Mars the anomalies The moon too., part II

agent99 · Aug 31, 2007

Jon, alto cirrius You mean alto stratus? "Alto" in weather terms means the middle atmosphere. Alto clouds such as alto-cumulous or alto-stratus are largely devoid of ice crystals, unlike the Cirrus type found above 15,000 feet depending on Earthly latitude. Jon, what I am talking about is those clouds on both images that are seen at the top of the picture frame, especialy the second picture at the top middle, there's a very rounded and big cloud. There's no mistaking it for a stratus-form cloud. Incidentally, "stratus" means flat-sheet like and "cumulous" is the opposite, being rounded. There also appears to be a distinct boundry between the cloud formations that are rounded and the air that contains the dust is devoid of clouds! In otherwords, there exists something akin to a "frontal zone", or maybe the land where those rounded clouds are is warmer than where the dust is, perhaps due to wind in that area. The clouds shown in your link show something like you describe as being alto-types, but also there is a mixture of cloud types. There also appears to be a circulation going on, especially in one of them.

JonClarke · Aug 31, 2007

I stand corrected (its been a few years since I last looked up cloud types). I was trying to think of the name for lumpy cirrus clouds. Cirro-cumulus is the closest terrestrial example, I suspect. But remember, unlike terrestrial cirro-cumulus clouds all Mars clouds are going to be ice crystals, either H2O or CO2. It's too cold for anything else. Except perhaps for a few low altitude equitorial ground fogs, which must just be water droplets (although these are early morning features as far as I know, when it would still be too cold for liquid water droplets). It would be best if you could label the image to show the feature in question. Remember the scale of the image too. The field of view is several 1000 km as the entire north polar cap can be seen. Individual clould types probably can't be distinguished at this scale, I suspect, alhtough there certainly are some dense knots there. I attach the original colour image. Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

yevaud · Aug 31, 2007

I was trying to think of the name for lumpy cirrus clouds. Not certain there is a designation. By definition, Cirrus or Cirro-Stratus are high altitude formations formed of, as you state, ice-crystals. They're usually thin and wispy (in the case of Cirrus) or quite a transparent layer that can be many km deep (in the case of Cirro-Stratus). I'm not certain there is a "lumpy" form, such as it were. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

agent99 · Aug 31, 2007

Yevaud, I'm not certain there is a "lumpy" form, such as it were. JonClark got that rite about cirrocumulous. They are not as common as cirrostratus but can be found with warm fronts ahead of nimbostratus. Jon, That image is huge! But as you know, I was refering to those you posted a while back in this thread showing the difference between dust and clouds, you know, the ones with the labels added for clarity. In those pictures, what was the altitude and what area size are we talking about? In the first picture of the two, the lumpy formations appear to be masked or spreading out. You can see it in the top middle, they really do look like nimbus clouds to me. If you look at the ones seen at the very bottom of the picture, they look really tiny yet still lumpy, then you compare that to those on the top of the picture and they are much much bigger!

yevaud · Aug 31, 2007

You completely misunderstand me. By definition, Cirrus and associated like types are comprised of largely ice-crystals at a high altitude. These types of cloud formations do not end up "lumpy" looking. Cirrus clouds are always "thin and wispy." FYI, there are no "Warm Fronts" (as understood by Terrestrial Meteorology) on Mars. There is terribly little convection and, although there are some steep day/night temperature ranges there, with the atmosphere being at such a low surface pressure, little in the way of anything you can name wrt weather phenomena common to Earth is present. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

yevaud · Aug 31, 2007

The following are typical Martian "Cloud" forms: Cyclonic Disturbances. Seen along the edge of the Polar caps during the Martian Spring or Fall. Lee Waves. A form of a "Gravity Wave," found in the lee of large obstacles on Mars. Wave Clouds. These occur at the lee of a large obstacle, again at the verge of the Polar caps or in the Tharsis and Lunae Planum regions. Essentially, these are a large form of a Lee wave. Cloud Streets. Streaky cloud formations with a measurable periodicity. Streaky Clouds. You can find these anywhere on Mars, but seem to concentrate in the highlands S/W of Syrtis Major. Fog. Already explained by Jon. Dust Plumes. Self-explanatory. If the above color image is of the clouds in question, then that is quite obviously a dust plume - you can clearly see it is associated with material originating from a source on the surface. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

JonClarke · Aug 31, 2007

According to wikipedia there is a class of clouds called cirro cumulus, http://en.wikipedia.org/wiki/Cirrocumulus Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

yevaud · Aug 31, 2007

Sure. And you'll doubtless virtually never find them present in Martian Meteorology. They require fairly robust convection, which is not something you'll see wrt to cloud formations on Mars, except perhaps at/within the surface boundary layer (which is rather limited in height on Mars). I merely felt Agent99 was applying Terrestrial concepts to Mars all too freely. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

3488 · Aug 31, 2007

I agree Yevaud. These types of cloud could not exist in the atmosphere of Mars anyway We do not have Cumulus family clouds at 30 KM / 19 miles above sea level on Earth, let alone sunlight only averages 44% terrestrial values too. Agent99 IS taking terrestrial concepts to Mars far too freely. That sort of atmosphere can support cirrus family, no probs, seen it many times with the Vikings, Pathfinder & the MERs from ground level. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

agent99 · Aug 31, 2007

Yevaud, You misunderstood ME! LOL! I never said that Mars has Cirrocumulous clouds. I was refering to the fact that there are cirrocumulous clouds generally speaking in aid of JonClarks comments about them. And there are warm fronts here on earth. They are mostly found in the northern hemisphere. Peace out you'all <img src="/images/icons/smile.gif" />

yevaud · Aug 31, 2007

As important - since I mentioned Convection - the Martian atmosphere is largely at thermal equilibrium (going past several not-equilibrium conditions I could state, all of which more-or-less fall into the categories I previously mentioned). This makes any concept of "Convection" on Mars as weak or non-existent. Without Convective activity, you cannot have many of the cloud forms we see daily on Earth. However, that being said, there are similar processes between the two worlds. For example, Orographic Uplift works exactly the same (although much more weakly on Mars). You'll see Lenticular clouds over large geographic features at times. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

yevaud · Aug 31, 2007

Trust me, my comments were not intended to be perjorative. But relating Earth-analogue cloud types to those of Mars is not a good thing. The dynamics of the Martian atmosphere, of it's "weather" are quite different than here. "Cirrus" as a descriptive is technically ok, as long as the analogy isn't taken too far. That was all. <img src="/images/icons/smile.gif" /> [Hey, wait. Wasn't this a discussion about the color of the Martian Sky? Gotta love this place.] <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

yevaud · Aug 31, 2007

You know, the weather processes of Mars is a downright fascinating subject. I spent a lot of time studying it once, years ago, in school. Different atmospheric components, lowered insolation, no geomagnetic field worth speaking of, large day/night temperature profile, profuse amounts of dust and aerosols, and so on. The list is endless. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

yevaud · Sep 1, 2007

Well, I apparently killed this thread dead. Remind me to only speak of superficialities here in the future. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

a_lost_packet_ · Sep 1, 2007

Don't worry. It'll come back. ZenOnMars will probably login and bump it sometime in the year 2019. <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

JonClarke · Sep 1, 2007

Try starting a thread in space science and astronomy <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

yevaud · Sep 1, 2007

Been there, done that. <img src="/images/icons/smile.gif" /> Since Moderatorship (sounds like we now run London, circa 1726, eh?), I figured my greatest good I could do was down this end of town. I don't get up that way as often as I'd like at all. Damnit. I am reduced to occasionally posting good science on the other side of the tracks. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

agent99 · Sep 3, 2007

Yevaud, But relating Earth-analogue cloud types to those of Mars is not a good thing. The dynamics of the Martian atmosphere, of it's "weather" are quite different than here. You would think so given what we are told, and I am questioning it due to the appearance the of clouds posted by JonClark - yes, blame him - from satelite images. "Cirrus" as a descriptive is technically ok, as long as the analogy isn't taken too far. That was all. It is, yes. [Hey, wait. Wasn't this a discussion about the color of the Martian Sky? Gotta love this place.] Do I detect a hint of sarcasm Yevaud? Yes, You are correct, one has to wonder if the sky is actually bluish rather than yellowish if there are rounded cloud formations clearly evident in satelite photos. There is no mistaking it, unless there was something wrong with the satelite imaging or some intervening process, that is, but I seriously doubt it. Maybe it's not from Mars, those images, maybe they are from Earth. But no, don't be silly, they are from Mars, and yes, you CAN see AT LEAST two types of clouds in those pictures i'm refering to. At least two types of clouds, wow, that is something, Furthermore, noting that those clouds are rounded, and are casting dark shadows, that can be seen even from that distance the images were taken from, they must be something more than just wispy remenants of minute amounts of vapour, and therefor thick and rounded, Remember, rounded clouds = convection. Surely you can't tell me that you don't see what I do? Everyone else that I showed who knows something about what clouds look like can see they are rounded. So what's the big deal with that? It goes against the theory of atmospheric thiness of Mars, also the temperature, as they are clearly not all ice-crystal clouds, a

a_lost_packet_ · Sep 3, 2007

Agent99 - Yes, You are correct, one has to wonder if the sky is actually bluish rather than yellowish if there are rounded cloud formations clearly evident in satelite photos. How do you make such an association? Furthermore, noting that those clouds are rounded, and are casting dark shadows, that can be seen even from that distance the images were taken from, they must be something more than just wispy remenants of minute amounts of vapour, and therefor thick and rounded, There are lots of dark shadows on the Moon. People even mistake them for aliens or evidence of a hoax. But, the Moon doesn't have an atmosphere as such. Are you saying that dark shadows imply an atmosphere or that no other cloud formation of material can cast a shadow? Remember, rounded clouds = convection. As this seems to be a significant point of yours, I will mention it and the state that I am not sure which picture it is you are referring to. I'll have to backtrack and look it up in order to respond more directly. However, if you will note, Yevaud did not state that convection did not exist in any form on Mars. His stress was really on how weak and/or how strange it is. (IIRC) In fact, any atmospheric system subjected to heat or other exciting energy would exhibit some sort of convection while under the effects of gravity. Even if it was thin and virtually non-existent. It may be "weird" but it would still obey the laws of physics, IMO. But, Yevaud is more equipped to directly answer to this than I. Surely you can't tell me that you don't see what I do? Everyone else that I showed who knows something about what clouds look like can see they are rounded. Did you show them to people who know what "clouds" on Mars look like? So what's the big <div class="Discussion_UserSignature"> I put on my robe and wizard hat... </div>

yevaud · Sep 3, 2007

Radiative Thermal Equilibrium: it means that the rate of cooling is matched by the rate of heating of the planet's atmosphere. Essentially there is only minor convective activity with which to drive the formation on numerous of our old familiar cloud-types. Another point: the total percentage of H20 present in Mar's atmosphere is 0.1 % - and any clouds that may form of partial or largely H20 vapor are restricted to the Radiative Boundary Layer - all of the first 4 km of the atmosphere. So any cloud formations at the altitudes we're discussing must be ice-crystals, and exist at a height that precludes any convective activity to form most cloud types. Heat is the driving source behind all weather. And Mars is stuck on "Freeze." <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

signalhill · Sep 3, 2007

"So any cloud formations at the altitudes we're discussing must be ice-crystals, and exist at a height that precludes any convective activity to form most cloud types. Heat is the driving source behind all weather. And Mars is stuck on "Freeze." Perhaps the cumulus clouds are composed of ice crystals. Perhaps they are CO2 cumulus clouds. Saturn is in cryogenic deep freeze and has a very dynamic atmosphere, albeit probably heated from within, yet is still freezing but violently churning. Jupiter is another example. There can be convection within cryogenic conditions. I would say Jupiter's atmosphere is not in thermal equilibrium. Mars is not Jupiter, i know, but given that Mars does have a dynamic atmosphere, capable of carrying cyclonic activity, it can be subject to hot and cold fronts giving rise to varied weather. why would Cumulus clouds not be part of this process?

yevaud · Sep 3, 2007

Yes, ice crystals, specifically C02 ice crystals. Warm or Cold Fronts are not Convection. Both (Fronts and Convection) are driven by heat differentials. But again, the Martian atmosphere achieves Radiative Thermal Equilibrium fast and stays there, each day. There are few if any significant heat differentials to drive Fronts - or convection. And convection is what many clouds are created by: the "stirring" of unstable, moisture-laden atmosphere. With precious little convection and such a tiny percentage of H20 in the atmosphere, it's quite difficult to see how a Cumulus anything could be developed. Anyways, that's my view on the matter. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

mental_avenger · Sep 3, 2007

Just a reminder to those who either donâ€™t remember, or might not have known in the first place. The Martian atmosphere, while very thin composition-wise, is relatively thick distance-wise. Remember, Odyssey2001 was aerobraking at Mars at the same altitude that Spaceship One officially entered â€œspaceâ€ on Earth. That has to create some atypical (compared to Earth) weather phenomenon. Earthâ€™s atmosphere is a very thin layer. If the Earth were the size of an onion, the atmosphere would be about the thickness of the outer brown onion skin. Earth = 8000 miles diameter All of the weather occurs within the first 7 miles. 90% of the atmosphere is contained within the first 50 miles. If the Earth were the size of a Basketball (9 inches in diameter) All of the weather occurs within the first .0078 of an inch 90% of the atmosphere is contained within the first .05625 of an inch Orbit of 240 miles (ISS) = .27 of an inch STS LEO = 186 miles = .21 of an inch Certainly, the relative depth of the atmosphere would have a significant effect on the weather. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

signalhill · Sep 3, 2007

"Just a reminder to those who either donâ€™t remember, or might not have known in the first place. The Martian atmosphere, while very thin composition-wise, is relatively thick distance-wise. Remember, Odyssey2001 was aerobraking at Mars at the same altitude that Spaceship One officially entered â€œspaceâ€ on Earth. That has to create some atypical (compared to Earth) weather phenomenon." So you are implying that cloud formations beyond only a high-altitude cirrus type could develop in the Martian atmosphere?

yevaud · Sep 3, 2007

No, he's reminding us that the physical composition of the Martian atmosphere is quite different than Earth's. As he should. And no, he is also not implying other cloud types could occur in the manner you're suggesting. *Sigh* Look, Atmospheric Physics on Earth and on Mars follow the same rules, merely with different inputs into the system, so to speak. Even with an altered Scale Height (a factor affected by what M_A posted), Radiative Transfer (different dynamics due to a mostly C02 atmosphere, low overall pressure atmosphere), and a number of other factors, it is barely possible for other types of clouds to even exist, especially at altitudes over 4 km. What is a "Cloud," eh? In almost every case, it's a mass of saturated air; saturated with moisture. There is precious little moisture contained in the Martian atmosphere. It's a formation frequently (mostly, really) caused by the disturbance of saturated air by convective currents. There is precious little convective activity on Mars. How then may a Cumulus cloud form even exist? <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

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