Venus Express Robotic News
September 27, 2011 18:31:23
Venus Weather Not Boring After All, NASA/International Study Shows
By Source: NASA

GREENBELT. MD  - At first glance, a weather forecaster for Venus would have either a really easy or a really boring job, depending on your point of view. The climate on Venus is widely known to be unpleasant -- at the surface, the planet roasts at more than 800 degrees Fahrenheit under a suffocating blanket of sulfuric acid clouds and a crushing atmosphere more than 90 times the pressure of Earth's. Intrepid future explorers should abandon any hope for better days, however, because it won't change much.

"Any variability in the weather on Venus is noteworthy, because the planet has so many features to keep atmospheric conditions the same," says Dr. Tim Livengood, a researcher with the National Center for Earth and Space Science Education, Capitol Heights, Md., and now with the University of Maryland, College Park, Md.

"Earth has seasons because its rotation axis is tilted by about 23 degrees, which changes the intensity of sunlight and the length of the day in each hemisphere throughout the year. However, Venus has been tilted so much, it's almost completely upside down, leaving it with a net tilt of less than three degrees from the sun, so the seasonal effect is negligible," explains Livengood, who is stationed at NASA's Goddard Space Flight Center in Greenbelt, Md. "Also, its orbit is even more circular than Earth's, which prevents it from getting significantly hotter or cooler by moving closer to or further away from the sun. And while you might expect things to cool down at night -- especially since Venus rotates so slowly that its night lasts almost two Earth months -- the thick atmosphere and sulfuric acid clouds act like a blanket while winds move heat around, keeping temperatures pretty even. Finally, almost all the planet's water has escaped to space, so you don't get any storms or precipitation like on Earth where water evaporates and condenses as clouds."

However, higher up, the weather gets more interesting, according to a new study of old data by NASA and international scientists. The team detected strange things going on in data from telescopic observations of Venus in infrared light at about 68 miles (110 kilometers) above the planet's surface, in cold, clear air above the acid clouds, in two layers called the mesosphere and the thermosphere.

"Although the air over the polar regions in these upper atmospheric layers on Venus was colder than the air over the equator in most measurements, occasionally it appeared to be warmer," said Dr. Theodor Kostiuk of NASA Goddard. "In Earth's atmosphere, a circulation pattern called a 'Hadley cell' occurs when warm air rises over the equator and flows toward the poles, where it cools and sinks. Since the atmosphere is denser closer to the surface, the descending air gets compressed and warms the upper atmosphere over Earth's poles. We saw the opposite on Venus. In addition, although the surface temperature is fairly even, we've seen substantial changes – up to 54 degrees Fahrenheit (about 30 K change) – within a few Earth days in the mesosphere – thermosphere layers over low latitudes on Venus. The poles appeared to be more stable, but we still saw changes up to 27 degrees Fahrenheit (about 15 K change)."

Kostiuk and Livengood are co-authors of a paper about these observations that appeared July 23 in the online edition of the journal Icarus.

"The mesosphere and thermosphere of Venus are dynamically active," said lead author Dr. Guido Sonnabend of the University of Cologne, Germany. "Wind patterns resulting from solar heating and east to west zonal winds compete, possibly resulting in altered local temperatures and their variability over time."

This upper atmospheric variability could have many possible causes, according to the team. Turbulence from global air currents at different altitudes flowing at more than 200 miles per hour in opposite directions could exchange hot air from below with cold air from above to force changes in the upper atmosphere. Also, giant vortexes swirl around each pole. They, too, could generate turbulence and change the pressure, causing the temperature to vary.

Since the atmospheric layers the team observed are above the cloud blanket, they may be affected by changes in sunlight intensity as day transitions to night, or as latitude increases toward the poles. These layers are high enough that they could even be affected by solar activity (the solar cycle), such as solar explosions called flares and eruptions of solar material called coronal mass ejections.

Changes were seen over periods spanning days, to weeks, to a decade. Temperatures measured in 1990-91 are warmer than in 2009. Measurements obtained in 2007 using Goddard’s Heterodyne Instrument for Planetary Wind and Composition (HIPWAC) observed warmer temperature in the equatorial region than in 2009. Having seen that the atmosphere can change, a lot more observations are needed to determine how so many phenomena can affect Venus' upper atmosphere over different intervals, according to the team.

"In addition to all these changes, we saw warmer temperatures than those predicted for this altitude by the leading accepted model, the Venus International Reference Atmosphere model," said Kostiuk. "This tells us that we have lots of work to do updating our upper atmospheric circulation model for Venus."

Although Venus is often referred to as Earth's twin, since they are almost the same size, it ended up with a climate very different from Earth. A deeper understanding of Venus' atmosphere will let researchers compare it to the evolution of Earth's atmosphere, giving insight as to why Earth now teems with life while Venus suffered a hellish fate.

The team measured temperature and wind speeds in Venus' upper atmosphere by observing an infrared glow emitted by carbon dioxide (CO2) molecules when they were energized by light from the sun. Infrared light is invisible to the human eye and is perceived by us as heat, but it can be detected by special instruments. In the research, it appeared as a line on a graph from a spectrometer, an instrument that separates light into its component colors, each of which corresponds to a specific frequency. The width of the line revealed the temperature, while shifts in its frequency gave the wind speed.

The researchers compared observations from 1990 and 1991 using Goddard's Infrared Heterodyne Spectrometer instrument at NASA's Infrared Telescope Facility on Mauna Kea, Hawaii, to observations from 2009 using the Cologne Tunable Heterodyne Infrared Spectrometer instrument at the National Optical Astronomy Observatory's McMath Telescope at Kitt Peak, Ariz.

 
 A set of images of the Venus south polar vortex in infrared light (at 3.8 microns) acquired by the Visible and Infrared Thermal Imaging Spectrometer instrument on ESA's Venus Express spacecraft. The images show the temperature of the cloud tops at about 65 km (40.4 miles) altitude. A darker region corresponds to higher temperature and thus lower altitude. The center of the vortex, at a temperature of about 250K (around minus 9.7 degrees Fahrenheit), is the deepest zone, exhibiting the highest temperature. Credit: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA

 

More Interactive Photography
Gale CratorInterActive First look crisp look around Gale Crator This 360-degree, full-resolution panorama from NASA's Curiosity rover shows the area all around...
Endeavour nose gear in OPFInterActive Endeavour nose gear in OPF This was shot from forward and underneath Space Shuttle Endeavour in the Orbiter Processing...
Endeavor engine compartmentInterActive Endeavor engine compartment View into the Space Shuttle's engine compartment with the three main engines removed.
Endeavor engine compartmentInterActive Endeavor engine compartment View into the Space Shuttle's engine compartment with the three main engines removed.
Endeavour Cargo BayInterActive Endeavour Cargo Bay This image was shot from the forward end of Space Shuttle Endeavour's cargo ba as it sits in...
Interior view of the Space Shuttle Endeavour forward flight deck. InterActive Interior view of the Space Shuttle Endeavour forward flight deck. Interior view of the Space Shuttle Endeavour aft flight deck.
Endeavour Forward Flight DeckInterActive Endeavour Forward Flight Deck Interior view of the Space Shuttle Endeavour forward flight deck.
Atlas V with Mars Science Laboratory payloadInterActive Atlas V with Mars Science Laboratory payload The rover Curiosity will carry the biggest, most advanced suite of instruments for scientific...
Curiosity roverInterActive Curiosity rover NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or...
Curiosity roverInterActive Curiosity rover NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or...
Gravity Recovery and Interior LaboratoryInterActive GRAIL The Gravity Recovery and Interior Laboratory mission's primary science objectives will be to...
Atlas V AV-029InterActive Atlas V AV-029 ULA Atlas V number AV-029 reaches launch pad on August 4th, 2011. In less than 1 day this Atlas...
Atlas V up closeInterActive Atlas V up close Get to know the Atlas V up close. Explore the rivets in this 74.62 megapixel image of the Atlas...
JUNO Atlas VInterActive JUNO Atlas V ULA Atlas V with the JUNO probe sitting atop at Cape Canaveral Air Force Station is ready for...
Atlantis at wheels stop on runway 15InterActive Atlantis on runway Space Shuttle Atlantis returned to Earth in the predawn hours of July 21st, 2011. Marking the...
Atlantis at wheels stop on runway 15InterActive Atlantis at wheels stop on runway 15 Space Shuttle Atlantis returned to Earth in the predawn hours of July 21st, 2011. Marking the...
Atlantis and towerInterActive Atlantis and tower Space shuttle Atlantis waits to receive payload for the final space shuttle mission STS-135,...
Atlantis payload preparationsInterActive Atlantis payload preparations Space shuttle Atlantis at pad 39A. The payload canister can be seen lifted in to position to...
Walk with the astronautsInterActive Walk with the astronauts A view of the 195ft level of the fixed service structure. This where the astronauts arrive at...
Last Space Shuttle prepares for launchInterActive Last Space Shuttle prepares for launch A close in look at space shuttle Atlantis on June 17th. Launch preparations are on going for...
The last space shuttle to be on the launch padInterActive The last space shuttle to be on the launch pad Space shuttle Atlantis, the last space shuttle to flight begins launch prepartions at pad 39A...
Last space shuttle arrives at launch padInterActive Last space shuttle arrives at launch pad Space shuttle Atlantis is seen here from the top of the rotating service structure the moring...
The last space shuttle has left the buildingInterActive The last space shuttle has left the building Space shuttle Atlantis rolls out of the Vehicle Assembly Building for the last time on the...
Space Shuttle Atlantis prepared to rollout to pad   InterActive Space Shuttle Atlantis prepared to rollout to pad Space shuttle Atlantis complete with the solid rocket boosters and external tank that will...
HiRes Atlantis hanging in VABInterActive HiRes Atlantis hanging in VAB HiRes image of Space Shuttle Atlantis hanging in the Vehical Assembly Building. This shot was...
Atlantis vertical from VAB Level 5InterActive Atlantis vertical from VAB Level 5 Space Shuttle Atlantis after being lifted into the verticle position before being mated to the...
Atlantis verticalInterActive Atlantis vertical Space Shuttle Atlantis hangs vertical before removing the rear hoist and lifting it for the...
Atlantis rolling verticalInterActive Atlantis rolling vertical Here Space Shuttle Atlantis is almost vertical being positioned to soon be mated to the...
Atlantis hanging in VABInterActive Atlantis hanging in VAB Space Shuttle Atlantis is seen here hanging about 10 feet above the VAB floor. It has justed...
Endeavour at nightInterActive Endeavour at night Space shuttle Endeavour seen here at night as launch preparation continue for the first launch...
Atlantis rolling over to VAB for final missionInterActive Atlantis rolling over to VAB for final mission Space Shuttle Atlantis rolling over the VAB for the last time. Atlantis is scheduled to be the...
Atlantis outside VAB for employee photosInterActive Atlantis outside VAB for employee photos Space shuttle Atlantis, the last space shuttle, pauses during rollover from the OPF to the VAB...
Hi Resolution image of the last space shuttleInterActive Hi Resolution image of the last space shuttle Hi Resolution composit image of the last space shuttle, Atlantis, as it sits atop the transport...
Atlantis in the VABInterActive Atlantis in the VAB Nice 360 degree view of the VAB with Atlantis being preped for the Lift and Mate procedure
Atlantis on the sled in VABInterActive Atlantis on the sled in VAB Explore the VAB with Space Shuttle Atlantis on the sled after rollover to the VAB jst before...
Atlantis being attached to slingInterActive Atlantis being attached to sling Full 360 degree panorama from inside the VAB as Space Shuttle Atlantis is attached to the sling...
Endeavour after RSS retractionInterActive Endeavour after RSS retraction Hi-Res image of Space Shuttle Endeavour on the launch pad 39A minutes after the RSS was...
The Mound STS-134 4/29 AttemptInterActive The Mound STS-134 4/29 Attempt This a 360 degree panorama from the mound of the KSC media center. This was the scence about an...
Alpha Magnetic Spectrometer (AMS)InterActive Alpha Magnetic Spectrometer (AMS) The Alpha Magnetic Spectrometer-2, a particle physics detector designed to search for various...
AMS in the SSPFInterActive AMS in the SSPF The Alpha Magnetic Spectrometer-2, a particle physics detector designed to search for various...
Here is Space Shuttle Endeavour just after sunriseInterActive Here is Space Shuttle Endeavour just after sunrise Here is Space Shuttle Endeavour just after sunrise the morning it arrived from the VAB. How...
Endeavour in the VABInterActive Endeavour in the VAB Space Shuttle Endeavour sitting stacked and ready atop the crawler to rollout the launch pad.
Endeavour in the VABInterActive Endeavour in the VAB Space Shuttle Endeavour sitting stacked and ready atop the crawler to rollout the launch pad.
Space Shuttle Discovery final towoverInterActive Space Shuttle Discovery final towover View of Space Shuttle Discovery 4 hours after returning to Earth for the last time. Discovery...
Space Shuttle Discovery Final LaunchInterActive Space Shuttle Discovery Final Launch This a 360 degree panorama taken 3 mile from the launch pad capturing the final lift off of...
Space shuttle Discovery final launchInterActive Space shuttle Discovery final launch This a 360 degree panorama taken 3 mile from the launch pad capturing the final lift off of...
Discovery at NightInterActive Discovery at Night This a panorama of Space Shuttle Discovery shortly after RSS retraction on 11/3/2010 preparing...
GRIP DC-8 PanoramaInterActive GRIP DC-8 Panorama Interior of forward section of NASA GRIP aircraft while configured for studding hurricane...
GRIP DC-8 InteriorInterActive GRIP DC-8 Interior Interior of forward section of NASA GRIP aircraft while configured for studding hurricane...
NASA GRIP DC-8InterActive NASA GRIP DC-8 The NASA DC-8 is a four-engine jet transport that has been highly modified to support the...
Endeavour on padInterActive Endeavour ready for launch HiRes image of Endeavour at Pad 39A
AMS-2 Antimatter TelescopeInterActive AMS-2 Antimatter Telescope Explore the SSPF and ESA's Antimatter Telescope. 360 rotating,zoomable Panorama!
Spectacular ultra hi-rez interactive shot of the Space Shuttle Endeavour on the launch pad for the last timeInterActive Explore LC-39A !! Spectacular ultra hi-rez interactive shot of the Space Shuttle Endeavour on the launch pad for...