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
Latest Publications (CH3Cl)
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 FiresGeophys. Res. Lett. doi:10.1029/2021gl096270, 2022
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 2017Atmos. Chem. Phys. doi:10.5194/acp-21-16645-2021, 2021
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 CompositionGeophys. Res. Lett. doi:10.1029/2020gl090831, 2020
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 observationsAtmos. Chem. Phys. doi:10.5194/acp-19-13647-2019, 2019
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 simulationsAtmos. Chem. Phys. doi:10.5194/acp-19-8311-2019, 2019
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 measurementsJournal of Geophysical Research: Atmospheres doi:10.1002/2016jd026408, 2017
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 soundingAtmos. Chem. Phys. doi:10.5194/acp-16-11521-2016, 2016
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 winterGeophys. Res. Lett. doi:10.1002/2015gl065864, 2015
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 stratosphereJournal of Geophysical Research: Atmospheres doi:10.1002/2013JD020235, 2013
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 2009Atmos. Chem. Phys. doi:10.5194/acp-11-6285-2011, 2011