Field Notes

Hill Slough: 2021-12-14 09:55:00 (DOY 348)
Author: Daphne Szutu
Others: Carlos

Summary: Swapped 7500 for calibration, changed eddy clock +1min, deployed new conductivity + water level sensor, 7700 optics desiccant needs to be swapped

2021-12-14
Hill Slough

Carlos and I arrived at 9:55 PST. It was chilly with a cold breeze, sunny with some cumulus clouds near the horizon. There was an atmospheric river in the past 48 hours that delivered about 100mm (4 inches) of rain here. The staff gauge read 183.5cm (6.02 feet) at 10:41 PST.

Carlos cleaned flux and rad sensors and topped off the wash reservoir, which had been about 1/2 empty. I downloaded met, camera, and USB GHG data. The 7700 spray nozzle was off the sensor so I put it back on.

We swapped the LI-7500 for calibration: sn 75H-2176 came off and sn 75H-2669 went on the tower. I uploaded a new configuration file and updated the pressure coefficients. I changed the 7550 clock +1 min from 10:09 to 10:10 to match the laptop time. I reset the 7550 and checked that the USB was logging and the 7700 was connected.

Even though we had swapped out the drierite and flushed out the headspace with zero air at the last site visit, The 7700 optics RH was at 40% and there was a red error text warning us to replace the desiccant. I removed the drierite bottle and replaced the purple drierite with sorta-blue silica gel desiccant. The desiccant plug seemed snug when I removed it, so maybe I had accidentally put in used drierite last time. Next time I'll bring a bottle with fresh drierite to replace it.

Carlos put on waders and got in the water to install our new METER HYDROS21 probe sn 1782503941 that measures conductivity, temperature, and depth (CTD). The sensor is installed 135cm below the top of the well pipe. This is a SDI-12 sensor that I wired into a control port. I uploaded a new datalogger program and the numbers looked reasonable. Carlos set up the aluminum ladder in the water next to the boardwalk which seemed to work well for getting in and out of the water.

LI-7500 readings (75H-2176--> 75H-2176 clean --> 75H-2669):
CO2 447ppm --> 428 --> 428
H2O 160ppm --> 337 --> 337
T 8.99C --> 9.3 --> 9.0
P 101.3kPa --> 101.3 --> 101.0
SS 76--> 99--> 100
LI7700 readings:
CH4 2.0ppm
RSSI 48--> 74 after cleaning

We left at 10:55 PST.

0 photos found

4 sets found

20 HS_met graphs found