Weather: A bit cloudy and windy

We began by refilling the water bucked, which was almost empty.

We looked at the footprint map that we had previously computed, and we decided the spots for the chamber measurements. Pep marked them with wooden poles.

Nil helped us clean the sensors, using the ethyl alcohol, and removing spiderwebs and other dirts. Parallelly, we downloaded met and flux data without any issue.

We checked the IP addresses to make sure they were still in automatic mode as we left them last time and confirmed that they were.

We also checked the clocks and noticed they were running about a minute behind UTC. After connecting the GPS, the clocks were calibrated correctly. There was a slight delay of 0.5s between the two gas sensors, but after a brief period they synchronized.

Nil and Angèlica checked if the anemometer was straight (since data processing showed a zenith angle mean different from zero). We found that the screws were a little loose, causing the anemometer to tilt slightly in one direction. We fixed that by tightening some of the screws (the tilt was not in the direction of the metallic pieces that join the different parts of the support structure).

When checking the thermocouples, we noticed a few issues. The reading on TC_min2_3 was still too high, so we re-taped it to stabilize the reading. We will need to check it next time. TC_min32_2 had lost its black covering, so we should replace it when we build the third tower, using a thermocouple from the spare equipment We also found that TC_32_3 was showing NaN values. The problem turned out to be a loose connection to the multiplexer, which we quickly fixed.

We then repositioned the soil sensors and radiometers. Adjusting the thermocouples was tricky without the proper tools, but we managed to do it. The soil sensors were placed in order from left to right as 1, 2, 3, looking from the tower towards the field. In the multiplexor, the order is also 1, 2, 3.

As for the field conditions, the vegetation was about 30 cm tall, and there was around 2-3 cm of water on the soil’s surface.

With all tasks completed, we wrapped up and headed to Els Muntells for a well-deserved lunch.

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