We met at UAB at 9 UTC and packed everything needed to assemble the Alfacada tower into the car. By 11:00 UTC, we departed from the university and made our way to Eurecat, where we picked up Pep’s keys for Alfacada. Afterwards we had lunch and arrived at the field at 15 UTC.

The weather was quite unstable throughout the day. The sky remained partially cloudy, and around 15:30 UTC, a light rain fell for about half an hour. There was a slight breeze and the temperature was mild.

Ethernet connection

We began by stopping data acquisition and taking the smartflux readings. To connect to SmartFlux and the datalogger, we had to change the PC IP from 14 (Alfacada) to 13 (Riet Vell), something that will need to be done each time we switch between towers.

Data downloading and usb memory

Once connected, we proceeded to download the data, which took approximately 25 minutes for the fluxdata. We extracted the USB from SmartFlux, which was at 7.7GB out of 14.9GB capacity. We deleted all existing files (saving a backup at the pc’s desktop).

We checked the datalogger memo an error message appeared that didn’t let us download the data. We waited for the fluxdata to finish downloading. We disconnected and connected everything again and reselected the folder’s path for the output. In the end we were able to download the metdata.

Li7500 showed a warning message: cannot contact status server. This disappeared after a few disconnection-reconnection attempts.

Sensor cleaning

We cleaned the radiometers, solar panels, LI-7000, and LI-7500. The methane sensor was very hard to clean and rssi did not go upper than 38%. We used a paper tissue and managed to get to 78%. After the rain, the RSSI dropped to 0%, and when we cleaned it again it went to 74%.

Thermocouples

The thermocouple 1 was 14cm off (the 0cm mark was at 14cm below surface), because of the tension the strings have on the profile. We repositioned it. We should probably only take tc3 into account for the period 21f-6m.

Clock synching

We also checked the clock synchronization. The datalogger was 4s behind the pc (utc). We reset the datalogger clock to match the pc clock. Since metadata is recorded at 30-minute intervals, this minor discrepancy was not a significant concern.

Additionally, we observed that the LI-7500DS was one second off from UTC (PC time), and the LI-7700 was synchronized with the LI-7500.

Others

We noticed the twig fence for the solar panels had been slightly damaged on one side. To reinforce it, we secured it with new zip ties.

We observed that the CH4 water bucket was about 60% full, confirming that it had been activated in the past weeks. We refilled it.

 

We left at 16.30 UTC and headed to Alfacada to unload the materials, leaving them in the field for the following day’s work.

 

 

 

To-do list:

• Check admin settings computer – Done, solved
• Think of a solution for TC (stronger profile? Substitute tc cable for a longer one?)- stronger profiles bought.

 

Readings:

	Before cleaning sensors	After cleaning sensors
LI-7500 readings
CO2 ppm	440	411
H20 ppm	13	13.7
T ºC	14.28	14.05
P kPa	101.7	101.75
SS %	84.3	97.4
LI-7700 readings
CH4 ppm	2.0	2.05
RSSI %	18.8	73.5