New ISIMIP2b protocol released

Dear ISIMIP community,

With this email, we’d like to make you aware of the new ISIMIP2b protocol, which now includes the extensions decided at the ISIMIP Strategy Group Meeting in Potsdam in September 2018.

The most prominent changes are

1. the addition of two new experiments (one on the quantification of high-end impacts (RCP8.5) and
2. an optional sensitivity run to quantify the effects of the new bias-adjustment method).

The changes are highlighted in yellow in the attached protocol and explained further in the changelog on our website and the list below this email.

In order to have sufficient time to analyze the new data and write papers before the AR6 submission deadline (01/07/2020), please submit your simulation results by June, 2019.

As for the 2a protocol, we are still waiting for the last input datasets to be completed and will share the protocol with you as soon as that is done.

Best wishes from Potsdam,

Felix for the ISIMIP coordination team

• New experiments with RCP8.5 and RCP6.0 added As decided at the ISIMIP Strategy Group Meeting, we added two new experiments, VIII and IX, to all sectors. Exp. VIII is driven by RCP8.5 climate input data to analyze high-end impacts, while the optional exp. IX uses RCP6.0 climate input data that were bias-adjusted and statistically downscaled with an improved method that shall be used in ISIMIP3b. Comparing exp. III and IX allows us to assess the sensitivity to using the ISIMIP2b method versus the ISIMIP3b method for bias adjustment and statistical downscaling. The scenario-design figures were adapted accordingly.
• Water: Bioenergy crop variables added We added bioenergy crop yields as output variables as part of the additions to the water protocol about reporting crop yields. The variables have been added to the water sector protocol, but not to the biomes protocol to avoid adding many new variables which are only relevant for those models including irrigation etc. and hence are also contributing to the water sector.
• Water: Interpretation of human-influence secnarios clarified For the purpose of the global water sector, “human influences” is defined as human interference directly with the hydrological fluxes of the water cycle for the purposes of any one or several of: water management (e.g. dams/reservoirs), irrigation, domestic water use, manufacturing and livestock production. I.e. human land use alone does not represent a human influence. Therefore, models that do not include any human influences (in the hydrological fluxes) at all, are to be referred to as nosoc, even if human land use is represented.
• Lakes: Several variables added The variables surface temperature, bottom temperature, upward shortwave radiation flux at the lake-atmosphere interface, turbulent diffusivity of heat, and light extinction coefficient were added to the protocol. We also added a suggestion for how to parameterize the light extinction coefficient. Several variables are to be reported on a higher (daily) resolution if possible.
• Lakes: Diagnostic for lake stratification added A diagnostic to calculate lake stratification following Millero & Poisson (1981) was added.
• Agriculture: Nitrate cycling added We have added new output variables to the agricultural sector to report on nitrogen cycling.
• Agriculture: Sector name changed The agricultural sector was renamed to “Agriculture (crop modelling)” to be consistent with the ISIMIP2a protocol.
• Forests: Management scenarios changed The new forest management scenarios specify different silvicultural measures that can be simulated to explore the effects of stand-scale forest management decisions in line with adaptation, mitigation and multi-purpose management objectives. The scenarios follow a common framework developed in the FORMASAM project but are specific for each of the ISIMIP/PROFOUND sites.
• Permafrost: Information on spin-up runs added The description of spin-up runs has been further specified. Spin-up runs should be using pre-industrial climate and year 1860 levels of “other human influences”.
• Biomes, forests: Sensitivity experiment IIIc added We added a co2-sensitivity run with RCP8.5 climate but co2 fixed at 2005-levels to the biomes and forest protocol in the table on sector-specific simulation runs.
• Biomes, permafrost: Variables to be reported on higher resolution In the permafrost and biomes sector, several variables are to be reported on a higher (daily) resolution, if possible.
• Instructions on file naming and formatting added We added instructions on how to split time-series data into different files. Additionally, we provide further information and examples on file naming and help on data formatting on our website and added the link to the protocol.
• Background information on bias adjustment added We added some explanatory text to describe how the ISIMIP2b bias adjustment was conducted compared to the Fast Track. In addition, RCP6.0 projections were bias-adjusted using a new method, which is planned to be used in ISIMIP3. A paper describing the new method has been submitted and is expected to go online soon.
• Information on processing of climate input-data removed from sector overviews Information on the recycling of pre-industrial control climate-input data removed from the scenario-overview table in each sector. This information was moved to the input-data section.
• Terrestrial biodiversity: Sector renamed We renamed the biodiversity sector to “terrestrial biodiversity”, because marine ecosystems belong to the fisheries sector.