A Study of Wind Streak and Dust Devil Track Direction in Syrtis Major to Establish Consistent Wind Direction and Determine if This Changes by Season. Mars Student Imaging Project March 2011 Rim Country Middle School Introduction Our question: Do Dust Devils and Wind Streaks consistently go in the same direction, similar to global circulation on Earth? Does this vary by season? Our question is important because it helps us to realize the factors (seasonal or otherwise) of wind and weather patterns on Mars. Understanding these factors can contribute to our own knowledge of these processes on Earth. It can also help us understand weather patterns on other planets. Our hypothesis: We predict that the wind in Syrtis Major will blow from East to West year round and is not be affected by season
Definitions Dust Devils are vortices of wind formed by the heating of the planets surface and differential temperatures of the atmosphere. It is hard to tell from the dust devil tracks which direction they are coming from and where they end. Wind streaks: the sediment that has been deposited or eroded at the back of the craters by the wind. This tail points the opposite direction that the wind blows. Wind Streaks, Dark: Light
Background Dust devils are formed on Mars in much the same way that we see them form on Earth. The Sun heats the surface of the planet, causing a vortex to form. The vortex is blown sideways by crosswinds. Because dust devils require surface heating during the formation of a dust devil, they are most commonly formed in the hot, dry days of summer. On Earth, the temperature needs to get above 80 degrees Fahrenheit for the air to get hot enough to begin the vortex. Although it is possible to have a dust devil form anywhere, for it to be visible the ground needs to be dry enough to pick up dust. This is why dust devils are more common in arid dry deserts, such as Arizona. The Dust Devil in Arizona are electrically charged, so the ones on Mars are likely charged the same way. Dust-devils are important in sustaining the aerosols that make up Mars red sky and in cleaning up the surface of Mars after a storm. Dust-devils form black tracks in the surface by removing the thin layer of dust on the surface revealing the surface below. Dust-devil tracks often appear in clusters, as dust-devils repeatedly form over the same terrain. Dust-devils on Mars can go up to nine kilometers above the surface. (see diagrams below) http://science.nasa.gov/science- news/science- at- nasa/2005/14jul_dustdevils/ As you can see in the picture to the left, the dust devils on Mars are significantly larger than dust devils on Earth.
Procedures/ Methods The tools that we used to record our data were the Mars Odyssey s THEMIS camera, and the official THEMIS website, themis.mars.asu.edu/. Our main focus was on Syrtis Major, and we hoped to find dust devil tracks and wind streaks. First, we used our primary and secondary images, along with archived THEMIS images nearby in Syrtis Major to look for aeolian formations (dust devil tracks and wind streaks). We used the following numbers to record our findings in excel. We used the key below to code for the direction of wind streaks or dust devil tracks. Then we organized and graphed the data. We also recorded the pictures ID number, central latitude and longitude, Mars year, solar longitude, and directions of formation. Key for Wind Streak and Dust Devil direction in data table. Dust Devils Wind Streaks N - S 1 N 6 E - W 2 S 7 NW - SE 3 E 8 NE - SW 4 W 9 RANDOM 5 NW 10 NE 11 SW 12 SE 13 RANDOM 5
Results: Raw Data: We collected 54 images within Syrtis Major, plus our primary and secondary targets, making 56 images overall. See the key above to help decode wind streak and dust devil direction. Wind Image ID # Longitude (E) Latitude (N) Solar Longitude Year Dust Devil Direction Streak Direction V10483013 63.702354 10.964514 24.478441 27 2 8 V02307010 63.87841 11.185384 30.891275 26 8 V26120012 63.51181 10.271925 341.67255 28 8 V34891011 66.08509 7.412488 359.826 29 11 V34267026 66.036446 7.54791 333.03308 29 11 V33493009 77.49419 18.172506 296.40604 29 13 V14501022 77.72776 18.084417 179.75256 27 V17834001 77.31416-0.492209 344.14645 27 12 V16611001 77.13148-0.415466 286.5594 27 13 V27405035 72.947914 17.465963 33.355305 29 13 V27455020 70.64747 18.765598 35.226627 29 13 V26232021 73.32635 16.962631 346.5204 28 13 V17646033 74.178246 17.685392 335.94092 27 8 V20766011 73.045815 18.248796 95.29067 28 13 V19206010 73.4374 19.018423 38.75194 28 8 V26594037 69.86142 16.370667 1.688169 29 13 V17721025 339.259 4.482602 339.259 27 8 V05902005 68.79282 5.231976 168.15654 26 8 V10670011 68.60858 5.365546 31.574678 27 8 V26881027 68.413315 4.687646 13.219376 29 8
V13116009 68.59795 2.948382 121.30204 27 V32645012 68.143776 3.736154 252.88446 29 11 V25995023 68.64303 3.710069 336.17007 28 11 V27742029 68.70645 3.69769 45.842167 29 11 V07837821 65.3791 3.26071 264.4964 26 11 V11656009 65.460075 3.84583 67.61142 27 11 V07837021 65.371 3.260102 264.4964 26 11 V10383015 68.038185 8.939999 20.632278 27 8 V10071016 68.23078 9.172451 8.361829 27 11 V10695006 67.94362 8.968804 32.514095 27 11 V18395010 67.053734 12.151818 7.558981 28 9 V26931032 66.883484 11.601605 15.187371 29 9 V37387013 66.6701 11.031589 92.91399 30 9 V08536018 67.18054 0.664219 300.03723 26 11 V09759019 67.08119-0.097215 355.6206 26 11 V26308001 67.30166-0.422909 349.72684 28 11 V10383017 66.82564-0.096413 20.63325 27 11 V16523013 66.90957 0.576665 282.10452 27 11 V26906032 66.537636-0.076922 14.205669 29 11 V18059001 66.66413-0.859718 353.73376 27 11 V26333001 66.08705-0.447024 350.78754 28 11 V17747001 66.93399-0.890294 340.35727 27 11 V27193035 66.86037 1.321954 25.333574 29 11 V26906032 66.537636-0.076922 14.205669 29 11 V27742027 69.44485 9.159065 45.841606 29 8 V25995021 69.40919 9.378468 336.16937 28 8 V26095019 67.80044 6.897545 340.5801 28 4
V26956033 64.969 6.596707 16.16816 29 12 V27530028 65.1483 5.645487 38.021744 29 11 V02282010 64.150536 6.070893 29.94872 26 11 V26669040 64.712616 5.604929 4.741872 29 11 V35615007 63.677795 5.046225 28.354155 30 1 11 V10071016 68.23078 9.172451 8.361829 27 12 V10383015 68.038185 8.939999 20.632278 27 9
MOLA map showing image locations in Syrtis Major
This graph shows the amount of wind streaks and dust devils found in the Mars season of spring. We found that the most common direction of wind streaks was coming from the North East and East. We did not have enough data to show a consistent pattern with dust devils.
In the summer we only found only three wind streaks. Two of the three wind streaks came from the East and the Southeast.
In the fall, we found five wind streaks, all coming from the Northeast.
We found a number of wind streaks in the Mars winter images. Most came from the Northeast and East.
We observed a total of 59 wind streaks and three dust devil tracks. The majority of the wind streaks appeared to have originated from an Easterly direction. We did not have enough data to determine dust devil direction.
Conclusions We researched whether dust devil tracks and wind streaks traveled consistently in the same direction, similar to global circulation on Earth, and if this changed by season. Our hypothesis was that the wind would go Northeast to Southwest year round and that there would be no variation by season. Our hypothesis was supported. The wind appeared to generally travel in a Northeast to Southwest direction. According to our data there was not much change in the wind by the season, but due to lack of data during the summer, we cannot make any certain conclusions. Discussion Errors and Bias: Possible errors that we might have made include the following: It is easy to mistake the direction of the wind streak tail, thus resulting in conflicting data. The tail points in the opposite direction from which the wind blows. We may have neglected to enter all images and it is likely that some data points were entered incorrectly. Very few of the images contained dust devil tracks; therefore we were unable to make any definite conclusions on general direction of dust devil tracks. It is difficult to determine when wind streaks are formed, as they may have formed in a previous season and still be visible later. We did not have multiple images of the same site so that we could compare different seasons.
References Christensen, P.R., B.M. Jakosky, H.H. Kieffer, M.C. Malin, H.Y. McSween, Jr., K. Nealson, G.L. Mehall, S.H. Silverman, S. Ferry, M. Caplinger, and M. Ravine, The Thermal Emission Imaging System (THEMIS) for the Mars 2001 Odyssey Mission, Space Science Reviews, 110, 85-130, 2004. Bell, Trudy. (2005, April 15). The devils on mars. Retrieved from http://science.nasa.gov/science-news/science-atnasa/2005/14jul_dustdevils/ Dust-Devil Tracks in Southern Schiaparelli Basin." http://www.nasa.gov. N.p., n.d. Web. 13 Dec 2010. <http://www.nasa.gov/mission_pages/mro/multimedia/mro20080123.html >. Taylor, A. (2009, November 6). Martian landscapes. Retrieved from http://www.boston.com/bigpicture/2009/11/martian_landscapes.html Themis: v27128030. (n.d.). Retrieved from http://viewer.mars.asu.edu/planetview/inst/themis/v27128030 Grossman, Lisa. "Mars Dust-Devil Mystery Solved On Earth." Wired Science. N.p., September 24, 2010. Web. 13 Dec 2010. Acknowledgements: We would like to recognize the following people for their contributions to this research project: Jon Hill Jessica Swann Sheri Klug-Boonstra
Future Investigations One of our team members discovered an interesting feature at the following coordinates: 63.92072E ; 11.55359N - THEMIS image ID: V02307010 (Mars Year 26) look at very top of image below. Using THEMIS, we found a very small, very dark crater with an excessively long, flaring dark wind streak emanating from it. This wind streak is very different from any others that we had observed. We weren t able to get a good look at the crater with the THEMIS camera. It was too small and got pixilated. The ejecta was barely visible in the MOC image and the crater was a little more visible, but still fuzzy. Our team determined that a higher resolution image is needed. Thus, we decided to HiWish to request an image of the area with the HiRise camera. We are hoping that a more detailed image will help answer the following questions: 1) Is the dark wind streak still present, since the THEMIS and MOC images were taken? 2) What does the crater looks like in Hi-Resolution is it very deep, or did it uncover dark soil? 3) Since the MOC and THEMIS images were taken a while ago, how much dust has accumulated over the site.