Field Notes

Trip note On May 30 2003 (d150)
Who: Liukang Xu
Weather; Sunny, Temperature around 90s

Problem: gillsonic at floor was dead since May 27 (d147) 12:30. At Vaira licor 7500 lost power again since d145 23:30, due to bad power lead connection. Since the sonic at floor system was down, I removed its licor sn 0065 and power lead, and install at Vaira site. Informed Dennis about the problems.

Tonzi ranch: arrived 4:24, temperature 14^oC. Heavy clouds in the morning, then clear out around noontime. Grass under trees still green, those at open space are almost dead.

Predawn water potential measurement

Dendrometer reading:

Soil moisture reading:

Grass height at tonzi (27.7±6.3 cm n=30), at Vaira (45.8±12.0, n=24)

Floor system: The gillsonic was frozen since d147 12:30, reboot pc still couldn’t start the gillsonic program. Only 700 Mb left on the hard drive, deleted all the 2002 data.

Download data. PV reading 12.5, 0.0, 1.3 at 6:30am

Tower system: flux system running good last week. PV reading was 12.5, 0.0, 2.3 at the top of the tower and 12.5, 0.0, 1.5 at the base of tower. Download data, after reboot pc, w, u, v, Tsonic, q and CO2 outputs were in the right range.

Vaira site: fence oK. Gillsonic program was running, but with zero outputs from licor sn 0073. I found it was due to the bad connection of power lead and the licor. I took licor sn 0065 at the floor and the power lead and installed at Vaira. I was able to bring the system back on. From the ramp structure of w, Ts, and CO2 signal, the grassland still taking carbon.