scholarly journals Retrieving the vertical distribution of stratospheric OClO from Odin/OSIRIS limb-scattered sunlight measurements

2005 ◽  
Vol 5 (3) ◽  
pp. 2989-3046 ◽  
Author(s):  
P. Krecl ◽  
C. S. Haley ◽  
J. Stegman ◽  
S. M. Brohede ◽  
G. Berthet
Keyword(s):  
Transport Model ◽  
Polar Vortex ◽  
Optical Absorption Spectroscopy ◽  
Polar Regions ◽  
Atmospheric Conditions ◽  
Chemical Transport Model ◽  
Austral Spring ◽  
Data Set ◽  
Spectral Window ◽  
Window Selection

Abstract. The first vertical profiles of stratospheric OClO retrieved from Odin/OSIRIS limb-scattered sunlight radiances are presented. The retrieval method is based on a two-step approach, using differential optical absorption spectroscopy combined with the maximum a posteriori estimator. The details of the spectral window selection, spectral corrections and inversion technique are discussed. The results show that OClO can be detected inside the South polar vortex region between about 12 and 20 km altitude with a 2–5 km height resolution and an estimated retrieval error better than 60% at the peak. OClO concentrations are consistent with chemical transport model simulations and show the expected relation to the atmospheric conditions in the lower stratosphere in the austral spring 2002. This unique data set of OClO profiles is very promising to study the stratospheric chlorine activation in both polar regions.

scholarly journals Retrieving the vertical distribution of stratospheric OClO from Odin/OSIRIS limb-scattered sunlight measurements

2006 ◽  
Vol 6 (7) ◽  
pp. 1879-1894 ◽  
Author(s):  
P. Krecl ◽  
C. S. Haley ◽  
J. Stegman ◽  
S. M. Brohede ◽  
G. Berthet
Keyword(s):  
Polar Vortex ◽  
Optical Absorption Spectroscopy ◽  
Polar Regions ◽  
Atmospheric Conditions ◽  
Austral Spring ◽  
Data Set ◽  
Spectral Window ◽  
Window Selection ◽  
And Inversion ◽  
The Vertical Distribution

Abstract. The first vertical profiles of stratospheric OClO retrieved from Odin/OSIRIS limb-scattered sunlight radiances are presented. The retrieval method is based on a two-step approach, using differential optical absorption spectroscopy combined with the maximum a posteriori estimator. The details of the spectral window selection, spectral corrections and inversion technique are discussed. The results show that OClO can be detected inside the South polar vortex region between about 14 and 22 km altitude with a 2–5 km height resolution and an estimated retrieval error better than 50% at the peak. OClO concentrations show the expected relation to the atmospheric conditions in the lower stratosphere in the austral spring 2002. This unique data set of OClO profiles is very promising to study the stratospheric chlorine activation in both polar regions.

Record springtime stratospheric ozone depletion at 80°N in 2020

2021 ◽  
Author(s):  
Ramina Alwarda ◽  
Kristof Bognar ◽  
Kimberly Strong ◽  
Martyn Chipperfield ◽  
Sandip Dhomse ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
The Arctic ◽  
Optical Absorption Spectroscopy ◽  
Chemical Transport Model ◽  
Polar Stratospheric Clouds ◽  
Ozone Loss ◽  
Stratospheric Clouds

<p>The Arctic winter of 2019-2020 was characterized by an unusually persistent polar vortex and temperatures in the lower stratosphere that were consistently below the threshold for the formation of polar stratospheric clouds (PSCs). These conditions led to ozone loss that is comparable to the Antarctic ozone hole. Ground-based measurements from a suite of instruments at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada (80.05°N, 86.42°W) were used to investigate chemical ozone depletion. The vortex was located above Eureka longer than in any previous year in the 20-year dataset and lidar measurements provided evidence of polar stratospheric clouds (PSCs) above Eureka. Additionally, UV-visible zenith-sky Differential Optical Absorption Spectroscopy (DOAS) measurements showed record ozone loss in the 20-year dataset, evidence of denitrification along with the slowest increase of NO<sub>2</sub> during spring, as well as enhanced reactive halogen species (OClO and BrO). Complementary measurements of HCl and ClONO<sub>2</sub> (chlorine reservoir species) from a Fourier transform infrared (FTIR) spectrometer showed unusually low columns that were comparable to 2011, the previous year with significant chemical ozone depletion. Record low values of HNO<sub>3</sub> in the FTIR dataset are in accordance with the evidence of PSCs and a denitrified atmosphere. Estimates of chemical ozone loss were derived using passive ozone from the SLIMCAT offline chemical transport model to account for dynamical contributions to the stratospheric ozone budget.</p>

A stratospheric NO2 climatology from Odin/OSIRIS limb-scatter measurements

2007 ◽  
Vol 85 (11) ◽  
pp. 1253-1274 ◽  
Author(s):  
S Brohede ◽  
C A McLinden ◽  
G Berthet ◽  
C S Haley ◽  
D Murtagh ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Transport Model ◽  
Polar Vortex ◽  
Scattering Data ◽  
Polar Regions ◽  
Local Solar Time ◽  
Chemical Transport Model ◽  
Solar Time ◽  
High Concentrations ◽  
Relative Differences

A climatology of stratospheric nitrogen dioxide (NO2), in terms of mean and standard deviation, as a function of latitude (5° bins); altitude (10–46 km in 2 km bins); local solar time (24 h); and month is constructed based on the Odin/OSIRIS limb-scattering data from 2002–2005. The measured profiles, given at specific local solar times, are scaled to all 24 h using a photochemical box model. The Odin orbit gives near global coverage around the equinoxes and hemispheric coverage elsewhere, due to lack of sunlight. The mean NO2 field at a specific local solar time involves high concentrations in the polar summer, peaking at around 25 km, with a negative equatorward gradient. Distinct high levels between 40–50° latitude at 30 km in the winter/spring hemisphere are also found, associated with the so-called {Noxon-cliff}. The diurnal cycle reveals the lowest NO2 concentrations just after sunrise and steep gradients at twilight. The 1σ standard deviation is generally quite low, around 20%, except for winter and spring high latitudes, where values are well above 50% and stretch through the entire stratosphere, a phenomenon probably related to the polar vortex. It is also found that NO2 concentrations are log-normally distributed. Comparisons to a climatology based on data from a (REPROBUS) chemical transport model for the same time period reveal relative differences below 20% in general, which is comparable to the estimated OSIRIS systematic uncertainty. Clear exceptions are the polar regions in winter/spring throughout the atmosphere and equatorial regions below 25 km, where OSIRIS is relatively higher by 40% and more. These discrepancies are most likely attributable to limitations of the model, but this has to be investigated further. PACS Nos.: 92.60.hd, 95.75.Rs, 95.55.Fw, 95.40.+s

scholarly journals A global climatology of stratospheric OClO derived from GOMOS measurement

2013 ◽  
Vol 6 (2) ◽  
pp. 3511-3543
Author(s):  
C. Tétard ◽  
D. Fussen ◽  
F. Vanhellemont ◽  
C. Bingen ◽  
E. Dekemper ◽  
...  
Keyword(s):  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Equatorial Region ◽  
Optical Absorption Spectroscopy ◽  
Polar Regions ◽  
Signal To Noise ◽  
Spectral Window ◽  
Stellar Occultation ◽  
Noise Ratio ◽  
Window Selection

Abstract. The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument on board the European platform ENVISAT was dedicated to the study of the atmosphere of the Earth using the stellar occultation technique. The spectral range of the GOMOS spectrometer extends from the UV to the near infrared, allowing for the retrieval of species such as O3, NO2, NO3, H2O, O2, air density, aerosol extinction and OClO. Nevertheless, OClO can not be retrieved using a single GOMOS measurement because of the weak signal-to-noise ratio and the small optical thickness associated with this molecule. We present here the method used to detect this molecule by using several GOMOS measurements. It is based on a two-step approach. First, several co-located measurements are combined in a statistical way to build an averaged measurement with a higher signal-to-noise ratio. Then, a Differential Optical Absorption Spectroscopy (DOAS) method is applied to retrieve OClO slant column densities. The statistics of the sets of GOMOS measurements used to build the averaged measurement and the spectral window selection are analyzed. The obtained retrievals are compared to results from two balloon-borne instruments. It appears that the inter-comparisons of OClO are generally satisfying. Then, two nighttime climatologies of OClO slant column densities based on GOMOS averaged measurements are presented. The first depicts annual global pictures of OClO from 2003 to 2011. From this climatology, the presence of an OClO layer in the equatorial region at about 35 km is confirmed and strong concentrations of OClO in both polar regions are observed, a sign of chlorine activation. The second climatology is a monthly time series. It clearly shows the chlorine activation of the lower stratosphere during winter. Moreover the equatorial OClO layer is observed during all the years without any significant variations. Finally, the anti-correlation between OClO and NO2 is highlighted. This very promising method, applied on GOMOS measurements, allowed us to build the first nighttime climatology of OClO.

scholarly journals Climatologies of subtropical mixing derived from 3D models

2003 ◽  
Vol 3 (4) ◽  
pp. 1007-1021 ◽  
Author(s):  
V. Eyring ◽  
M. Dameris ◽  
V. Grewe ◽  
I. Langbein ◽  
W. Kouker
Keyword(s):  
Climate Model ◽  
Transport Model ◽  
Polar Vortex ◽  
3D Models ◽  
Atmospheric Conditions ◽  
Chemical Transport Model ◽  
Air Masses ◽  
Chemical Tracers ◽  
Latitude Distribution ◽  
First Time

Abstract. Fingerlike structures reaching from lower into extra-tropical latitudes significantly contribute to the tropical-extratropical exchange of air masses. This is also an exchange of upper tropospheric and stratospheric air. Those so called streamers can, on a horizontal plane, be detected in N2O or O3 since they are characterised by high N2O or low O3 values compared to undisturbed mid-latitude values. A climatology of streamer events has been established, employing the chemical-transport model KASIMA, which is driven by ECMWF re-analyses (ERA) and operational analyses. For the first time, the seasonal and geographical distribution of streamer frequencies has been determined on the basis of 9 years of meteorological analyses. For the current investigation, a meridional gradient criterion has been newly formulated and applied to the N2O distributions calculated with KASIMA. A climatology has been derived by counting all streamer events between 21 and 25 km for the years 1990 to 1998. The results have been compared with a streamer climatology which has been established in the same way employing data of a multi-year simulation with the coupled chemistry-climate model ECHAM4.L39(DLR)/CHEM (E39/C). Both climatologies are qualitatively in agreement, in particular in the northern hemisphere, where much higher streamer frequencies are found in winter than in summer. In the southern hemisphere, the KASIMA analyses indicate strongest streamer activity in September. E39/C streamer frequencies clearly displays an offset from June to October, pointing to model deficiencies with respect to tropospheric dynamics. KASIMA and E39/C results agree well from November to May. Some of the findings give strong indications that the streamer events found in the altitude region between 21 and 25 km are mainly forced from the troposphere and are not directly related to the dynamics of the stratosphere, in particular not to the dynamics of the polar vortex. Sensitivity simulations with E39/C, which represent recent and possible future atmospheric conditions, have been employed to answer the question how climate change would alter streamer frequencies. This shows that the seasonal cycle does not change but that significant changes occur in months of minimum and maximum streamer frequencies. This could have an impact on the mid-latitude distribution of chemical tracers and compounds.

scholarly journals Chemical composition and severe ozone loss derived from SCIAMACHY and GOME-2 observations during Arctic winter 2010/2011 in comparisons to Arctic winters in the past

2013 ◽  
Vol 13 (6) ◽  
pp. 16597-16660 ◽  
Author(s):  
R. Hommel ◽  
K.-U. Eichmann ◽  
J. Aschmann ◽  
K. Bramstedt ◽  
M. Weber ◽  
...  
Keyword(s):  
Transport Model ◽  
Polar Vortex ◽  
Significant Loss ◽  
The Arctic ◽  
Optical Absorption Spectroscopy ◽  
Late Winter ◽  
Chemical Transport Model ◽  
Total Column Ozone ◽  
Bromine Oxide ◽  
Total Column

Abstract. Record breaking losses of ozone (O3) in the Arctic stratosphere have been reported in winter and spring 2011. Trace gas amounts and polar stratospheric cloud (PSC) distributions retrieved using differential optical absorption spectroscopy (DOAS) and scattering theory applied to the measurements of radiance and irradiance by satellite-born and ground-based instrumentation, document the unusual behaviour. A chemical transport model has been used to relate and compare Arctic winter-spring conditions in 2011 with those in previous years. We examine in detail the composition and transformations occurring in the Arctic polar vortex using total column and vertical profile data products for O3, bromine oxide (BrO), nitrogen dioxide (NO2), chlorine dioxide (OClO), and PSCs retrieved from measurements made by the instrument SCIAMACHY onboard the ESA satellite Envisat, as well as the total column ozone amount, retrieved from the measurements of GOME-2 on the EUMETSAT operational meteorological polar orbiter Metop-A. In the late winter and spring 2010/2011 the chemical loss of O3 in the polar vortex is consistent with and confirms findings reported elsewhere. More than 70% of O3 was depleted between the 425 K and 525 K isentropic surfaces, i.e. in the altitude range ~16–20 km. In contrast, during the same period in the previous winter only slightly more than 20% depletion occurred below 20 km, whereas 40% of the O3 was removed above the 575 K isentrope (~23 km). This loss above the 575 K isentrope is explained by the catalytic destruction by the NOx descending from the mesosphere. At lower altitudes O3 loss results from processing by halogen driven O3 catalytic removal cycles, activated by the large volume of PSC generated throughout this winter and spring. The mid-winter 2011 conditions, prior to the catalytic cycles being fully effective, are also investigated. Surprisingly, a significant loss of O3 with 60% is observed in mid-January 2011 below 500 K (~19 km), which was then sustained for approximately a week. This "mini-hole" event had an exceptionally large spatial extent. Such meteorologically driven changes in polar stratospheric O3 are expected to increase in frequency as anthropogenically induced climate change evolves.

scholarly journals Comparison of ozone profiles from DIAL, MLS, and chemical transport model simulations over Río Gallegos, Argentina during the spring Antarctic vortex breakup, 2009

2017 ◽  
Author(s):  
Takafumi Sugita ◽  
Hideharu Akiyoshi ◽  
Elián Wolfram ◽  
Jacobo Salvador ◽  
Hirofumi Ohyama ◽  
...  
Keyword(s):  
Transport Model ◽  
Polar Vortex ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Austral Spring ◽  
Lower Altitude ◽  
Model Simulations ◽  
Ground Measurement ◽  
The Difference ◽  
Mean Differences

Abstract. This study evaluates the agreement between ozone profiles derived from the ground-based DIfferential Absorption Lidar (DIAL), satellite-borne Aura Microwave Limb Sounder (MLS), and 3-D chemical transport model simulations (MIROC-CTM) over the South Patagonian Atmospheric Observatory (OAPA, 51.6° S, 69.3° W) in Río Gallegos, Argentina from September to November 2009. In this austral spring, measurements were performed in the vicinity of the polar vortex, and inside it on some occasions; they revealed the variability in potential vorticity (PV) of measured air masses. Comparisons between DIAL and MLS were performed between 6 hPa and 100 hPa with 500 km and 24 h coincidence criteria. The results show a good agreement between DIAL and MLS with mean differences of ±0.1 ppmv (MLS – DIAL, n = 180) between 6 hPa and 56 hPa. MIROC-CTM also agrees to DIAL, with mean differences of ±0.3 ppmv (MIROC-CTM – DIAL, n = 23) between 10 hPa and 56 hPa. Both comparisons provide mean differences of 0.5 ppmv (MLS) to 0.8–0.9 ppmv (MIROC-CTM) at the 83–100 hPa levels. DIAL tends to underestimate ozone values at this lower altitude region. Between 6 hPa and 8 hPa, the MIROC-CTM ozone value is 0.4–0.6 ppmv (5–8 %) smaller than those from DIAL. Applying the scaled PV criterion for matching pairs in the DIAL/MLS comparison, the variability in the difference decreases 21–47 % between 10 hPa and 56 hPa. However, the mean differences are slight for all pressure levels, except 6 hPa. Because ground measurement sites in the Southern Hemisphere are very sparse at mid- to high-latitudes, i.e., 35–60° S, the OAPA site is unique for evaluating the bias and long-term stability of satellite instruments. The good performance of this DIAL system will be useful for such purposes in the future.

scholarly journals Comparison of ozone profiles from DIAL, MLS, and chemical transport model simulations over Río Gallegos, Argentina, during the spring Antarctic vortex breakup, 2009

2017 ◽  
Vol 10 (12) ◽  
pp. 4947-4964 ◽  
Author(s):  
Takafumi Sugita ◽  
Hideharu Akiyoshi ◽  
Elián Wolfram ◽  
Jacobo Salvador ◽  
Hirofumi Ohyama ◽  
...  
Keyword(s):  
Transport Model ◽  
Polar Vortex ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Austral Spring ◽  
Lower Altitude ◽  
Ground Measurement ◽  
Southern Patagonia ◽  
The Difference ◽  
Mean Differences

Abstract. This study evaluates the agreement between ozone profiles derived from the ground-based differential absorption lidar (DIAL), satellite-borne Aura Microwave Limb Sounder (MLS), and 3-D chemical transport model (CTM) simulations such as the Model for Interdisciplinary Research on Climate (MIROC-CTM) over the Atmospheric Observatory of Southern Patagonia (Observatorio Atmosférico de la Patagonia Austral, OAPA; 51.6° S, 69.3° W) in Río Gallegos, Argentina, from September to November 2009. In this austral spring, measurements were performed in the vicinity of the polar vortex and inside it on some occasions; they revealed the variability in the potential vorticity (PV) of measured air masses. Comparisons between DIAL and MLS were performed between 6 and 100 hPa with 500 km and 24 h coincidence criteria. The results show a good agreement between DIAL and MLS with mean differences of ±0.1 ppmv (MLS − DIAL, n  =  180) between 6 and 56 hPa. MIROC-CTM also agrees with DIAL, with mean differences of ±0.3 ppmv (MIROC-CTM − DIAL, n  =  23) between 10 and 56 hPa. Both comparisons provide mean differences of 0.5 ppmv (MLS) to 0.8–0.9 ppmv (MIROC-CTM) at the 83–100 hPa levels. DIAL tends to underestimate ozone values at this lower altitude region. Between 6 and 8 hPa, the MIROC-CTM ozone value is 0.4–0.6 ppmv (5–8 %) smaller than those from DIAL. Applying the scaled PV (sPV) criterion for matching pairs in the DIAL–MLS comparison, the variability in the difference decreases 21–47 % between 10 and 56 hPa. However, the mean differences are small for all pressure levels, except 6 hPa. Because ground measurement sites in the Southern Hemisphere (SH) are very sparse at mid- to high latitudes, i.e., 35–60° S, the OAPA site is important for evaluating the bias and long-term stability of satellite instruments. The good performance of this DIAL system will be useful for such purposes in the future.

scholarly journals Climatologies of streamer events derived from a transport model and a coupled chemistry-climate model

2002 ◽  
Vol 2 (6) ◽  
pp. 2297-2342 ◽  
Author(s):  
V. Eyring ◽  
M. Dameris ◽  
V. Grewe ◽  
I. Langbein ◽  
W. Kouker
Keyword(s):  
Climate Model ◽  
Transport Model ◽  
Polar Vortex ◽  
Atmospheric Conditions ◽  
Chemical Transport Model ◽  
Air Masses ◽  
Chemical Tracers ◽  
Model Configuration ◽  
Latitude Distribution ◽  
First Time

Abstract. Streamers, i.e. finger-like structures, reach from lower into extra-tropical latitudes. They can be detected in N2O or O3 distributions on single lower stratospheric layers in mid-latitudes since they are characterised by high N2O or low O3 values compared to undisturbed mid-latitude values. If irreversible mixing occurs, streamer events significantly contribute to the transfer of tropical air masses to mid-latitudes which is also an exchange of upper tropospheric and stratospheric air. A climatology of streamer events has been established, employing the chemical-transport model KASIMA, which is driven by ECMWF re-analyses (ERA) and operational analyses. For the first time, the seasonal and the geographical distribution of streamer frequencies has been determined on the basis of 9 years of observations. For the current investigation, a meridional gradient criterion has been newly formulated and applied to the N2O distributions calculated with KASIMA. The climatology has been derived by counting all streamer events between 21 and 25 km for the years 1990 to 1998. It has been further used for the validation of a streamer climatology which has been established in the same way employing data of a multi-year simulation with the coupled chemistry-climate model ECHAM4.L39(DLR)/CHEM (E39/C). It turned out that both climatologies are qualitatively in fair agreement, in particular in the northern hemisphere, where much higher streamer frequencies are found in winter than in summer. In the southern hemisphere, KASIMA analyses indicate strongest streamer activity in September. E39/C streamer frequencies clearly offers an offset from June to October, pointing to model deficiencies with respect to tropospheric dynamics. KASIMA and E39/C results fairly agree from November to May. Some of the findings give strong indications that the streamer events found in the altitude region between 21 and 25 km are mainly forced from the troposphere and are not directly related to the dynamics of the stratosphere, in particular not to the dynamics of the polar vortex. Sensitivity simulations with E39/C, which represent recent and possible future atmospheric conditions, have been employed to answer the question how climate change would alter streamer frequencies. It is shown that the seasonal cycle does not change but that significant changes occur in months of minimum and maximum streamer frequencies. This could have an impact on mid-latitude distribution of chemical tracers and compounds. The influence of streamers on the mid-latitude ozone budget has been assessed by applying a special E39/C model configuration. The streamer transport of low ozone is simply inhibited by filling up its ozone content according to the surrounding air masses. It shows that the importance of streamers for the ozone budget strongly decreases with altitude. At 15 km streamers lead to a decrease of ozone by 80%, whereas around 25 km it is only 1 to 5% and at mid-latitude tropopause, ozone decreases by 30% (summer) to 50% (winter).

scholarly journals Atmospheric tracers during the 2003–2004 stratospheric warming event and impact of ozone intrusions in the troposphere

2008 ◽  
Vol 8 (4) ◽  
pp. 13633-13666 ◽  
Author(s):  
Y. Liu ◽  
C. X. Liu ◽  
H. P. Wang ◽  
X. Tie ◽  
S. T. Gao ◽  
...  
Keyword(s):  
Transport Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Planetary Waves ◽  
Polar Regions ◽  
Chemical Transport Model ◽  
Ozone Concentrations ◽  
Ozone Flux ◽  
Column Ozone ◽  
Atmospheric Tracers

Abstract. We use the stratospheric/tropospheric chemical transport model MOZART-3 to study the distribution and transport of stratospheric O3 during the exceptionally intense stratospheric sudden warming event observed in January 2004 in the Northern polar region. A comparison between observations by the MIPAS instrument on board the ENVISAT spacecraft and model simulations shows that the evolution of the polar vortex and of planetary waves during the warming event plays an important role in controlling the spatial distribution of stratospheric ozone and the downward ozone flux in the lower stratospheric and upper tropospheric regions. Compared to the situation during the winter of 2002–2003, lower ozone concentrations were transported from the polar regions (polar vortex) to mid-latitudes, leading to exceptional large areas of low ozone concentrations outside the polar vortex and "low-ozone pockets" in the middle stratosphere. The unusually long-lasting stratospheric westward winds (easterlies) during the 2003–2004 event greatly restricted the upward propagation of planetary waves, causing the weak transport of ozone-rich air originated from low latitudes to the middle polar stratosphere (10 hPa). The restricted wave activities led to a reduced downward ozone flux from the lower stratosphere (LS) to the upper troposphere (UT), especially in East Asia. Consequently, in this region during wintertime (December and January), the column ozone between 100 and 300 hPa was about 10% lower during the 2003–2004 event compared to the situation in 2002–2003.

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