Caltech EM27/SUN FTS

Version as of 21:59, 19 Sep 2020

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We have used this instrument and anticipate further use in conjunction with TCCON instruments (e.g. the one at Caltech) to provide ground validation for and check for biases in OCO-2.   We also anticipating using this instrument to examine emissions of various gases from point locations and sources in the South Coast air Basin (SCB).

This project is currently (May 2016) worked on by graduate student Jacob Hedelius with some assistance from various other in the Carbon Cycle side and from collaborators at JPL. Former Caltech participants include Camille Viatte (who now primarily works with OCO-2 data, and still works with it on occasion).

An online e-notebook for this instrument is avaliable on the private TCCON-wiki page.

https://tccon-wiki.caltech.edu/Sites/Caltech/EM27

Specifications

Resolution: 0.5 cm-1

Geometric distance moved: 0.45 cm

Optical path difference: 1.8 cm

Range: ~40009000 cm-1

Gases measured: CO2, CH4, CO, H2O, N2O, O2

 

Projects Worked on

OCO-2 Validation

Because of the TCCON site at Caltech, Pasadena has frequently been targeted by OCO-2.  We have gone out several times (6+) to various places in Pasadena on OCO-2 targeted days.  In a single day we are able to make measurements at about 3 to 6 locations.  All of our equipment easily fits inside the back of a pickup truck.  Usually on these days we start and end by comparing with TCCON (see figure).

mobileFTS at Caltech.jpg


Measurements Around Emission Source

In January 2015 we hosted a mobile FTS campaign.  This campaign had 2 goals: 1) intercompare the mobile FT spectrometers and 2) measure emissions from a source in the SCB.  This campaign included participants from Caltech, JPL, LANL, and Harvard.  This was the first campaign of the mobile FT spectrometers in the U.S.  Overall we accomplished our goals, though every is working to provide the final versions of their data.  This campaign invovled work with 4 mobile FT spectrometers, 1 TCCON spectrometer, 2 picarro CRDS, and various meterological stations.