Progress in understanding and predicting weather and climate as well as their environmental effects requires information on the three-dimensional state of the atmosphere at any given time. This information is not always available in sufficient accuracy, sufficient resolution and over a sufficiently long time period. With models becoming more and more accurate and with changing of research foci towards extremes and the hydrological cycle, further efforts are again needed from the data side. One such aspect is the backward extension of upper-air data sets. This would be beneficial in the context of extremes (a longer record features more extremes), predictability and hindcast experiments (a longer record better samples variability) and climate analysis. However, extending upper-air data sets back in time poses new challenges to the data community, some of which are addressed in this project. Several efforts are underway to provide new data sets, but the subsequent effort of stringently comparing and validating these data is lagging behind. Also, case studies are needed that demonstrate the power and - even more important - the limitations of these new data sets. The importance of thorough data validation cannot be emphasised enough in our present world where any data set is just a mouse click away. The goal of this project is to (1) extend current data sets backwards by contributing to a data assi-milation project, (2) validate historical upper-level data products, and (3) analyse the data with a focus on the 1940s and 1950s. In particular, we intend to analyse the European droughts 1945-1952, the 1950s Sahel pluvial, and the snow-rich Eurasian winters in the 1950s. Results will provide (a) an assessment of the quality of different data sets and their suitability for different purposes and (b) new insights into the mechanisms governing large-scale climate variability. Most importantly, the project will provide information on the quality of essential climate variables (ECV) in standard data sets in simple form.
Prof. Dr. Stefan Brönnimann, Dr. Alexander Stickler, Richard Wartenburger
01.10.2010 - 30.09.2013