Drones!

Hey fellow nerds! Hope you're all enjoying the beginning of the week! I can’t believe it’s already June and officially summer! Between moving into a new place and doing deep edits on my thesis proposal, I’m working on a new summer schedule now that I don’t have to TA or take classes. I’m using the extra time to focus on research, and maybe a few fun things like shopping and traveling.

Got to hike to the Bright Angel Trail with my Dad and Sam in May!

Anyway, I’m itching to talk about drones! I’ve been working with and flying drones a lot this past semester as a way to learn a new skill for data acquisition for my research. It turns out learning how to fly a drone is not as easy as it looks…

The struggle is real!

But it’s been incredibly fun! You can fly drones for a number of reasons, whether it’s professional or recreational, like fancy-looking videos, photos, and surveys. For me, I’m learning that I can take large scale but detailed imagery of my study sites so that I can create high-quality hydrologic models for my research. To practice, I first performed a survey of a stretch of Revere Beach north of Boston:

Here's my study site on Revere Beach!

The purpose of the survey was to make sure that drone surveys could actually serve as an efficient alternative to manually conducted surveys for measuring beach erosion. We flew four flights on a beautiful April morning and were able to create this map:

Here's the orthmosaic showing the imagery from the drone survey with the locations of the four manual cross sections.

It was tricky, though. We were so close to the Boston Airport that the FAA authorities asked us to fly below an altitude of 80 feet to make sure we didn’t run the risk of hitting any planes. On top of that, piping plovers were nesting nearby, so we had to make sure that our drone didn’t disturb the birds. Luckily, we were not hit either a plane or a bird, and were able to come up with a few comparisons of manual to drone surveys:

 

Some of the cross sections are a little nicer than others!

I’m still doing some image processing to make the imagery a bit more accurate, and when I get it, I’ll definitely post it! But, in the meantime, feel free to contact me or comment below if you have any thoughts or questions!

Remote Sensing & Lagoons: How to measure inundation with aerial images

Hey geo-loves! Hope everyone was able to enjoy the weekend despite the political events that recently transpired. Going to the Women’s March in Boston last week was a really inspiring way to see people come together.

One of my photos from Instagram of the protest last weekend.

So, I’d like to talk a little bit more about my lagoons (they feel like my lagoons because I look at them so much!) and what I’m doing with them. Right now, I’m developing remote sensing for my lagoons in Salar de Atacama in Chile. What is remote sensing? It’s when you take satellite data (which in my case are images) and manipulate that data to get information.

In my case, I’ve been taking images of my lagoons and outlining the extent of their surface area in ArcGIS. By outlining the lagoons, I’m able to measure how the surface water expands and retreats through time. I am specifically focusing on a time period after a large precipitation event that occurred in March of 2015 to see how the lagoons responded to precipitation-driven recharge. Here’s a “before and after” shot of the lagoons on March 17, 2015 versus May 20, 2015.

Can you see the difference?

There’s a pretty noticeable difference, isn’t there? To measure the surface area of the lagoons, I draw polygons around the surface water extent and then use ArcGIS to measure their surface area.

I’m really excited for some new maps with even better resolution that will come out on the Landsat Imagery website later in February. I’m also excited to take this remote sensing a step further and measure the coloration of the pixels in each image to get even more accurate surface area measurements.

So what do we see in these lagoons’ responses to the March 2015 storm? First, we see that not all lagoons react uniformly. Those differences in response may indicate variations in topography, in discharge, or in recharge based on each locale’s stratigraphy. Second, we notice that the most recent lagoon changes may be a part of an ongoing decline in the over all extent of lagoons throughout the salar.

Why are these variations in lagoon surface area occurring? That’s for me to explore further in my thesis, and I’ll make sure to keep you guys updated every step of the way. In the mean time, feel free to comment on this post or e-mail me with questions or thoughts! Have a good weekend!

¿Qué pasó con las Lagunas?

Hope you all had a lovely holiday season so far! I’m in Kentucky visiting family, and I’ve been really enjoying just relaxing. Anyway, since I’ve finished a section of my prospectus, I figured I would share a bit more on my research focus for all of you who are interested.

Photo taken by my advisor of a transitional pool looking southeast towards the Andes.

Lately, I’ve been really fascinated with the lagoons that are located in Salar de Atacama (SdA). Here’s a quick refresher: SdA is a basin in the Atacama Desert in northern Chile, which is the driest nonpolar desert in the world and is therefore a great place to study groundwater dynamics in arid regions. SdA is also the home of the densest naturally occurring brine, which is water that has a lot of dissolved halite (i.e. salt) and other compounds that make it denser than fresh water. My general interest is defining the factors (like evaporation, dissolution, and changes in the hydraulic gradient) that drive groundwater flow in brine-rich and arid environments which, as I’ve mentioned in a previous post, are unique from mechanisms seen more temperate climates. 

Eastern view of Lagunas Miscanti and Miniques, looking towards the east at the Andes. Photo courtesy of my advisor!

I think that the lagoons are the key to studying those factors further. Why? Because the lagoons are located along the boundaries of SdA’s surrounding mountains and the basin’s halite nucleus, which is basically a giant chunk of salt that has accumulated in the valley floor of the basin from tens of thousands of years of evaporation. The lagoons are also located along the transition zone between the relatively fresh groundwater and the brine. These lagoons are only slightly briny, whereas the groundwater under the halite nucleus is incredibly briny (in fact, it’s likely the heaviest brine naturally found anywhere in the world). This means that the lagoons are likely being recharged from relatively fresh water coming from the uphill Altiplano region in the Andes. So, these lagoons and the area around them are a great place to study the processes by which freshwater turns into such heavy brine.

Flamingos depend on the algae and the crustaceans that live in the lagoons. Photo courtesy of my advisor.

So how can I study the lagoons and the areas around the lagoons to figure out how this brine develops? One good way is to delineate the extent of the brine and to figure out where the groundwater becomes so concentrated with dissolved sodium and lithium. A lot of work has already defined the lateral extent of brine, but the vertical extent of the brine is still poorly defined. There are also a lot of insightful techniques for tracing groundwater flow by studying changes in temperature, isotope ratios, and dissolved lithium and sodium. I’ll make sure to explain each tracer in more detail later on.

So, based on what we know, it looks like the lagoons are responsible for generating some of the densest brines on earth. Why? The extremely high evaporation rates extract water out of the lagoons and leave behind the dissolved compounds like sodium and lithium to create the denser brine, which eventually sinks down and into the rest of the brine that underlies the halite nucleus. The lagoons are likely the only place for this process to occur because the surface of the halite nucleus acts like a barrier against evaporation with almost no porosity and a very high albedo.

Here’s a little peak into my progress! Let me know if you have any questions, and Happy New Year!

Not all groundwater flows downhill

Happy Sunday! To start off the new week, I have some delicious tidbits on my research for you. This past Monday, I went with my advisor and another grad student to Worcester Polytechnic Institute for the NSF-sponsored Water Workshop. I presented a poster on my work, so I figured I’d talk about the details of my research focus a bit more.

Standing next to my poster for the Water Workshop at WPI!

Everyone agrees that water flows downhill. But does groundwater always flow downhill? That is, does groundwater flow always follow the topography? Not necessarily. Many people before me have proved that the groundwater table does not reflect the topography for a lot of aquifers. This depends on a lot of things, including recharge, depth of the groundwater table, the height of the aquifer, and the extent of the watershed. Strangely enough, not a single one of these factors dominate whether groundwater in an unconfined aquifer flows contrary to topography. They rather work together at different intervals to create this counter-topography behavior. And someone (i.e. me?) could spend a whole career investigating how all those factors affect one another to produce this affect.

It turns out that this behavior, which we call recharge-controlled flow, happens in a lot of places around the world, including parts of Massachusetts. More commonly, you see recharge-controlled flow in arid regions like the southwestern United States and my current study area, the Atacama!

Corenthal et al. (2016)

What’s going on in the Atacama, the world’s driest nonpolar desert, is really fascinating. Figure A is a conceptual illustration that shows how the groundwater table flows under all these high peaks to reach the salar, which is a salt flat. Based on what my research team and I know, the factors controlling groundwater flow in the Atacama include recharge (or rather, lack thereof) and the depth of the groundwater table from the surface.

The lack of recharge in Salar de Atacama as the world’s driest nonpolar desert means that its groundwater needs to come from somewhere else. That somewhere else is the relatively wetter, higher elevation peaks that we call the Altiplano (i.e. “high plains” in Spanish). This difference in recharge over time creates a difference in hydrologic head that causes the groundwater to defy all the topographical peaks in the Altiplano to flow towards Salar de Atacama.

Since Atacama is so dry, this groundwater flow creates a negative water balance equation as it continues to flow from areas with little precipitation to areas with almost no precipitation at all. In other words, more water is leaving the system than coming in. Because of this imbalance, the groundwater table probably continues to lower. As a groundwater table lowers, it becomes less dependent on the topographic variations.

This behavior has a lot of interesting and concerning implications. Atacama’s groundwater, which is the area’s only source of water, is nowhere near sustainable. This point is really important for the people and businesses that depend on this water. Plus, since groundwater takes a long time to travel, the distance that the Atacama’s water has travelled means that it is incredibly old. It’s probably on the order of thousands to tens of thousands of years old!

Well, here’s a quick taste of what I’ve been focusing on this semester. I promise I’ll talk about it more soon!

IT'S GETTING REAL: RESEARCH MEETING ON ALTIPLANO WATER STUDIES

Happy Fourth of July! It’s been an activity-filled weekend for me. After helping a friend move, having a giant iftar, and then spending a sun-bleached day at New Hampshire’s Hampton Beach, I’m very ready for a day to just sit and chill for a while at my favorite coffee shop, the Thinking Cup on Boston’s Newbury Street.  Or, at least, I’ll chill until the fireworks happen! Anyway, this past Friday I drove to UMass Amherst to meet with a group of professors and students that work on my new research focus, so I figured I’d chat about that a bit.

The meeting was really interesting because students were presenting research on water-related topics for the Altiplano* region beyond just groundwater, which is going to be my research focus, so it gave me a more holistic perspective on all the complex factors that affect the area’s hydrologic system**. From MIT, one student was dating ancient corals to study the past levels of prehistoric lakes, which would give insight into how the area’s climate has changed over time; a second student uses satellite images to get a more moderate understanding of how the Altiplano’s current lakes fluctuate seasonally. So it sounds like, going back fifteen thousand to a hundred and fifty thousand years, that whole area of Chile used to be a much wetter and much more temperate climate than it is now. And, even though the region is generally very arid, the lakes dramatically fluctuate based on the little rain that comes.

A UMass student, who’s also working with my advisor, talked about his work on the chemistry of near-surface waters in the eastern area of the Atacama. It was really good to hear from him and made me excited to work with him in the future. Another student from Penn State shared her killer study on Calcium isotope variations throughout specific areas of the Altiplano to pose different questions about how the hydrologic system affect those isotope variations. Basically, the water’s chemistry suggests that the hydrologic system is incredibly complex, with mind-blowingly old water mixing with much newer water in different ways throughout the Altiplano.

Afterwards, my advisor invited us all to his place for snacks and drinks. He’s so chill. Below are some photos from the day.

Anyway, the closer I get to entering graduate school, it’s really nice to find different ways to get focused and excited about what I’m about to do. Just being able to spend an entire day to think deeply about how complicated my future research would be gave me a huge peace of mind, especially when I saw all these impressive graduate students. Just watching them unpack their ideas, to see how they delve so intricately into their focus, helped me to see how I could do that same.

For all the upcoming graduate students out there, if you’re feeling like you need to find that focus and refuel that positive energy, you can always start your education before it happens. Especially in academia for natural sciences, you can learn from students in your program, discuss project ideas with your potential future advisor, read articles on your field of interest, or chat with researchers outside your program. Never be embarrassed to ask a question, and if someone gives you the “academic stink eye” because they presumably think it’s a dumb question, ignore them and ask someone else. And, above all else, give yourself lots of positive energy!

Meeting Room at UMass

After-Meeting Chill Session with my Advisor!

*Altiplano refers to the northeastern area of Chile that is way lifted high above sea level. It’s an interesting area to study because precipitation is so rare there, since the altitude blocks moisture and also the weather systems curl around and away from the area thanks to climate-defining convection currents. 

** Hydrologic system refers to the process by which water cycles through the atmosphere, precipitates to become surface water, drains into the soil to become groundwater, enters surface waters, and then gets evaporated back into the atmosphere.

MY THESIS WORK: LITHIUM-RICH WATER IN CHILE'S ATACAMA DESERT

 It’s been kind of a wacky but beautiful week for me. After returning from my Father’s Day camping trip with Dad, I’ve been exhausted and sleep looks so good but the energy from Ramadan lures me into staying up late. So now I’m nursing endless cups of chai tea at the office just to keep myself awake! I’ll press the reset button with a long sleep-in this weekend.

Anyway, it’s getting to that time where I’m preparing to return to school for my graduate degree! And I figured I’d share a bit about my work to see if anyone’s interested in learning about it, discussing it, or even potentially collaborating on it.

A photo posted by Robert Andreu Ferrer (@isard_pel_mon) on Jun 23, 2016 at 12:03pm PDT

Basically, I’ll be studying the lithium-rich waters of an aquifer that’s located in the Atacama Desert in Chile. This whole project is cool for a number of reasons, the first being that this happens to be the driest desert in the entire world second only to Antarctica. Yet, it happens to have a bunch of springs that have created these small pools all over the place. If you calculate the evaporation rate on these suckers, you’d see that the spring has to be pulling in a mind-blowingly huge amount of water from the ground (cuz it ain’t coming from the sky). My advisor has already worked with a previous student on calculations for the size of this aquifer’s watershed, and it’s calculated to be so big that it stretches into Argentina. It’s bananas.

Random fact: This one pool in the Atacama is a big-time breeding ground for flamingos. Seriously. So random. 

So what am I going to do in this super-cool-freak-show of a desert? I’m basically going to help to figure out where the lithium is coming from. This turns out to be an important question, since this one spot happens to be one of the biggest sources of lithium in the world. We all need batteries! And, on top of that, I get to learn Spanish!

I’m excited to share more about how my research is going as it progresses. Stay tuned!