Applied Physics B

, Volume 75, Issue 2–3, pp 183–194 | Cite as

A fast-response near-infrared tunable diode laser absorption spectrometer for in situ measurements of CH4 in the upper troposphere and lower stratosphere

  • E.C. Richard
  • K.K. Kelly
  • R.H. Winkler
  • R. Wilson
  • T.L. Thompson
  • R.J. McLaughlin
  • A.L. Schmeltekopf
  • A.F. Tuck

Abstract.

We describe a near-infrared in situ tunable diode laser spectrometer developed for atmospheric measurements of CH4 in the upper troposphere and lower stratosphere (UT/LS). The instrument is designed to provide fast-response (0.5–1 Hz) measurements and operate autonomously on the NASA WB-57F high-altitude aircraft. A single-mode InGaAsP distributed feedback laser diode operating at 1.6537 μm scans continuously over the R(3) rotation–vibration transition in the 2ν3 band. We use a direct absorption technique incorporating a custom-designed long path length (252 m) low-volume (3.6 L) astigmatic Herriott cell. The present detection sensitivity is 5×1010 molecules cm-3, corresponding to ∼20 ppbv in the UT/LS, with the main limit to instrument precision being background optical interference fringes. In-flight performance is demonstrated by presentation of recent data.

PACS: 07.60.-j; 07.88+y; 07.07.-a; 07.07.Df; 39.30.+w 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • E.C. Richard
    • 1
  • K.K. Kelly
    • 1
  • R.H. Winkler
    • 1
  • R. Wilson
    • 1
  • T.L. Thompson
    • 1
  • R.J. McLaughlin
    • 1
  • A.L. Schmeltekopf
    • 1
  • A.F. Tuck
    • 1
  1. 1.NOAA Aeronomy Laboratory, 325 Broadway R/AL6, Boulder, CO 80305-3328, USAUS

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