Precursors for Aerosols and Ozone
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Precursor species lead to the production of aerosols and ozone. Precursors include nitrogen dioxide (NO2), sulphur dioxide (SO2), carbon monoxide (CO) and formaldehyde (HCHO). Aerosols and ozone in the near-surface atmosphere can directly harm human health and produce detrimental environmental impacts (e.g., crop damage, acid rain). Reductions in near-surface aerosols and ozone have been observed in specific regions where the emissions of some precursors are regulated. |
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| Domain: | Atmosphere | |
| Subdomain: | Atmospheric Composition | |
| Scientific Area: | Carbon cycle and other GHGs | |
| ECV Steward: | ||
| Products: | CO Tropospheric Column, CO Mole fraction, NO2 Mole Fraction, HCHO Tropospheric Column, SO2 Tropospheric Column, SO2 Stratospheric Column, NO2 Tropospheric Column | |
ECV Products and Requirements
These products and requirements reflect the Implementation Plan 2022 (GCOS-244).
The requirements are found in the complete 2022 ECVs Requirements document as well: ECV Precursors for Aerosols and Ozone.
| Products | CO Tropospheric Column | CO Mole fraction | NO2 Mole Fraction | ||||
| (*) | Unit | Values | Values | Unit | Values | ||
| Horizontal Resolution | G | km | 10 | 10 | km | 20 | |
| B | 30 | 30 | 100 | ||||
| T | 100 | 100 | 500 | ||||
| Vertical Resolution | G | m | - | 1 | km | 1 | |
| B | - | 3 | 3 | ||||
| T | - | 5 | 5 | ||||
| Temporal Resolution | G | d | 1/24 | 1/24 | d | 1/4 | |
| B | 1 | 1 | 1 | ||||
| T | 30 | 30 | 30 | ||||
| Timeliness | G | d | 1 | 1 | d | 1 | |
| B | 7 | 7 | 7 | ||||
| T | 30 | 30 | 30 | ||||
| Required Measurement Uncertainty (2-sigma) | G | ppb | 1 | 1 | ppb | 20 | |
| B | 5 | 5 | 40 | ||||
| T | 10 | 10 | 60 | ||||
| Stability | G | ppb/decade | <1 | <1 | ppb/decade | 4 | |
| B | 1 | 1 | 8 | ||||
| T | 2 | 3 | 12 |
| Products | HCHO Tropospheric Column | SO2 Tropospheric Column | SO2 Stratospheric Column | NO2 Tropospheric Column | ||
| (*) | Unit | Values | Values | Values | Values | |
| Horizontal Resolution | G | km | 10 | 10 | 10 | 10 |
| B | 30 | 30 | 30 | 30 | ||
| T | 100 | 100 | 100 | 100 | ||
| Vertical Resolution | G | - | - | - | - | |
| B | - | - | - | - | ||
| T | - | - | - | - | ||
| Temporal Resolution | G | d | 1/24 | 1/24 | 1/24 | 1/24 |
| B | 1 | 1 | 1 | 1 | ||
| T | 30 | 30 | 30 | 30 | ||
| Timeliness | G | d | 1 | 1 | 1 | 1 |
| B | 7 | 7 | 7 | 7 | ||
| T | 30 | 30 | 30 | 30 | ||
| Required Measurement Uncertainty (2-sigma) | G | molecules cm-2 | max (20%, 8E15) | max (30%,6E15) | max(30%,6E15) | max(20%, 1E15) |
| B | max (40%,16E15) | max(60%, 12E15) | max(60%, 12E15) | max(40%, 2E15) | ||
| T | max (100%,40E15) | max(100%, 20E15) | max(100%, 20E15) | max(100%, 5E15) | ||
| Stability | G | molecules cm-2 / decade | max (4%, 8E15) | max(6%,1.2E15) | max(10%,3E15) | max(4%, 1E15) |
| B | max (8%,8E15) | max(12%, 2.4E15) | max(20%,4E15) | max(8%, 1E15) | ||
| T | max (20%,8E15) | max(20%, 4E15) | max(30%, 7E15) | max(20%, 1E15) |
(*) Goal (G): an ideal requirement above which further improvements are not necessary. Breakthrough (B): an intermediate level between threshold and goal which, if achieved, would result in a significant improvement for the targeted application. The breakthrough value may also indicate the level at which specified uses within climate monitoring become possible. It may be appropriate to have different breakthrough values for different uses. Threshold (T): the minimum requirement to be met to ensure that data are useful
Data Sources
This list provides sources for openly accessible data sets with worldwide coverage for which metadata is available. It is curated by the respective GCOS ECV Steward(s). The list does not claim to be complete. Anyone with a suitable dataset who wishes it to be added to this list should contact the GCOS Secretariat.
In Situ and Ground-Based Remote Sensing:
- Network for the Detection of Atmospheric Composition Change (NDACC)
- World Data Centre for Reactive Gases (WDCRG)
- National Aeronautics and Space Administration (NASA)
Reanalysis:
- REANALYSES.ORG (Inventory for Reanalysis)
- Copernicus Atmospheric Monitoring Service (CAMS), MACC Reanalysis of global atmospheric composition, European Centre for Medium-Range Weather Forecasts (ECMWF)
- Monitoring Atmospheric Composition & Climate (MACC), European Centre for Medium-Range Weather Forecasts (ECMWF)
Satellite:
- Satellite ECV Inventory by the CEOS/CGMS Working Group on Climate (WGClimate)
- NASA Measurements Of Pollution In The Troposphere (MOPITT)
