2 0 0 9 P a r i s / M e u d o n

IWCMO Conference

Masatsugu MINAMI: A Few Propositions on Some Martian Phenomena

Talk presented at the IWCMO conference, Meudon, 19th September 2009



ERE, picking out some famous Martian phenomena, I would like to talk about some propositions or assertions which may look strange or heterodoxical at first glance.


Proposition I. Nix Olympica is different by definition from the summit of Olympus Mons covered by the white orographic cloud


The summit of Olympus Mons looks at times dark and sometimes whitish. Even when it is white, there are two cases which are sometimes confused. Here we shall propose that the so-called Nix-Olympica is quite different from the case where the summit of Olympus Mons is covered by the bright white cloud. As to Nix Olympica, E M Antoniadi wrote in this way citing Schiparelli sentences. This first box surrounded by red line is made larger. As this report says, Nix Olympica was first discovered by Schiaparelli on 10 November 1879, which was two days before the opposition day of the year on 12 November 1879. So the brightening of the summit was given rise to because of some kind of the opposition effect. By the 登pposition effect we mean that the summit shines on the occasion of opposition because of some kind of reflection of the Sun light.

Unfortunately I am not informed of the ephemeris in 1879, but here we give a recurrence formula of the Mars orbit with respect to the Earth orbit, (see for more details the following site


which was first given in 1984 in Japanese) and so we can roughly know that the oppositions nicely recur every 284 years, 205 years, 331 years or 126 years (if the value n/m is nearly equal to the irrational number 7.390..., the year 2n+m will be a possible recurrence year), and here picking out the 126 year recurrence, we come to know the opposition in 1879 was quite akin to the one in the just forgoing 2005 opposition. In 2005, the opposition day was on 7 November 2005, and the Martian season was 320 degrees of Ls, and it is well known that at this time of the Martian year Olympus Mons is free from any afternoon cloud. So the brightness was never due to any white cloud. As Antoniadi cites, Schiaparelli observed it one month later also, while it was already difficult to see because the brightness was much decreased because of a large phase angle.


As to the 2005 case, for example Christophe Pellier here nicely experienced the very opposition effect, and I suppose he has a keen opinion on the phenomenon.


The above full description by Antoniadi additionally says that at Milano Nix Olympica was dimly visible on 15 May 1888: In 1888, the planet was at opposition on 11 April. If we employ the 111 year recurrence cycle it corresponds to 24 April 1999. Anyway the day when the planet was closest to the Earth in 1999 was on 1 May, and the season was 132 degrees of Ls, and so in this case the Olympus Mons was fully covered by the orographic cloud. In this sense Schiaparelli and Antoniadi themselves look confused.

In 1926, Antoniadi wrote that he saw Nix Olympica on the 1st day of November. The 1926 year, if we employ the well known 79 year recurrence, it resembles also to the year 2005, and so this must have been another opposition effect. In the case of 29 & 30 December 1928, it corresponds to the 2007, and so it must have been just after the spring equinox, so that it is delicate because the white orographic cloud would appear.


In 2010, the next year, in January we can welcome the opposition day in which Nix Olympica is visible from the US, but maybe slightly misty in the early afternoon because of the season.


As to the case of Percival Lowell in 1903, it corresponds to 1982, and its season at opposition was 34 degrees of Ls and hence it was probably the cloud brightening.


Proposition II. Most of the dust disturbances occur in the early mornings.


I myself do not know how many theories or conjectures concerning the emergences of dust storms, but usually I suppose it is imagined the mechanism is such that the storm is entrained in a hot daytime especially in a hot season. However up until now as far as I know nobody or no instrument witnessed any instant when the non-polar dust storm is just happening nor when the storm rapidly develops under the eyes or cameras. As far as we know, on the contrary, any dust storm which has been observed stays almost stable macroscopically during the daytime. The first series of the images here presented are the ones obtained in 2001, every of which shows the resonant dust disturbance near M Cimmerium just on the five days after the emergence of the 2001 global dust storm. As you see, no drastic change of the shape of the dust cores is macroscopically visible.


Another set of images here is consisted from the images obtained in 2005 on 18 October by European and American observers. Note that the dust was trapped quite early in the morning as shown on these images. Fortunately I witnessed it on the day at the Lick Observatory and Laurie Hatch here also observed the instant when the dust was sinking at the eastern terminator. So it was chased for more than eight hours. Note that the dust which has a particular shape remains the same throughout the day. Especially it is noticeable the first two images by David Arditti and Jan Adelaar show already the typical shape which is just formed within a few hours after the dawn terminator. A full presentation of the last two images on 18 October by Bill Flanagan are here, where it should be noted that the dust is misty in B implying that the dust is quite new and full of water vapour. Note further the dust was not seen on the preceding day (17 October) as shown here on the images made also by Bill. Note that he cleverly shot the images at the similar angle on the following day (18 October).





Then we may ask the time when the dust occurs. If it does not occur in the daytime, does it do at night? Just on the images on 17 October one may point out that it suggests a small but strange, interesting precursory matter in Chryse, but it may be ridiculous to imagine that it largely developed at night just like a Typhoon or Hurricane. When the Martian atmosphere is usual, the night stratosphere must be down to the ground and it is supposed that no tropospheric action occurs near the ground. And so any disturbance in the evening may subside usually at night. So a leftover critical possibility is left, we should say, at the boundary of the night and the daytime. So we can suppose that in the early morning every dust is entrained when the temperature and other meteorological conditions heavily change. The strange matter found on the preceding day may be an important key to open the door to the morning mechanism (it might have had a potential), and it must have been a sign of something but have not been any germ of the following dust storm.


It is also suggestive to look at a streak line of the dust front seen on 22 October 2005. Here are shown some excellent images of Bill Flanagan. This streak looks parallel to the dawn line as shown in an earlier image as this (original image is due to Don Bates).


We also note that in the 1971 case of the great dust storm, William Baum reported as follows:


的n September 1971,, there was no visible evidence of any unusual activity on September 21st, but early the following morning as Noachis emerged from the morning terminator, it was brighter and whiter than any features of the storm during the days that followed.

At that time Mars was after opposition, and the phase angle was already as large as 30 degrees, and so very preferable to see the morning terminator which was quite inside. It is important to pay attention to the word whiter, and so the water vapour worked well at the early emergence.


We should say any orbiter should pay much attention to the morning terminator.


Finally we should comment that in order to deny the present proposition, it may be easy: Just find a counter example, that is, to find out a classical dust which bursts out in the daytime and rapidly develops.


We incidentally remark that the supposition or mechanism of the emergence of the classical dust at the morning terminator may be akin to the well-known fact that the perimeter of the polar cap is the very place which causes the polar dust. The boundary at the polar cap or the morning terminator is always exposed to the drastic change of meteorological conditions, and if some conditions of catastrophe could assemble, the dust would happen to be entrained.


Proposition III. Blue haze or blue clearing is a false idea


Even now it is said something about the Blue haze or Blue clearing at the opposition time. But nowadays it should be said these ideas should be given up especially to save the time. These ideas were constructed when they believed that the Martian world was full of seven colours like on the Earth. On the contrary we should say that the Martian world quite lacks the blue colour in reality. Some markings which can be trapped by the blue filters are caused by the drifting white cloud or mist, whose light of short wave lengths just make a pattern. The reason why it was observed well by W48 is because the larger images easily send slightly longer wave lengths. Do not say it is a 澱lue clearing if you see some dark markings in 500nm, but it may disappear in 410nm.

This does never imply that the observations by the use of blue filters are useless. On the contrary, it is important because the Blue component more depicts the spread of the water vapour as well as the dry iced area.


Proposition IV. A certain Solar activity precedes some Martian phenomena

On the 4th day of November in 2003, I visually detected a faint protrusion from the southern terminator at LCM=203 degrees of West. I did not take this so seriously, but on 7 November 2003 I again came across the protrusion similar to the previous one at the same angle, and so I phoned up Isao Miyazaki by mobile at the ocular part, and asked him to check it. Unfortunately however the sky at Okinawa was poor the night, but on the following day Miyazaki succeeded in observing it visually and then took the ccd images. This protrusion was not any kind of the white cloud or dust, but looked just like an auroral protrusion over Ausonia to Hellas.





Here we do not discuss about this phenomenon, but just would like to point out that just before the days the Sun was very active and on 28 October it emitted the proton flux of a total of 29500, and an X17 class big flare. Proton flux was extraordinary even at that time, and in a calm year like in 1988, it was twelve to 92 at maximum throughout the year.

I would like also to say that I have an impression that the emergences of the unseasonal dust clouds are also the ones affected by the solar activity. Effect is not so direct as the auroral protrusion phenomenon, and may be associated with a retardation. The above mentioned activity at the end of October in 2003 also emitted an X28 flare on 4 November and I suppose this kind of activity must have affected the dust disturbance which occurred really at the area of Solis Lacus observed from 13 October 2003 at the season of 280 degrees of Ls. The retardation is about one month and a half.


In 2005, the Sun emitted an X17 flare on 7 September, and one month and a half later aforementioned dust storm started from the area of Solis Lacus on 18 October at the season of 308 degrees of Ls.


The activity of the Sun is very independent of the season of the planet Mars. Conversely the Sun may interfere the thin atmospheric circumstances of the planet. The dust season may be normal at around the southern summer solstice, plausible from several points of view. But it is highly possible that the unseasonal emergences of the dusts must be affected the Sun activities.


In 2007, the Sun was very quiet but the dust occurred on around 22 June at 262 degrees of Ls, and hence it might have been seasonal. Even then at the beginning of June the Sun made a bit of action as shown here, and so it might have played a partial role of trigger:


Jan 16 2 0

Jan 21 1 0

Jan 25 2 0

Feb 16 1 0

Apr 24 1 0

May 03 1 0

May 16 1 0

June 01 1 3 Max M2.8

June 02 0 2 Max M2.5

June 03 2 3 Max M7.0

June 04 0 1

June 05 2 0

June 06 2 0

June 07 2 0

June 08 5 0

June 09 1 0

June 10 1 0

July 10 6 0

Aug 06 2 0

Aug 24 1 0

Dec 13 2 0

Dec 14 1 0

Dec 17 1 0

Dec 18 2 0

Dec 31 1 0

Jan 01 1 0

In 2001, in April there occurred several big flares including an X20 flare on 2 April and an X15 flare on 15 April. From around May there were seen several dust disturbances around the higher southern hemisphere, and eventually on 24 June a quiet but large dust burst out at a very unseasonal season at 184 degrees of Ls.

Unfortunately the data of flare and so on are not known in the remote past and so cannot be compared with the older dust storms. But it is in some cases somewhat possible to compare with the large Sun-spot-active-groups with the emergence of dusts.


Masatsugu MINAMI, Director, the OAA Mars Section, Japan

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