Chemical change in the Arctic Vortex during AASE II

Wesley A Traub,David G Johnson,Kelly V Chance,Kenneth W Jucks

doi:10.1029/94gl01324

Wesley A Traub, David G Johnson + Show 2 more

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https://doi.org/10.1029/94gl01324

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Abstract

We measured column abundances of HF, HCl, O3, HNO3, and H2O on the NASA DC‐8 during the AASE II campaign, using thermal emission spectroscopy. We made multiple traversals of the Arctic vortex and surroundings. Using HF as a tracer, we remove the effects of subsidence from the measured column abundances; perturbations in the resulting column abundances are attributed to chemical processing. We find that by January 1992 the stratospheric column in the vortex had been chemically depleted by about (55±10)% in HCl and (35±10)% in O3, and enhanced by about (15±10)% in HNO3 and (0±10)% in H2O.

Highlights

A major goal of the second Airborne Arctic Stratospheric Expedition (AASE II) in 1991–92 was to quantify the effects of dynamics and chemistry during the Arctic winter
As one of 13 experiments flown on the DC-8 during AASE II, the Smithsonian's far-infrared spectrometer (FIRS-2) measured column abundances using the thermal emission spectrum of the stratosphere, during both day and night
We report the results of our measurements of HCl, O3, HNO3, and H2O, using HF as a tracer to remove the effects of subsidence and to infer chemical change

Summary

Introduction

A major goal of the second Airborne Arctic Stratospheric Expedition (AASE II) in 1991–92 was to quantify the effects of dynamics and chemistry during the Arctic winter. Details are given in Johnson et al [1995] This method assumes that: (1) stratospheric mixing ratio profiles are dependent only on subsidence and chemical change, i.e., independent of latitude, longitude, and time; and (2) the effects of chemical change can be adequately represented by scaling the entire vertical profile. The advantage of the binning method is that it produces uniform sampling over a wide range of PV; the modest price paid is that the correlation length along the PV axis is variable, viz., slightly more than 2 points, on average. The results of this 3-stage analysis are shown in Figure 2 for HCl, O3, HNO3, and H2O. The January measurements at values of PV 3¡ 5 10¢ 5 were made at latitudes having 24 hours of darkness in January

Findings

Discussion

Conclusion