Impact model: LPJmL5-7-10-fire

Sector
Biomes
Region
global

This model version combines recent changes to the default LPJmL version (5.7.10) with recent updates to the Spitfire model, that are not yet part of the default version of LPJmL. Compared to earlier rounds of ISIMIP, this version includes a representation of the nitrogen cycle. Note that this version differs from the LPJmL version used for the agriculture sector in ISIMIP 3a & 3b.

Information for the model LPJmL5-7-10-fire 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.

Person responsible for model simulations in this simulation round
Sebastian Ostberg: ostberg@pik-potsdam.de, 0000-0002-2368-7015, Potsdam Institute for Climate Impact Research (Germany)
Additional persons involved: Luke Oberhagemann, Maik Billing & Markus Drüke (Spitfire update)
Basic information
Model Version: 5.7.10-fire
Reference Paper: Main Reference: Wirth S, Braun J, Heinke J, Ostberg S, Rolinski S, Schaphoff S, Stenzel F, von Bloh W, Müller C et al. Biological nitrogen fixation of natural and agricultural vegetation simulated with LPJmL 5.7.9. EGUsphere [preprint],None,,2024
Reference Paper: Other References:
Resolution
Vertically resolved: No
Person responsible for model simulations in this simulation round
Sebastian Ostberg: ostberg@pik-potsdam.de, 0000-0002-2368-7015, Potsdam Institute for Climate Impact Research (Germany)
Additional persons involved: Luke Oberhagemann, Maik Billing & Markus Drüke (Spitfire update)
Output Data
Experiments: (*) obsclim_1901soc_1901co2, obsclim_2015soc_1901co2, obsclim_nat_default, obsclim_2015soc_default, counterclim_histsoc_default, counterclim_histsoc_obsco2, obsclim_histsoc_1901co2, counterclim_nat_default, counterclim_1901soc_default, counterclim_2015soc_default, obsclim_1901soc_default, obsclim_histsoc_default, obsclim_histsoc_nofire
Climate Drivers: 20CRV3, 20CRV3-ERA5, 20CRV3-W5E5, GSWP3-W5E5
Date: 2024-01-23
Basic information
Model Version: 5.7.10-fire
Model Output License: CC0
Model License: AGPL-3.0 license
Simulation Round Specific Description: Please cite both reference papers listed below since there is no single paper describing the model version used in ISIMIP3a.
Reference Paper: Main Reference: Wirth S, Braun J, Heinke J, Ostberg S, Rolinski S, Schaphoff S, Stenzel F, von Bloh W, Müller C et al. Biological nitrogen fixation of natural and agricultural vegetation simulated with LPJmL 5.7.9. EGUsphere [preprint],None,,2024
Reference Paper: Other References:
Resolution
Spatial aggregation: regular grid
Horizontal resolution: 0.5°x0.5°
Vertically resolved: Yes
Number of vertical layers: 5 hydrologically active soil layers
Additional spatial aggregation & resolution information: We use a mask prescribing the continental fraction of each cell. Use provided "cellarea" and "contfrac" outputs for aggregation over multiple cells.
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
Observed atmospheric climate data sets used: GSWP3-W5E5 (ISIMIP3a), 20CRv3, 20CRv3-ERA5, 20CRv3-W5E5
Emissions data sets used: Atmospheric composition (ISIMIP3a)
Socio-economic data sets used: National, gridded historical population
Land use data sets used: Historical, gridded land use
Additional input data sets: Lake area fraction based on GLWD, modified version of GGCMI phase 3 crop calendar, CRU land-sea mask (corresponds to ISIMIP landseamask_water-global except for 1 cell), continental fraction based on GADM, soil data based on HWSD
Climate variables: huss, sfcWind, tasmax, tas, tasmin, rsds, pr
Additional information about input variables: long wave net radiation calculated from long wave downwelling radiation and mean temperature
Exceptions to Protocol
Exceptions: Landuse input provided by ISIMIP was extended further back in time for model spinup in "histsoc" experiments to avoid artefacts of long-running constant landuse. "1901soc" and "2015oc" experiments used constant landuse also for spinup as prescribed by protocol.
Spin-up
Was a spin-up performed?: Yes
Spin-up design: First spinup without any human forcing for 3500 years followed by transitional run of 400 years with human forcing (either constant (1901soc, 2015soc), or transient (histsoc) or no human forcing (nat)). No-fire sensitivity experiment also does not use fire during spinup and transitional run.
Natural Vegetation
Natural vegetation partition: Dynamic vegetation composition for natural vegetation
Natural vegetation dynamics: Bioclimatic limits determine whether PFTs can establish. Established PFTs compete for light, water and nitrogen and are also affected by disturbance, e.g. fire.
Soil layers: From top to bottom: 20 cm, 30 cm, 50 cm, 100 cm, 100 cm.
Management & Adaptation Measures
Management: Prescribed (constant) sowing dates and prescribed PHU requirements (transient over time) for annual crops. N fertilizer application according to ISIMIP input. Irrigation possible on irrigated areas according to landuse input and based on dynamically calculated irrigation requirements and water availability. Effects of tillage on croplands included in simulations. Prescribed constant livestock density on pastures. Note: Landuse fractions in ISIMIP input refer to the grid area and have been rescaled based on our continental area fraction mask.
Extreme Events & Disturbances
Key challenges: No effects of pests or water logging. Fire disturbance simulated on natural vegetation and pastures. No fires on cropland. Frost damage possible for annual crops.
Model set-up specifications
How do you simulate bioenergy? i.e. what pft do you simulate on bioenergy land?: No bioenergy plantations in historical landuse input.
How do you simulate pasture (which pft)?: Pastures have a mixture of herbaceous PFTs. Livestock grazing is simulated as pasture management. PFT-specific outputs for grass PFTs refer to grasses in natural vegetation. Only bulk values are provided for pastures.
Key model processes
Dynamic vegetation: yes, bioclimatic limits and competition for light, water and nitrogen.
Nitrogen limitation: yes
Co2 effects: yes, Farquhar/Collatz photosynthesis
Light interception: big-leaf approach
Light utilization: Farquhar/Collatz photosynthesis
Phenology: differentiation between evergreen (constant leaf coverage over the year), raingreen (maximum leaf coverage until water stress threshold) and summergreen (budburst and senescence controlled by base temperature, leaf cover increases with accumulated heat sum) trees
Water stress: influence on photosynthesis, allocation (roots/leaf), triggers leaf abscission in raingreen trees
Heat stress: aggregated degree-day sum over PFT-specific temperature base, only on boreal trees
Evapo-transpiration approach: PET: Priestley-Taylor (modified for transpiration)
Differences in rooting depth: no
Root distribution over depth: PFT-specific following Jobbagy & Jackson 2000
Closed energy balance: yes
Coupling/feedback between soil moisture and surface temperature: yes
Latent heat: yes
Sensible heat: yes, but only for soil temperature
How do you compute soil organic carbon during land use (do you mix the previous pft soc into agricultural soc)?: Upon land use conversion, mixing of nat. veg. soc and agricultural soc. Mixing of soc of different crops between crop seasons.
Do you separate soil organic carbon in pasture from natural grass?: Yes, pastures simulated as separate stands/tiles. Natural grasses grow together with trees on one nat. veg. stand/tile with shared soc.
Do you harvest npp of crops? do you including grazing? how does harvested npp decay?: For crops: harvest of storage organs and partial harvest of crop residues. For pastures: livestock grazing with prescribed livestock density.
How do you to treat biofuel npp and biofuel harvest?: No biofuels simulated in ISIMIP3a
Does non-harvested crop npp go to litter in your output?: Non-harvested crop biomass goes to litter.
Causes of mortality in vegetation models
Age/senescence: no
Fire: Daily fire danger based on water vapour pressure deficit. Fire spread controlled by fuel load, fuel characteristics (incl. moisture) and wind speed. Human-caused and lightning-caused ignitions. Post-fire mortality can result from crown or cambial damage.
Drought: no
Insects: no
Storm: no
Stochastic random disturbance: no
Other: light competition
Remarks: growth efficiency, climatic stress (heat threshold, long-term mean outside bioclimatic limits), plant density (FPC>1)
NBP components
Fire: yes, burnt carbon from standing biomass or litter released directly to atmosphere
Land-use change: Above-ground wood biomass transferred to product pools. Remaining biomass (leaves, below-ground biomass) transferred to litter pools. Product pools and litter pools decay over time. Special case land-use change for reservoir: Litter and soil pools transferred to reservoir pool which does not decay.
Harvest: Harvested biomass from cropland released to atmosphere. Harvested biomass from pastures partially returned to litter pool as feces/urine, partially released to atmosphere.
Comments: Note: NBP is provided only as an annual flux because land-use change and decay from product pools are annual processes in LPJmL. Other components of NBP change at sub-annual scales.
Species / Plant Functional Types (PFTs)
List of species / pfts: tropical broadleaved evergreen tree (trbe); tropical broadleaved raingreen tree (trbr); temperate needleleaved evergreen tree (tene); temperate broadleaved evergreen tree (tebe); temperate broadleaved summergreen tree (tebs); boreal needleleaved evergreen tree (bone); boreal broadleaved summergreen tree (bobs); boreal needleleaved summergreen tree (bons); tropical C4 grass (trh); temperate C3 grass (teh); polar C3 grass (poh). Internally, LPJmL distinguishes the following crops or crop groups: temperate cereals, rice, maize, tropical cereals, pulses, temperate roots, tropical roots, sunflower, soybean, groundnut, rapeseed, sugarcane, other annual and perennial crops. However, these are not reported separately.
Comments: Fluxes and pools on managed lands are only distinguished into rainfed crops (crop-noirr), rainfed pasture (past-noirr), irrigated crops (crop-cirr), irrigated pasture (past-cirr).
Model output specifications
Output format: Most outputs are reported per continental area (including inland water bodies). A few outputs are reported per land area (if they are not defined for inland water bodies) or per grid cell area. Reference area is included as a metadata attribute in each output file. To derive continental area, multiply output variable "cellarea" with output variable "contfrac".
Output per pft?: PFT-specific outputs are provided per unit area of the respective PFT, as requested by the protocol. Multiply by reported PFT fraction for a weighted aggregation to the grid cell total.
Considerations: We advice caution when analysing PFT-specific outputs. Within LPJmL, natural PFTs grow together on one stand/tile. Pools and fluxes are generally normalized to the individual or the stand/tile, not per PFT area. PFT-specific raw outputs have been re-normalized to the reported PFT area as requested by the protocol. However, note that the fractional coverage of the PFTs is not constant during the year, but can only be reported as an annual output. In fact, the cover fraction can change quite drastically, especially in the case of fire. The reported PFT fraction refers to the PFT fraction at the end of the year, except for PFTs that have been killed during the year, where the reported PFT fraction is the last fraction before the PFT was killed (to avoid non-zero fluxes with zero cover fraction). As such, the sum of PFT fractions may exceed 100% if PFTs were killed during the year. Also, all PFT-specific fluxes and pools have been scaled using the reported PFT fraction to allow for a weighted aggregation to the grid cell total. However, this means that reported PFT fractions may be inconsistent with monthly PFT-specific variables during the year and thus lead to unrealistic value ranges of these monthly variables (commonly if the cover fraction at the end of the year is much smaller than during the year). We highly suggest that if you want to average PFT-specific fluxes or pools over time to do a weighted aggregation by PFT cover fraction.
Land-use change implementation
Is crop harvest included? if so, how?: Harvest of crop storage organ, partial harvest of crop residues.
Is cropland soil management included? if so, how?: Tillage on croplands
Is grass harvest included? if so, how?: Livestock grazing. Prescribed livestock density and quality of fodder determine daily forage demand. C and N may leave the system directly as CO2 (from respiration), CH4 (from enteric fermentation) and livestock products (milk) or return to the litter pool as urine/feces.
Is shifting cultivation included?: no
Is wood harvest included? if so, how?: no
Which transition rules are applied to decide where agriculture is conducted?: No explicit simulation of gross land-use changes, only net land-use change between natural vegetation and managed land pool. Cropland and pasture drawn from managed land pool.
Carbon-cycle benchmarking
Does your model reach a (near) steady state after spin up (characterized by nbp of < 0.2 pgc y-1)? (yes/no, provide number): yes, NBP averaged over last 50 years of nat. veg. spinup: -0.009 PgC/yr (20crv3), 0.015 PgC/yr (20crv3-era5), 0.011 PgC/yr (20crv3-w5e5), 0.039 PgC/yr (gswp3-w5e5)
What is your modeled nbp for the 1990-2000 decade? is it within 1.2 +/- 0.8 gtc/yr (1-sigma) of observed data from o2/n2 trends (keeling and manning 2014) for 1990-1999 (yes/no, provide number): NBP averaged over 1990-1999: -0.07 PgC/yr (20crv3), 0.31 PgC/yr (20crv3-era5), 0.65 PgC/yr (20crv3-w5e5), 0.51 PgC/yr (gswp3-w5e5)
Fire modules
Aggregation of reported burnt area: Burned area [ha] calculated daily for each nat. veg. and pasture stand/tile. Burned areas summed up over stands/tiles and converted into reported burned area fraction. Daily burned areas summed up to determine monthly burned area. Note: Burned area per stand/tile cannot exceed 100% during a year. Once full stand/tile has burned, no more fires simulated for the rest of the year.
Land-use classes allowed to burn: natural vegetation (including bare soil), ISIMIP-pasture
Included fire-ignition factors: lightning, human-caused ignitions
Is fire ignition implemented as a random process?: no
Is human influence on fire ignition and/or suppression included? how?: Human-caused ignitions are modelled as a function of human population density assuming that ignition rates are higher in remote regions and declines with an increasing level of urbanization and the associated effects of landscape fragmentation, infrastructure, and improved fire monitoring.
How is fire spread/extent modelled?: Fire extent is a function of the number of ignition events, fire danger and an area calculated based on the forward and backward rate of spread. The rate of spread depends on the dead fuel characteristics, fuel load in the respective dead fuel classes, and wind speed.
Are deforestation or land clearing fires included?: no
What is the minimum burned area fraction at grid level?: 0 (no minimum)