Aura MLS

CH3Cl

Contact: Michelle Santee

Methyl chloride (chloromethane, CH3Cl) is the most abundant chlorine-containing compound in the atmosphere.

As the largest natural source of stratospheric chlorine, CH3Cl contributed 16% of the stratospheric total inorganic chlorine budget in 2000 and thus accounts for a significant fraction of chlorine-catalyzed ozone destruction. Known sources of CH3Cl emissions are predominantly natural, although biomass burning (most of which is human-induced) was recently estimated to account for nearly 25% of its global source strength.

How it is part of MLS Science Objectives

The importance of CH3Cl is expected to increase in the future as emission controls alter the relative contributions from natural and anthropogenic halogen sources. Moreover, since CH3Cl emissions from many natural sources vary depending on environmental conditions, changes in global climate and land use patterns may increase CH3Cl fluxes, potentially offsetting some of the projected decline in stratospheric chlorine and delaying ozone recovery. Thus the MLS CH3Cl measurements will establish a baseline against which the future stratospheric CH3Cl burden may be assessed.

How EOS MLS measures CH3Cl

The standard methyl chloride product is taken from the 640 GHz retrieval.

CH3Cl Information from the Spectroscopy Database

Quick Product Information for data version v5

  • Swath Name: CH3Cl
  • Status Flag: Only use profiles for which the Status field is zero.
  • Useful Range: 147 - 4.6 hPa
  • DAAC Short Name: ML2CH3CL
  • Precision: Only use values for which the estimated precision is a positive number.
  • Quality Threshold: >1.3
  • Convergence Threshold: <1.05

Download Aura MLS CH3Cl v5 data

Latest Publications (CH3Cl)

  1. 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
  2. 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
  3. 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
  4. Errera, Q., S. Chabrillat, Y. Christophe, J. Debosscher, D. Hubert, W. Lahoz, M. Santee, M. Shiotani, S. Skachko, T. von Clarmann and K. Walker
    Technical note: Reanalysis of Aura MLS chemical observations
    Atmos. Chem. Phys. doi:10.5194/acp-19-13647-2019, 2019
  5. Johansson, S., M. Santee, J. Grooß, M. Höpfner, M. Braun, F. Friedl-Vallon, F. Khosrawi, O. Kirner, E. Kretschmer, H. Oelhaf, J. Orphal, B. Sinnhuber, I. Tritscher, J. Ungermann, K. Walker and W. Woiwode
    Unusual chlorine partitioning in the 2015/16 Arctic winter lowermost stratosphere: observations and simulations
    Atmos. Chem. Phys. doi:10.5194/acp-19-8311-2019, 2019
  6. Santee, M.L., G.L. Manney, N.J. Livesey, M.J. Schwartz, J.L. Neu and W.G. Read
    A comprehensive overview of the climatological composition of the Asian summer monsoon anticyclone based on 10 years of Aura Microwave Limb Sounder measurements
    Journal of Geophysical Research: Atmospheres doi:10.1002/2016jd026408, 2017
  7. Millan, L., N. Livesey, M. Santee, J. Neu, G. Manney and R. Fuller
    Case studies of the impact of orbital sampling on stratospheric trend detection and derivation of tropical vertical velocities: solar occultation vs. limb emission sounding
    Atmos. Chem. Phys. doi:10.5194/acp-16-11521-2016, 2016
  8. Manney, G., Z. Lawrence, M. Santee, W. Read, N. Livesey, A. Lambert, L. Froidevaux, H. Pumphrey and M. Schwartz
    A minor sudden stratospheric warming with a major impact: Transport and polar processing in the 2014/2015 Arctic winter
    Geophys. Res. Lett. doi:10.1002/2015gl065864, 2015
  9. Santee, M.L., N.J. Livesey, G.L. Manney, A. Lambert and W.G. Read
    Methyl chloride from the Aura Microwave Limb Sounder: First global climatology and assessment of variability in the upper troposphere and stratosphere
    Journal of Geophysical Research: Atmospheres doi:10.1002/2013JD020235, 2013
  10. Pumphrey, H.C., M.L. Santee, N.J. Livesey, M.J. Schwartz and W.G. Read
    Microwave Limb Sounder observations of biomass-burning products from the Australian bush fires of February 2009
    Atmos. Chem. Phys. doi:10.5194/acp-11-6285-2011, 2011