Impact model: IMAGE

Contact Person
  • Elke Stehfest (, Netherland Environmental Assessment Agency (PBL) (Netherlands)

Information for the model IMAGE is provided for the simulation rounds shown in the tabs below. Click on the appropriate tab to get the information for the simulation round you are interested in.

Basic information
Model Version: 3.0
Spatial Aggregation: regular grid
Spatial Resolution: 30 arcmin
Additional Spatial Aggregation & Resolution Information: land use on 5 arcmin, crop model on 30 arcmin
Temporal Resolution Of Input Data: Climate Variables: daily
Temporal Resolution Of Input Data: Co2: annual
Temporal Resolution Of Input Data: Land Use/Land Cover: constant
Temporal Resolution Of Input Data: Soil: constant
Input data sets used
Climate Variables: tasmax, tasmin, pr
Was A Spin-Up Performed?: Yes
Spin-Up Design: 270 years
Management & Adaptation Measures
Management: internally determined growing season, therefore autonomous adaptation
Key input and Management
Crops: mai, whe(w,s), soy, rice
Land Cover: potential suitable cropland area according to climatic conditions, current harvested areas
Planting Date Decision: Simulate planting dates according to climatic conditions
Planting Density: Planting density=1
Crop Cultivars: Simulate crop Growing Degree Days (GDDs) requirement according to estimated annual GDDs from daily temperature and vernalization requirements computed based on past climate experience (whe, sunfl, rapes); basetemperature computed based on past climate (mai); static (others)
Irrigation: limited water availability, water applied if water deficit and available
Initial Soil Water: 100 year spin up
Key model processes
Leaf Area Development: Dynamic simulation based on development and growth processes
Light Interception: Simple approach
Light Utilization: Simple (descriptive) Radiation use efficiency approach
Yield Formation: fixed harvest index
Crop Phenology: temperature or photoperiod (day length)?
Root Distribution Over Depth: Exponential
Stresses Involved: Water stress
Type Of Water Stress: ratio of supply to demand of water
Water Dynamics: soil water capacity with 5 soil layers
Evapo-Transpiration: Priestly-Taylor
Soil Cn Modeling: C model
Co2 Effects: Leaf-level photosynthesis-rubisco or on QE and Amax
Methods for model calibration and validation
Parameters, Number And Description: 2: maximum LAI under unstressed conditions, management factor
Calibrated Values: Specific for each crop and region
Output Variable And Dataset For Calibration Validation: Yield (FAO yield statistics)
Spatial Scale Of Calibration/Validation: National
Temporal Scale Of Calibration/Validation: Average 1970-2005
Criteria For Evaluation (Validation): Iterative parameter fitting (management factor) to perfect fit