Field Notes

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Other sites visited today: Gilbert Tract

Hill Slough: 2022-08-24 14:40:00 (DOY 236)
Author: Daphne Szutu
Others: Ari

Summary: Moved eosGP and CTD sensor to channel, Installed CR23X and solar panel/li battery at channel, Changed EXO from 2min to 5min samples, high tide and windy

2022-08-24
Hill Slough

Ari and I arrived at 14:40 PDT. It was a clear day, sunny with good visibility. Windy, of course. On the way here we stopped at the Ace hardware in Rio Vista to pick up a phillips/flathead screwdriver drill bit and some stainless steel carabiners.

It was near high tide and you couldn’t visibly distinguish the channel from the rest of the wetland. My first time here in a while at such high water level. At 16:06 PST, the staff gauge read an average of 5.65ft. It was hard to read the staff gauge because the waves caused the water level to slosh against the gauge by 0.1 ft.

The main goal today was to move the remaining two water sensors to the channel so they could stay consistently submerged. Low tide occasionally leaves the tower area dry, so the water sensor data has been messy with the sensors sometimes being in the air or buried in the mud. The sensors HYDROS 21 (CTD-10) sn 1782503941 and eosGP sn GP20160127 were moved from the tower to the channel about 50m to the east. We also installed a CR23X sn 2299 and a 20W solar panel sn C1031127-2306254 on the railing. Both are connected to a 12V 66Wh lithium battery.

Ari hung the sensors from the south side of the boardwalk. For now they are ziptied to the EXO chain but she would like to move them eventually to their own anchor point so the sensors are not banging against each other. The miniDOT and eosGP in the channel can probably hang freely, but the EXO and CTD may need more vertical stabilization to prevent random noise in the water pressure data. I also swapped in one of the non-stainless steel carabiners on the EXO for a new stainless steel one.

Both sensors were wired to the CR23X and programmed to collect data every 10s. Eventually we plan to connect the EXO2 output to the CR23X as well, but we’re still waiting for a part to arrive (signal output adapter that converts output to SDI-12 or serial), which will probably be collected every 5min. The CR23X is storing data as 30min averages, but this is back up data storage because the 10s data is also sent to the CR1000 and 30min averages are stored as usual in the met data table.

The CR23X is wired to the main CR1000 via a long 2-wire cable that is about 53m long (three shorter wires spliced together in the lab). Instruction 106 (SDI-12 sensor) allows the CR23X to act as an SDI-12 sensor itself and send data to another datalogger, in this case the main met CR1000. The cable runs along the south side of the boardwalk. I didn’t have long zipties so for now it’s secured to a few posts with shorter zipties. I will replace them with longer zipties another time.

I updated the main met CR1000 program to query the CR23X every 10s for its raw data. The variables collected remain the same so nothing should change in the met table output. Real-time data on the CR23X and CR1000 seemed reasonable. The CTD channels were not working initially on the CR23X but worked when I swapped the 12V ports for the eosGP and CTD. Since they were both working I left the wiring as is even though it’s a little messy.

Ari checked the EXO data and exported data since end of July. She changed the sampling interval from 2min to 5min. I think the battery level was still ok.

At the tower, I downloaded met, cam, and USB GHG data. I changed the eddy clock +25sec at 15:59 and restarted logging. I brought the FD chamber cable back to the lab since we don’t plan to deploy a FD chamber here.

Ari cleaned flux and rad sensors and sampled water from the sipper. Back at the car, she measured the water sample with the handheld YSI conductivity probe at 21.5 mS/cm at 27.1C.

We swapped the LI-7500 for calibration: sn 0035 came off and sn 75H-2176 went on.

Sn 0035 read: 403ppm CO2, 705mmol/m3 H2O, 26.1C, 100.9kPa, 97SS
After cleaning, sn 0035 read: 407ppm CO2, 666mmol/m3 H2O, 26.6C, 100.9kPa, 98SS
sn 75H-2176 read: 406 ppm CO2, 651mmol/m3 H2O, 26.9C, 100.9kPA, 97SS
The 7700 read: 1.95ppm CH4, 46RSSI – 72 after cleaning

We left at 17:10 PDT.

1 photos found

20220824HS_ChannelSolar.jpg ( 2022-08-24 16:44:14 ) Full size: 1440x1920
Small solar panel and CR23X installed on railing at channel. The CR23X is collecting data from a dissolved CO2 probe (eosGP) and a conductivity-temperature-depth probe (HYDROS21).