Wavelet analyses of the surface winds at Dumont dUrville, an East Antarctic station, have been performed for the months April, June, September, and December 1993, representing autumn, winter, spring, and summer respectively. The 3 hourly 10 min averaged meteorological station data have been used. The site is characterized by intense katabatic winds that arrive from southeast. During the year 1993 the maximum occurrence of wind was from 160° direction sector. The wavelet transform spectra of horizontal wind show prominent periodicities in the interval between 2 and 20 days. The spectral energies in the diurnal scale are comparatively very low even in summer. A comparison with wavelet spectra of pressure for synoptic scale (2-10 days) confirms the influence of synoptic disturbances that are frequent in coastal regions of the Antarctic continent. The same analysis carried out on the wind components, parallel and transverse to the main katabatic flow direction, reveals that these periodicities are mainly due to the katabatic flow behavior. Althoug the katabatic wind flow is the dominant force characterizing the day-to-day weather conditions, the influence of transient cyclones offshore cannot be ignored; in situations of considerable synoptic activity the intensity and duration of katabatic wind flow are prolonged.
Influence of cyclonic perturbations on surface winds around Dumont d?Urville, East Antarctica,using wavelet transform.
G Mastrantonio;S Argentini;
2001
Abstract
Wavelet analyses of the surface winds at Dumont dUrville, an East Antarctic station, have been performed for the months April, June, September, and December 1993, representing autumn, winter, spring, and summer respectively. The 3 hourly 10 min averaged meteorological station data have been used. The site is characterized by intense katabatic winds that arrive from southeast. During the year 1993 the maximum occurrence of wind was from 160° direction sector. The wavelet transform spectra of horizontal wind show prominent periodicities in the interval between 2 and 20 days. The spectral energies in the diurnal scale are comparatively very low even in summer. A comparison with wavelet spectra of pressure for synoptic scale (2-10 days) confirms the influence of synoptic disturbances that are frequent in coastal regions of the Antarctic continent. The same analysis carried out on the wind components, parallel and transverse to the main katabatic flow direction, reveals that these periodicities are mainly due to the katabatic flow behavior. Althoug the katabatic wind flow is the dominant force characterizing the day-to-day weather conditions, the influence of transient cyclones offshore cannot be ignored; in situations of considerable synoptic activity the intensity and duration of katabatic wind flow are prolonged.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
