Field Notes

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Tonzi: 2024-09-27 09:40:00 (DOY 271)
Author: Joe Verfaillie
Others: Kuno

Summary: Standard fieldwork, Chamber measurements, midday water potential, hot and dry

Tonzi
2024-09-27

Kuno and I arrived at about 10:40 PDT. It was clear, sunny and hot but with a nice breeze. Seems like the sun feels hotter at this time of year, maybe drier, less water in the air. The trees are slowly getting browner, there is still some water in the pond and the grass is crispy. The road was very dry and dusty.

Kuno went to work finishing up installing the last 6 stem chambers, bringing the total to 36 chambers across 6 trees. Additionally, a soil collar for smart chamber measurements was placed near one of the trees. Tree stem CH4 fluxes predominantly indicated uptake, though some trees exhibited emissions, even at greater heights. Soil CO2 fluxes ranged from 0.5 to 1.62 umol m-2 s-1, CH4 fluxes from -0.13 to -0.320 nmol m-2 s-1, and N2O fluxes from -0.002 to 0.046 nmol m-2 s-1, all of which were generally very low. Bark moisture was under detection limits but bark temperature ranged from 24.7C (around 11am) to 36.3C (around 3PM). Soil temperature was around 38C.

I did the standard fieldwork collecting Tower and Floor fluxes, manual soil moisture, well and DBH readings, serviced the z-cams. I swapped the IRGAs for calibration. At the Tower sn 0418 came off and sn 1594 went on. At the Floor sn 0041 came off and sn 0065 went on. Pressure coefficients and clocks were updated and the boxes restarted.
Tower 0418 read: 429.1ppm CO2, 427.7mmol/m3 H2O, 28.3C, 98.6kPa, 95.7SS - unclean
Tower 1594 read: 434.5ppm CO2, 355.8mmol/m3 H2O, 26.9C, 98.6kPa, 99.8SS
Floor 0041 read: 435.2ppm CO2, 365.2mmol/m3 H2O, 28.8C, 98.8kPa, 96.8SS
Floor 0065 read: 436.2ppm CO2, 354.2mmol/m3 H2O, 28.9C, 98.8kPa, 94.5SS

There were rain spots in the dust on the radiometers that I cleaned off. The IRGA's SS was a bit low thus the difference in readings at the Tower. At the Floor I clean the IRGA before the screen shot. I did midday water potential - not much change from last time.

I went to Vaira from 13:15 to about 14:00 PDT

Back at Tonzi, I copied the met data from the Tower. The lowest GMP343 had a bad reading again. A power cycle seemed to fix it. I checked that the wiring was tight. I scraped a bunch of bird poop out of the box and put a rock in the cable port. I will need to look at that data to see if I can figure out what is happening to that GMP.

While I waited for Kuno to finish up I gathered up some broken acrylic from an old chamber south of the soil CO2 fence and made a todo list:
Remove plastic bin new animal proof bin
4x4 post fence for Floor solar
Remove wagon
Two dead batteries plus two fence chargers
Remove coax line

We left at 15:00 PDT

Field Data

No tank data

No TZ Well data found

No TZ Moisture Point data found

No VR Moisture Point data found

No TZ grass heigth found

No VR grass heigth found

No TZ Tree DBH found

No water potential data found

No TZ Grass Biomass data found

No TZ OakLeaves Biomass data found

No TZ PineNeedles Biomass data found