flows at an Asymmetric Valley Exit: Observations and Model Studies at the Lech Valley Exit

Cited by 5 publications

References 31 publications

Exploring the potential of the RPA system SUMO for multipurpose boundary-layer missions during the BLLAST campaign

Exploring the potential of the RPA system SUMO for multipurpose boundary-layer missions during the BLLAST campaign

Exploring the potential of the RPA system SUMO for multi-purpose boundary layer missions during the BLLAST campaign

Diurnal Mountain Wind Systems

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