Update introduction

protocol/01.introduction.md

@@ -6,25 +6,21 @@ ISIMIP is intended to be structured in successive rounds connected to the differ
 
 The main components of the ISIMIP framework are:
 
-* A common set of climate and other forcing data which will be distributed via a central database;
-* A common modelling protocol to ensure consistency across sectors and scales in terms of data, format and experiment set-up;
-* A central archive where the output data will be collected and made available to the scientific community.
+* A common set of **climate and other forcing data** which will be distributed via a central database;
+* A common **modelling protocol** to ensure consistency across sectors and scales in terms of data, format and experiment set-up;
+* A central **repository** where the output data will be collected and made available to the scientific community.
 
 ### 1.2 Simulation round
 
 ::: show simulation_round=ISIMIP3a
 
-    #### Historical runs with climate-related forcing based on observations
-
-    The ISIMIP3a part of the third round framework is dedicated to i) impact model evaluation and improvement and ii) detection and attribution of observed impacts according to the framework of IPCC AR5 Working Group II Chapter 18. To this end all simulations are forced by observed climate and direct human forcing and a de-trended version of the observed climate allowing for the generation of a “no climate change” baseline (counterfactual, if available).
+    **ISIMIP3a** is dedicated to **model evaluation** or **impact attribution**. To this end simulations are forced by observed climate and direct human forcing. In addition, a de-trended version of the observed climate allows for the generation of a *no climate change* baseline (counterfactual, if available).
 
     To ensure consistency between ISIMIP3a and ISIMIP3b as well as the different experiments within a simulation round, we require that modelling groups use the same version of an impact model for the experiments in ISIMIP3a and ISIMIP3b.
 
 ::: show simulation_round=ISIMIP3b
 
-    #### GCM-based simulations assuming fixed 2015 direct human influences for the future
-
-    The ISIMIP3b part of the third simulation round is dedicated to a quantification of climate-related risks at different levels of climate change and direct human forcing. The Group 1 simulations refer to the pre-industrial and historical period of the CMIP6-based climate simulations. Group 2 covers all future projections assuming fixed 2015 levels of direct human forcing and different future projections of climate (SSP1-2.6, SSP3-7.0 and SSP5-8.5). Group 3 simulations account for future changes in the direct human forcing and are intended to be started once the corresponding direct human forcing input data is available.
+    **ISIMIP3b** is dedicated to a **quantification of climate-related risks** at different levels of climate change and direct human forcing. The **Group I** simulations refer to the pre-industrial and historical period of the CMIP6-based climate simulations. **Group II** covers all future projections assuming fixed 2015 levels of direct human forcing and different future projections of climate (SSP1-2.6, SSP3-7.0 and SSP5-8.5). **Group III** simulations account for future changes in the direct human forcing and are intended to be started once the corresponding direct human forcing input data is available.
 
     To ensure consistency between ISIMIP3a and ISIMIP3b as well as the different experiments within a simulation round, we require that modelling groups use the same version of an impact model for the experiments in ISIMIP3a and ISIMIP3b.