The data portal and the data and metadata modeling and storage as well should all follow international standards and rely on open-source solutions. The format chosen for the storage of CEOP-AEGIS output data is NetCDF, developed by Unidata. This data format is flexible, self-describing, and ca- pable to store large sets of array-oriented multidimensional data in a single file. It is an open-source solution that can be used in combination with the OPeNDAP technology to access NetCDF datasets remotely over the internet by the use of an OPeNDAP server and an OPeNDAP enabled client.
The data portal should consist of a back-end data server for data stor- age and of a front-end user interface for data access. This web based user interface will represent the CEOP-AEGIS Data Portal and will be part of a contribution to the Global Earth Observation System of Systems (GEOSS). The back-end data server should be based on the OPeNDAP technology, so that it can be used in combination with the NetCDF data format. The front- end must be a web based user interface that should be accessible with any internet browser by taking advantage of the the OPeNDAP technology. This can be achieved by the use of the Dapper / DChart open-source technology, developed by Joe Sirott at NOAA/PMEL.
The objective of this thesis is two-fold with one final additional element: • On the one hand, the technical capabilities of the NetCDF data format as well as its data modeling and metadata modeling standards need to be profoundly evaluated in order to take correct decisions on how to produce suitable NetCDF datasets. Moreover, the OPeNDAP data for- mat and protocol as well as the Dapper / DChart technology on which relies the data repository and user interface must be evaluated with the same elaborateness. This is important for the decision making process of NetCDF modeling so that interoperable datasets with a maximum compatibility and functionality to OPeNDAP and Dapper / DChart as well can be created. Out of these evaluations, decisions must be taken about what NetCDF data format, data model and metadata conven- tion should be employed within CEOP-AEGIS for the project output data. Following from this, the resulting NetCDF implementation for the output data must be adapted to the needs of the CEOP-AEGIS project, as well as to the technical requirements of Dapper / DChart.
• On the other hand, any data provided from CEOP-AEGIS project part- ners need to be post-processed and merged together in space and time to obtain aggregated and standardized high valuable datasets that can be feed to the CEOP-AEGIS Data Portal. For doing so, an upstream data interface that is intended to convert data from project partners to OPeNDAP compliant NetCDF datasets must be designed and im- plemented within this thesis. This data interface must produce stan- dardized NetCDF output data that is respecting the decision about NetCDF data and metadata modeling, as they were taken in the pre- vious detailed evaluation steps of NetCDF, OPeNDAP and Dapper / DChart. The data interface should easily allow to add and modify metadata. Some functions that check if the defined NetCDF model is obeyed would be useful. It should also be possible to modify this interface without much work so that also unexpected data formats can be read and standardized NetCDF output data be produced out of it.
• Finally, some already available project datasets should be post-processed through the developed data interface and converted into the designated form of NetCDF. This data should subsequently be published in the CEOP-AEGIS Data Portal. Dapper and DChart need to be configured for this purpose. For some case studies, a few additional cartographic products in form of animations may be produced out of the standard- ized data.
In summary, it is essential to properly design a data interface that con- verts heterogeneous input data of project partners in standardized and ag- gregated output data files. These files must be based on a standardized, consistent and adequate data and metadata model to ensure maximum com- patibility and functionality within the CEOP-AEGIS Data Portal and subse- quently interoperability within the use by the related scientific communities. The results of this thesis will be a contribution to the CEOP-AEGIS work package number eight (WP 8): Monitoring the water balance and water yield of the Plateau. This work package defines intentions in regard of an inte- grated analysis of ground and satellite observations in order to estimate the water balance of the Tibetan Plateau, as well as in matters of the develop- ment and demonstration of a prototype observation system to monitor the water yield of this area. This includes the establishment of a pilot database management system that supports the hydrological monitoring of the Plateau (CEOP-AEGIS Inc. 2009).