Field Notes

Twitchell Rice: 2013-07-26 09:00:00 (DOY 207)
Author: Cove Sturtevant
Others: Laurie, Yanel

Summary: Data download and regular field work. Cut down cattails in front of tower. Bumped flux system to 20 Hz. SoilT1_04 bad. Reason for spurious afternoon dip in Rg could not be found.

We arrived about 09:00 PDT. It was sunny, cool (17 C), and windy. I attended to the tower and downloaded data while Laurie did clip plots and Yanel did spectral. Iryna was also at the site doing LAI measurements.

The rice is chugging right along, now about 60 cm high. The large swath of cattails in front of the tower was chest high. I cut them down to the water line with clippers.

7500 readings:
CO2 = 390 ppm (387 after cleaning)
H2O = 610 mmol m-3 (680 after cleaning)
signal strength = 79.9% (80.2% after cleaning)
t = 18.4 C
p = 102.17 kPa
sos = 344.0 m s-1

7700 readings:
CH4 = 1.85 ppm variable by 0.1 (1.87 and more stable after cleaning)
RSSI = 24.6 (bumped to 69 after cleaning)
Reservoir was full.

After downloading data I bumped the 7550 USB output rate to 20 Hz. I also changed the sonic settings to output serial at 57600 baud (for communicating with the laptop) and the measurement output rate to 20 Hz. I checked that all readings on the USB file were updating at 20 Hz.

Met data looked good except that the temperature reading for SoilT1_04 is clearly bad (reading 55 C while others were reading 20-21 C). Sara checked the data and didnt see any problems, so this is probably a new development. I checked the connections in the multiplexor, and all was fine. So at some point we should pull the temperature rod and replace the thermocouple.

Sara also noted a spurious afternoon dip in the Rg readings at Twitchell. I checked the pyranometer glass on the afternoon side but could not see any imperfections.

I checked the sonic sn (120906).

0 photos found

6 sets found

12 TW_met graphs found