Field Notes

When: Dec 14, 2002, D348
Where: Tonzi/Vaira Ranches
Who: ddb
Weather: extremely cloudy, cool and very windy. Much rain the previous night

Arrived at the Tonzi ranch around 0830. The previous day was extremely stormy. We are setting up an El Nino winter and the past few days have produced over 2 inches of rain in the bay area. The rangeland is greening up and no cows seemed to be present.

Due to cloudy weather power was down on the tower system. The regulator was in the red mode, but batteries read 12 volts. Reset the regulator just in case it was tripped by the bad weather; later I found that the system rebooted up.

Re-adjusted the new net radiometer at the forest floor (sn 990352, 14.2 microvolts per W m-2. I also re oriented the azimuth so it was not looking at the walking path to the tower. It is more easterly now. Liukang needs to work this value into the average of the forest floor net radiation sensors.

Floor system was operating. This is great because we are able to capture some data from the rain pulse. File name FL2_348.flx

W: -0.6
U: -1.5
V: -2.0
T: 25.0
Q: 2.4
C: 1.7

Floor power
12.1 volts
array current: 1.0 amp
load current: 2.6 amp

I am concerned about the huge T value. It is about 10 C greater than air temperature. This is at the upper limit of the specs. I’d like to have this sonic swapped and sent back for re-calibration.

Checked the outputs of the data loggers manually. Sensors seem on scale and operating. Can connect to each logger. Since Ted hard wired the coax we seem to get solid contact.

Checked out Jianwu’s soil Vaisala sensors. CO2 is building up in the soil. Readings were:

2040
4410
4740 ppm

The gortex coverings seem to be working and keeping the sensors working and dry, as the soil is near saturation at that location (38%).

Took soil moisture and plant height data.

9:45 There was enough sun that the tower system re-booted.

~10:00 at Vaira ranch. Power down, so did not download data. Measured soil moisture and grass height.

To do. Lets lower the cross arm boom of the rad sensors to 2.0 m so we can reach the sensors and clean them better. There is no need to keep it at 2.5 m since the sonic is at 2.0 and we’ll install a reference rad sensor at about 1 m soon. Grass is a bit taller at Vaira. No cows present.

Aspirator is still off. We need to install a new and working one. Lets get the Gill hood and build one like Matthias.

Soil Moisture.

Grass Height

Side note: all the cow fences were operating.