NOTE: Tools needed; 7/16" open ended wrench (for loosening fittings and to open the CU LiCor Box). ------------------------------------------- Date: Fri, 06 Sep 2002 17:39:55 -0600 From: Britton Stephens To: Jielun Sun Cc: deander@usgs.gov, wmbaugh@earthlink.net, sean Burns , campos@ucar.edu, delany@ucar.edu, guenther@mail.acd.ucar.edu, lenschow@ucar.edu, lemone@ucar.edu, russ Monson , oncley@ucar.edu, aturnip@stripe.colorado.edu Subject: first intercomparison runs With Tony's help, I ran the four intercomparison gases on Dean's, Andrew's, and both of Tony's LiCors yesterday, and hopefully we (+Sean) will be able to get a lot of replications done in the next few weeks. The procedures are slightly different for each system, and I've outlined them below - Dean, Andrew, and Tony please proof yours to make sure what we're doing is OK. I've alse copied my field notes below so that folks will be able to identify yesterday's intercomparison periods in their data and calculate the appropriate concentrations. In the future I'd like to put these notes in the field log, but haven't yet figured out how to do it online. The 4 cylinders are around 350, 370, 390, and 415 ppm - I will hang onto the 'official' numbers until we get results in from the runs. I will be at a conference in New Hampshire almost all of next week, but I encourage Sean and Tony to attempt to do a few runs while I'm gone (please call my cell phone 303-887-4402 if you have any questions). The cylinders are currently at the NCAR tower. They are on a pack frame and can be carried between sites if you like, but the are HEAVY so please use a cart if you don't want a good workout. Thanks a lot, Britt ---------------------------------------------- INTERCOMPARISON SYSTEM (ICS) PROCEDURES 1. Initialization a) identify cylinders A, B, C, and D by tracing tubes from 4-way valve (letters are written on the side of the 4-way valve and the inside tops of cylinders - just note that because of the tubing routing, the valve handle does not always point to the selected cylinder). b) record the high gauge pressures for all 4 cylinders (a low value would indicate a leak or that the 4-way valve was not in a between-position off state). c) open all 4 cylinder valves and record the high gauge pressures again. 2. Dean's system a) cycle 4-way valve, adjusting regulator output pressures to A=4, B=4, C=10, and D=4 psi while flushing each line for 15-30 seconds. b) connect common tube to brass 3-way valve (in middle of main shelf, upstream of LiCor and downstream of selector valves) (using 1/8 turn past finger tight). c) press *5 on CR10 controller and note datalogger time d) press *6,A,A and note selected line in position 3 e) press *6,A,A,A,A,A,A and note LiCor pressure in position 7 (~525 torr) e) avoiding calibration periods, which are for 60 seconds every even 2 hours in datalogger time, switch 3-way valve and record datalogger time and line f) cycle 4-way valve, remaining on each position for 3 minutes and adjusting regulators at start of each period to match the licor pressure +/- 10 torr (~525 torr on *6 position 7) g) switch 3-way valve back and record datalogger time and line h) leave 4-way valve in a between-position off state and disconnect common tube from 3-way valve 3. Andrew's system a) cycle 4-way valve, adjusting regulator output pressures to A=max, B=max, C=28, and D=20 psi while flushing each line for 5-10 seconds. b) connect common tube to brass 3-way valve (on output line of green span tank at base of tower). c) note line pressure on gauge attached to 3-way valve (~20 psi) d) open LiCor box and note line postition (some of the indicator lights are very dim) e) avoiding calibration periods, which are for several minutes every even 4 hours in local time, toggle auto-man switch to man, toggle C2 switch, and record time (LT on watch) and line f) return to base of tower and switch 3-way valve g) cycle 4-way valve, remaining on each position for 3 minutes and adjusting regulators at start of each period to match the line pressure +/- 1 psi (~20 psi on gauge, regulators on A and B will only provide 8-10 psi) h) switch 3-way valve back i) toggle C2 switch and auto-man switch to auto, record time and line, and close LiCor box j) leave 4-way valve in a between-position off state and disconnect common tube from 3-way valve 4. Tony's 2 LiCors a) cycle 4-way valve, adjusting regulator output pressures to A=4, B=4, C=10, and D=4 psi while flushing each line for 15-30 seconds. b) connect common tube to brass 3-way valve (on left outside of box) c) note line pressure on gauge attached to 3-way valve (~ -1.5 psi for A and ~ -3.5 psi for B) d) ***Tony please remind me how to tell what line the system is on*** e) avoiding calibration periods, which are for 6 minutes (Tony may change) minutes with 24 minutes of sampling between, switch 3-way valve and record time (LT on watch) and line g) cycle 4-way valve, remaining on each position for 3 minutes and adjusting regulators at start of each period to match the line pressure +/- 0.5 psi (~ -1.5 or -3.5 psi on gauge) h) switch 3-way valve back and record time and line i) disconnect common tube from 3-way valve j) there probably won't be enough time to do both systems during one sample period, so wait until system has done calibration before repeating steps (b)-(i) on second LiCor k) leave 4-way valve in a between-position off state and disconnect common tube from 3-way valve 5. Shutdown a) close all 4 cylinder valves b) put packframe under a tarp or cover regulators with a plastic bag (not critical) c) enter field notes into online log