Field Notes

<--2015-11-25 13:14:00 | 2015-12-11 11:45:00-->
Other sites visited today: East End | West Pond | Twitchell Alfalfa

Twitchell Rice: 2015-12-08 09:30:00 (DOY 342)
Author: Joe Verfaillie
Others: Kyle, Dennis, Xu Du LGR

Summary: Set up temporary site for LGR COS experiment, wet and foggy, fixed leaky wash tubing.

Twitchell
2015-12-08

I arrived about 9:30 with Kyle.

We first set up a temporary site near the trailer building at the south side of the fields to test an LGR Carbonyl sulfide (COS) analyzer. It was cold and foggy with little to no wind. We ran 200ft of extension cords from the east side of the building to the northwest near the edge of a safflower field. The safflower, Bermuda grass, and weeds are all very brown. To the west there are sheep grazing. We installed a biomet tripod with a Licor GHG system (sn TG1-0424, sn AIU-1570, sn 75H-2669, sn 153805) and a big plastic box for the LGR equipment. The center of the eddy equipment is 2.32m agl. 26cm from sonic to 7500 and 29cm from sonic to 7700. The sonic heading is 90deg true. The safflower height was measured at the following heights: 49, 54, 59, 60, 62, 69, 62, 62, 53, 56cm the average is 58.6cm.

About 11am we went to work at East End while we waited for LGR to show up. Dennis arrived while we were at East End.

We arrived at the Rice field about 12:00 noon. It was cool and overcast with a light mist. The field is flooded and there were some birds around.

There were lots of dew covered spider webs on the eddy sensors, and a light mist wetting the mirrors/lenses.
The 7500 read: 579ppm CO2, 208mmol/m3 H2O, 72SS, 11.3C, 102.8kPa â€“ after cleaning 79SS
The 7700 read: 2.2ppm CH4, 16RSSI â€“ It was hard to get the mirrors clean because of the mist, eventually we got a RSSI of 50 for a few seconds. We tested the auto wash system and found a leak about 10cm from the spray head. There was enough slack in the tubing that we were able to cut the leaking section off and reattach the tubing. But all the tubing looked to be in poor shape. We should replace it soon.

Xu Du from LGR arrived about 12:30 and we returned to the temporary site near the trailer. Du brought the COS system in a field pelican case and a pump and power supply. It all fit in the box. We tied the inlet to the post just below the 7500 at about the level of the bottom mirror of the 7700. The inlet has a rubber cone to protect it from rain. Du worked on setting up and calibrating the system while we went to West Pond and Alfalfa. He left a tank of cal gas tied to the tripod leg that will automatically calibrate the system at regular intervals.

Kyle took 360x180 panoramas

We also me Rick Carter and he showed me where our scaffolding is stored at his place.

2 photos found

20151208TW_TundraSwanFog.jpg ( 2015-12-08 12:53:04 ) Full size: 1024x768
view of field site