Some Preliminary Results
Jul 3, 2019
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.  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. .
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. .
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.  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.  (black and grey) for the Earth and Moon.
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.
This week I will be discussing the Thermal Emission Spectrometer (TES) Dust Cover Index (DCI) map of Mars.
1. What is the TES DCI?
- The TES DCI is a measure of the relative abundance of the spectrally obscuring dust across the surface of Mars. It is independent of albedo and it is based on the fact that fine grains of silicates show an average emissivity from 1350 to 1400 cm-1, where surfaces with high abundance of silicate particulates (dust-covered surfaces) show lower emissivity and surfaces with an absence of silicates particulates (dust-free surfaces) show high emissivity.
2. What is the value range of the TES DCI?
- The values of the TES DCI range from 0.89 to 1.00, where lower values represent dust-covered surfaces and higher values represent dust-free surfaces.
3. What are the average TES DCI values for dust-covered and dust-free surfaces on Mars?
- Dust-covered surfaces have an average value of 0.931 ± 0.009, and dust-free surfaces have a value of 0.969 ± 0.007 (see Figure 1).
Figure 1: Global map of the TES DCI of Mars on top of the Mars Orbiter Laser Altimeter shade relief base map. Courtesy of NASA/JPL/Goddard
4. What wavelengths the TES DCI uses?
- TES DCI is sensitive to thermal-IR wavelengths (few tens of microns), making it a perfect metric to measure physical characteristics of surfaces.
Here, we identified the TES DCI average values for some volcanic surfaces on Mars and plot them against their RMS slope (see Figure 2), to help us establish how the TES DCI affects our surface roughness values for these surfaces. Note that the TES DCI range for this work is from ~ 0.92 to 0.98. With a range of 0.06, every change is significant; even a difference of 0.01, 0.02, or 0.03. In this plot, we see that duster surfaces have low RMS slope (they are smoother) with some exceptions and vice versa.
Figure 2: RMS slope vs TES DCI for volcanic surfaces of Mars.
Ruff, S. W., and P. R. Christensen, Bright and dark regions on Mars: Particle size and mineralogical characteristics based on Thermal Emission Spectrometer data, J. Geophys. Res., 107(E12), 5127, doi:10.1029/2001JE001580, 2002.
These past few weeks have been very intense and super busy. And when I said busy and intense, I refer to:
1. Finished up writing the first draft of Chapter 2 (Datasets and Methodology).
2. Processed a huge amount of HiRISE stereo-pairs into DTMs and extracted the surface roughness for many lava flows and then plotted them into an RMS slope vs Hurst Exponent graph.
3. Identified the TES Dust Cover Index (DCI) for each of those lava flows and plotted them in an RSM slope vs TES DCI graph.
4. Took a course on the Moon as part of the CanMoon analogue mission.
5. Got accepted into the Natural Space Risks Summer School 2019 at the Paris Observatory. (YAY!!)
6. Applied and got interviewed for a volunteer position at the Children Aid Society of London and Middlesex.
7. Still editing Chapter 1 (Introduction). It’s hard to write when one is so busy doing lab and class work.
8. Made and outline for Chapter 3 (Results).
Here I am showing the latest RSM slope vs Hurst exponent plot for Martian lava flows (this work), the Moon, and Earth (Neish et al., 2017). It is quite notable the difference in surface roughness between Martian and COTM lava flows. Here, Martian lava flows tend to have RMS slopes from 0 degrees up to 15 degrees, and a Hurst exponent from ~0.5 to 9. These values are more similar to those surface roughness values from Iceland, Mauna Ulu, and the Moon. More interpretations are yet to come.
Even though I have made a lot of progress with my work these past few weeks, I have not gotten the change to sit down and interpret more in detail my results. More interpretations are yet to come.
Next blogs will include:
1. RMS slope vs TES DCI plot.
2. RMS slope vs H for different Mars volcanic regions.
3. RMS slope vs H for CTX DTMs.
4. Radar image with radar bright and radar smooth areas already processed.
This is all for now!!!
My LPSC 2019 Experience
May 1, 2019
This week, my blog is dedicated to my LPSC 2019 experience.
I want to start by saying that it was an A M A Z I N G experience. Way better and more different than previous years. I remember my very first LPSC. It did not go as good as I plan it. This was because I did not know many people, was so intimidated by everyone, and my imposter syndrome was on fire. I also remember being so nervous all the time, that every time I will meet a new person I could not even talk in English. The words would not come out of my mouth. My mind was blank. But this year was different. I was confident, handling my stress very well and did not let my imposter syndrome take over me. I met so many people from different universities and other institutions. I even met and hangout with a Canadian astronaut. And this time my words came out from my mouth!!! I was feeling so welcoming and belonging in this scientific world.
This year, my abstract got chosen for a talk presentation. All week long, I practiced my talk around 20 times with friends, colleagues and at the early career presenters’ event. As crazy as it sounds, it was actually very helpful. Every time I gave my practice talk to different people, they had questions and suggestions that helped me when giving my real talk. After my real talk, I got so many questions from the audience. Questions that surprisingly I knew all the answers for.
After my talk and at the exhibits and poster sessions, many people stopped me to tell me "hey, I was in your talk, it was amazing. I learned so much from it". I was impressed and feeling very happy and proud about myself.
Thank you, Catherine, for making this happen.
Here are some picture from my week at LPSC 2019. Enjoy!!!
This is me giving my real talk!!
Here I am thouching three planetary bodies at the same time, Earth, Moon, and Mars!!!
Hanging out with Canadian Astronaut Dr. Jenny Sidey-Gibbons!!
Boricua Planeteers reunion at LPSC 2019!
Arecibo reunion at LPSC 2019!!!