Field Notes

When: June 20, 2002 D171
Where: Tonzi/Vaira Ranches
Who: Liukang Xu, Jianwu Tang
Weather Sunny, temperature up 80s

Trip Purpose: Predawn water potential, check 3 flux systems and download data, soil moisture probe reading, dendrometer reading, A/Ci curve for oak leaf at Tonzi Ranch. Swap licor 7500 at Vaira. Soil and stem respiration measurements, install soil CO2 sensor.

Overall: all flux systems were running great last week. We only lost few hours flux data at floor site. Both tower and Vaira systems were non-stop running since my last visit. All met and soil instruments worked fine and communicated with PC.

Tonzi Ranch:

Arrived at 4:15 am for predawn water potential, clear sky.

Dendrometer reading:

Soil moisture probe reading.

Floor flux system: Fence OK, flux system was running good last week. We only missed flux data during the period of d166 2200 to d167 0500. All data loggers communicated with PC. Nancy’s two data loggers have bunch of channels with –6999 output. PV reading 13.5V, 13.7A and 1.9A with fully charged battery at 11:30 am. Sonic outputs are as;

Tower flux system: Fence OK, gillsonic running non-stop last week. Download data. PV reading 13.3, 7.2, and 2.7A at 11:00. Battery half full.

Jianwu did some stem respiration and obtained higher values than soil respiration. Stem respiration averaged about 2.5 umol/m2s, while soil respiration averaged about 1.0 umol/m2s.

I finished three A/Ci curves on oak leaf.

Vaira Ranch: arrived at 7:50. Fence Ok, flux system also running great last week, non-stop since my last visit. PV reading 13.0, 7.6, and 2.8 with half full battery at 9:00am. Replaced licor7500: sn 0065 came off and sn 0073 went on. Soil moisture probe reading (see above). Sonic outputs after download data and swap the li-cor;