Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: F. E. Grahek x
  • Refine by Access: All Content x
Clear All Modify Search
B. A. Ridley
and
F. E. Grahek

Abstract

Details of a reaction vessel suitable for atmospheric measurements of nitric oxide at parts per trillion mixing ratios using the chemiluminescent reaction with ozone are provided. It is designed to operate at an ambient air flow of 1 standard liter per minute, much lower than most current high performance instruments. The savings in weight, space and power for a complete instrument allow obvious advantages for multispecies measurements using smaller aircraft.

Full access
B. A. Ridley
,
F. E. Grahek
, and
J. G. Walega

Abstract

An instrument for tropospheric O3 measurements based on the chemiluminescent reaction between nitric oxide and ozone is described. It was designed as part of a larger instrument package for simultaneous measurements of NO, NO2, NO y and O3 using smaller aircraft. The sensitivity of the O3 instrument is 2000 counts per second per ppbv O3, giving very high signal-to-noise ratios and a detection limit well below 0.1 ppbv. The instrument has been used in several research programs using the NCAR Sabreliner jet aircraft, and some results from these flights are presented. As configured for these flights, the instrument is operated with a 2-s integration time. However, suitable and readily made changes in operating conditions should allow sufficiently fast response for eddy correlation flux measurements from an aircraft or in ground-based programs.

Full access
R. D. Cadle
,
F. E. Grahek
,
B. W. Gandrud
, and
A. L. Lazrus

Abstract

The relative efficiencies of impactors of the type used by Junge and co-workers for collecting stratosphere sulfate particles and of filters used in these laboratories have been determined by flying these collecting devices on the same aircraft in the stratosphere. The impactors have less than 20% of the efficiency of the filters for total sulfate. At most, a small percentage of the stratospheric sulfate was present as the ammonium salt. At least about half of the ammonium ion found on the impactors could have resulted from reaction of the collected samples with ammonia in tropospheric air.

Full access