ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 45 Issue 2 > 2019,45(2):251-262. DOI:10.7519/j.issn.1000-0526.2019.02.010 Prev Next
Case Study of Wind Characteristics of Different Strong Wind Systems
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Abstract:
Using the wind data observed from the 80 m meteorological tower in Dongguan of Guangdong Province during the passes of Typhoon Molave, severe convection and severe cold air, the mean wind and fluctuating wind characteristics of different strong wind weather systems in the nearsurface boundary layer are analyzed. The results show that: (1) the wind speed variation of the severe convection No.1 is most dramatic and the 10 min mean wind speed amplitude of severe convection can go up to 1.8 times and 3.7 times as much as that of typhoon and severe cold air. The 10 min mean wind direction amplitude can be 120°·(10 min)-1. (2) The power law exponent of typhoon strong wind profile is 0.177 which is larger than 0.15 that is recommended as the power law exponent of exposure class B in Chinese National Code (GB 5009-2012). The power law exponent of severe convection is near 0.12 which is recommended as the exposure class A in the code and the power law exponent of severe cold air is only 0.10. (3) The 10 min average turbulence intensity of No.1 severe convection can go up to 1.4-2.1 times and 1.7-2.0 times as much as that of typhoon and severe cold air. (4) The attack angles of typhoon and severe convection change between -3°-3° while the attack angle of severe cold air changes near 0°. (5) The turbulence integral length scales increase due to the impact of strong wind processes. The horizontal (longitudinal and transverse) turbulence integral length scales of typhoon can obviously increase by an order of magnitude. (6) The typhoon strong wind spectra does not satisfy the -5/3 law and the isotropy assumption. The power spectral density (PSD) value of typhoon is significantly larger than that of severe convection and severe cold air. The PSD value of typhoon is about 3 times as large as that of severe convection and severe cold air.
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