NOy‐N2O correlation observed inside the Arctic vortex in February 1997: Dynamical and chemical effects

Kondo, Yutaka; Koike, M.; Engel, Andreas; Schmidt, Ulrich; Mueller, M.; Sugita, T.; Kanzawa, Hiroshi; Nakazawa, Takakiyo; Aoki, Shuji; Irie, Hitoshi; Toriyama, N.; Suzuki, Takeshi; Sasano, Yasuhiro

doi:10.1029/1999jd900020

Cited by 36 publications

(42 citation statements)

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“…The HNO 3 evaporation from these large particles at lower altitudes may explain the enhancements in the NOy gas phase abundance as observed by the DC-8 [Huebler et al, 1990]. Despite these indications of local denitrification in the Arctic, it is clear that mixing processes can lead to variations in the nitric acid abundance that can be mistaken for denitrification [Michelsen et al, 1998;Kondo et al, 1999]. Hence it is not evident from present in situ data sets that denitrification is a widespread phenomena in the Arctic.…”

Section: Introductioncontrasting

confidence: 38%

Analysis of lidar observations of Arctic polar stratospheric clouds during January 1989

Toon¹,

Tabazadeh²,

Browell³

et al. 2000

J. Geophys. Res.

123

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Abstract. We present analyses of lidar backscatter and depolarization ratios for polar stratospheric clouds (PSCs) observed during the 1989 Airborne Arctic Stratospheric Experiment. The backscatter and depolarization ratios are available at one visible and one infrared wavelength. Water ice PSCs were identified at low ambient temperatures based upon their relatively large backscattering and depolarization ratios. The remaining clouds fall into four major categories. First, we observe a class of clouds that are not depolarizing at either of the two wavelengths. These clouds are identified as Type 1 b PSCs, which are assumed to be composed of ternary solutions of H2SO4/HNO•/H20. Type 1 b clouds were never dominant, though on some dates they accounted for 25 to 40 % of the observations. We find from the wavelength dependence of the backscattering by these clouds that their size distributions must be very narrow. Other optical observations of these clouds should consider the possible impact of these narrow size distributions on their data analysis. These clouds have a relatively large total particulate mass that is comparable to the known gas phase reservoir of nitric acid. The number density of Type lb particles is similar to the concentrations of the ambient sulfate aerosols. The second category of clouds is highly depolarizing at both lidar wavelengths, but has relatively low backscattering ratios. We identify these clouds as Type 1 a PSCs (assumed to be nitric acid tri-or dihydrate) which form only on a small subset by number, approximately 1% or less, of the ambient sulfate aerosols. These clouds were the first to be observed, and were especially co•n•non on the first few flights. They accounted for more than 70% of the observations on three flights. Type l a particles are near 1 •m or larger in radius. The third type of cloud is depolarizing at visible wavelengths, but not at near infrared wavelengths. These clouds were seen during portions of nearly every flight and comprised 10 to 25% of all of the observations. These clouds, which we refer to as Type 1 c, are composed of small, solid particles. These clouds contain a relatively large mass of material, comparable to the gas phase reservoir of nitric acid. Type 1 c particles are a few tenths of a micrometer in radius and have a concentration that is similar to that of the ambient sulfate aerosols. The final class of clouds has no depolarization at the lidar's visible wavelength but has significant depolarization at the infrared wavelength. Such particles were seen on many of the flights and sometimes accounted for as much as 30% of all the observations. We interpret these clouds as being mixtures of Type 1 a and 1 b PSCs. Although some polar stratospheric clouds have fairly homogeneous properties over very large spatial scales, many have variable properties at relatively small scales. Thus the various types of particles are often observed within a single cloud. Homogeneous clouds composed only of solid particles seem inconsistent with a wave cloud origin. How...

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Section: Introductioncontrasting

confidence: 38%

Analysis of lidar observations of Arctic polar stratospheric clouds during January 1989

Toon¹,

Tabazadeh²,

Browell³

et al. 2000

J. Geophys. Res.

123

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“…Fahey et al, 1990). Kondo et al (1999) and Wetzel et al (2002) were able to show that their observed anomalous correlation between N 2 O and NO y inside the polar vortex in February and March 1997 was indeed mainly caused by dynamical effects.…”

Section: Introductionmentioning

confidence: 75%

Observation of mesospheric air inside the arctic stratospheric polar vortex in early 2003

et al. 2006

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Abstract. During several balloon flights inside the Arctic polar vortex in early 2003, unusual trace gas distributions were observed, which indicate a strong influence of mesospheric air in the stratosphere. The tuneable diode laser (TDL) instrument SPIRALE (Spectroscopie Infra-Rouge par Absorption de Lasers Embarqués) measured unusually high CO values (up to 600 ppb) on 27 January at about 30 km altitude. The cryosampler BONBON sampled air masses with very high molecular Hydrogen, extremely low SF 6 and enhanced CO values on 6 March at about 25 km altitude. Finally, the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) Fourier Transform Infra-Red (FTIR) spectrometer showed NO y values which are significantly higher than NO y * (the NO y derived from a correlation between N 2 O and NO y under undisturbed conditions), on 21 and 22 March in a layer centred at 22 km altitude. Thus, the mesospheric air seems to have been present in a layer descending from about 30 km in late January to 25 km altitude in early March and about 22 km altitude on 20 March. We present corroborating evidence from a model study using the KASIMA (KArlsruhe SImulation model of the Middle Atmosphere) model that also shows a layer of mesospheric air, which descended into the stratosphere in November and early December 2002, before the minor warming which occurred in late December 2002 lead to a descent of upper stratospheric air, cutting off a layer in which mesospheric air is present. This layer then descended inside the vortex over the course of the winter. The same feature is found in trajectory calculations, based on a large number of trajectories started in the vicinity of the observations on 6 March. Based on the difference between the mean age derived from SF 6 (which has an irreversible mesoCorrespondence to: A. Engel (an.engel@meteor.uni-frankfurt.de) spheric loss) and from CO 2 (whose mesospheric loss is much smaller and reversible) we estimate that the fraction of mesospheric air in the layer observed on 6 March, must have been somewhere between 35% and 100%.

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“…The most compelling evidence of this comes from observations of anomalous vortex relationships between certain pairs of long-lived tracers (Michelson et al 1998;Kondo 1999;Plumb et al 2000;Rex et al 2000), whose only apparent explanation is that surf zone air is being mixed into the vortex. Indeed, it now appears that distinct compact relationships were established within the Arctic vortex by late winter of 2000 , implying also the presence of rapid mixing within (in addition to possible weak mixing into) the vortex.…”

Section: Tracers In the Vortexmentioning

confidence: 99%

Stratospheric Transport

Plumb

2002

Journal of the Meteorological Society of Japan

329

301

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Improvements in our understanding of transport processes in the stratosphere have progressed hand in hand with advances in understanding of stratospheric dynamics and with accumulating remote and in situ observations of the distributions of, and relationships between, stratospheric tracers. It is convenient to regard the stratosphere as being separated into four regions: the summer hemisphere, the tropics, the wintertime midlatitude ''surf zone'', and the winter polar vortex. Stratospheric transport is dominated by mean diabatic advection (upwelling in the tropics, downwelling in the surf zone and the vortex) and, especially, by rapid isentropic stirring within the surf zone. These characteristics determine the global-scale distributions of tracers, and their mutual relationships. Despite our much-improved understanding of these processes, many chemical transport models still appear to exhibit significant shortcomings in simulating stratospheric transport, as is evidenced by their tendency to underestimate the age of stratospheric air.

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NO_y‐N₂O correlation observed inside the Arctic vortex in February 1997: Dynamical and chemical effects

Cited by 36 publications

References 36 publications

Analysis of lidar observations of Arctic polar stratospheric clouds during January 1989

Analysis of lidar observations of Arctic polar stratospheric clouds during January 1989

Observation of mesospheric air inside the arctic stratospheric polar vortex in early 2003

Stratospheric Transport

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