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). Information on how to access the complete CMIP5 dataset can be found in the Documentation section.
The term "single levels" is used to express that the variables computed at multiple vertical levels are excluded from this catalogue entry. The term "experiments" refers to the four main categories of CMIP5 simulations:
- Pre-industrial control experiments (Pi-control) with prescribed, non-evolving concentrations of atmospheric gases and aerosols as they are supposed to be before the industrial period;
- Historical experiments which cover the period where climate observations do exist;
- Ensemble of experiments from the Atmospheric Model Intercomparison Project (AMIP), which prescrives the oceanic variables for all models and during the all period of the experiment. This configuration removes the added complexity of ocean-atmosphere feedbacks in the climate system;
- Ensemble of climatic projection experiments following the Representative Concentration Pathways (RCP) 2.6, 4.5, 6.0 and 8.5.
Typically, the same experiment was done using different models. In addition, for each model, the same experiment was repeatedly done using slightly different conditions producing in that way an ensemble of experiments closely related. Each member of that ensemble is named after a triad of integers associated to the letters r, i and p. These three letter cover variations in initial conditions and dates as well as in the physical parameters of the models. The associated numbers are typically assigned sequentially. For instance, the member "r1i1p1" and the member "r1i2p2" for the same model and experiment indicate that the corresponding simulations differ since the initial conditions and the physical parameters of the model for the second member were changed relatively to the first member.
CMIP5 data were used extensively in the Intergovernmental Panel on Climate Change 5th Assessment Report (IPCC AR5) which was published in September 2009. The use of these data is often aimed at:
- addressing outstanding scientific questions that arose as part of the IPCC AR4 (the Intergovernmental Panel on Climate Change 4th Assessment Report) process;
- improving the understanding of climate;
- providing estimates of future climate change that will be useful to those considering its possible consequences;
- determining why similarly forced models produce a range of responses;
- assessing the mechanisms responsible for model differences in poorly understood feedbacks associated with the carbon cycle and with clouds;
- 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.
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 | 1800-2100 (shorter for some experiments) |
| 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. |
| Mean 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 | 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. |