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Occultations:ÌýLabel, type, datetime, and location of occultations that have occurred and those that will occur within the next two months as predicted using a high precision orbit propagator.

SCISAT occultations can be viewed using theÌý.

ACE-FTS Data can be downloaded via sign up at .

Level 0:ÌýInterferograms

Level 1:ÌýSpectra

Level 2:ÌýTemperature, Pressure and Volume Mixing Ratio (VMR) profiles as a function of altitude

ACE-FTS Level 2 version 5.3 is the current processing version.

Level 2 Data include VMR profiles for the following trace gas molecules:

Version 1.0:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, N₂O₅, ClONO₂, CCl₂F₂, CCl₃F, COF₂, CHF₂Cl, HDO, SF₆

Version 2.0:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, N₂O₅, ClONO₂, CCl₂F₂, CCl₃F, COF₂, CHF₂Cl, SF₆, OCS, HCN, CF₄, CH₃Cl, C₂H₂, C₂H₆, N₂

Version 2.1:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, N₂O₅, ClONO₂, CCl₂F₂, CCl₃F, COF₂, CHF₂Cl, SF₆, OCS, HCN, CF₄, CH₃Cl, C₂H₂, C₂H₆, N₂, ClO

Version 2.2:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, N₂O₅, ClONO₂, CCl₂F₂, CCl₃F, COF₂, CHF₂Cl, HDO, SF₆, OCS, HCN, CF₄, CH₃Cl, C₂H₂, C₂H₆, N₂, ClO, as well as isotopologues for some of these molecules.
Public Data DOI:Ìý

Version 3.0:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, N₂O₅, ClONO₂, CFC-12 (CCl₂F₂), CFC-11 (CCl₃F), COF₂, HCFC-22 (CHClF₂), HDO, SF₆, OCS, HCN, CF₄, CH₃Cl, C₂H₂, C₂H₆, N₂, CO₂, H₂CO, H₂O₂, O₂, HO₂NO₂, HCOOH, CH₃OH, COCl₂, CCl₄, COClF, HCFC-142b (ClF₂C-CH₃), CFC-113 (Cl₂FC-CClF₂), HCFC-141b (Cl₂FC-CH₃), as well as isotopologues for some of these molecules

Version 3.5/3.6:ÌýH₂O, O₃, O₂, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, N₂O₅, ClONO₂, CFC-12 (CCl₂F₂), CFC-11 (CCl₃F), COF₂, HCFC-22 (CHClF₂), HDO, SF₆, OCS, HCN, CF₄, CH₃Cl, C₂H₂, CHF₂Cl C₂H₆, N₂, CO₂, H₂CO, H₂O₂, HO₂NO₂, HCOOH, CH₃OH, COCl₂, CCl₄, COClF, HCFC-142b (ClF₂C-CH₃), CFC-113 (Cl₂FC-CClF₂), HCFC-141b (Cl₂FC-CH₃), as well as isotopologues for some of these molecules.
Public Data DOI:Ìý

Version 4.0:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, OCS, N₂O₅, ClONO₂, HCN, CH₃Cl, CF₄, CFC-12 (CCl₂F₂), CFC-11 (CCl₃F), COF₂, COCl₂, COClF, C₂H₆, C₂H₂, HCFC-22 (CHClF₂), HCOOH, SF₆, HO₂NO₂, H₂O₂, H₂CO, CH₃OH, CCl₄, N₂, O₂, CFC-113 (Cl₂FC-CClF₂), HCFC-141b (Cl₂FC-CH₃), HCFC-142b (ClF₂C-CH₃), HFC-134a (F₃C-CFH₂), PAN (CH₃C(O)OONO₂), CHF₃, acetone (C₃H₆O), SO₂, CH₃CN, ClO, CO₂, as well as isotopologues for some of these molecules.
Public Data DOI:Ìý

Version 4.1/4.2:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, OCS, N₂O₅, ClONO₂, HCN, CH₃Cl, CF₄, CFC-12 (CCl₂F₂), CFC-11 (CCl₃F), COF₂, COCl₂, COClF, C₂H₆, C₂H₂, HCFC-22 (CHClF₂), HCOOH, SF₆, HO₂NO₂, H₂O₂, H₂CO, CH₃OH, CCl₄, N₂, O₂, CFC-113 (Cl₂FC-CClF₂), HCFC-141b (Cl₂FC-CH₃), HCFC-142b (ClF₂C-CH₃), HFC-134a (F₃C-CFH₂), PAN (CH₃C(O)OONO₂), CHF₃, acetone (C₃H₆O), SO₂, CH₃CN, ClO, CO₂, as well as isotopologues for some of these molecules.
Public Data DOI:Ìý

Version 5.2:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, OCS, N₂O₅, ClONO₂, HCN, CH₃Cl, CF₄, CFC-12 (CCl₂F₂), CFC-11 (CCl₃F), COF₂, COCl₂, COClF, C₂H₆, C₂H₂, HCFC-22 (CHClF₂), HCOOH, SF₆, HO₂NO₂, H₂O₂, H₂CO, CH₃OH, CCl₄, N₂, O₂, CFC-113 (Cl₂FC-CClF₂), HCFC-141b (Cl₂FC-CH₃), HCFC-142b (ClF₂C-CH₃), HFC-134a (F₃C-CFH₂), PAN (CH₃C(O)OONO₂), CHF₃, acetone (C₃H₆O), SO₂, CH₃CN, ClO, CO₂, HFC-32, HOCl, as well as isotopologues for some of these molecules and line-of-sight winds.
Public Data DOI:Ìý

Version 5.3:ÌýH₂O, O₃, N₂O, CO, CH₄, NO, NO₂, HNO₃, HF, HCl, OCS, N₂O₅, ClONO₂, HCN, CH₃Cl, CF₄, CFC-12 (CCl₂F₂), CFC-11 (CCl₃F), COF₂, COCl₂, COClF, C₂H₆, C₂H₂, HCFC-22 (CHClF₂), HCOOH, SF₆, HO₂NO₂, H₂O₂, H₂CO, CH₃OH, CCl₄, N₂, O₂, CFC-113 (Cl₂FC-CClF₂), HCFC-141b (Cl₂FC-CH₃), HCFC-142b (ClF₂C-CH₃), HFC-134a (F₃C-CFH₂), PAN (CH₃C(O)OONO₂), CHF₃, acetone (C₃H₆O), SO₂, CH₃CN, ClO, CO₂, HFC-32, HOCl, as well as isotopologues for some of these molecules and line-of-sight winds.

NO₂Ìýand O₃Ìýprofiles are retrieved from the UV spectrometer at the measurement tangent altitudes and interpolated at the regular tangent height grid.

O₃Ìýprofiles are retrieved from the VISIBLE spectrometer at the measurement tangent altitudes and interpolated at the regular tangent height grid.

In any publications using ACE data, it is important to acknowledge the Canadian Space Agency for the funding of the SCISAT satellite. Any text that recognizes the Canadian Space Agency as funding the ACE Mission is permitted, but we have provided a sample to use that meets this requirement. This simple statement has been used in many publications with ACE data.

"The Atmospheric Chemistry Experiment (ACE), also known as SCISAT, is a Canadian-led mission mainly supported by the Canadian Space Agency."

Access to the current version 5.3 ACE data is available , but previous versions are available as public datasets with the doi's listed above.

The fifth edition ofÌýSpectra of Atoms and MoleculesÌý(Oxford University Press, 2025) is an invaluable companion for the ACE mission. For example, the book has a chapter on spectra of clouds and aerosols based on ACE data.