Field Notes

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Hill Slough: 2022-08-04 15:00:00 (DOY 216)
Author: Daphne Szutu
Others: Carlos

Summary: Regular data collection/cleaning, only a few days of data on EXO--changed batteries, cleaned sensors, and restarted deployment

2022-08-04
Hill Slough

Carlos and I arrived around 15:00 PDT. It was very windy with scattered thin clouds. It was low tide and the water remained below the staff gauge the whole time we were there. Carlos measured the staff gauge at 3.77ft at 15:18 PST.

We started by checking the EXO. After we launched the Kor software, the data started downloading automatically. Upon first connecting, there was no active deployment ( in Deployment tab) and there were only a few days of data with the last data point being 2022-07-28 around 9pm. Battery was 33%. Used space was 1.54%. Again, no indication of why data collection would only last a few days. I couldn't find the data on the laptop after we got back in the lab. I think we were supposed to export the data to a .csv or something to actually save it as a file on the laptop.

We pulled the probe out of the water to look at it. There were a lot of small shrimp and maybe eggs inside and out of the copper mesh and all around the sensors. Maybe a finer mesh would help, or another layer of copper mesh at an angle with the original mesh. We removed the copper mesh and used water and a toothbrush to clean off almost all of the tiny shrimp. We also used the toothbrush to clean the 3 sensors--they had a film on top of them that came off easily with the toothbrush.

We also put in 4 new D-size batteries and had to use channel locks to open the slippery battery cap. We made sure the batteries went in the correct orientation and closed the battery cap securely (using a channel lock to make sure it's snug--tried not to crank down too hard). After the swap, the battery level = 100%. Joe may order a new cable with bare ends so we can install a solar panel and battery.

Carlos started a new deployment around 14:50 PDT and checked it again around 15:25 PDT. He confirmed it was still logging and watched the central wiper go around at the expected time.

At the tower, I downloaded met, cam, and USB GHG data. Carlos topped off the wash reservoir and cleaned flux and rad sensors. The GHG spars were dusty. I changed the eddy clock +35sec from 15:09:20 to 15:09:55 to match the laptop time and restarted logging afterwards. I took a water sample from the sipper and put it in a capped plastic vial to measure at the car using the handheld YSI probe.

Sample, temperature-compensated conductivity, temperature, notes
Porewater, 21.55mS, 28.9C, 15:10 PST

I cleaned the bottom two solar panels (couldn't reach the top solar panel).

The 7500 read: 387ppm CO2, 850mmol/m3 H2O, 29.9C, 101.1kPa, 90SS – 97 after cleaning
The 7700 read: 1.94ppm CH4, 30RSSI – 69 after cleaning

We left at 16:45 PDT.

3 photos found

20220804HS_ExoScreen1.jpg ( 2022-08-04 16:25:32 ) Full size: 1920x1440
EXO screenshot showing full battery and suspicious "Next sample time." Sonde time is 15:25 so the next sample time should be 15:26. However, "Next Sample Time" is stuck on "8/4/2022 14:50:00" which is the first sample time of the deployment.

20220804HS_ExoScreen3.jpg ( 2022-08-04 16:26:35 ) Full size: 1920x1440
EXO screenshot from checking the EXO before we left. Second-to-last line shows the most recent field file only had 2 days of data from 2022-07-26 to 2022-07-28 8:55:59. Last line shows data collected since redeployment earlier today.