Researchers in Pasadena, Calif., using NASA’s Mars Reconnaissance Orbiter, have found that the water-ice clouds of Mars makes its atmosphere have more water in it than Earth’s.
This finding, along with the theory that dry ice blocks caused the mysterious tracks scientists have detected on the sand dunes of Mars, is yet another strong indication that the Red Planet might once have had life on it.
Armin Kleinboehl of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., who is the lead author of a new report on these findings, believes that the water-ice clouds also might explain the twice-daily rise and fall of temperature in the Martian atmosphere.
Scientists have known about the twice-daily temperature fluctuations, but were unsure as to why this happened on Mars two times a day, while on the Earth, it happens just once.
“We see a temperature maximum in the middle of the day, but we also see a temperature maximum a little after midnight,” said Kleinboehl.
This 58 degree Fahrenheit (32 kelvins) temperature swing, as detected by the orbiter’s Mars Climate Sounder instrument, demonstrate a pattern that is dominant globally and year-round.
NASA’s Mars Climate Sounder observations sampled a range of times of day and night all over Mars. Their observations and conclusions are being published in the journal Geophysical Research Letters.
On Mars, according to NASA, the global oscillations of wind, temperature, and pressure which repeat each day or fraction of a day are called “atmospheric tides.” These are driven by variation in heating between day and night, unlike the Earth’s tides, which are influenced by the moon’s gravity.
The Earth has its own atmospheric tides but ours, in contrast with those of Mars, produce little temperature difference in the lower atmosphere away from the ground.
These atmospheric tides, on Mars — which has only about one percent as much atmosphere as Earth — dominate short-term temperature variations throughout the atmosphere.
Mars has semi-diurnal atmospheric tides. These are ones that occur twice a day. This semi-diurnal pattern was noticed back in the 1970’s, but previously, they had been thought to only appear in the dusty seasons. The cause was considered to be related to sunlight warming dust in the atmosphere.
According to the lead author of this NASA study, Kleinboehl:
“We were surprised to find this strong twice-a-day structure in the temperatures of the non-dusty Mars atmosphere. 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.”
The answer as to what drove the response, he and his four co-authors discovered, were the water-ice clouds of Mars. The Martian atmosphere has these clouds for most of its year.
The unexpected semi-diurnal temperature pattern, with its maximum temperature swings occurring away from the tropics, has been replicated in Mars climate models when the radiative effects of water-ice clouds are included.
The clouds look like thin cirrus clouds on Earth. They absorb infrared light coming from the planet’s surface. That absorption alone is enough to heat the middle atmosphere each day.
“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 stated.
“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.”
As further research and studies on Mars are conducted by NASA, perhaps we will better understand why our sister planet has turned out so different from ours, barren, when in comparison, the Earth is full of life.
The research of Kleinboehl and his co-authors at NASA proves that Mars has more water in its atmosphere than Earth. Then, why doesn’t it have as much of an atmosphere, and as much life as the Earth? Perhaps further research will reveal the answers to these questions.
Written by: Douglas Cobb