Field Notes

When: May 16, 2002, d136 Thu
Where: Tonzi/Vaira Ranches
Who: Liukang Xu
Weather Sunny, temperature up 80s

Trip Purpose: Check 3 flux systems and download data, soil moisture probe reading, grass height measurement, grass LAI at Tonzi, dendrometer reading, A/Ci curve for oak leaf at Tonzi Ranch.

Overall: all flux systems were running great last week; All met instruments work fine. The grasses at Vaira are all dead, turn to yellow color. At Tonzi, grass under the tree is still some green. In open space, grass also dead.

Tonzi Ranch: Arrived at 10:00 am, clear sky.

Dendrometer reading:

The tree trunk is still expanding, see the dendrometer reading comparison with last week. why?

Soil moisture probe reading:

Tower flux system: Fence working, flux system was running. Ted: On d130, watchdog turned the laptop off at 4:30, but it did not turn back on until next day at 5:00 am. I remember this happened at tower before, but never happen for floor and Vaira system. Any idea what is wrong ?

PV reading, 14.2V, 13.0A and 2.8A battery fully charged.

Gill Sonic output:

Floor system: Fence working and flux system running good. All data-loggers are communicating with PC. Download data. Gillsonic outputs:

PV reading 13.9V, 10.9A (number jumping around 9.0-10.9A), 1.7A. Battery fully charged.

Grass height measurement (n=30, m=26.4cm, std=7.3cm).

Since the grass in the open space is dead, I took only two LAI samples from under canopy space.

Finished 3 A-Ci curves on oak leaf, took some oak leaf samples.

Vaira Ranch: Arrived at 4:10 pm. All grass are dead, only some of grass heads are still green. We can set the grass green leaf area equal to zero. Fence working, flux system working. Good communication between dataloogers and pc.

Gillsonic output.s

Grass height measurement (n=30, m=50.6cm, and std=10.1cm). Soil moisture probe reading, see above.