In this study, the crosswind (wind component perpendicular to a path, U ⊥) 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 ⊥ ( U ⊥), while the lidar allows acquisition of path-resolved U ⊥ ( U ⊥ ( x), where x is the position along the path). The goal of this study is to evaluate the performance of scintillometer U ⊥ estimates for conditions under which U ⊥ ( x) is variable. Two methods are applied to estimate U ⊥ 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 ⊥ 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 ⊥ in the complex urban environment. The detailed investigation of four cases indicates that the cumulative-spectrum method is less susceptible to a variable U ⊥ ( x) than the look-up-table method. However, the look-up-table method can be adjusted to improve its capabilities for estimating U ⊥ under conditions under for which U ⊥ ( x) is variable.
CITATION STYLE
Van Dinther, D., Wood, C. R., Hartogensis, O. K., Nordbo, A., & O’Connor, E. J. (2015). Observing crosswind over urban terrain using scintillometer and Doppler lidar. Atmospheric Measurement Techniques, 8(4), 1901–1911. https://doi.org/10.5194/amt-8-1901-2015
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