Reference list of 120 datasets from time series station Payerne used for exploratory search

The analysis of time-dependent data is an important problem in many application domains, and interactive visualization of time-series data can help in understanding patterns in large time series data. Many effective approaches already exist for visual analysis of univariate time series supporting tasks such as assessment of data quality, detection of outliers, or identification of periodically or frequently occurring patterns. However, much fewer approaches exist which support multivariate time series. The existence of multiple values per time stamp makes the analysis task per se harder, and existing visualization techniques often do not scale well. We introduce an approach for visual analysis of large multivariate time-dependent data, based on the idea of projecting multivariate measurements to a 2D display, visualizing the time dimension by trajectories. We use visual data aggregation metaphors based on grouping of similar data elements to scale with multivariate time series. Aggregation procedures can either be based on statistical properties of the data or on data clustering routines. Appropriately defined user controls allow to navigate and explore the data and interactively steer the parameters of the data aggregation to enhance data analysis. We present an implementation of our approach and apply it on a comprehensive data set from the field of earth bservation, demonstrating the applicability and usefulness of our approach.

Nutrient concentrations along a North-South transect in the North Atlantic measured during Maria S. Merain cruise MSM03/1 (VISION) cruise

Samples were taken along a transect in the North Atlantic Ocean from 66°139.27'N; 29°136.65'W to 34°124.87'N; 28°128.90'W during the VISION cruise (diVersIty, Structure and functION) MSM03/01 on board the research vessel Maria S. Merian from September 21 to September 30, 2006. Along this transect, each station was sampled at 12 depths, from 10m down to 250m or 500m. Samples were collected with a rosette of 20-l Niskin bottles mounted on a conductivity-temperature-density profiler. Water samples for nutrients analysis were filtered directly after sampling through 0.45-µm in-line filters attached to a 60-ml pre-cleaned syringe into two 12-ml polystyrole tubes. Samples were stored at 4°C (dissolved silicate) or 80°C (ammonium, phosphate, nitrate and nitrite) The samples were spectrophotometrically measured with a continuous-flow analyzer using standard AA3 methods (Seal Analytical, Norderstedt, Germany) using a variant of the method of Grasshoff et al. (1983).