Abstract. This paper describes the new First Guess Daily product of the Global Precipitation Climatology Centre (GPCC). The new product gives an estimate of the global daily precipitation gridded at a spatial resolution of 1• latitude by 1 • longitude. It is based on rain gauge data reported in near-real time via the Global Telecommunication System (GTS) and available about three to five days after the end of each observation month. In addition to the gridded daily precipitation totals in mm day −1 , the standard deviation in mm day −1 , the kriging interpolation error in % and the number of measurements per grid cell are also encoded into the monthly netCDF product file and provided for all months since January 2009. Prior to their interpolation, the measured precipitation values undergo a preliminary automatic quality control. For the calculation of the areal mean of the grid, anomalies are interpolated with ordinary block kriging. This approach allows for a near-real-time release. Therefore, the purely GTS-based data processing lacks an intensive quality control as well as a high data density and is denoted as First Guess. The daily data set is referenced under doi:10.5676/DWD_GPCC/FG_D_100. Two further products, the Full Data Daily and a merged satellite-gauge product, are currently under development at Deutscher Wetterdienst (DWD). These additional products will not be available in near-real time, but based on significantly more and strictly quality controlled observations. All GPCC products are provided free of charge via the GPCC webpage: ftp://ftp-anon.dwd.de/pub/data/gpcc/html/download_gate.html.

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Measuring biological samples by atom probe tomography (APT) in their natural environment, i.e. aqueous solution, would take this analytical method, which is currently well established for metals, semi-conductive materials and non-metals, to a new level. It would give information about the 3D chemical structure of biological systems, which could enable unprecedented insights into biological systems and processes, such as virus protein interactions. For this future aim, we present as a first essential step the APT analysis of pure water (Milli-Q) which is the main component of biological systems. After Cryo-preparation, nanometric water tips are field evaporated with assistance by short laser pulses. The obtained data sets of several tens of millions of atoms reveal a complex evaporation behavior. Understanding the field evaporation process of water is fundamental for the measurement of more complex biological systems. For the identification of the individual signals in the mass spectrum, DFT calculations were performed to prove the stability of the detected molecules.

To benefit from the latest technical improvements in atom probe analysis, a new tomographic atom probe has been built at the University of Münster, Germany. The instrument utilizes a femtosecond laser system with a high repetition rate combined with the ability of using a micrometer-sized extraction electrode and a wide angle configuration. Since field evaporation is triggered by laser pulses instead of high-voltage pulses, the instrument offers the ability to expand the range of analyzed materials to poorly conducting or insulating materials such as oxides, glasses, ceramics, and polymeric materials. The article describes the design of the instrument and presents characterizing measurements on metals, semiconductors, and oxide ceramic.

Phase separation of g 0 precipitates determines the microstructure and mechanical properties of nickel-based superalloys. In the course of ageing, disordered g spheres form inside ordered (L1 2 ) g 0 precipitates, undergo a morphological change to plates and finally split the g 0 precipitates. The presence of g particles inside g 0 affects coarsening kinetics and increases alloy hardness. Here we use atom probe tomography to visualize phase separation in a Ni 86.1 Al 8.5 Ti 5.4 alloy in three dimensions and to quantify the composition of all the phases with near-atomic resolution. We find that g 0 precipitates are supersaturated in nickel, thereby driving the formation of g particles and observe a compositional evolution of the g particles, which accompanies their morphological change. Our results suggest that by controlling nickel supersaturation we can tailor the phase separation and thereby the properties of nickel-based superalloys.