Carolina R SV

MSc Student 

Earth & Planetary Sciences Univeristy of Western Ontario 

 

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    Some Preliminary Results

    Hi all, 

    Today, I am showing some of the preliminary results for this project.

    Let’s recap for a bit before I throw these preliminary results.... 

    So, from the Arecibo backscattered radar image of Mars, we can see that the major volcanic regions of Mars are very bright, which means that these surfaces are extremely rough. These surfaces also have high CPR values, which are also produced by extremely rough surfaces. Also, some lava flows seen on Earth (Iceland, Hawaii, COTM) and the Moon (Ina D) share these radar characteristics (high CPR values and radar-bight returns) with those lavas seen on Mars. Having these in mind, we are quantifying the surface roughness for volcanic surfaces on Mars using very high-resolution datasets. We are also comparing the surface roughness parameters from this work to Neish et al. [2017] work for terrestrial and lunar lava flows. This will help us constrain the surface roughness of the red planet and infer how its lava flows were emplaced.  

     

    As for today, we have 40 HiRISE DTMs of the radar-bright and radar-smooth surfaces of Mars; 34 from ASP and 6 from SOCET SET. From the 34 ASP-derived DTMs, 29 have been already used to extract the surface roughness (RMS slope and Hurst exponent) for Martian lava flows; while 5 are still in the process. Also, 7 HiRISE stereo-pairs from radar-bright and radar smooth surfaces of Mars are still in line to be processed. Figure 1 shows the locations of all the HiRISE DTMs processed completely (red), the ones which I still need to extract their surface roughness (green), and the ones in line to be processed into DTMs (yellow).

    Figure 1: Arecibo radar image of Mars showing the locations for the DTMs used in this project. Three of these locations are south from the Doppler equator.

    Modified from: Harmon et al. [2012].

     

    Since the lava flows on Mars are widely dispersed along its surface, I have divided them into five main regions (see figure 2) and plotted their surface roughness (see figure 3).  As for now, the RMS slope range from 0 to 15 degrees with an average slope lesser that one; while the Hurst exponent range from around 0.5 to 0.9 and has an average of around 0.8. 

    Figure 2: Arecibo radar image of Mars showing the five main regions were the volcanic regions were classified. 

    Modified from: Harmon et al. [2012].

     

    Figure 3: RMS slope and Hurst exponent parameters derived from Martian lava flows classified into five main regions. 

     

    I have also classified these surfaces into radar-smooth and radar-bright surfaces and have plotted their surface roughness for comparison (see Figure 4). It looks like the roughest lava flow is radar-smooth. Weird... I was expecting a radar-bright surface for such relatively high RMS slope.  However, I still need to put more thought into this plot to explain such values. 

     

    Figure 4: RMS slope and Hurst exponent parameters derived from Martian lava flows classified into radar-bright and radar-smooth surfaces. 

     

    Finally, I plotted the surface roughness derived from this work with Neish et al. [2017] work for the Earth and Moon for comparison (see Figure 5).  From this plot, we can see that the majority of the Martian lava flows are smooth and resembles Ina D surface roughness. However, there are a few that share the same surface roughness parameters to those lavas on COTM, Iceland, and Mauna Ulu.

     

    Figure 5: RMS slope and Hurst exponent parameters derived from this work (red) and Neish et al. [2017] (black and grey) for the Earth and Moon. 

     

     

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    This is more or less all of now! 

    See you next week. 

    FYI: In my next blog post I will talk about how the TES DCI affects the surfaces roughness parameters obtained. 

     

     

     

     

     

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