Field Notes

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Other sites visited today: Bouldin Alfalfa | Bouldin Corn
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Hill Slough: 2021-07-20 08:10:00 (DOY 201)
Author: Joe Verfaillie
Others: Ariane, Carlos, Daphne, Joe, Dennis, Scott

Summary: Regular data collection/cleaning. Soil cores, RTK measurements and vegetation plots

Hill Slough
2021-07-20

Daphne, Ariane, Dennis, Carlos and I arrived at 8:15 PDT. Scott Jones (USGS) arrived soon after to pick up the corers we borrowed and brought a RTK GPS unit to get cm scale locations for the coring sites. Temperatures in the morning were cool, there was a clear sky with no clouds and it was windy as usual. The ditch along the road is drying up and smells bad. I think they recently cut it off from the tides.

Carlos, Dennis, Scott and Ariane started at the most upland location (hsm_9) and collected a long core with the narrow auger and 3 short replicate cores. Soils were very dry, and the bottom of the acrylic tubes bent. Soils formed aggregates that often collapsed when extruding the tubes. Bottom layers of the long cores were a mixture of fine sand and clay that changed to more sandy textures upcore. It took a while to finish slicing the long core, so a group of people moved to the second upland site (closest to the tower) to take the remaining two short cores that couldn't be collected on July 8th.

After slicing the long core at hsm_9, Scott, Dennis and Ariane walked to all the other locations where soil cores had been collected in early July. Scott took RTK measurements and did vegetation plots, he also took an RTK measurement at the tower, near the sonic. According to the RTK the tower was at about 1.2 m and the lowest sites (hsm_4 and hsm_6) were at about 0.8 m. Mean sea level measured at the NOAA Port Chicago station is 1.116 m, so it is likely that these lower sites become open water for some time.

Daphne and I serviced the tower. The pi-cam clock was okay, we cleaned the flux and radiation sensors.
The 7500 read: 397ppm CO2, 620mmol/m3, 17.0C, 101.8kPa, 1012SS â€“ 102 after cleaning
The 7700 read: 1.88ppm CH4, 33RSSI â€“ 71 after cleaning.
I added about 1/4 water to the wash reservoir. The leading edges of the eddy sensors are dirty â€“ I did not clean.

We unfastened the FD chamber sn FD20190028, laid it on its side and ran a performance check on it. It read 171.6ppm from the soil chamber and 172.2ppm for the ambient chamber. We reset it to 400ppm, and reinstalled the chamber.

Daphne and I helped finish up the soil cores and then waited while Dennis, Ariane, and Scott hiked to and mapped all the soil core sites.

We left at 11:30.

0 photos found

4 sets found

20 HS_met graphs found