Field Notes

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Hill Slough: 2023-06-14 16:30:00 (DOY 165)
Author: Joe Verfaillie
Others: Daphne

Summary: Thought about a 7700 calibration but too windy, installed pH probe with new sensor cap but didn't seem to improve reading - still logging, checked and refilled solar battery cells.

Hill Slough
2023-06-14

Daphne and I arrived at about 16:30 PDT. It was mild, overcast and windy. We were hoping to do a 7700 calibration but decided it was too windy. We did the rest of the field work and Daphne will try to do the 7700 calibration first thing tomorrow when the wind is supposed to be less. The tide was at about mid-level and ebbing – Daphne thought it smelled like a porta-potty. The staff gauge read 4.5ft at 16:25 PST. We could see some reeds coming up just north and south of the boardwalk walkway. Maybe cattail.

Daphne tried to add the pH probe sn 22D102641 with a new sensor cap to the EXO. But when she did the calibration it was way off and similar to the old one that was swapped out. Standard pH 7 = probe pH 1.3, standard pH 4 = probe pH -2.3. She did not save the calibration, just left it as the factory calibration. We don’t have any way to test the pH probe in the lab without removing the whole EXO so we decided to redeploy it and let it collect data. In August when it’s due for a full cleaning and calibration, we will try to calibrate/fix the pH.

While Daphne was working on the EXO I checked the water levels in the solar batteries. By pulling the batteries partly out of the box I could see into all but six cells (two caps). None of the cells I could see were super low – no plates exposed. I went ahead and added DI water to top them up. The six cells I could not see I filled by sound and over filled one cell. I think they will be okay.

We did the standard data collection. Daphne collected the minidot, Flux, met and camera data. She did not swap the desiccant in the minidot. I cleaned the eddy sensors and radiometers. The nuts on the radiometer boom pivot bolt loosen and tighten as the boom is rotated. I think adding a locking washer between the two nuts might keep them in place when the boom rotates.

The 7500 read: 408ppm CO2, 613mmol/m3 H2O, 21.9C, 101.0kPa, 94SS – 99 after cleaning
The 7700 read: 1.93ppm CH4, 45RSSI – 71 after cleaning.

The leading (windward) edges of the eddy sensors are super dirty and should be cleaned up especially the 7700 for calibration tomorrow. The 7550 clock was adjusted from 16:33:00 to 16:33:55 to match the laptop time and logging restarted. The wash reservoir was about ¼ low and was refilled.

I saw a police truck stop next to where our truck was parked. They weren’t there very long and we didn’t get a parking ticket so I guess they saw us on the tower and figured we were legit.

We left at 17:40 PDT

1 photos found

20230614HS_EmergentVegetation.jpg ( 2023-06-14 17:41:42 ) Full size: 1440x1920
A few small reeds emerging from the water. Maybe cattail?