Experienced flux tower technician, Alfonso Olimpo, shares advice for others looking to break into the field of eddy covariance and challenges of sensor maintenance at a remote tropical site.
Transcript
Jess: Barro Colorado island is an interesting place. It is a nature preserve in the middle of a manmade lake. How do you get there?
Alfonso: BCI is an island in the middle of the Panama Channel. The government of Panama gave to the American government this island to make research. This island emerged when they hold the Chagres River by a dam. The Gatun Lake was made in the middle of the channel. We have a town called Gamboa and we can get a boat to get into the island. We spend 40 minutes to get there. Scientists that go to the island to study, main staff, they work there every day. From the lab, you have to walk fifty minutes - more than half an hour to reach the tower on a trail that is like a mountain.
Jess: When you're on the trail, is there any wildlife that you notice going to the tower?
Alfonso: Oh yes, yes. When you walk you can see spider monkeys, howler monkeys, parrots. There are a lot of animals in the island.
Jess: Do you have to carry bear spray for jaguars?
Alfonso: There are a small...like, a cat. They call it here “onza”, onza or cunaguaro. This kind of animal only go out at night. Pero, in the evening, the thing that you can see is gatosolos. The name is “coatí”. They are savage. The other thing that you can find - pigs. They don't see you. They only can hear you or smell you. They are with you when you are almost beside them. One animal interesting is a sloth. This animal, very slow to defecate. They have to go down the tree and then go up again. One day I found a sloth doing that in the middle of the trail. So I wait, I see him. Pero, when he realized that I am seeing? Go up, don't finish.
Jess: The AVA tower is a 12-story tall structure built in 2012 as part of the Forest Global Earth Observatory or Forest-GEO by Dr. Matteo Detto. You also co-lead a multi-institutional project called the Next Generation Ecosystem Experiments-Tropics or NGEE-Tropics. How have you managed to collaborate with people who are so far away?
Alfonso: One of my primary responsibilities is the operation and maintenance of the eddy covariance system. During the installation phase, I worked closely with principal investigators and postdoctoral researchers providing on-site technological support including logistics, coordination, and implementation. This collaboration enabled me to later support a similar deployment in Manaus and Malaysia. Ongoing collaboration is maintained through regular meetings, facility coordination, and integration with the broader NGEE-Tropics framework. So, they came to Panama. We had a one-week meeting. I work with them, they go, I download the data, then we have video meetings. This meeting can be 10 scientists talking about different things. We make a “round robin”. So, when they call us, okay, “what happened in Manaus?” People talking about the paper. And when reached to Panama, I can tell them updates of what happened with equipment, how it’s going.
Jess: It seems like an intense day going to the site or demonstrating how the device works or the sensors work in the real environment.
Alfonso: For example, the last week Dr. Jeff Warren is working in Oak Ridge National Lab and he came here to make the calibration of TDR sensors (i.e., time-domain reflectometers) with soil moisture. So, I collect the soil before, dried the soil, and he came and in one week make the work that is intense. I always ask them to stay more. If they don't finish, I continue with the part that they don't finish.
Jess: Yeah, I can relate to those challenges. Our field site's pretty remote. and then on top of it you've got to be home by dark because there's not really enough lights to find your way.
Alfonso: When I work in the tower, if I go in the morning and I have to climb the tower, I climb and I stay two hours or three hours in the tower. Pero, but, I have to go down at 1pm and I have to start walking down to the top at 2 because the boat leaves at 3:40 and they don't wait for no one. The island has facilities where the scientists can rest - rooms, food, everything. Normally I don't stay. I only go and I stay when I need to do it, just to save funds.
Jess: And the 30 minutes that you wait before you climb the tower, that's to catch your breath after walking up the mountain?
Alfonso: Yes. I'm prepared to climb 40 meters.
Jess: I bet.
Alfonso: Sometimes, it takes me more.
Jess: Yeah, and you don't want to slip either if there's like rain or if there's dew or...you know?
Alfonso: Yes.
Jess: You've worked at STRI for the last seven years. What environmental changes have you observed firsthand through your time at the site? Have you witnessed things like droughts and warming, which the tower was originally installed to monitor?
Alfonso: I have observed increasing variability in the rain pattern, including the last El Niño event, where the day that you expect rain, not rain, and the day that you expect that has to be dry, dry, dry is not dry. Things change. In this moment when it was very cold in the States, here has to be dry, and was raining. So that switches the responses of the trees. They started to get out the flowers faster because they don't know, “okay, I'm in a dry season”. But the raining arrives, the forest feels that, and you see. We have another site in Panama City. It's more dry, because this experiment is like a gradient. In the north of the country in Colón is wet. In the middle where is BCI, is wet more or less, or wet always. Pero in the south, it’s dry. So when here it’s dry, dry, dry, in the island it’s raining. You can have two kind of sensors, in the rain, with this difference. That's one of the main [point] of the project - to see what happened with these gradients. That's why we have another equipment in Manaus and in Malaysia - rain more than here. It's a different forest, pero the same tropic.
Jess: You don't have snow, but you've got all those other things like the bugs, the monkeys.
Alfonso: That's another animal that I don't mention. Insects.
Jess: The Smithsonian field station on Barro Colorado was established in 1923, but didn't officially become the Smithsonian Tropical Research Institute until 1966. What was your familiarity with eddy covariance flux systems or biological field stations in general, before starting your current position? How did you learn the things that you know now?
Alfonso: I am learning, still learning. Prior to doing this role, I had a general understanding of what is an “eddy covariance system”, but not directly an operational experience. My background is [that] I am a system engineer. I have more than 15 years of experience working in telecommunications, computers, networks. The eddy covariance system is delicate to operate, delicate to get the data, and more in any environment to maintain the system or the equipment collecting data. It's not a computer; it's not a cable. We have to be careful to maintain this kind of thing. After I started to go to the field, I started to learn the connection, how to maintain, etc. At the beginning, Matteo Detto told me how the system works: what the thing you have to do, what things you don't have to do. Move this, not move this. But when the system fails, I have to change it alone. In that moment, I apply my experience to maintain the system. My primary objective is that this tower is working 24 hours. That's one of the most...not difficult, but challenging things here in the tropics.
Jess: Yeah, you're out there, no cell service, no internet. You can't necessarily, like, ask someone for help when you're 100 feet up in a canopy and facing a problem.
Alfonso: Pero, one of the things that I do is check the data. I check the raw data so I know when the sensor is working okay. I know the boundaries where the data that you are collecting has to be, and then if it’s on or off. If you can make the system on again and the equipment are okay, you leave it there. Pero when...when you see a spike, for example in the anemometer, we have to take it down and replace it. I take this and send it to, in our case, it’s Campbell. They make the calibration and the maintenance that [is] needed. We have marine air from the Caribbean. So, some things rust more fast than others. Pero, but, if I found something disconnected, the battery is down, the cable is broken, the connector is damaged - I replace all. I try to make the system work again. Normally, I found the solution.
Jess: Sea foam is an issue at our site as well. People might not realize it, but just because something's waterproof doesn't mean that it's water vapor proof. Sometimes gases can get inside things and cause corrosion.
Alfonso: When the values change, [sometimes the problem is just that] it’s raining, a little rain. You can think that everything is bad, pero it's not necessarily.
Jess: I would check my site quite often when I had first started in my position, and the sensor was quite often blocked, and I would panic and be like, “I need to go to the field immediately!” Now I look...I look first thing at the weather and usually, it is rain. So what is your advice to others who want to learn eddy flux but don't know where to start?
Alfonso: You can read about [it]. Now, we have YouTube. Everybody has a video. We have tutorials, but normally it's not the same [as] on the field. The first thing that you need to do is go to the field to see how the things are. Participate in the field campaign. You need to compare your results with others. I can assume that the data is okay, but the sensor is totally far away [from what is normal for] the values, or the graphic is noisy. You can spend one year thinking that the thing is okay, and if nobody else looks at the data, you will lose that year. Working directly with equipment accelerates learning and builds practical understanding that cannot be gained from theory alone. Finally, engage with the community, ask questions, seek mentorship, and learn from experienced operators in the same field. The collaboration is totally necessary.