Sea level is a very sensitive index of climate change and variability. As the ocean warms in response to global warming, sea waters expand and, as a result, sea level rises. When mountain glaciers melt in response to increasing air temperature, sea level rises because more freshwater glacial runoff discharges into the oceans. Similarly, ice mass loss from the ice sheets causes sea-level rise. The increase of freshwater flowing into the oceans reduces its salinity, decreasing its density and affecting ocean circulation patterns that in turn affect sea level and its spatial variability.
The global mean level of the oceans is an indicator of climate change. It incorporates the reactions from several different components of the climate system. Precise monitoring of changes in the mean level of the oceans is vitally important for understanding not just the climate but also the socioeconomic consequences of any rise in sea level.
Sea Level products & equivalent CMIP5/Obs4MIPs Parameters
The table below shows the Sea Level outputs that have equivalent CMIP5 parameters and hence are suitable for submission to Obs4MIPs (Observations for Model Intercomparisons), an activity to make observational products more accessible for climate model intercomparisons.
|CMIP5 Table||CMIP5 Matching Parameter : CMIP5 Name||CMIP5 Priority|
|Global Mean Sea Level||OImon||Global Average Sea Level Change : zosga||1|
|Regional Mean Sea Level||-||-||-|
|Maps of the Amplitude and Phase of the Annual Cycle||Omon||Global Average Sea Level Change : zosga||1|
|Sea Level Anomalies||fx||Surface Altitude : orog||1|
|Errors of Oceanic Indicators||-||-||-|
Parameter characteristics & GCOS/CMC Requirements
|Split at 3km is arbitrary|
|Types of errors|
|Single sensor uncertainty estimates for every observation (SSEOB)|
|Single sensor accuracy estimates for every observation (SSAOB)|
|Single sensor uncertainty estimates for TCDR (SSECDR)|
|Single sensor accuracy estimates for TCDR (SSACDR)|
|Error covariance matrix for TCDR (ERRCOV)|
|L3 merged product accuracy (ERRMERG)|