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

Observing crosswind over urban terrain using scintillometer and Doppler lidar

Atmospheric Measurement Techniques ◽

10.5194/amt-8-1901-2015 ◽

2015 ◽

Vol 8 (4) ◽

pp. 1901-1911 ◽

Cited By ~ 5

Author(s):

D. van Dinther ◽

C. R. Wood ◽

O. K. Hartogensis ◽

A. Nordbo ◽

E. J. O'Connor

Keyword(s):

Urban Environment ◽

Wind Component ◽

Doppler Lidar ◽

Spectrum Method ◽

Table Method ◽

Look Up Table ◽

Urban Terrain ◽

Time Lagged ◽

The Look ◽

Lagged Correlation

Abstract. In this study, the crosswind (wind component perpendicular to a path, U&bot;) is measured by a scintillometer and estimated with Doppler lidar above the urban environment of Helsinki, Finland, for 15 days. The scintillometer allows acquisition of a path-averaged value of U&bot; (U&bot;), while the lidar allows acquisition of path-resolved U&bot; (U&bot; (x), where x is the position along the path). The goal of this study is to evaluate the performance of scintillometer U&bot; estimates for conditions under which U&bot; (x) is variable. Two methods are applied to estimate U&bot; from the scintillometer signal: the cumulative-spectrum method (relies on scintillation spectra) and the look-up-table method (relies on time-lagged correlation functions). The values of U&bot; of both methods compare well with the lidar estimates, with root-mean-square deviations of 0.71 and 0.73 m s−1. This indicates that, given the data treatment applied in this study, both measurement technologies are able to obtain estimates of U&bot; in the complex urban environment. The detailed investigation of four cases indicates that the cumulative-spectrum method is less susceptible to a variable U&bot; (x) than the look-up-table method. However, the look-up-table method can be adjusted to improve its capabilities for estimating U&bot; under conditions under for which U&bot; (x) is variable.

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Observing crosswind over urban terrain using scintillometer and Doppler lidar

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-6431-2014 ◽

2014 ◽

Vol 7 (7) ◽

pp. 6431-6456

Author(s):

D. van Dinther ◽

C. R. Wood ◽

O. K. Hartogensis ◽

A. Nordbo ◽

E. J. O'Connor

Keyword(s):

Urban Environment ◽

Lookup Table ◽

Wind Component ◽

Doppler Lidar ◽

Spectrum Method ◽

Table Method ◽

Lidar Measurements ◽

Urban Terrain ◽

Time Lagged ◽

Variable Wind

Abstract. In this study, the crosswind (wind component perpendicular to a path, U&bot;) is measured by a scintillometer and Doppler lidar above the urban environment of Helsinki, Finland, for 3 weeks. The scintillometer allows acquisition of a path-averaged value of U&bot; (U&bot;), while the Doppler lidar allows acquisition of path-resolved U&bot; (U&bot; (x), where x is the position along the path). The goal of this study is to evaluate the applicability of scintillometer U&bot;-measurements for conditions where U&bot; (x) is variable. If the scintillometer is applicable in such variable-wind conditions, it can also be used in the urban environment. Two methods were applied to obtain U&bot; from the scintillometer signal; the cumulative spectrum method (relies on scintillation spectra), and the lookup table method (relies on time-lagged correlation functions). Both methods compared reasonably well with the Doppler lidar measurements, especially considering the challenging urban environment in which they were measuring; with RMSE of 0.71 and 0.73 m s−1. This indicates that both measurement technologies are able to obtain U&bot; in the complex urban environment. The in detail investigation of four cases indicate that the cumulative spectrum method is less susceptible to a variable U&bot; (x) than the lookup table method. However, the lookup table method can be adjusted to improve its capabilities to obtain U&bot; for conditions where U&bot; (x) is variable.

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