Field Notes

When: D157, June 6, 2002
Who: Dbaldocchi + T Hehn
Where: Tonzi

Arrived at field site around 10:30 PST. Clear, Hot and intermittent winds. The grass is mostly dry, though smidgens of green can be seen, mostly associated with wildflowers and grass infloresence. Purple and yellow wild flowers present everywhere.

First checked the floor system. It is running fine and the fence was operating. No cows were present near the site.

Some spider webs on the sonic. Removed them. Lowered thermostat on the computer box to 80F so it goes on earlier in the morning and keeps the PC cooler.

Power at floor system: Batteries: 13.7 V; Power generated: 14 amps; Power consumed: 1.9 amps.

Traces on the PC were fine.

Checked the Data loggers. Communication was fine. Voltages powering the pcs were fine. Only problems were with CR10X4, one of Nancy’s Sap flow systems.

Sensors T2_7, T2_8, T2_9 and the Ratio were reading –9999.

Downloaded raw flux data. Moved Cr10x_#.dat to the Tonzi_2002 directory after renaming the files T_02_157_#.dat. Forgot to copy and move the *.23x and the *.10x files with the recent met. Need to do so next time.

~11:30 Swapped Licors. sn 0073 came off and sn 0042 went on. Checked voltages and they were fine., q=2.6; c=1.67. New and clean data should start around 12:00.

12:30 Started working on the tall tower. Noted that the fan was already on on the PC box, but moved the thermostat to 80F as low as it would go to ventilate the box all day during the summer. Why not there is plenty of sun and juice and will help keep the pc from overheating.

The variances of q and C are small so the plot of these values seem like a sine wave.

Noted that 3.65 Gig was free on the hard drive. Forgot to check the other PCs. Do so next time.

~14:00 swapped IRGas. sn 0041 came off and sn 0035 went on. After q= 1.77; C= 1.48.

Have been suspicious of the boom angle since we had moved it several times in the past. Checked its orientation and found that the magnetic North was facing about 280 degrees. It is hard to be more precise than +/- 10. I checked it from several vantage points and all seemed about 280, but it could be between 280 and 290 with higher certainty.

Another effort was to install additional understory net radiometers on tripods. Attempted to install 2 sensors, but one was dead. Ted will have information on sensor numbers, channels etc.

Noted that wooded path near data logger box was over one soil TC system. Moved it away.

13:00 Sampled Moisture Point sensors.

7931AFE, near tower

574B4B, open near solar panels

402165, near understory flux system

Stem Diameter 1330 PST

Vaira Ranch

Arrived ~15:00 PST

Downloaded data. Swapped Vaisala T/RH sensors. Want to have a new and clean sensor.

sn U3030046 came off and sn W0730037 went on.

Attempting to install the 4 way KZ net radiometer. Installed tripod, but need to refine program. Will wire it up next time. This will give us incoming and outgoing longwave and shortwave radiation.