MOBYnet Stability page

A radiometer (CAS, Instrument Systems) and a stability source (SQM-5002, Yankee Environmental Systems) have been purchased for the MOBY-NET project. The idea is to ship the monitor system with the optical buoy between deployments (somewhere besides Hawaii) and calibration (at the MOBY Hawaii site).  We will be doing the characterization here, and I will also do some calibrations so we can estimate the levels as well as track what may be changing with independent sources or radiometers. 

Problems seen:

  1. CAS problem 1: Foreoptic selections for the MOBY NET CAS. Solution: we have ordered two fiber bundle systems – irradiance and bare fiber; TBD design radiance head
  2. SQM Problem 1: SQM housekeeping logging software. Solution: we have put YES’ V0 into Labview 2013 and call this V1. After deciding operating protocols, we will make a V2
  3. SQM Problem 2: SQM adaptor plate for holding the instruments. Solution: we will keep the YES plate and use its 4.125” ID hole to mate to.
  4. SQM Problem 3: New SQM manual and Notes as we go along. Solution: we making notes in the manual or the web site.>
  5. SQM Problem 4: No spare SQM lamps. Solution: we ordered replacement lamps and will make the mounting fixtures and pot them in the NIST shops.
  6. SQM Problem 5: There is little UV because the window is glass and the diffuser is acrylic. Solution: replace both with fused silica (quartz)-based materials
  7. SQM Problem 6: With the new quartz diffuser and the white fiducial, two of the three SQM monitor photodiodes saturated with the HI level. See NIST-2016-01

Photos

Documents

Page Number
Link
Description
Date
 
1.01 NIST-2015-01 SQM diffuser experiment - 3 Dec 2015: Which diffuser is the most uniform? 8 Dec 2015
1.02 NIST-2016-01 SQM PD monitors saturation experiment 7 Mar 2016
       
Plots of Individual data files
2.01 SQMcfg 1001 Summary table of all cfg 1001 files 7 Mar 2016
       
Plots of more than just the individual SQM files
100.01 CAS matchups Plots showing the SQM data that are matched up with CAS data start-end times 11 May 2017
       

 

Page Number
Link to PDF
Description
Date
Stability of the CAS and SQM PFDs from Carol
200.01 30-Oct-2017

I have restricted the CAS views of the SQM to when the CAS is mounted in the SQM and after 22-Mar-2017, although the pages do not state this explicitly. This is followed by results of the CAS viewing the three RSL sphere sources – NPR, NII, and the OL455. Finally, the results of the VXR viewing the CAS are given. The VXR channels 1 to 6 are at ocean color bands: 412, 441, 548, 661, 775, and 870.

I have restricted the measurements to VXR and my SEI 4500 looking at the SQM from a distance of about 20 cm, and the CAS viewing the SQM when mounted in it (d = 0). I do not have the SEI 4500 data automated yet.  I am only operating LO and MED from now on, as HI does not add much in radiance level. To monitor the stability of the CAS, it views the three RSL sphere sources; the VXR views these sphere sources at the same time. I will update this pdf when I get new measurements, and I may add VXR data from measuring NPR, NII, and OL455.

 7 Nov 2017
200.02 7-Nov-2017 added the VXR time series on the spheres as well as the SQM 7 Nov 2017