Webaccess to the CESAR data: the CESAR DATABASE SYSTEM portal

The Cabauw Experimental Site for Atmospheric Research (CESAR) was established in 2002 as a consortium of eight Dutch institutes. CESAR is an atmospheric reference site of major importance in the European and mondial research networks. CESAR covers a wide spectrum of measurements and observations acquired by very different instruments on site and in its near surroundings. Instruments include remote sensing systems, tower and surface instruments, and also soil and hydrological instruments. The data collected by these systems is very different both in nature and content. Data is delivered in both in near real time and offline. To utilize the CESAR data to it’s full potential it is important to be able to access, exchange and retrieve the data in an user friendly way with an acceptable response time and witout any operator interference. A data management and distribution system was considered crucial to obtain this goal.
Therefore KNMI developed in-house a CESAR database system (CDS) to address the need for CESAR data delivery and distribution. The frontend comprises a self-registration, a search function with a limited number of search options, and a download basket for ordering data files. Metadata on the dataset level is provided in the webportal, as well as an option to preview the data by the quicklooks stored along with data files in the database. The data itself are all stored in netCDF format and comply with the CF1.4 convention. The backend of the system includes ftp-buffers for upload of the data by the data providers and for near real time distribution also by ftp. The core of the backend is based on the Netherlands Atmospheric Data Centre (NADC) software, which handles all the ingestion, archiving, metadata extraction and the generation and distribution of the logging and error reports. An offline facility has been implemented to retrieve statistics about user visits and download orders.
After some months of testing the CDS has become operational in July 2009 and will be gradual filled with more and more different datasets from either the operational continuous measurement program, visiting researchers or campaign hosted at CESAR. We will present the CDS in more detail and show some examples of the user interface.