Add overview for wp1 and wp2

source/Overview.md

+The central goal of Nukleus is the provision or generation of weather and
+climate information with high spatial and temporal resolution. Such information
+can be used to make reliable statements about regional and local
+climate change adaptation and mitigation strategies.
+
 ## Work package 1:
-TBC
+New high resolution climate model simulations will be performed because the
+information needed for climate change adaptation and mitigation strategies is
+too coarse on existing simulation output. Work package 1 will conduct
+a high-resolution ensemble simulations. Based on a pre-defined simulation
+protocol high-resolution climate information on scales of up to 3km
+is generated for a region covering Germany using dynamic downscaling of three
+different limited area models. The resulting ensemble of dynamically downscaled
+model simulations is extended by statistical-dynamical.
 
 ## Work package 2:
-TBC
+The evaluation and assessment of existing and new climate simulations from
+work package 1 alike are the corner stones or work package 2.
+The systematic deviations of the underlying climate simulations depend on the
+chosen model system. Global models may differ, for example, in how well the
+frequency of observed weather patterns can be reproduced. There may also be
+differences in regional distribution, which may affect the model regions
+differently. Tele-connection patterns of year-to-year variability
+(e.g. NAO) or multi-decadal variability may also differ. These variations may
+affect the different climate indicators. Values and distributions of these
+indicators can deviate from observations. In order to be able to make reliable
+statements about the effects of climate change, it is necessary to evaluate
+and assess the utilised data. This is realised for the already existing
+simulations and new model simulations alike. Furthermore, the selection of
+suitable forcing data from CMIP5 and especially the future CMIP6 simulations
+as well as CORDEX is important information for work package 1. As far as
+possible, the model data should be bias-corrected in a consistent manner in
+order to provide the model regions with the best possible multivariate climate
+climate information to the model regions.
+
 
-## Work package 3: *Interfaces*
+## Work package 3:
 
 Work package 3 deals with the development of a cross-project interfaces
 such as technology for effective data provision or software development on