Changes

The campaign is now halfway through: We are taking data since Feb 03, and we (that is the Mainz Particle Chemistry group) plan to leave on March 06. Now is the time for a change: I (Johannes) am flying home to Germany today, and Sören has arrived at the site yesterday to take over. After 4 weeks Brazil I am quite happy to come home again, although I enjoyed the time here. Once the instruments were out of customs, everything went quite smoothly, and the days at the field site were really nice. The data we took so far are very interesting, during the last "science meeting" at the field site (see foto) we had a very intensive discussion on the origin of the particles and air masses we observed here.
At the field site it is rather empty these days: There is a workshop an Amazonas Aerosols nearby, which was originally scheduled after the campaign, but since the campaign had to be shifted, it is now in the middle of the campaign. That means that many people have left to go to the workshop, and the field site is run by only six persons who take care also of foreign instruments.

While I look forward to arriving in a cold, winterly Germany, I hope that everything is still running well at the field site, and I can post further information here when news from the site reach me.

Update

(posted on behalf of Michel and Delphine, who are at the site right now)

We can now say the campaign has officially started. A true Brazilian start that is, with several waves of installations, numerous delays and the occasional drama created by an inopportune rainstorm. For the last seven days practically all the instruments that are supposed to be measuring are running and getting data. For most of us it seems as if we’ve been living at the site for a long time, even though we have only been here for a little more than a week. Our food is quiet monotonous, but still very good: we have pasta with garlic, rice, black beans, and some salad every day for lunch and dinner, only the meat part of the meal changes, well change means either chicken or meat. Also we have tried to keep our beer supply as constant as possible, with the temperatures and humidity we have, drinking 3 beers a day is a low count, and even the non drinkers have acquired a drinking habit. I have to say, the beer keeps the conversations flowing, everyone happy and keeps us away from thinking about the snakes (not trivial, considering the venomous one that apparently lives under the dining hall. With the large, hairy tarantula-like spider.) The sleeping part has gone amazingly well, we don’t have a big snorer that keeps everyone awake all night, and the heat is not as bad as I thought it was going to be, we even occasionally have cool mornings. It is a testament to our ability to adapt that people who were only a couple of weeks ago in the midst of Colorado and Germany winters find 23C to be chilly.

Our every day life has also begun to take a regular schedule: early in the morning the cook wakes us up turning the Brazilian radio on around 6, and don’t think this is a request, it is his schedule, we have just “adapted” to it… we then have our regular toast with eggs, coffee – with that constant hope for that occasional treat of sweetened fried dough to dip in the coffee. After breakfast, almost everyone goes up to the container to check that instruments ran smoothly throughout the night, get the data out for the last day, and go back to the cabin to begin a preliminary analysis. We sit in front of the computer as if we were back in our regular office until lunch is ready, and after lunch we either go back to the computer or to fix whatever problem the instrument might have, of course if it was fixed in the morning, the computer takes over.

(Editor’s note: This ‘typical office morning’ only holds true for those lucky enough to have functioning instruments. The rest of us spend hours trying to troubleshoot broken valves, find leaks and cobble together inlets from string and leftover tubing…) However, we can all agree that the “day breakers” are definitely more interesting than at our regular office: a 3 meter snake deciding to rest in the middle of the road, monkeys screaming (and the resulting futile, but daily attempts to find them with binoculars or cameras), rain showers so strong that a small river is carved through the road, or the little puppy (full name: Pegaleve Pirahna Anklebiter) from the cabin biting our ankles to get some attention. And even more interesting are our conversations at night: it is not common to have people from China, Germany, Canada, Brazil, Austria, Mexico, Spain, Israel, Sweden, the US, England, and India sitting at the same table expressing their ideas. Particularly when there’s no internet or television to distract from conversation. I think we have successfully figured out how the settle all diplomacy issues in the Middle East – not to mention global climate change and US primary elections. The one thing we can’t agree on is how to play pool. There is a pool table here, albeit cursed with a strong curvature, narrow pockets and an ever-changing set of rules that inevitably give advantage to the Brazilians. The key seems to be arguing loudly.

I believe most of us are very happy with our daily routines, and not having internet access has somehow made everyone more relaxed. The perfect example of the low-key attitude around here was two nights ago, when the lights went out in the lodge after dinner. Not a single person got flustered – there was a calm, slow move to acquire flashlights. The only concern was over the instruments, and an initial search party was sent up to the container. But all was well, and the power-sucking culprit in the lodge appears to have been the hot water heater in the shower. And, really, who needs a hot shower in the middle of the Amazonian jungle, anyways?

Michel and Delphine

How do we collect particles

We are finally in the place we wanted to be after two weeks of waiting. We had a great trip from Manaus, no problems with anything falling from the truck and we only had some bad rain for the last 5 km on the mud road, but when we arrived at the site it stopped. Now it was time to set up our instruments; I’m in charge of an optical particle counter (I’ll explain what it does exactly in another entry) and Johannes is in charge of an aerosol mass spectrometer; there are plenty of other instruments which I hope I can get the people in charge of them to write a little about them, or I’ll explain to the best of my knowledge the way they work and what they measure.

Johannes explained what are we doing in the rain forest and what do we want to measure, now I’ll explain how do we get the particles we want to measure, we need to collect the particles some how if not all the fancy instruments we have are useless, here is where the high towers you’ve seen in other pictures come into play. Why don’t we just collect the particles at ground level? Because we will not be measuring the particles we want to measure. We will be collecting dust from our shoes, the cigarette smoke from our fellow friends taking a break, or the particles from the only car that passes by once a day to bring people to the site, so as you can imagine our samples will be contaminated, the data will be useless. We want the particles from the rain forest, so to collect them with the least amount of “foreign particles” we take them 10 meters and 40 meters above the ground. However, we cannot just put a hose, tie it to the tower and measure, remember we want to measure the aerosols not the water vapor in the air. If you’ve been to the rain forest you can remember it is very humid, we need to get rid of all the water vapor in the air. To do these we literally dry the particles before they go into the instruments by making them pass through “marbles” made out of very absorbing material. We also need to heat up the tubes. In a hot sunny day the temperature on top of the trees is higher than at the ground, so the pumps from the instruments will be sucking hot humid air from the top and as the temperature decreases on the way down water droplets will form, and we don’t want water, besides sticking to the tubes and not letting all the particles go through it will ruin the pumps from the instruments.

In summary, we collect particles by sucking air from 10 or 40 meters above the ground making them go through a heated tube, then we dry them and finally they get distributed to the different instruments.