Free Newsletters - Space - Defense - Environment - Energy
. Mars Exploration News .

Mars Water-Ice Clouds Are Key to Odd Thermal Rhythm
by Staff Writers
Pasadena CA (JPL) Jun 14, 2013

This graphic depicts the Mars Climate Sounder instrument on NASA's Mars Reconnaissance Orbiter measuring the temperature of a cross section of the Martian atmosphere as the orbiter passes above the south polar region.

Researchers using NASA's Mars Reconnaissance Orbiter have found that temperatures in the Martian atmosphere regularly rise and fall not just once each day, but twice.

"We see a temperature maximum in the middle of the day, but we also see a temperature maximum a little after midnight," said Armin Kleinboehl of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who is the lead author of a new report on these findings.

Temperatures swing by as much as 58 degrees Fahrenheit (32 kelvins) in this odd, twice-a-day pattern, as detected by the orbiter's Mars Climate Sounder instrument.

The new set of Mars Climate Sounder observations sampled a range of times of day and night all over Mars. The observations found that the pattern is dominant globally and year-round. The report is being published in the journal Geophysical Research Letters.

Global oscillations of wind, temperature and pressure repeating each day or fraction of a day are called atmospheric tides. In contrast to ocean tides, they are driven by variation in heating between day and night.

Earth has atmospheric tides, too, but the ones on Earth produce little temperature difference in the lower atmosphere away from the ground. On Mars, which has only about one percent as much atmosphere as Earth, they dominate short-term temperature variations throughout the atmosphere.

Tides that go up and down once per day are called "diurnal." The twice-a-day ones are called "semi-diurnal." The semi-diurnal pattern on Mars was first seen in the 1970s, but until now it had been thought to appear just in dusty seasons, related to sunlight warming dust in the atmosphere.

"We were surprised to find this strong twice-a-day structure in the temperatures of the non-dusty Mars atmosphere," Kleinboehl said.

"While the diurnal tide as a dominant temperature response to the day-night cycle of solar heating on Mars has been known for decades, the discovery of a persistent semi-diurnal response even outside of major dust storms was quite unexpected, and caused us to wonder what drove this response."

He and his four co-authors found the answer in the water-ice clouds of Mars. The Martian atmosphere has water-ice clouds for most of the year. Clouds in the equatorial region between about 6 to 19 miles (10 to 30 kilometers) above the surface of Mars absorb infrared light emitted from the surface during daytime. These are relatively transparent clouds, like thin cirrus clouds on Earth.

Still, the absorption by these clouds is enough to heat the middle atmosphere each day. The observed semi-diurnal temperature pattern, with its maximum temperature swings occurring away from the tropics, was also unexpected, but has been replicated in Mars climate models when the radiative effects of water-ice clouds are included.

"We think of Mars as a cold and dry world with little water, but there is actually more water vapor in the Martian atmosphere than in the upper layers of Earth's atmosphere," Kleinboehl said.

"Water-ice clouds have been known to form in regions of cold temperatures, but the feedback of these clouds on the Mars temperature structure had not been appreciated. We know now that we will have to consider the cloud structure if we want to understand the Martian atmosphere. This is comparable to scientific studies concerning Earth's atmosphere, where we have to better understand clouds to estimate their influence on climate."


Related Links
Mars Reconnaissance Orbiter
Mars News and Information at
Lunar Dreams and more

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Remaining Martian Atmosphere Still Dynamic
Vienna, Austria (JPL) Apr 09, 2013
Mars has lost much of its original atmosphere, but what's left remains quite active, recent findings from NASA's Mars rover Curiosity indicate. Rover team members reported diverse findings at the European Geosciences Union 2013 General Assembly, in Vienna. Evidence has strengthened this month that Mars lost much of its original atmosphere by a process of gas escaping from the top of the at ... read more

LADEE Arrives at Wallops for Moon Mission

NASA's GRAIL Mission Solves Mystery of Moon's Surface Gravity

Moon dust samples missing for 40 years found in Calif. warehouse

Unusual minerals in moon craters may have been delivered from space

China astronauts enter space module

China to send second woman into space: officials

Tiangong-1 ready for docking and entry

Shenzhou-10 mission to teach students in orbit

Europe's space truck docks with ISS

Russian cargo supply craft separates from International Space Station

Russian Space Freighter to Depart From Orbital Station

Star Canadian spaceman Chris Hadfield retiring

Planning Accelerates For Pluto Encounter

'Vulcan' wins Pluto moon name vote

Public to vote on names for Pluto moons

The PI's Perspective: The Seven-Year Itch

Cassini Finds Hints of Activity at Saturn Moon Dione

Wild Weather Could Be Ahead on Titan

Cassini Shapes First Global Topographic Map of Titan

'Tis the Season -- for Plasma Changes at Saturn

SMOS maps record soil water before flood

Landsat Satellite Looks Back at El Paso, Forward to a New Mission

NASA Builds Sophisticated Earth-Observing Microwave Radiometer

Big data from space: Imagery of Rome delivered in near real time

The Body Electric: Researchers Move Closer to Low-Cost, Implantable Electronics

TED conference sets stage for a week of bright ideas

NASA's Orion Spacecraft Proves Sound Under Pressure

Expert slams Congress over ban on U.S.-China space cooperation

Sunny Super-Earth?

Kepler Stars and Planets are Bigger than Previously Thought

Astronomers gear up to discover Earth-like planets

Stars Don't Obliterate Their Planets (Very Often)

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement