what drives the high-speed winds in venus's atmosphere
Atmosphere of Venus
All winds on Venus are ultimately driven by convection . Hot air rises in the equatorial zone , where solar heating is concentrated , and flows to the poles . Such an almost - planetwide overturning of the troposphere is called Hadley circulation . However , the meridional air motions are much slower than zonal winds . The poleward limit of the planet wide Hadley cell on Venus is near ± 60 ° latitudes . Here air starts to descend and returns to the equator below the clouds . This interpretation is supported by the distribution of the carbon monoxide , which is also concentrated in the vicinity of ± 60 ° latitudes . Poleward of the Hadley cell a different pattern of circulation is observed . In the latitude range 60 ° -- 70 ° cold polar collars exist . They are characterised by temperatures about 30 -- 40 K lower than in the upper troposphere at nearby latitudes . The lower temperature is probably caused by the upwelling of the air in them and by the resulting adiabatic cooling . Such an interpretation is supported by the denser and higher clouds in the collars . The clouds lie at 70 -- 72 km altitude in the collars -- about 5 km higher than at the poles and low latitudes . A connection may exist between the cold collars and high speed midlatitude jets in which winds blow as fast as 140 m / s . Such jets are a natural consequence of the Hadley -- type circulation and should exist on Venus between 55 -- 60 ° latitude . 
All winds on Venus are ultimately driven by convection . Hot air rises in the equatorial zone , where solar heating is concentrated , and flows to the poles . Such an almost - planetwide overturning of the troposphere is called Hadley circulation . However , the meridional air motions are much slower than zonal winds . The poleward limit of the planet wide Hadley cell on Venus is near ± 60 ° latitudes . Here air starts to descend and returns to the equator below the clouds . This interpretation is supported by the distribution of the carbon monoxide , which is also concentrated in the vicinity of ± 60 ° latitudes . Poleward of the Hadley cell a different pattern of circulation is observed . In the latitude range 60 ° -- 70 ° cold polar collars exist . They are characterised by temperatures about 30 -- 40 K lower than in the upper troposphere at nearby latitudes . The lower temperature is probably caused by the upwelling of the air in them and by the resulting adiabatic cooling . Such an interpretation is supported by the denser and higher clouds in the collars . The clouds lie at 70 -- 72 km altitude in the collars -- about 5 km higher than at the poles and low latitudes . A connection may exist between the cold collars and high speed midlatitude jets in which winds blow as fast as 140 m / s . Such jets are a natural consequence of the Hadley -- type circulation and should exist on Venus between 55 -- 60 ° latitude .
All winds on Venus are ultimately driven by convection. Hot air rises in the equatorial zone, where solar heating is concentrated, and flows to the poles. Such an almost - planetwide overturning of the troposphere is called Hadley circulation.  Poleward of the Hadley cell a different pattern of circulation is observed. In the latitude range 60 ° -- 70 ° cold polar collars exist.  The clouds lie at 70 -- 72 km altitude in the collars -- about 5 km higher than at the poles and low latitudes.  A connection may exist between the cold collars and high speed midlatitude jets in which winds blow as fast as 140 m / s.
All winds on Venus are ultimately driven by convection . Hot air rises in the equatorial zone , where solar heating is concentrated , and flows to the poles . Such an almost - planetwide overturning of the troposphere is called Hadley circulation . Poleward of the Hadley cell a different pattern of circulation is observed . In the latitude range 60 ° -- 70 ° cold polar collars exist . The clouds lie at 70 -- 72 km altitude in the collars -- about 5 km higher than at the poles and low latitudes . A connection may exist between the cold collars and high speed midlatitude jets in which winds blow as fast as 140 m / s .