Field Notes
<--2012-08-30 11:00:00 | 2012-09-13 11:30:00-->Other sites visited today: Tonzi | Sherman Island | Mayberry | West Pond | DWR Corn
Twitchell Rice: 2012-09-06 11:00:00 (DOY 250)
Author: Joe Verfaillie
Others: Cove
Summary: Calibrated 7700, Swapped 7550 and 7500A, Removed SHF plate for calibration, straighten new radiometer.
| Twitchell
2012-09-06 I arrived about 11am PDT with Cove. It was warm and sunny with some morning clouds dissipating to the east. We met Brian and Jim and the trailer. Brian says the corn harvest is a month or two away yet. Jim says the rice is going slowly, but they will start to drain the fields in a week or so. The DWR wet land construction is on schedule to start next summer. At the tower we tried to straighten the sonic. We adjusted the feet of the tripod tower until the sonic was more plumb. We calibrated the LI7700 (sn TG1-0211). We used a tank of Ultra Zero Air (1900psi) and a tank of 4.982ppm CH4 in air (950psi). We flowed the gas at a relatively high rate to wash out the cell space quickly. The last calibration was at Licor on 2011-12-03. Before calibration RSSI went from 27 to 63 with cleaning. T=22.5C, P=101.45kPa. Zero was off by 0.050ppm and span was off by 0.002ppm at 4.980ppm. After calibrating the 7700 we swapped the LI7550 box and LI7500A head. I had been unsuccessful in swapping heads previously because the box kept entering a reboot cycle with either of the other heads I tried. This time we swapped the box removing sn 0614 and installing sn 0674. Then we uploaded the configuration from the 0614 box. This restored all the output settings, and coefficients and zero/span values for the head. But this did not set the clock properly. I set the clock to automatic, UP/Pacific and local standard time. I also had to connect to the LI7700. We then uploaded the coefficients and zero/span values for the new head (sn 2176). We removed the head (sn 2150) and installed the new head. We removed USB drive from the old box and downloaded it. We reinserted the USB drive in the new box and all seemed well. We pulled the USB drive to check the data. When we reinserted the USB drive it had problems. We removed the one file on it and tried again but still not luck. Resetting the 7550 box seemed to solve the problem but then we could not connect to the box with the netbook. Cycling power on the box seemed to fix all the problems. In the end the eddy read: 370ppm CO2, 668mmol/m3 H2O, 43.8AGC, 347.5m/s SOS The net radiometer was tilted – Cove fixed it. We removed SHF plate #2 (sn 002211) for calibration. I put a jumper in the empty channel to zero it. Jaclyn and Laurie were there doing the standard field work. |
2 photos found
TW_autocam_20120906_1045.jpg ( 2012-09-06 10:45:02 ) Full size: 1920x1440
Tower has been straightened
TW_autocam_20120906_1115.jpg ( 2012-09-06 11:15:02 ) Full size: 1920x1440
LI7700 calibration
6 sets found
12 TW_met graphs found
5 TW_flux graphs found
Can't check TWSI_mixed
Can't check SIMBTWEE_met
1 TW_cam graphs found
Can't check TATWBABCSB_cam