Wind circulation regimes at Venus' cloud tops: Ground-based Doppler velocimetry using CFHT/ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx/VIRTIS in February 2011

Titulo: 
Wind circulation regimes at Venus' cloud tops: Ground-based Doppler velocimetry using CFHT/ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx/VIRTIS in February 2011
Autores: 
Machado, P; Widemann, T; Luz, D; Peralta, J
Resumen: 
We present new results based on ground-based Doppler spectroscopic measurements, obtained with the ESPaDOnS spectrograph at Canada-France-Hawaii telescope (CFHT) and simultaneous observations of velocity fields, obtained from space by the VIRTIS-M instrument on board the Venus Express spacecraft. These measurements are based on high-resolution spectra of Fraunhofer lines in the visible to NIR range (0.37-1.05 mu m) acquired on February 19-21, 2011 at a resolution of about 80,000, measuring Venus' winds at 70 km, using incoming solar radiation scattered by cloud top particles in the observer's direction (Widemann, T., et al., [2007]. Planet. Space Sci. 55, 1741-1756; Widemann, T., et al., [2008]. Planet. Space Sci. 56, 1320-1334). The zonal wind field has been characterized by latitudinal bands, at a phase angle Phi = (68.7 +/- 0.3)degrees, between +10 degrees N and 60 degrees S, by steps of 10 degrees, and from [phi - phi(E)] = -50 degrees to sub-Earth longitude phi(E) = 0 degrees, by steps of 12 degrees. From space, VIRTIS-M UV (0.38 mu m) imaging exposures on the dayside were acquired simultaneously in orbit 1786, providing the first simultaneous cloud-tracking measurements with Doppler velocimetry. From the ground, we measured a zonal mean background velocity of (nu) over bar (z)= (117.3 +/- 18.0) m s(-1) on February 19, and (nu) over bar (z) = (117.5 +/- 14.5) m s(-1) on February 21. We detect an unambiguous poleward meridional flow on the morning dayside hemisphere of (18.8 +/- 12.3) m s(-1) on February 19/21. Latitudinal variations of the zonal and meridional winds are further compared with the simultaneous VIRTIS data. We discuss temporal variability as well as its statistical significance. (C) 2014 Elsevier Inc. All rights reserved.
Autor principal: 
Machado, P
Autor/es del IAA: 
Peralta, Javier
DOI: 
10.1016/j.icarus.2014.08.030
Revista: 
ICARUS
Fecha de publicación: 
2014/11/15
Volumen: 
243
Páginas: 
249-263
Tipo de documento: 
Article
Palabras clave: 
Venus, atmosphere; Atmospheres, dynamics; Spectroscopy