MLS Research

Extra-tropical Strat-Trop Exchange

Contact Gloria Manney

Understanding dynamical, transport and chemical processes in the extra-tropical (ET) upper troposphere and lower stratosphere (UTLS) is critical to advancing climate change and pollution transport studies.

For example, water vapor and ozone are both key greenhouse gases in the UTLS, and their distributions are strongly affected by stratosphere-troposphere exchange processes. In the lowermost stratosphere (the portion of the extratropics where some part of the lower latitude region is in the troposphere), there is a complex interplay of stratospheric (e.g., chemical ozone loss) and tropospheric (e.g., pollution generation and transport, fire-related convection) processes, and intrusions of stratospheric air into the troposphere and vice versa are common.

The coupled chemistry and climate of the UTLS respond to both tropospheric climate change [e.g. Santer et al., 2004; WMO, 2007] and to O3 depletion in the lower stratosphere (link to polar processes section) [e.g., Seidel and Randel, 2006]; the complexity of causes of tropopause-level changes makes our ability to accurately detail UTLS variability especially critical. Both radiative forcing and surface temperature are most sensitive to O3 changes near the tropopause [e.g., Forster and Shine, 1999].

Radiative effects of water vapor near the ET tropopause have been shown to be instrumental in determining the thermal structure in the UTLS [e.g., Randel 2007]. Upper tropospheric winds (the jet streams whose tops extend into the lowermost stratosphere) and tropopause characteristics have been shown to be sensitive to climate change [e.g., Lorenz and DeWeaver, 2007; Archer and Caldeira, 2008].

The Antarctic O3 hole has caused significant temperature changes in the lower stratosphere; a significant part of the ozone depletion occurs in the sub-vortex (the lowest part of the polar vortex that extends into the lowermost stratosphere), where it can be more efficiently transported to midlatitudes and possibly into the troposphere.

Changes in the Brewer-Dobson Circulation (the large-scale seasonally varying circulation of the stratosphere), synoptic eddies (storms) in the upper troposphere, and midlatitude convection are expected to alter the extent and consequences of ET stratosphere-troposphere exchange.

Pollution products transported from the troposphere up into the lower stratosphere influence ozone chemistry there [e.g. Hegglin et al., 2006; WMO, 2007]; conversely, stratospheric O3 transported down also influences tropospheric chemistry [e.g., WMO, 2007; Hsu and Prather, 2009].

Until recent years, most satellite measurements did not extend down into the ET UTLS, and studies of the ET UTLS were primarily limited to analysis of sporadic and sparse (albeit very high spatial and temporal resolution) aircraft data.

With the launch of the Aura satellite, MLS provides measurements of O3, HNO3, CO and H2O, as well as temperature, covering the lowermost stratosphere with global daily coverage; other measurements (e.g., HCl and ClO) extend into the upper part of this region.

Meteorological analyses from advanced data assimilation systems (DAS) provide comprehensive information on the jet streams (the winds that control transport and mixing of trace gases), tropopause variations, and temperature structure in the UTLS, that is, the dynamical factors that control trace gas transport and influence chemical processes.

Studies using MLS data, in conjunction with DAS analyses and high resolution but sparse aircraft data, can contribute to advancing our understanding of the ET UTLS and its role in climate change processes.

MLS-related publications related to extra-tropical stratosphere-troposphere exchange

  1. Rawat, P., M. Naja, E. Fishbein, P. Thapliyal, R. Kumar, P. Bhardwaj, A. Jaiswal, S. Tiwari, S. Venkataramani and S. Lal
    Performance of AIRS ozone retrieval over the central Himalayas: Case studies of biomass burning, downward ozone transport and radiative forcing using long-term observations
    Atmospheric Measurement Techniques Discussions doi:10.5194/amt-2022-187, in review
  2. Vogel, A., J. Ungermann and H. Elbern
    Analyzing trace gas filaments in the Ex-UTLS by 4D-variationalassimilation of airborne tomographic retrievals
    Atmos. Chem. Phys. Discuss. doi:10.5194/acp-2017-308, in review
  3. Liang, Z., F. Zhu, T. Liang, F. Luo and J. Luo
    Spatiotemporal Distribution of CO in the UTLS Region in the Asian Summer Monsoon Season: Analysis of MLS Observations and CMIP6 Simulations
    Remote Sens. doi:10.3390/rs15020367, 2023
  4. Roy, C., A.R. Ravishankara, P. Newman, L. David, S. Fadnavis, S. Rathod, L. Lait, R. Krishnan, H. Clark and B. Sauvage
    Estimation of Stratospheric Intrusions During Indian Cyclones
    Journal of Geophysical Research: Atmospheres doi:10.1029/2022jd037519, 2023
  5. Solomon, S., K. Stone, P. Yu, D.M. Murphy, D. Kinnison, A.R. Ravishankara and P. Wang
    Chlorine activation and enhanced ozone depletion induced by wildfire aerosol
  6. Wang, P., S. Solomon and K. Stone
    Stratospheric chlorine processing after the 2020 Australian wildfires derived from satellite data
    Proc. Nat. Acad. Sci. doi:10.1073/pnas.2213910120, 2023
  7. Blunden, J. and T. Boyer
    State of the Climate in 2021
    Bull. Am. Meteorol. Soc. doi:10.1175/2022bamsstateoftheclimate.1, 2022
  8. Fazel-Rastgar, F. and V. Sivakumar
    A severe weather system accompanied by a stratospheric intrusion during unusual warm winter in 2015 over the South Africa: An initial synoptic analysis
    Remote Sensing Applications: Society and Environment doi:10.1016/j.rsase.2022.100833, 2022
  9. Fujiwara, M., G.L. Manney, L.J. Gray and J.S. Wright
    SPARC Reanalysis Intercomparison Project S-RIP Final Report
    n/a 2022
  10. Li, D., J. Bian, X. Zhang, B. Vogel, R. Müller and G. Günther
    Impact of typhoon Soudelor on ozone and water vapor in the Asian monsoon anticyclone western Pacific mode
    Atmospheric Science Letters doi:10.1002/asl.1147, 2022
  11. Martinsson, B., J. Friberg, O. Sandvik and M. Sporre
    Five-satellite-sensor study of the rapid decline of wildfire smoke in the stratosphere
    Atmos. Chem. Phys. 10.5194/acp-22-3967-2022, 2022
  12. Pan, L., D. Kinnison, Q. Liang, M. Chin, M. Santee, J. Flemming, W. Smith, S. Honomichl, J. Bresch, L. Lait, Y. Zhu, S. Tilmes, P. Colarco, J. Warner, A. Vuvan, C. Clerbaux, E. Atlas, P. Newman, T. Thornberry, W. Randel and O. Toon
    A Multimodel Investigation of Asian Summer Monsoon UTLS Transport Over the Western Pacific
    Journal of Geophysical Research: Atmospheres doi:10.1029/2022jd037511, 2022
  13. Peng, K., J. Luo, J. Mu, X. Cao, H. Tian, L. Shang and Y. Guo
    Impact of intensity variability of the Asian summer monsoon anticyclone on the chemical distribution in the upper troposphere and lower stratosphere
    Atmospheric and Oceanic Science Letters 10.1016/j.aosl.2021.100144, 2022
  14. Qie, K., W. Wang, W. Tian, R. Huang, M. Xu, T. Wang and Y. Peng
    Enhanced upward motion through the troposphere over the tropical western Pacific and its implications for the transport of trace gases from the troposphere to the stratosphere
    Atmos. Chem. Phys. doi:10.5194/acp-22-4393-2022, 2022
  15. Salawitch, R. and L. McBride
    Australian wildfires depleted the ozone layer
  16. Santee, M.L., A. Lambert, G.L. Manney, N.J. Livesey, L. Froidevaux, J.L. Neu, M.J. Schwartz, L.F. Millán, F. Werner, W.G. Read, M. Park, R.A. Fuller and B.M. Ward
    Prolonged and Pervasive Perturbations in the Composition of the Southern Hemisphere Midlatitude Lower Stratosphere From the Australian New Year's Fires
    Geophys. Res. Lett. doi:10.1029/2021gl096270, 2022
  17. Xiong, X., X. Liu, W. Wu, K.E. Knowland, Q. Yang, J. Welsh and D. Zhou
    Satellite observation of stratospheric intrusions and ozone transport using CrIS on SNPP
    Atmospheric Environment doi:10.1016/j.atmosenv.2022.118956, 2022
  18. Babu, S.R., M.V. Ratnam, G. Basha, S. Pani and N. Lin
    Structure, dynamics, and trace gas variability within the Asian summer monsoon anticyclone in the extreme El Niño of 2015–2016
    Atmos. Chem. Phys. doi:10.5194/acp-21-5533-2021, 2021
  19. Blunden, J. and T. Boyer
    State of the Climate in 2020
    Bull. Am. Meteorol. Soc. doi:10.1175/2021bamsstateoftheclimate.1, 2021
  20. Bossolasco, A., F. Jegou, P. Sellitto, G. Berthet, C. Kloss and B. Legras
    Global modeling studies of composition and decadal trends of the Asian Tropopause Aerosol Layer
    Atmos. Chem. Phys. doi:10.5194/acp-21-2745-2021, 2021
  21. Emmanuel, M., S.V. Sunilkumar, M. Muhsin, P.R.S. Chandran, K. Parameswaran, B.S. Kumar, A. Maitra, A.N.V. Satyanarayana and N. Nagendra
    Effect of monsoon dynamics and deep convection on the upper troposphere lower stratosphere water vapour over Indian monsoon region
  22. Fujiwara, M., T. Sakai, T. Nagai, K. Shiraishi, Y. Inai, S. Khaykin, H. Xi, T. Shibata, M. Shiotani and L. Pan
    Lower-stratospheric aerosol measurements in eastward-shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018
    Atmos. Chem. Phys. doi:10.5194/acp-21-3073-2021, 2021
  23. Gharibzadeh, M., A. Bidokhti and K. Alam
    The interaction of ozone and aerosol in a semi-arid region in the Middle East: Ozone formation and radiative forcing implications
    Atmospheric Environment doi:10.1016/j.atmosenv.2020.118015, 2021
  24. He, X., J. Luo, X. Xu, L. Ren, H. Tian, L. Shang and P. Xu
    The QBO Modulation on CO Distribution in the UTLS Over the Asian Monsoon Region During Boreal Summer
    Front. Earth Sci. doi:10.3389/feart.2021.625990, 2021
  25. Jenkins, G., V.D. Castro, B. Cunha, I. Fontanez and R. Holzworth
    The Evolution of the Wave‐One Ozone Maximum During the 2017 LASIC Field Campaign at Ascension Island
    Journal of Geophysical Research: Atmospheres doi:10.1029/2020jd033972, 2021
  26. Karpowicz, B., W. McCarty and K. Wargan
    Investigating the utility of hyperspectral sounders in the 9.6 μm band to improve ozone analyses
    Q. J. Roy. Meteorol. Soc. doi:10.1002/qj.4198, 2021
  27. Kumar, K., B. Singh and Kumar, K.
    Intriguing aspects of Asian Summer Monsoon Anticyclone Ozone variability from Microwave Limb Sounder measurements
    Atmos. Res. 10.1016/j.atmosres.2021.105479, 2021
  28. Park, M., H. Worden, D. Kinnison, B. Gaubert, S. Tilmes, L. Emmons, M. Santee, L. Froidevaux and C. Boone
    Fate of pollution emitted during the 2015 Indonesian Fire Season
    Journal of Geophysical Research: Atmospheres doi:10.1029/2020jd033474, 2021
  29. Plaza, N., A. Podglajen, C. Peña-Ortiz and F. Ploeger
    Processes influencing lower stratospheric water vapour in monsoon anticyclones: insights from Lagrangian modelling
    Atmos. Chem. Phys. doi:10.5194/acp-21-9585-2021, 2021
  30. Pumphrey, H., M. Schwartz, M. Santee, G. Kablick III, M. Fromm and N. Livesey
    Microwave Limb Sounder MLS observations of biomass burning products in the stratosphere from Canadian forest fires in August 2017
    Atmos. Chem. Phys. doi:10.5194/acp-21-16645-2021, 2021
  31. Rieger, L.A., W.J. Randel, A.E. Bourassa and S. Solomon
    Stratospheric Temperature and Ozone Anomalies Associated With the 2020 Australian New Year Fires
    Geophys. Res. Lett. doi:10.1029/2021gl095898, 2021
  32. Tang, Q., M. Prather, J. Hsu, D. Ruiz, P. Cameron-Smith, S. Xie and J. Golaz
    Evaluation of the interactive stratospheric ozone O3v2 module in the E3SM version 1 Earth system model
    Geoscientific Model Development doi:10.5194/gmd-14-1219-2021, 2021
  33. Wang, M. and Q. Fu
    Stratosphere‐Troposphere Exchange of Air Masses and Ozone Concentrations Based on Reanalyses and Observations
    Journal of Geophysical Research: Atmospheres doi:10.1029/2021jd035159, 2021
  34. Barret, B., E. Emili and E.L. Flochmoen
    A tropopause-related climatological a priori profile for IASI-SOFRID ozone retrievals: improvements and validation
    Atmospheric Measurement Techniques doi:10.5194/amt-13-5237-2020, 2020
  35. Blunden, J. and D.S. Arndt
    State of the Climate in 2019
    Bull. Am. Meteorol. Soc. doi:10.1175/2020bamsstateoftheclimate.1, 2020
  36. Fadnavis, S., C. Sioris, N. Wagh, R. Chattopadhyay, M. Tao, P. Chavan and T. Chakroborty
    A rising trend of double tropopauses over South Asia in a warming environment: Implications for moistening of the lower stratosphere
    International Journal of Climatology doi:10.1002/joc.6677, 2020
  37. Girach, I., P. Nair, N. Ojha and L. Sahu
    Tropospheric carbon monoxide over the northern Indian Ocean during winter: influence of inter-continental transport
    Climate Dynamics doi:10.1007/s00382-020-05269-4, 2020
  38. Honomichl, S. and L. Pan
    Transport From the Asian Summer Monsoon Anticyclone Over the Western Pacific
    Journal of Geophysical Research: Atmospheres doi:10.1029/2019jd032094, 2020
  39. Itahashi, S., R. Mathur, C. Hogrefe and Y. Zhang
    Modeling stratospheric intrusion and trans-Pacific transport on tropospheric ozone using hemispheric CMAQ during April 2010 -- Part 1: Model evaluation and air mass characterization for stratosphere-troposphere transport
    Atmos. Chem. Phys. doi:10.5194/acp-20-3373-2020, 2020
  40. Khaykin, S., B. Legras, S. Bucci, P. Sellitto, L. Isaksen, F. Tencé, S. Bekki, A. Bourassa, L. Rieger, D. Zawada, J. Jumelet and S. Godin-Beekmann
    The 2019/20 Australian wildfires generated a persistent smoke-charged vortex rising up to 35 km altitude
    Commun Earth Environ doi:10.1038/s43247-020-00022-5, 2020
  41. Miyazaki, K., K. Bowman, K. Yumimoto, T. Walker and K. Sudo
    Evaluation of a multi-model, multi-constituent assimilation framework for tropospheric chemical reanalysis
    Atmos. Chem. Phys. doi:10.5194/acp-20-931-2020, 2020
  42. Qu, Z., Y. Huang, P. Vaillancourt, J. Cole, J. Milbrandt, M. Yau, K. Walker and J.D. Grandpré
    Simulation of convective moistening of the extratropical lower stratosphere using a numerical weather prediction model
    Atmos. Chem. Phys. doi:10.5194/acp-20-2143-2020, 2020
  43. Robinson, J., A. Kotsakis, F. Santos, R. Swap, K.E. Knowland, G. Labow, V. Connors, M. Tzortziou, N. Abuhassan, M. Tiefengraber and A. Cede
    Using networked Pandora observations to capture spatiotemporal changes in total column ozone associated with stratosphere-to-troposphere transport
  44. Schoeberl, M.R., L. Pfister, T. Wang, J. Kummer, A.E. Dessler and W. Yu
    Erythemal Radiation, Column Ozone, and the North American Monsoon
    Journal of Geophysical Research: Atmospheres doi:10.1029/2019jd032283, 2020
  45. Schwartz, M., M. Santee, H. Pumphrey, G. Manney, A. Lambert, N. Livesey, L. Millán, J. Neu, W. Read and F. Werner
    Australian New Year's PyroCb Impact on Stratospheric Composition
    Geophys. Res. Lett. doi:10.1029/2020gl090831, 2020
  46. Uma, K.N., T.S. Mohan and S. Das
    Role of Intra-Seasonal Variability in the Indian Summer Monsoon on the Hydration and Dehydration of the Upper Troposphere
    Theoretical and Applied Climatology doi:10.1007/s00704-020-03243-y, 2020
  47. Werner, F., M.J. Schwartz, N.J. Livesey, W.G. Read and M.L. Santee
    Extreme Outliers in Lower Stratospheric Water Vapor Over North America Observed by MLS: Relation to Overshooting Convection Diagnosed From Colocated Aqua‐MODIS Data
    Geophys. Res. Lett. doi:10.1029/2020gl090131, 2020
  48. Xu, X., H. Tian, K. Qie, X. He, R. Zhang and H. Tu
    A Study on the Trend of the Upper Tropospheric Water Vapor over the Tibetan Plateau in Summer
    Asia-Pacific Journal of Atmospheric Sciences doi:10.1007/s13143-020-00191-5, 2020
  49. Yu, W., A. Dessler, M. Park and E. Jensen
    Influence of convection on stratospheric water vapor in the North American monsoon region
    Atmos. Chem. Phys. doi:10.5194/acp-20-12153-2020, 2020
  50. Blunden, J. and D. Arndt
    State of the Climate in 2018
    Bull. Am. Meteorol. Soc. doi:10.1175/2019bamsstateoftheclimate.1, 2019