As you can see in the picture to the left, the dust devils on Mars are significantly larger than dust devils on Earth.

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1 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

2 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

3 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) 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.

4 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

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 V V V V V V V V V V V V V V V V V V V V

6 V V V V V V V V V V V V V V V V V V V V V V V V V V V

7 V V V V V V V

8 MOLA map showing image locations in Syrtis Major

9 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.

10 In the summer we only found only three wind streaks. Two of the three wind streaks came from the East and the Southeast.

11 In the fall, we found five wind streaks, all coming from the Northeast.

12 We found a number of wind streaks in the Mars winter images. Most came from the Northeast and East.

13 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.

14 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.

15 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, , Bell, Trudy. (2005, April 15). The devils on mars. Retrieved from Dust-Devil Tracks in Southern Schiaparelli Basin." N.p., n.d. Web. 13 Dec < >. Taylor, A. (2009, November 6). Martian landscapes. Retrieved from Themis: v (n.d.). Retrieved from Grossman, Lisa. "Mars Dust-Devil Mystery Solved On Earth." Wired Science. N.p., September 24, Web. 13 Dec Acknowledgements: We would like to recognize the following people for their contributions to this research project: Jon Hill Jessica Swann Sheri Klug-Boonstra

16 Future Investigations One of our team members discovered an interesting feature at the following coordinates: E ; N - THEMIS image ID: V (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.

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