Current status of the BALTEX in-situ reference sites in CEOP

The Coordinated Energy and water cycle Observations Project (CEOP) has been developed and implemented within the Global Energy and Water Cycle Experiment (GEWEX) of the World Climate Research Programme (WCRP) with the fundamental aim to establish an integrated global observing system for the water cycle which responds to both scientific and social needs of the human society. The CEOP implementation strategy includes both science studies on a number of topics relevant to understand the global energy and water cycle (e.g., monsoon studies, cold region process studies, semi-arid studies) and the collection, central archiving, and management of

· data from experimental and operational satellites,
· model output products from leading numerical weather prediction and climate modelling centres around the world, and
· comprehensive land surface / atmosphere data sets collected at a number of world-wide distributed reference sites.

BALTEX has nominated three observatory sites to act as in-situ reference sites from its member states, namely Sodankylä (Finland), Cabauw (The Netherlands), and Lindenberg (Germany). These sites represent different major climate and vegetation zones in the BALTEX study domain. Data archiving from these sites at the CEOP Central Data Archive at NCAR-EOL in Boulder goes back to 2002. The intention is to provide a full decadal data set on land surface – atmosphere interaction processes, the data include standard surface meteorology data, soil temperature and soil moisture information, the full set of flux data describing the radiation and energy budget at the Earth’s surface, tower profiles of basic atmospheric state variables and radiosonde data characterising the staus of the whole atmospheric column at the sites.

The present paper will review the current status of the contribution of the BALTEX reference sites to the CEOP in-situ adta archive. A few examples will be given demonstrating the potential of using these data sets for numerical weather prediction and climate model validation studies.