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Mesoscale wind patterns over the complex urban terrain around Stuttgart investigated with dual-Doppler lidar profiles

Wittkamp, Niklas; Adler, Bianca; Kalthoff, Norbert; Kiseleva, Olga

Abstract:
The flow in the atmospheric boundary layer (ABL) over cities is crucial for the urban climate as it controls the exchange of heat, moisture and pollutants within the ABL and with the surroundings. In particular for cities in mountainous terrain, the mesoscale flow shows a high spatial and temporal variability, which poses great challenges to the means of observation. We used the dual-Doppler lidar scan strategy of virtual towers (VT), to measure profiles of the horizontal wind in the ABL over the city of Stuttgart in southwestern Germany. To study the mesoscale variability of the horizontal wind, we placed six VTs in the topographically structured investigation area, which is characterised by a basin-shaped valley opening into a major valley. Comparisons with radiosonde data show that reliable wind information can be retrieved from the VT measurements after careful processing. A statistical analysis reveals a strong dependence of the flow in the valleys below ridge height on the bulk Richardson number (BRN). A critical BRN of 1.25 is identified for the area, below which the flow below ridge height is dynamically unstable and coupled to the ambient flow above. ... mehr

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Originalveröffentlichung
DOI: 10.1127/metz/2020/1029
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Forschungsbereich Troposphäre (IMK-TRO)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 01.2021
Sprache Englisch
Identifikator ISSN: 0941-2948
KITopen-ID: 1000129633
HGF-Programm 12.11.31 (POF IV, LK 01) New observational systems and cross platform integration
Erschienen in Meteorologische Zeitschrift
Verlag E Schweizerbart Science Publishers
Schlagwörter virtual towers; thermally driven circulation; bulk Richardson number; atmospheric boundary layer; wind field; urban climate under change – [UC]2
Nachgewiesen in Dimensions
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