Impact model: JULES-B1 (formerly JULES_UoE)

JULES-B1 (formerly JULES_UoE) is one of the 8 global models following the ISIMIP2a protocol which form the base of simulations for the ISIMIP2a biome sector outputs; for a full technical description of the ISIMIP2a Simulation Data from Biomes Sector, see this DOI link:

Contact Person

Information for the model JULES-B1 (formerly JULES_UoE) 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: JULES v4.4
Reference Paper: Main Reference: Clark D, Mercado L, Sitch S, Jones C, Gedney N, Best M, Pryor M, Rooney G, Essery R, Blyth E, Boucher O, Harding R, Huntingford C, Cox P et al. The Joint UK Land Environment Simulator (JULES), model description – Part 2: Carbon fluxes and vegetation dynamics. Geoscientific Model Development,4,701-722,2011
Reference Paper: Other References:
Output Data
Experiments: historical
Climate Drivers: GSWP3, PGMFD v.2 (Princeton), WATCH (WFD)
Date: 2016-04-22
Spatial Aggregation: regular grid
Spatial Resolution: 0.5°x0.5°
Temporal Resolution Of Input Data: Climate Variables: daily
Temporal Resolution Of Input Data: Co2: annual
Temporal Resolution Of Input Data: Land Use/Land Cover: annual
Temporal Resolution Of Input Data: Soil: constant
Input data sets used
Observed Atmospheric Climate Data Sets Used: GSWP3, PGMFD v.2 (Princeton), WATCH (WFD)
Climate Variables: co2, tasmax, tas, tasmin, rlds, huss, wind, rsds, ps, pr
Was A Spin-Up Performed?: Yes
Spin-Up Design: We use the 1901-1910 climate condition, pre-industry CO2 (287.14 ppm), land cover map of 1860 to do an equilibrium run of 100 years with TRIFFID on an equilibrium mode followed by a spin-up until the soil carbon to be equilibrium. Then a simulation from 1861 to 1900 was performed with varied CO2 and land-cover/land-use change, and climate of 1901-1910 cycled. The final transient simulation of 1901-2012 was forced by varied climate, CO2 and land-cover/land-use change.
Natural Vegetation
Natural Vegetation Partition: Dynamic vegetation scheme, 9PFT, PFT can coexist on the same grid cell
Natural Vegetation Dynamics: Competition between natural PFTs is based on a tree-shrub-grass dominance hierarchy,
Management & Adaptation Measures
Management: No specific management. Crop area are represented by C3 and C4 grasses
Model output specifications
Output Format: per grid cell (land only), thus when calculating global or regional total, please multiply by grid-cell area of each grid
Output Per Pft?: output per PFT per unit area of that PFT in the grid cell. Grid box average requires weighting by the fractional coverage of each PFT in the gridbox.
Considerations: 13 PFTs including bare soil, lakes,Urban area, ice etc. For monthly value, please multiply PFT specific value by PFT fraction of each PFTs
Key model processes
Dynamic Vegetation: Competition between natural PFTs is based on a tree-shrub-grass dominance hierarchy,
Co2 Effects: Collatz photosynthesis
Light Utilization: follow the JULES canopy radiation model 5 that uses a two-stream approximation of radiation interception in a 10-layer canopy. There two leaves in each canopy layer (sunlit and shaded)
Phenology: Phenology follows the temperature (GDD)
Water Stress: Water stress affects the photosynthesis and leaf maintenance respiration
Heat Stress: aggregated degree-day sum that affect phenology
Evapo-Transpiration Approach: Collatz approach
Root Distribution Over Depth: PFT-dependent
Permafrost: None
Closed Energy Balance: Yes
Coupling/Feedback Between Soil Moisture And Surface Temperature: yes
Latent Heat: yes
Sensible Heat: yes
NBP components
Land-Use Change: yes
Species / Plant Functional Types (PFTs)
List Of Species / Pfts: tropical broadleaf evergreen trees (BDT); temperatre broadleaf evergreen trees (BET_te);deciduous broadleaf trees (BET_tr); evergreen needleleaf trees (NET ); deciduous needleleaf trees (NDT); c3 grass (C3); c4 grass (C4);evergreen shrub (ESh); deciduous shrub (DSh) ; Urban (Urb),Inland Water (Water); Bare soil (Soil); ice (ice)