Surface Pressure
Southern Oscillation Index (SOI)
Figure: The Southern Oscillation Index (SOI) is a standardized index based on the observed sea level pressure differences between Tahiti and Darwin, Australia. The SOI is one measure of the large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific (i.e., the state of the Southern Oscillation) during El Niño and La Niña episodes. In general, smoothed time series of the SOI correspond very well with changes in ocean temperatures across the eastern tropical Pacific. The negative phase of the SOI represents below-normal air pressure at Tahiti and above-normal air pressure at Darwin. Prolonged periods of negative (positive) SOI values coincide with abnormally warm (cold) ocean waters across the eastern tropical Pacific typical of El Niño (La Niña) episodes. Source: The index is calculated by National Oceanic and Atmospheric Administration's NOAA Climate Prediction Center (CPC) (http://www.cpc.ncep.noaa.gov/data/indices/soi). |
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 Surface Pressure.
| Products | Air Pressure (near surface) | ||
| (*) | Unit | Values | |
| Horizontal Resolution | G | km | 10 |
| B | 100 | ||
| T | 500 | ||
| Vertical Resolution | G | - | |
| B | - | ||
| T | - | ||
| Temporal Resolution | G | h | 1 |
| B | 6 | ||
| T | 12 | ||
| Timeliness | G | h | 6 |
| B | 24 | ||
| T | 720 | ||
| Required Measurement Uncertainty (2-sigma) | G | hPa | 0.5 |
| B | 1 | ||
| T | 1 | ||
| Stability | G | hPa/decade | 0.02 |
| B | 0.1 | ||
| T | 0.2 |
(*) 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 abombelli
wmo [dot] int (GCOS Secretariat).
In Situ:
- Integrated Surface Database (ISD) of the National Centers for Environmental Information (NCEI) of the National Oceanic and Atmospheric Administration (NOAA)
- International Comprehensive Ocean-Atmosphere Data Set (ICOADS)
Reanalysis:
- REANALYSES.ORG (Inventory for Reanalysis)
