MOPITT

MOPITT
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Name	MOPITT
Mission type	Earth observation
Operator	National Aeronautics and Space Administration / Canadian Space Agency
Launch date	1999-12-07
Launch vehicle	Taurus
Spacecraft	Terra
Orbit type	Sun-synchronous orbit
Status	Operational (as of 2024)

MOPITT is a spaceborne instrument for global monitoring of atmospheric carbon monoxide in the troposphere and lower stratosphere. It was launched aboard the Terra spacecraft as part of the Earth Observing System and has provided continuous records used by researchers at institutions such as National Center for Atmospheric Research, University of Toronto, NASA Goddard Space Flight Center, and the Canadian Space Agency. The instrument supports studies spanning air quality, transport, and climate processes involving interactions among regions including Siberia, Amazon Rainforest, Sahara Desert, East Asia, and North America.

Overview

MOPITT was developed through collaborations among University of Toronto, Mission Control Center (Canada), Laboratory for Atmospheric and Space Physics, and NASA Ames Research Center. The mission objectives focused on mapping global distributions and temporal variations of carbon monoxide from near-surface to mid-tropospheric layers to inform studies of biomass burning in regions such as Indonesia, Borneo, and Amazon Basin and fossil-fuel emissions from urban centers like Los Angeles, Beijing, and London. The instrument complements observations from platforms including Total Ozone Mapping Spectrometer, Atmospheric Infrared Sounder, OMI, and SCIAMACHY to support integrated analyses of atmospheric composition across scales relevant to initiatives like Global Climate Observing System and GEOS-Chem-based inversion studies.

Instrument Design and Operation

MOPITT is a nadir-viewing gas correlation radiometer employing gas correlation cells for the detection of carbon monoxide and channelized infrared detectors similar in heritage to instruments used on Nimbus 7 and other planetary missions. The optical assembly uses a scanning mirror, input optics, and spectrally selective cells filled with reference gases to provide differential absorption measurements in the 4.7 µm and 2.3 µm bands. The instrument design draws on technologies advanced at laboratories such as Instituto de Astrofísica de Canarias and Defense Research and Development Canada and uses cryogenic and thermal control approaches developed for missions including Cassini–Huygens and Mars Reconnaissance Orbiter. Operational parameters include a cross-track swath delivering global coverage with repeat cycles used in conjunction with cloud screening information from Moderate Resolution Imaging Spectroradiometer aboard Terra.

Data Products and Retrieval Methods

MOPITT produces multi-decadal Level 1 radiances, Level 2 profile retrievals of carbon monoxide mixing ratio, and Level 3 gridded monthly means and trend maps. Retrieval algorithms employ optimal estimation and radiative transfer models developed from codes like RTTOV and incorporate a priori profiles from chemical transport models such as GEOS-Chem, MOZART, and CAM-Chem. Data assimilation and inversion efforts link MOPITT retrievals with reanalysis systems like ECMWF and NASA GEOS to constrain emissions estimates and atmospheric transport. Ancillary datasets used in retrievals include cloud masks from MODIS, surface emissivity maps derived from Landsat, and meteorological analyses from National Centers for Environmental Prediction.

Scientific Results and Applications

MOPITT records have quantified global and regional trends in carbon monoxide associated with anthropogenic activity, biomass burning, and interannual variability driven by events such as El Niño–Southern Oscillation phases and large volcanic eruptions like Mount Pinatubo. Studies using MOPITT have improved source attribution for pollution episodes affecting metropolitan areas including Mexico City, Delhi, and Tokyo and contributed to evaluations of emission inventories such as those from the Intergovernmental Panel on Climate Change scenarios and the EDGAR database. Applications extend to air quality forecasting integrated with systems at Environment and Climate Change Canada and U.S. Environmental Protection Agency, long-term climate forcing assessments related to ozone precursor budgets assessed by IPCC-affiliated researchers, and fire dynamics studies connected to programs like Global Fire Emissions Database.

Calibration, Validation, and Error Characterization

Calibration of MOPITT involved prelaunch laboratory characterization and on-orbit strategies including comparisons with in situ networks such as NASA ARCTAS, WMO Global Atmosphere Watch, and campaigns like TRACE-P and INTEX-B. Validation efforts used aircraft measurements from platforms such as NASA DC-8 and NOAA WP-3D Orion and ground-based Fourier-transform infrared spectroscopy stations in networks including NDACC and AERONET for cross-constraints. Error budgets account for spectroscopic uncertainties referenced to compilations like the HITRAN database, instrument noise, retrieval smoothing, and cloud contamination; metrics reported in peer-reviewed studies by researchers from Harvard University, Imperial College London, and University of Maryland quantify systematic and random components and inform reprocessing decisions.

Mission History and Collaborations

Since launch in 1999, the instrument operations and science team have involved multi-institutional partnerships across Canada and United States agencies, academic groups including Massachusetts Institute of Technology, University of Cambridge, University of Tokyo, and international collaborators from France, Germany, Australia, and Japan. Key milestones include successive reprocessing versions of the dataset, synergistic projects with missions like Aqua and Aura, and contribution to large coordinated field campaigns such as INTEX and BORTAS. The mission has been supported by data centers including Langley Research Center and multinational archives that facilitate wide use by the atmospheric chemistry and climate communities.

Category:Earth observation satellites Category:Atmospheric chemistry instruments