University of Leeds, Leeds, UK
Wegener Center for Climate and Global Change, Graz, Austria
- Valentina Aquila, Johns Hopkins University/NASA Goddard, Baltimore, USA (SPARC SSiRC contact)
- Stefan Brönnimann, University of Bern, Switzerland
- Chantal Claud, LMD, Ecole Polytechnique, CNRS, Palaiseau, France
- Martin Dameris, Institute of Atmospheric Physics, DLR, Oberpfaffenhofen, Germany (SPARC CCMI contact)
- Qiang Fu, Department of Atmospheric Sciences, University of Washington, Seattle, USA
- Nathan Gillett, Canadian Center for Climate Modeling and Analysis, Victoria, BC, Canada
- Leopold Haimberger, Institute for Meteorology and Geophysics, University of Vienna, Austria
- Ben Ho, UCAR, COSMIC, Boulder, USA
- Philippe Keckhut, LATMOS, Université Pierre-et-Marie-Curie, Paris, France
- Ulrike Langematz, Institute for Meteorology, Freie Universität Berlin, Germany (SPARC HEPPA/SOLARIS contact)
- Thierry Leblanc, JPL, Pasadena, USA (GCOS GRUAN contact)
- Craig Long, Climate Prediction Center NCEP, National Weather Service, NOAA, Camp Springs, USA (SPARC S-RIP contact)
- Carl Mears, Remote Sensing Systems, Santa Rosa, USA
- Lorenzo M. Polvani, Columbia University, New York, NY, USA
- William (Bill) Randel, NCAR, Boulder, USA
- Karen Rosenlof, Chemical Sciences Division, NOAA ESRL, Boulder, CO, USA (SPARC WAVAS contact)
- Ben Santer, PCMDI, Lawrence Livermore National Laboratory, Livermore, USA
- Torsten Schmidt, Helmholtz Centre, German Research Centre for Geosciences, Potsdam, Germany
- Michael Schwartz, JPL, Pasadena, USA
- Viktoria Sofieva, Finnish Meteorological Institute, Helsinki, Finland
- Dave Thompson, Colorado State University, Fort Collins, USA
- Cheng-Zhi Zou, Center for Satellite Applications and Research, NOAA/NESDIS, Camp Springs, USA
The focus of the Atmospheric Temperature Changes and their Drivers (ATC) activity is on characterising observed temperature changes and their uncertainties from different measurements, and on disentangling the drivers of past and future temperature changes in observations and global models. The ATC activity has evolved and broadened out from the work of the long-standing SPARC Stratospheric Temperature Trends activity. The science objectives of the new ATC activity align with the themes in SPARC’s new Implementation Plan on ‘Long-term Records for Climate Understanding’, ‘Chemistry and Climate’, and ‘Atmospheric Dynamics and Predictability’. Output from the group provides key information for UNEP/WMO Ozone Assessments and the Intergovernmental Panel on Climate Change (IPCC) Reports, as well as for other SPARC activities including CCMI and S-RIP.
Atmospheric temperature variability and trends, and their uncertainty in climate records
The IPCC AR5 states as a key uncertainty: “There is only medium to low confidence in the rate of change of tropospheric warming and its vertical structure…. There is low confidence in the rate and vertical structure of the stratospheric cooling”. The aim of the ATC activity is to gain a better insight into atmospheric climate variability and trends from the troposphere to the mesosphere. This includes the evaluation of the inter-consistency of atmospheric temperature observations, comparison with (chemistry) climate models and reanalyses, and the provision of uncertainty information. Specific foci include: (1) extension of region of interest to the troposphere and the mesosphere; (2) inclusion of emerging novel observational records (such as radio occultation and Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) radiosondes); and (3) improving uncertainty information towards enhancing the maturity and benchmarking of climate records.
Radiative and dynamical contributions to observed and modelled temperature changes
Understanding the causes of temperature variations and trends requires knowledge of dynamical and radiative processes. Considerable effort has been placed in comparing model simulations of atmospheric temperatures to observations, but these studies have not attempted to assess the consistency between changes in temperature, composition (e.g. water vapour and ozone) and dynamics. The ATC activity is focused on assessing these contributions and their effect on observed and simulated atmospheric temperature trends. Specific foci include: (1) the contribution of greenhouse gases, ozone, and water vapour to temperature trends; (2) the role of natural variations (solar cycle, volcanoes, dynamical variability) in determining temperature variability; and (3) determining the drivers of temperature variability and trends on seasonal and regional scales.
Ding, Q., & Fu, Q. (2017). A warming tropical central Pacific dries the lower stratosphere. Climate Dynamics. https://doi.org/10.1007/s00382-017-3774-y
Funatsu, B. M., Claud, C., Keckhut, P., Hauchecorne, A., & Leblanc, T. (2016). Regional and seasonal stratospheric temperature trends in the last decade (2002–2014) from AMSU observations. Journal of Geophysical Research: Atmospheres, 2015JD024305. https://doi.org/10.1002/2015JD024305
Garfinkel, C. I., Son, S.-W., Song, K., Aquila, V., & Oman, L. D. (2017). Stratospheric variability contributed to and sustained the recent hiatus in Eurasian winter warming. Geophysical Research Letters, 44(1), 2016GL072035. https://doi.org/10.1002/2016GL072035
Ho, S.-P., Peng, L., & Vömel, H. (2017). Characterization of the long-term radiosonde temperature biases in the upper troposphere and lower stratosphere using COSMIC and Metop-A/GRAS data from 2006 to 2014. Atmospheric Chemistry and Physics, 17(7), 4493–4511. https://doi.org/10.5194/acp-17-4493-2017
Ivy, D. J., Solomon, S., & Rieder, H. E. (2015). Radiative and Dynamical Influences on Polar Stratospheric Temperature Trends. Journal of Climate. https://doi.org/10.1175/JCLI-D-15-0503.1
Ivy, D. J., Solomon, S., Calvo, N., & Thompson, D. W. J. (2017). Observed connections of Arctic stratospheric ozone extremes to Northern Hemisphere surface climate. Environmental Research Letters, 12(2), 024004.
Khaykin, S. M., Funatsu, B. M., Hauchecorne, A., Godin-Beekmann, S., Claud, C., Keckhut, P., et al. (2017). Postmillennium changes in stratospheric temperature consistently resolved by GPS radio occultation and AMSU observations. Geophysical Research Letters, 44(14), 2017GL074353. https://doi.org/10.1002/2017GL074353
Li, J., Thompson, D. W. J., Barnes, E. A., & Solomon, S. (2017). Quantifying the Lead Time Required for a Linear Trend to Emerge from Natural Climate Variability. Journal of Climate. https://doi.org/10.1175/JCLI-D-16-0280.1
Long, C. S., Fujiwara, M., Davis, S., Mitchell, D. M., & Wright, C. J. (2017). Climatology and interannual variability of dynamic variables in multiple reanalyses evaluated by the SPARC Reanalysis Intercomparison Project (S-RIP). Atmos. Chem. Phys., 17(23), 14593–14629. https://doi.org/10.5194/acp-17-14593-2017
Maycock, A. C. (2016). The contribution of ozone to future stratospheric temperature trends. Geophysical Research Letters, 2016GL068511. https://doi.org/10.1002/2016GL068511
Maycock, A. C., & Hitchcock, P. (2015). Do split and displacement sudden stratospheric warmings have different annular mode signatures? Geophysical Research Letters, 2015GL066754. https://doi.org/10.1002/2015GL066754
Maycock, A C., W J. Randel, A K. Steiner, J Cristy, R Saunders, D W. J. Thompson, C-Z Zou, N. L Abraham, H Akiyoshi, A T. Archibald, N Butchart, M Chipperfield, M Dameris, M Deushi, S Dhomse, G Di Genova, P Jöckel, A Y Karpechko, D E. Kinnison, O Kirner, F Ladstädter, M Michou, O Morgenstern, L Oman, G Pitari, D A. Plummer, L E. Revell, E Rozanov, A Stenke, D Visioni, Y Yamashita, G Zeng, Revisiting the mystery of recent stratospheric temperature trends, submitted.
McLandress, C., Shepherd, T. G., Jonsson, A. I., von Clarmann, T., & Funke, B. (2015). A method for merging nadir-sounding climate records, with an application to the global-mean stratospheric temperature data sets from SSU and AMSU. Atmospheric Chemistry and Physics, 15(16), 9271–9284. https://doi.org/10.5194/acp-15-9271-2015
Mears, C. A., & Wentz, F. J. (2017). A Satellite-Derived Lower-Tropospheric Atmospheric Temperature Dataset Using an Optimized Adjustment for Diurnal Effects. Journal of Climate, 30(19), 7695–7718. https://doi.org/10.1175/JCLI-D-16-0768.1
Ming, A., Maycock, A. C., Hitchcock, P., & Haynes, P. (2017). The radiative role of ozone and water vapour in the annual temperature cycle in the tropical tropopause layer. Atmos. Chem. Phys., 17(9), 5677–5701. https://doi.org/10.5194/acp-17-5677-2017
Nash, J., & Saunders, R. (2013). A review of Stratospheric Sounding Unit radiance observations in support of climate trends investigations and reanalysis (Met Office Technical Report No. 586) (pp. 58).
Nash, J., & Saunders, R. (2015). A review of Stratospheric Sounding Unit radiance observations for climate trends and reanalyses. Quarterly Journal of the Royal Meteorological Society, 141(691), 2103–2113. https://doi.org/10.1002/qj.2505
Randel, W. J., Smith, A. K., Wu, F., Zou, C.-Z., & Qian, H. (2016). Stratospheric temperature trends over 1979-2015 derived from combined SSU, MLS and SABER satellite observations. Journal of Climate. https://doi.org/10.1175/JCLI-D-15-0629.1
Randel, W. J., Polvani, L., Wu, F., Kinnison, D. E., Zou, C.-Z., & Mears, C. (2017). Troposphere-Stratosphere Temperature Trends Derived From Satellite Data Compared With Ensemble Simulations From WACCM. Journal of Geophysical Research: Atmospheres, 122(18), 2017JD027158. https://doi.org/10.1002/2017JD027158
Santer, B. D., Solomon, S., Pallotta, G., Mears, C., Po-Chedley, S., Fu, Q., et al. (2016). Comparing tropospheric warming in climate models and satellite data. Journal of Climate. https://doi.org/10.1175/JCLI-D-16-0333.1
Santer, B. D., Fyfe, J. C., Pallotta, G., Flato, G. M., Meehl, G. A., England, M. H., et al. (2017). Causes of differences in model and satellite tropospheric warming rates. Nature Geosci, 10(7), 478–485.
Santer, B. D., Solomon, S., Wentz, F. J., Fu, Q., Po-Chedley, S., Mears, C., et al. (2017). Tropospheric Warming Over The Past Two Decades. Scientific Reports, 7(1), 2336. https://doi.org/10.1038/s41598-017-02520-7
Scherllin-Pirscher, B., Randel, W. J., & Kim, J. (2017). Tropical temperature variability and Kelvin-wave activity in the UTLS from GPS RO measurements. Atmospheric Chemistry and Physics, 17(2), 793–806. https://doi.org/10.5194/acp-17-793-2017
Schmidt, T., Schoon, L., Dobslaw, H., Matthes, K., Thomas, M., & Wickert, J. (2016). UTLS temperature validation of MPI-ESM decadal hindcast experiments with GPS radio occultations. Meteorologische Zeitschrift, 25(6), 673–683. https://doi.org/10.1127/metz/2015/0601
Seidel, D. J., Li, J., Mears, C., Moradi, I., Nash, J., Randel, W. J., et al. (2016). Stratospheric temperature changes during the satellite era. Journal of Geophysical Research: Atmospheres, 121(2), 2015JD024039. https://doi.org/10.1002/2015JD024039
Steiner, A. K., Lackner, B. C., & Ringer, M. A. (2018). Tropical convection regimes in climate models: evaluation with satellite observations. Atmospheric Chemistry and Physics, 1–26. https://doi.org/10.5194/acp-2017-669, in press.
Thompson, D. W. J., Seidel, D. J., Randel, W. J., Zou, C.-Z., Butler, A. H., Mears, C., et al. (2012). The mystery of recent stratospheric temperature trends. Nature, 491(7426), 692–697. https://doi.org/10.1038/nature11579
Wilhelmsen, H., Ladstädter, F., Scherllin-Pirscher, B., & Steiner, A. K. (2018). Atmospheric QBO and ENSO indices with high vertical resolution from GNSS radio occultation temperature measurements. Atmos. Meas. Tech., 11(3), 1333–1346. https://doi.org/10.5194/amt-11-1333-2018
Zou, C.-Z., & Qian, H. (2016). Stratospheric Temperature Climate Data Record from Merged SSU and AMSU-A Observations. Journal of Atmospheric and Oceanic Technology, 33(9), 1967–1984. https://doi.org/10.1175/JTECH-D-16-0018.1
Zou, C.-Z., Qian, H., Wang, W., Wang, L., & Long, C. (2014). Recalibration and merging of SSU observations for stratospheric temperature trend studies. Journal of Geophysical Research: Atmospheres, 119(23), 2014JD021603. https://doi.org/10.1002/2014JD021603
SPARC activity reports:
- SPARC Newsletter No. 47 (2016), p. 36: Report on the 1st Atmospheric Temperature Changes and their Drivers (ARC) Activity Workshop, by Maycock A.C., A.K. Steiner, and B. Randel
- SPARC Newsletter No. 45 (2015), p. 31: SPARC workshop on Stratospheric Temperature Trends, Randel, B., D. Seidel, and D. Thompson.
Website for further information
Presentations from the 1st ATC Workshop held in April 2016 are available on request.