NOyfrom Michelson Interferometer for Passive Atmospheric Sounding on Environmental Satellite during the Southern Hemisphere polar vortex split in September/October 2002

2005 ◽  
Vol 110 (D11) ◽  
Author(s):  
G. Mengistu Tsidu
Keyword(s):  
Southern Hemisphere ◽  
Michelson Interferometer ◽  
Polar Vortex ◽  
Atmospheric Sounding ◽  
Vortex Split

scholarly journals Growth rates of stratospheric HCFC-22

2007 ◽  
Vol 7 (4) ◽  
pp. 10515-10541
Author(s):  
D. P. Moore ◽  
J. J. Remedios
Keyword(s):  
Growth Rate ◽  
Southern Hemisphere ◽  
Atmospheric Chemistry ◽  
Growth Rates ◽  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
Data Set ◽  
Atmospheric Sounding ◽  
Global Data ◽  
Made In

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding onboard ENVISAT (MIPAS-E) offers the opportunity to detect and spectrally resolve many atmospheric minor constituents affecting atmospheric chemistry. In this paper, we describe an algorithm produced to retrieve HCFC–22 profiles from MIPAS-E measurements made in 2003 and present results from this scheme between 300 and 50 mb. By comparison with ATMOS (AT–3) version 3 data, we find a mean Northern Hemisphere mid-latitude (20–50° N) HCFC–22 growth rate between 1994 and 2003 of 5.4±0.7 pptv/yr in the lower stratosphere (LS) and a mean LS Southern Hemisphere growth rate (60–80°S) of 6.0±0.7 pptv/yr in the same period. We test the feasibility of using a global data set to estimate the chemical lifetime of HCFC–22 in the LS and we derive this for two regions; 20–50° N (259±38 years) and 60–80° S (288±34 years). From these data we note a global LS lifetime of 274±25 years, significantly longer than previous estimates.

scholarly journals HOCl chemistry in the Antarctic stratospheric vortex 2002, as observed with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)

2008 ◽  
Vol 8 (6) ◽  
pp. 18967-18992
Author(s):  
T. von Clarmann ◽  
N. Glatthor ◽  
R. Ruhnke ◽  
G. P. Stiller ◽  
O. Kirner ◽  
...  
Keyword(s):  
Heterogeneous Reaction ◽  
Michelson Interferometer ◽  
Polar Vortex ◽  
Heterogeneous Chemistry ◽  
Polar Stratospheric Clouds ◽  
Mean Values ◽  
Mixing Ratios ◽  
Atmospheric Sounding ◽  
Antarctic Polar Vortex ◽  
Stratospheric Clouds

Abstract. In the 2002 Antarctic polar vortex enhanced HOCl mixing ratios were detected by the Michelson Interferometer for Passive Atmospheric Sounding both at altitudes of around 35 km, where HOCl abundances are ruled by gas phase chemistry and at around 24 km, which belongs to the altitude domain where heterogeneous chlorine chemistry is relevant. At altitudes of 33 to 40 km, where in midlatitudinal and tropical atmospheres peak HOCl mixing ratios significantly above 0.2 ppbv (in terms of daily mean values) are observed, polar vortex HOCl mixing ratios were found to be around 0.14 ppbv as long as the polar vortex was intact, centered at the pole, and thus received relatively little sunlight. After deformation and displacement of the polar vortex in the course of a major warming, ClO rich vortex air was more exposed to sunlight, where enhanced HOx abundances led to largely increased HOCl mixing ratios (up to 0.3 ppbv), exceeding typical midlatitudinal and tropical amounts significantly. The HOCl increase was preceded by an increase of ClO. Model runs could reproduce these measurements only when the Stimpfle et al. (1979) rate constant for the reaction ClO+HO2→HOCl+O2 was used but not with the current JPL recommendation. At an altitude of 24 km, HOCl mixing ratios of up to 0.15 ppbv were detected. This HOCl enhancement, which is already visible in 18 September data, is attributed to heterogeneous chemistry, which is in agreement with observations of polar stratospheric clouds. Comparison with a model run where no polar stratospheric clouds appeared during the observation period suggests that a significant part of HOCl was generated from ClO rather than directly via heterogeneous reaction. Excess ClO and HOCl in the measurements is attributed to ongoing heterogeneous chemistry which is not reproduced by the model. In the following days, a decay of HOCl abundances was observed and on 11 October, polar vortex mean daytime mixing ratios were only 0.03 ppbv.

scholarly journals A multi-wavelength classification method for polar stratospheric cloud types using infrared limb spectra

2016 ◽  
Vol 9 (8) ◽  
pp. 3619-3639 ◽  
Author(s):  
Reinhold Spang ◽  
Lars Hoffmann ◽  
Michael Höpfner ◽  
Sabine Griessbach ◽  
Rolf Müller ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Michelson Interferometer ◽  
Polar Vortex ◽  
Bayesian Classifier ◽  
Solid Particles ◽  
Detection Sensitivity ◽  
Ratio Method ◽  
Transfer Model ◽  
Model Calculations ◽  
The Antarctic

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument on board the ESA Envisat satellite operated from July 2002 until April 2012. The infrared limb emission measurements represent a unique dataset of daytime and night-time observations of polar stratospheric clouds (PSCs) up to both poles. Cloud detection sensitivity is comparable to space-borne lidars, and it is possible to classify different cloud types from the spectral measurements in different atmospheric windows regions. Here we present a new infrared PSC classification scheme based on the combination of a well-established two-colour ratio method and multiple 2-D brightness temperature difference probability density functions. The method is a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption. The method has been tested in conjunction with a database of radiative transfer model calculations of realistic PSC particle size distributions, geometries, and composition. The Bayesian classifier distinguishes between solid particles of ice and nitric acid trihydrate (NAT), as well as liquid droplets of super-cooled ternary solution (STS). The classification results are compared to coincident measurements from the space-borne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument over the temporal overlap of both satellite missions (June 2006–March 2012). Both datasets show a good agreement for the specific PSC classes, although the viewing geometries and the vertical and horizontal resolution are quite different. Discrepancies are observed between the CALIOP and the MIPAS ice class. The Bayesian classifier for MIPAS identifies substantially more ice clouds in the Southern Hemisphere polar vortex than CALIOP. This disagreement is attributed in part to the difference in the sensitivity on mixed-type clouds. Ice seems to dominate the spectral behaviour in the limb infrared spectra and may cause an overestimation in ice occurrence compared to the real fraction of ice within the PSC area in the polar vortex. The entire MIPAS measurement period was processed with the new classification approach. Examples like the detection of the Antarctic NAT belt during early winter, and its possible link to mountain wave events over the Antarctic Peninsula, which are observed by the Atmospheric Infrared Sounder (AIRS) instrument, highlight the importance of a climatology of 9 Southern Hemisphere and 10 Northern Hemisphere winters in total. The new dataset is valuable both for detailed process studies, and for comparisons with and improvements of the PSC parameterizations used in chemistry transport and climate models.

scholarly journals Growth rates of stratospheric HCFC-22

2008 ◽  
Vol 8 (1) ◽  
pp. 73-82 ◽  
Author(s):  
D. P. Moore ◽  
J. J. Remedios
Keyword(s):  
Growth Rate ◽  
Southern Hemisphere ◽  
Atmospheric Chemistry ◽  
Growth Rates ◽  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
Data Set ◽  
Atmospheric Sounding ◽  
Global Data ◽  
Made In

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding onboard ENVISAT (MIPAS-E) offers the opportunity to detect and spectrally resolve many atmospheric minor constituents affecting atmospheric chemistry. In this paper, we describe an algorithm produced to retrieve HCFC–22 profiles from MIPAS-E measurements made in 2003 and present results from this scheme between 300 and 50 mb. By comparison with ATMOS (AT–3) version 3 data, we find a mean Northern Hemisphere mid-latitude (20–50° N) HCFC–22 growth rate between 1994 and 2003 of 5.4±0.7 pptv/yr in the lower stratosphere (LS) and a mean LS Southern Hemisphere growth rate (60–80° S) of 6.0±0.7 pptv/yr in the same period. We test the feasibility of using a global data set to estimate the chemical lifetime of HCFC–22 in the LS and we derive this for two regions: 20–50° N (246±38 years) and 60–80° S (274±34 years). From these data we note a global LS lifetime of 260±25 years, significantly longer than previous estimates.

An Observational Study of the Final Breakdown of the Southern Hemisphere Stratospheric Vortex in 2002

2005 ◽  
Vol 62 (3) ◽  
pp. 735-747 ◽  
Author(s):  
Yvan J. Orsolini ◽  
Cora E. Randall ◽  
Gloria L. Manney ◽  
Douglas R. Allen
Keyword(s):  
Southern Hemisphere ◽  
Vortex Core ◽  
Vortex Breakdown ◽  
Michelson Interferometer ◽  
European Space Agency ◽  
Polar Vortex ◽  
Stratospheric Aerosol ◽  
Satellite Observations ◽  
Stratospheric Polar Vortex ◽  
Space Agency

Abstract The 2002 Southern Hemisphere final warming occurred early, following an unusually active winter and the first recorded major warming in the Antarctic. The breakdown of the stratospheric polar vortex in October and November 2002 is examined using new satellite observations from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard the European Space Agency (ESA) Environment Satellite (ENVISAT) and meteorological analyses, both high-resolution fields from the European Centre for Medium-Range Weather Forecasts and the coarser Met Office analyses. The results derived from MIPAS observations are compared to measurements and inferences from well-validated solar occultation satellite instruments [Halogen Occultation Experiment (HALOE), Polar Ozone and Aerosol Measurement III (POAM III), and Stratospheric Aerosol and Gas Experiments II and III (SAGE II and III)] and to finescale tracer fields reconstructed by transporting trace gases based on MIPAS or climatological data using a reverse-trajectory method. These comparisons confirm the features in the MIPAS data and the interpretation of the evolution of the flow during the vortex decay revealed by those features. Mapped ozone and water vapor from MIPAS and the analyzed isentropic potential vorticity vividly display the vortex breakdown, which occurred earlier than usual. A large tongue of vortex air was pulled out westward and coiled up in an anticyclone, while the vortex core remnant shrank and drifted eastward and equatorward over the South Atlantic. By roughly mid-November, the vortex remnant at 10 mb had shrunk below scales resolved by the satellite observations, while a vortex core remained in the lower stratosphere.

scholarly journals Global distributions of acetone in the upper troposphere from MIPAS spectra

2012 ◽  
Vol 12 (2) ◽  
pp. 757-768 ◽  
Author(s):  
D. P. Moore ◽  
J. J. Remedios ◽  
A. M. Waterfall
Keyword(s):  
North America ◽  
Southern Hemisphere ◽  
Biomass Burning ◽  
Michelson Interferometer ◽  
Transport Processes ◽  
Hemispheric Differences ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Atmospheric Sounding ◽  
European Values

Abstract. This study reports the first global measurements of acetone (C3H6O) in the upper troposphere (UT). Profiles were obtained between 9 km and 15 km from measurements made by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard Envisat in August 2003. Errors per profile are lower than 40 % between 180 hPa and 350 hPa. We report strong hemispheric differences in the acetone volume mixing ratios (VMRs), with average concentrations highest in the Northern Hemisphere (NH) mid-latitude UT, between 1000 pptv and 1600 pptv with maxima up to 2300 pptv. Our results show a strong enhancement of acetone relative to CO, particularly over Europe (7 pptv ppbv−1), confirming aircraft studies. Ten-day backward trajectories from these high European values show strong contributions from air flows over North America (56 %) and 25 % from Southernmost Asia. Enhanced acetone is also observed over Greenland, Siberia and biomass burning regions of Africa. Zonal distributions show that acetone VMRs decrease rapidly with increasing altitude (decreasing pressure), particularly in the NH. Poleward of 45° S, acetone VMRs remain fairly consistent with average VMRs between 400 pptv and 500 pptv. In 5-day averages at 9 km, NH VMRs poleward of 45° N are consistently higher than Southern Hemisphere observations poleward of 45° S, by between 750 pptv and 1100 pptv. The results show a clear influence of mid-latitude and transport processes on the acetone summertime distribution.

scholarly journals HOCl chemistry in the Antarctic Stratospheric Vortex 2002, as observed with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)

2009 ◽  
Vol 9 (5) ◽  
pp. 1817-1829 ◽  
Author(s):  
T. von Clarmann ◽  
N. Glatthor ◽  
R. Ruhnke ◽  
G. P. Stiller ◽  
O. Kirner ◽  
...  
Keyword(s):  
Heterogeneous Reaction ◽  
Potential Temperature ◽  
Michelson Interferometer ◽  
Polar Vortex ◽  
Heterogeneous Chemistry ◽  
Polar Stratospheric Clouds ◽  
Mean Values ◽  
Mixing Ratios ◽  
Atmospheric Sounding ◽  
Stratospheric Clouds

Abstract. In the 2002 Antarctic polar vortex enhanced HOCl mixing ratios were detected by the Michelson Interferometer for Passive Atmospheric Sounding both at altitudes of around 35 km (1000 K potential temperature), where HOCl abundances are ruled by gas phase chemistry and at around 18–24 km (475–625 K), which belongs to the altitude domain where heterogeneous chlorine chemistry is relevant. At altitudes of 33 to 40 km polar vortex HOCl mixing ratios were found to be around 0.14 ppbv as long as the polar vortex was intact, centered at the pole, and thus received relatively little sunlight. This is the altitude region where in midlatitudinal and tropic atmospheres peak HOCl mixing ratios significantly above 0.2 ppbv (in terms of daily mean values) are observed. After deformation and displacement of the polar vortex in the course of a major warming, ClO-rich vortex air was more exposed to sunlight, where enhanced HOx abundances led to largely increased HOCl mixing ratios (up to 0.3 ppbv), exceeding typical midlatitudinal and tropical amounts significantly. The HOCl increase was preceded by an increase of ClO. Model runs could reproduce these measurements only when the Stimpfle et al. (1979) rate constant for the reaction ClO+HO2→HOCl+O2 was used but not with the current JPL recommendation. At an altitude of 24 km, HOCl mixing ratios of up to 0.15 ppbv were detected. This HOCl enhancement, which is already visible in 18 September data, is attributed to heterogeneous chemistry, which is in agreement with observations of polar stratospheric clouds. The measurements were compared to a model run where no polar stratospheric clouds appeared during the observation period. The fact that HOCl still was produced in the model run suggests that a significant part of HOCl was generated from ClO rather than directly via heterogeneous reaction. Excess ClO, lower ClONO2 and earlier loss of HOCl in the measurements are attributed to ongoing heterogeneous chemistry which is not reproduced by the model. On 11 October, polar vortex mean daytime mixing ratios were only 0.03 ppbv.

scholarly journals The MIPAS HOCl climatology

2011 ◽  
Vol 11 (7) ◽  
pp. 20793-20822
Author(s):  
T. von Clarmann ◽  
B. Funke ◽  
N. Glatthor ◽  
S. Kellmann ◽  
M. Kiefer ◽  
...  
Keyword(s):  
Michelson Interferometer ◽  
Polar Vortex ◽  
Solar Proton ◽  
Proton Event ◽  
Mixing Ratios ◽  
Atmospheric Sounding ◽  
Summer Hemisphere ◽  
Activation Conditions ◽  
The Antarctic ◽  
Winter Hemisphere

Abstract. Monthly zonal mean HOCl measurements by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) are presented for the episode from June 2002 to March 2004. Highest molar mixing ratios are found at pressure levels between 6 and 2 hPa, whereby largest mixing ratios occasionally exceed 200 ppt. The mixing ratio maximum is generally at lower altitudes in the summer hemisphere than in the winter hemisphere except for chlorine activation conditions in polar vortices, where enhanced HOCl abundances are also found in the lower stratosphere. During nighttime the maximum is found at higher altitudes than during daytime. Particularly low values are found in subpolar regions in the winter hemisphere, coinciding with the mixing barrier formed by the polar vortex boundary. The Antarctic polar winter HOCl distribution in 2002, the year of the split of the southern polar vortex, resembles northern polar winters rather than other southern polar winters. Increased HOCl amounts in response to the so-called Halloween solar proton event in autumn 2003 affect the representativeness of data recorded during this particular episode. Calculations with the EMAC model reproduce the structure of the measured HOCl distribution but predict approximately 40 % less HOCl except during polar night in the mid-stratosphere where calculated HOCl mixing ratios exceed observed ones.

scholarly journals Nonstationarity in Southern Hemisphere Climate Variability Associated with the Seasonal Breakdown of the Stratospheric Polar Vortex

2017 ◽  
Vol 30 (18) ◽  
pp. 7125-7139 ◽  
Author(s):  
Nicholas J. Byrne ◽  
Theodore G. Shepherd ◽  
Tim Woollings ◽  
R. Alan Plumb
Keyword(s):  
Climate Variability ◽  
Southern Hemisphere ◽  
Seasonal Cycle ◽  
Vortex Breakdown ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Early Summer ◽  
Stratospheric Polar Vortex ◽  
Time Symmetry

Abstract Statistical models of climate generally regard climate variability as anomalies about a climatological seasonal cycle, which are treated as a stationary stochastic process plus a long-term seasonally dependent trend. However, the climate system has deterministic aspects apart from the climatological seasonal cycle and long-term trends, and the assumption of stationary statistics is only an approximation. The variability of the Southern Hemisphere zonal-mean circulation in the period encompassing late spring and summer is an important climate phenomenon and has been the subject of numerous studies. It is shown here, using reanalysis data, that this variability is rendered highly nonstationary by the organizing influence of the seasonal breakdown of the stratospheric polar vortex, which breaks time symmetry. It is argued that the zonal-mean tropospheric circulation variability during this period is best viewed as interannual variability in the transition between the springtime and summertime regimes induced by variability in the vortex breakdown. In particular, the apparent long-term poleward jet shift during the early-summer season can be more simply understood as a delay in the equatorward shift associated with this regime transition. The implications of such a perspective for various open questions are discussed.

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