Field Notes

Gilbert Tract: 2025-01-02 16:45:00 (DOY 2)
Author: Daphne Szutu
Others: Joe

Summary: End-of-year data collection, missing 2 weeks of met data-- datalogger hiccup, missing 2 weeks of ADCP data--unknown, missing 5 days of channel EXO data--low power, super high tide

2025-01-02
Gilbert Tract

Joe and I arrived at 16:45 PST as the sun was setting over Mt. Diablo. “The mountain is on fire!” Happy new year! It was cool and mostly clear with high, thin clouds and we could hear lots of birds and the occasional distant cow. Some of the vegetation on the levee slope was died back or blown down, so we can now see the battery box from the road.

It was super high tide and Joe moved around some of the cinder blocks so we could hop our way to the tower. He had to put on waders to access the boardwalk. Although the boardwalk was about 10cm underwater, he could clearly see a rectangle of brown/dried azolla where the boardwalk was, surrounded by green azalea where the open water is. Even though the water level goes up and down, there doesn’t seem to be much horizontal water movement. The staff gauge read 116.5cm at 16:57 PST.

I downloaded met, cam, and USB GHG data. The camera and USB GHG data seemed fine, but we only had one new line of met data on 2024-12-19 09:30. I tried all of the usual tricks of “downloading all data” and “downloading data since a selected date/time” and power cycling the datalogger, but no new data showed up. The datalogger program was running according to File Control, but I stopped and re-started the program.

The Campbell conductivity data had been dropping out here and probably needs to be lowered. We’ll have to check again next time since we don’t have met data here for the last 2 weeks.

I downloaded the miniDOT data and swapped its desiccant. I downloaded the Song Meter Micro data and swapped its desiccant. Its battery was at 83%. Joe cleaned flux and rad sensors and confirmed that the precip bucket funnel was clear.

Joe measured the surface water conductivity by the boardwalk.
Surface, 556uS, 10.7C

7500 read: 450ppm CO2, 446mmol/m3 H2O, 10.3C, 101.7kPa, 99SS —99 after cleaning
7700 read: 2.29ppm CH4, 54RSSI – 83 after cleaning

We got to the channel at 17:15 PST under dim lighting. The water level was so high that it was hard to pull the ADCP and channel miniDOT up far enough. Joe still got his hands wet removing the channel miniDOT from its cable ties. I downloaded the channel miniDOT and swapped its desiccant. We had planned to swap out the one non-SS ADCP bolt for a SS bolt, but the whole mounting plate was still underwater and we couldn’t tell which bolt was not SS.

I had trouble connecting to the SL. I power cycled it, which didn’t help. I went through the “Recover Instrument” workflow, which is a prompted version of a power cycle. After that, I was able to connect to the SL, but the data ended on 2024-12-19 23:30. I don’t know why the SL and the met datalogger would both have a hiccup on the same day as our last site visit.

The CR6 data seemed fine, although we are missing 5 days of data from 2024-12-20 to 2024-12-25, probably because of the dark and rainy weather.

Joe used his phone flashlight to light our way back to the car. We stopped at the tower briefly at 17:45 PST on the way out to check that the met data was recording. There was one new line of met data at 17:30 PST.

The automatic gate wasn’t opening when we pulled up to it. A construction worker was parked on the outside of the gate and he got out to open the gate for us. Turns out it’s a manual gate for the next few days.

Maintenance to-do:
- Lower Campbell conductivity sensor
- Install floating DO, and thermocouple profile?
- Remove another azolla decomposition profile for Kuno?
- Remove NDVI sensors from rad boom (they’re already unwired)
- Start collecting DIC/DOC samples from channel - check protocol for what bottles/chemicals to order

We left at 17:50 PST.

2 photos found

20250102GT_MoonVenusDiablo.jpg ( 2025-01-02 17:21:03 ) Full size: 1440x1920
view of field site