Month: August 2021

Reposted from Dr. Roy Spencer’s blog

August 2, 2021 by Roy W. Spencer, Ph. D.

The global average lower tropospheric temperature (LT) anomaly of version 6.0 for July 2021 was +0.20 degrees. C, compared to the value from June 2021 of -0.01 degrees. C.

REMEMBER: We have changed the 30-year averaging period from which we calculate anomalies from the old period 1981-2010 to 1991-2020. This change does not affect temperature trends.

The linear warming trend since January 1979 has remained at +0.14 ° C / decade (+0.12 ° C / decade over the global oceans and +0.18 ° C / decade above the global land average).

Various regional LT deviations from the 30-year (1991-2020) average of the last 19 months are:

YEAR MO GLOBE NHEM. SCHEM. TROPIC USA48 ARCTIC AUST
2020 01 0.42 0.44 0.40 0.52 0.57 -0.22 0.41
2020 02 0.59 0.74 0.45 0.63 0.17 -0.27 0.20
2020 03 0.35 0.42 0.27 0.53 0.81 -0.95 -0.04
2020 04 0.26 0.26 0.25 0.35 -0.70 0.63 0.78
2020 05 0.42 0.43 0.41 0.53 0.07 0.84 -0.20
2020 06 0.30 0.29 0.30 0.31 0.26 0.54 0.97
2020 07 0.31 0.31 0.31 0.28 0.44 0.27 0.26
2020 08 0.30 0.34 0.26 0.45 0.35 0.30 0.24
2020 09 0.40 0.42 0.39 0.29 0.69 0.24 0.64
2020 10 0.38 0.53 0.22 0.24 0.86 0.95 -0.01
2020 11 0.40 0.52 0.27 0.17 1.45 1.09 1.28
2020 12 0.15 0.08 0.21 -0.07 0.29 0.44 0.13
2021 01 0.12 0.34 -0.09 -0.08 0.36 0.50 -0.52
2021 02 0.20 0.32 0.08 -0.14 -0.65 0.07 -0.27
2021 03 -0.01 0.13 -0.14 -0.29 0.59 -0.78 -0.79
2021 04 -0.05 0.05 -0.15 -0.28 -0.02 0.02 0.29
2021 05 0.08 0.14 0.03 0.06 -0.41 -0.04 0.02
2021 06 -0.01 0.31 -0.32 -0.14 1.44 0.63 -0.76
2021 07 0.20 0.33 0.07 0.13 0.58 0.43 0.80

The full UAH Global Temperature Report, along with the LT Global Gridpoint Anomaly Image for July 2021, should be available here in the next few days.

The global and regional monthly anomalies for the various atmospheric layers we monitor should be available in the next few days in the following locations:

Lower troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt
Middle troposphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tmt/uahncdc_mt_6.0.txt
Tropopause: http://vortex.nsstc.uah.edu/data/msu/v6.0/ttp/uahncdc_tp_6.0.txt
Lower stratosphere: http://vortex.nsstc.uah.edu/data/msu/v6.0/tls/uahncdc_ls_6.0.txt

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The bureaucracy of government control is slowly fading away in space exploration, at least in the US.  A series of delays, cost overruns, and imposed requirements have finally started taking its toll on the Space Launch System (SLS), the next generation NASA rocket system.  Now, the space agency has finally conceded a point to the commercial launch industry.  It has elected to use Space X’s Falcon Heavy to launch one of its upcoming flagship missions – Europa Clipper.

That decision was made despite a massive push from SLS contractors to try to keep the mission on board.  In fact, Congress originally had not allowed NASA to open Europa Clipper’s contract up to other bidders.  Pressure came from the constituents of the variety of Congressional districts that the SLS is built in.  But the downsides of using the oft-delayed system became too big to ignore.

Another artist’s illustration of Europa Clipper
Credit – NASA / JPL-Caltech

One downside was the cost – and not only of the rocket itself.  Overall the Falcon Heavy, which is reusable, unlike the SLS, is expected to save $2 billion when it launches the Clipper on its path to Jupiter.  About half of that savings will come from avoiding a costly redesign.

That redesign had to do with the vibrational load of the SLS system on launch.  Known in the jargon as “torsional load”, the current iteration of the Clipper could not withstand those forces, according to a NASA inquest.  To redesign the whole Clipper to make it compatible with the SLS’s launch forces would have cost around $1 billion alone. Adding a single use, expensive rocket to the mix adds another $1 billion to the launch costs.

The first commercial launch (and second successful launch) of the SpaceX Falcon Heavy.
Credit: SpaceX

Another nail in the coffin was timeline – the SLS has been repeatedly delayed and is now more than 2 years behind schedule, though it still hasn’t completed its first launch yet, which is expected in November.  Falcon Heavy on the other hand, started development after the SLS and has already proved flight worthy, having 3 successful flights to date and a number of ongoing launch contracts.  SLS is primarily designed to support Artemis, NASA’s effort to return to the moon.  It was unclear, given the commitment the SLS program had made to Artemis and its repeated delays, whether or not the system would even be ready to support the Clipper’s Launch in 2024, and its usefulness for other science missions has been called into question as well.

Even with $2 billion in savings on the table, as well as the risk of missing the entire original launch window, Congress still stuck by SLS.  Until earlier this year at least, when it passed a budget amendment that would allow NASA to pursue other contractors for the launch of the mission.  When the agency announced that SpaceX had landed the new contract, it didn’t surprise veteran launch watchers.  But it did add another feather in the cap of the commercial launch industry – and saved the American taxpayer almost $2 billion.

Learn More:
Extreme Tech – NASA Ditches SLS for SpaceX to Launch Europa Clipper
NASA – NASA Awards Launch Services Contract for Europa Clipper Mission
The Verge – NASA’s Europa Clipper will fly on SpaceX’s Falcon Heavy
Space.com – A SpaceX Falcon Heavy rocket will launch NASA’s Europa Clipper mission to icy Jupiter moon

Lead Image:
Artist’s conception of Europa Clipper.
Credit – NASA / JPL-Caltech

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From NASA

This image from NASA’s Mars Reconnaissance Orbiter shows ice sheets at the south pole of Mars. The spacecraft discovered clays near this ice; Scientists have suggested that such clays are the source of radar reflections previously interpreted as liquid water.Credits: NASA / JPL-Caltech / University of Arizona / JHU

Three studies published last month cast doubt on the premise of subterranean lakes below Mars’ South Pole.

Where there is water, there is life. That is at least the case on Earth, and it is also the reason why scientists are still irritated by any evidence that suggests that there is liquid water on cold, dry Mars. The Red Planet is a difficult place to look for liquid water: while water ice is abundant, any water warm enough to be liquid on the surface would only take moments before it settles in the delicate air of Mars turned into steam.

Hence the interest that was aroused in 2018 when a team led by Roberto Orosei from the Italian Istituto Nazionale di Astrofisica announced that they had found evidence of underground lakes deep under the ice cap at the south pole of Mars. The evidence they cite comes from a radar instrument aboard the ESA (European Space Agency) Mars Express orbiter.

The colored dots represent locations where bright radar reflections were detected by the ESA orbiter Mars Express at the south polar cap of Mars. Such reflections were previously interpreted as subterranean liquid water, but their prevalence and proximity to the cold surface suggest it may be something else.Credits: ESA / NASA / JPL-Caltech

Radar signals that can penetrate rocks and ice change when reflected from different materials. In this case, they generated particularly bright signals under the polar cap that could be interpreted as liquid water. The possibility of a potentially habitable environment for microbes was exciting.

But after a closer look at the data and experiments in a cold laboratory here on Earth, some scientists now think that sound, not water, could be generating the signals. In the past month, a trio of new papers solved the mystery – and possibly dried up the lake hypothesis.

Isaac Smith of York University in Toronto teamed up while working in a laboratory to freeze smectite clays with liquid nitrogen to test how they respond to radar signals. The results have challenged the hypothesis that underground lakes are found at the South Pole of Mars.Credits: York University / Craig Rezza

A scientific ecosystem

Meetings like this offer an opportunity to test new theories and question one another. “Communities can generate their own small scientific ecosystems,” said Jeffrey Plaut of NASA’s Jet Propulsion Laboratory, one of the scientists who traveled to the conference. He is also, together with Orosei, the chief investigator of the instrument behind the fascinating radar signals called MARSIS or the Mars Advanced Radar for Subsurface and Ionosphere Sounding. “These communities can be self-sustaining,” he continued, “because you bounce a question off someone and maybe a year or two later you help find an answer.”

Polar explorers on Mars belong to a small, tight-knit community. Not long after the Lake Paper was published, around 80 of these scientists met for the International Conference on the Science and Exploration of Mars in Ushuaia, a coastal village on the southern tip of Argentina.

Much of the conversation revolved around the underground lakes. How much heat would it take to keep the water flowing under all the ice? Could brine lower the freezing point of water enough to keep it fluid?

Of course, it wouldn’t be the first time an exciting water-related hypothesis has sparked a spate of research. In 2015, NASA’s Mars Reconnaissance Orbiter found what looked like strips of wet sand running down the slopes, a phenomenon known as the “recurring slope lineae”. But repeated observations with the spacecraft’s HiRISE – or High-Resolution Imaging Science Experiment – camera have since shown that this is more the result of sand currents. A paper published earlier this year found many recurring slope lineae after a global dust storm on Mars in 2018. The results suggested that dust settling on slopes triggers sand currents, which in turn expose the darker subsurface materials that make up the lineae give characteristic coloring.

As with the wet sand hypothesis, several scientists began thinking about how to test the subterranean lakes hypothesis. “We felt we should try to address this,” said Isaac Smith of York University in Toronto, who organized the Ushuaia conference and led the latest study showing that clay can explain the observations.

Too cold for lakes

Plaut was among these scientists. He and Aditya Khuller, an Arizona State University PhD student doing an internship at JPL, analyzed 44,000 radar echoes from the base of the polar cap from 15 years of MARSIS data. They showed dozens more bright reflections like those in the 2018 study. But in their recent article in Geophysical Research Letters, they found many of these signals in near-surface areas where it should be too cold to remain fluid, even with water Perchlorates, a type of salt commonly found on Mars that can lower the freezing temperature of water.

Two separate teams of scientists then analyzed the radar signals to see if something else could be generating the signals.

ASU’s Carver Bierson completed a theoretical study that suggested several possible materials that could cause the signals, including clays, metal-containing minerals, and salt ice. But Isaac Smith of York University, who knew that a group of clays called smectites existed all over Mars, went even further in a separate third article: he measured smectite properties in a laboratory.

Smectites look like ordinary rock, but were formed a long time ago by liquid water. Smith placed several samples of smectite in a cylinder designed to measure how radar signals interact with them. He also doused them with liquid nitrogen and froze them to minus 58 degrees Fahrenheit (minus 50 degrees Celsius) – close to what they would be at the south pole of Mars.

“The lab was cold,” said Smith. “It was winter in Canada at the time, and pumping liquid nitrogen into the room made it colder. Because of COVID-19, I was wrapped in a hat, jacket, gloves, scarf and mask. It was pretty uncomfortable. “

After freezing the sound samples, Smith found that their response matched the MARSIS radar observations almost perfectly. Then he and his team searched for sound on Mars near these radar observations. They relied on data from MROs carrying a mineral mapper called the Compact Reconnaissance Imaging Spectrometer, or CRISM.

Bingo. While CRISM cannot see through ice, Smith found smectites scattered near the ice cap of the South Pole. Smith’s team showed that frozen smectite can create the reflections – no unusual amounts of salt or heat are required – and that they are present at the South Pole.

There is no way to confirm the bright radar signals without landing at the south pole of Mars and digging through miles of ice. But recent publications have given plausible explanations that are more logical than liquid water.

“In planetary research, we often only approach the truth slowly,” says Plaut. “The original paper didn’t prove it was water, and these new papers don’t prove it. But we try to narrow the possibilities as much as possible in order to reach a consensus. “

More about MRO

To learn more about the Mars Reconnaissance Orbiter, visit:

https://mars.nasa.gov/mro/

https://www.nasa.gov/mission_pages/MRO/main/index.html

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