Field Notes
<--2013-09-05 10:30:00 | 2013-09-18 11:15:00-->Other sites visited today: Sherman Island | Mayberry | Twitchell Rice | Twitchell Alfalfa | West Pond
DWR Corn: 2013-09-11 12:20:00 (DOY 254)
Author: Cove Sturtevant
Others: Dennis, Sara, Eva
Summary: Site very dusty, but all generally well. Bumped 7700 output rate down to 20 Hz to test noise reduction. Expect 15% raw data loss due to time sync mismatch with CR1000.
| Wetland Construction 2013-09-11 We arrived around 12:20 PDT. It was partly cloudy, breezy, and warm (22 C). More tractor activity through the tower field and those to the west. In fact, one kept circling the tower while we were there to see how much dust was possible to lodge in my ear canals. I downloaded data while present company cleaned the sensors, solar panels and radiation instruments. Afterward, Dennis and Eva went off to rustle up some pheasants we heard in the field to the west. 7500 readings: CO2 = 14.0 mmol m-3 (16.0 after cleaning) H2O = 1075 mmol m-3 (650 after cleaning) Diag: 249 (248 after cleaning) t = 26.5 C p = 101.5 kPa sos = 345.0 m s-1 7700 readings: CH4: 1.97 ppm (1.87 after cleaning) RSSI: 12.2% (75% after cleaning) Reservoir was full refilled. The low RSSI was simply due to a fine layer of dust covering everything. I bumped the 7700 sensor down to 20 Hz to test for a week after we all discussed the increased variance at higher sampling rates. Unfortunately, there is a tradeoff here in that not all 7700 samples are recorded at this output rate. The time sync mismatch between the 7700 and the CR1000 is really only ameliorated when the 7700 output rate is at 40 Hz. At 40 Hz, the 7500 and 7700 sample sizes were identical. I did a quick check of the 7700 samples at the 20Hz output rate and found that the CR1000 dropped about 15%. I will compare the fluxes before and after this change to test which setting is best. MET looked good. |
3 photos found
DC_autocam_20130912_0845.jpg ( 2013-09-12 08:45:02 ) Full size: 1920x1440
view of field site
DC_autocam_20130911_0945.jpg ( 2013-09-11 09:45:02 ) Full size: 1920x1440
Tractor building levee
DC_autocam_20130910_1645.jpg ( 2013-09-10 16:45:03 ) Full size: 1920x1440
Dust
3 sets found
Can't check DC_mixed
3 DC_mixed graphs found
2 DC_met graphs found
4 DC_flux graphs found