This catalogue entry provides monthly climate projections on single levels from a large number of experiments, models, members and time periods computed in the framework of fifth phase of the Coupled Model Intercomparison Project (CMIP5). The term "single levels" is used to express that the variables are computed at one vertical level which can be surface (or a level close to the surface) or a dedicated pressure level in the atmosphere. Multiple vertical levels are excluded from this catalogue entry.
CMIP5 data are used extensively in the Intergovernmental Panel on Climate Change Assessment Reports (the latest one is IPCC AR5, which was published in 2014). The use of these data is mostly aimed at:
- addressing outstanding scientific questions that arose as part of the IPCC reporting process;
- improving the understanding of the climate system;
- providing estimates of future climate change and related uncertainties;
- providing input data for the adaptation to the climate change;
- examining climate predictability and exploring the ability of models to predict climate on decadal time scales;
- evaluating how realistic the different models are in simulating the recent past.
The term "experiments" refers to the three main categories of CMIP5 simulations:
- Historical experiments which cover the period where modern climate observations exist. These experiments show how the GCMs performs for the past climate and can be used as a reference period for comparison with scenario runs for the future. The period covered is typically 1850-2005.;
- Ensemble of experiments from the Atmospheric Model Intercomparison Project (AMIP), which prescribes the oceanic variables for all models and during all period of the experiment. This configuration removes the added complexity of ocean-atmosphere feedbacks in the climate system. The period covered is typically 1950-2005.
- Ensemble of climate projection experiments following the Representative Concentration Pathways (RCP) 2.6, 4.5, 6.0 and 8.5. The RCP scenarios provide different pathways of the future climate forcing. The period covered is typically 2006-2100, some extended RCP experimental data is available from 2100-2300.
In CMIP5, the same experiments were run using different GCMs. In addition, for each model, the same experiment was repeatedly done using slightly different conditions (like initial conditions or different physical parameterisations for instance) producing in that way an ensemble of experiments closely related. Note that CMIP5 GCM data can be also used as lateral boundary conditions for Regional Climate Models (RCMs). RCMs are also available in the CDS (see CORDEX datasets).
The data are produced by the participating institutes of the CMIP5 project. The latest CMIP GCM experiments will form the CMIP6 dataset, which will be published in the CDS in a later stage.
More details about the product are given in the Documentation section.
| DATA DESCRIPTION | |
|---|---|
| Horizontal coverage | Global |
| Horizontal resolution | From 0.125°x0.125° to 5°x5° depending on the model |
| Vertical resolution | Variables are provided in one single level (which may differ among variables). |
| Temporal coverage | 1850-2300 (dependent on the experiment). |
| Temporal resolution | Month |
| File format | NetCDF |
| Data type | Grid |
| MAIN VARIABLES | ||
|---|---|---|
| Name | Units | Description |
| 10m u component of wind | m s-1 | Magnitude of the eastward component of the two-dimensional horizontal air velocity near the surface. |
| 10m v component of wind | m s-1 | Magnitude of the northward component of the two-dimensional horizontal air velocity near the surface. |
| 10m wind_speed | m s-1 | Magnitude of the two-dimensional horizontal air velocity near thesurface. |
| 2m temperature | K | Temperature of the air near the surface. |
| Eastward turbulent surface stress | N s m-2 | Eastward component of the horizontal drag exerted by the atmosphere on the surface through turbulent processes. |
| Evaporation | kg m-2 s-1 | Evaporation rate. It includes conversion to vapor phase from both the liquid and solid phase, i.e., includes sublimation. |
| Maximum 2m temperature in the last 24 hours | K | Daily maximum near-surface air temperature. |
| Mean precipitation flux | kg m-2 s-1 | Amount of water per unit area and time. |
| Sea level pressure | Pa | Time average of the air pressure at sea level. |
| Minimum 2m temperature in the last 24 hours | K | Daily minimum near-surface air temperature. |
| Near surface relative humidity | % | Amount of moisture in the air near the surface divided by the maximum amount of moisture that could exist in the air at a specific temperature and location. |
| Near surface specific humidity | 1 | Amount of moisture in the air near the surface divided by amount of air plus moist at that location. |
| Northward turbulent surface stress | N s m-2 | Northward component of the horizontal drag exerted by the atmosphere on the surface through turbulent processes. |
| Runoff | kg m-2 s-1 | Amount per unit area of surface and subsurface liquid water which drains from land. |
| Sea ice fraction | Dimensionless | Area of the sea surface occupied by sea ice. |
| Sea ice plus snow amount | kg m-2 | Mass per unit area of sea ice plus snow in the ocean portion of the grid cell averaged over the entire ocean portion, including the ice-free fraction. Reported as 0.0 in regions free of sea ice. |
| Sea ice surface temperature | K | Temperature that exists at the interface of tea sea-ice and the overlying medium which may be air or snow. |
| Sea ice thickness | m | Vertical extent of ocean sea ice. |
| Sea surface height above geoid | m | Vertical distance between the actual sea surface and a surface of constant geopotential with which mean sea level would coincide if the ocean were at rest. |
| Sea surface temperature | K | Temperature of sea water near the surface. |
| Skin temperature | K | Temperature at the interface (not the bulk temperature of the medium above or below) between air and sea for open-sea regions. |
| Snow depth over sea ice | K | Mean thickness of snow in the ocean portion of the grid cell (averaging over the entire ocean portion, including the snow-free ocean fraction). Reported as 0.0 in regions free of snow-covered sea ice. |
| Snowfall flux | kg m-2 s-1 | Mass of water in the form of snow precipitating per unit area. |
| Soil moisture content | kg m-2 | Vertical sum per unit area from the surface down to the bottom of the soil model of water in all phases contained in soil. |
| Surface latent heat flux | W m-2 | Flux per unit area of heat between the surface and the air on account of evaporation including sublimation. Positive when directed upward (negative downward). |
| Surface pressure | Pa | Pressure of air at the lower boundary of the atmopshere |
| Surface sensible heat flux | W m-2 | Flux per unit area of heat between the surface and the air by motion of air only. Positive when directed upward (negative downward). |
| Surface snow amount | kg m-2 | Snow amount on the ground, excluding that on the plant or vegetation canopy, per unit area. |
| Surface solar radiation downwards | W m-2 | Radiative shortwave flux of energy downward at the surface. |
| Surface thermal radiation downwards | W m-2 | Radiation inciding on the surface from the above per unit area. |
| Surface upwelling longwave radiation | W m-2 | Longwave radiation from the surface per unit area. |
| Surface upwelling shortwave radiation | W m-2 | Shortwave radiation from the surface per unit area. |
| Toa incident solar radiation | W m-2 | Incident solar radiation at the top of atmosphere |
| Toa outgoing longwave radiation | W m-2 | Longwave radiation from the top of the atmosphere to space per unit area. |
| Toa outgoing shortwave radiation | W m-2 | Shortwave radiation from the top of the atmosphere to space per unit area. |
| Total cloud cover | 1 | Total refers to the whole atmosphere column, as seen from the surface or the top of the atmosphere. Cloud cover refers to fraction of horizontal area occupied by clouds. |