Beschreibung: Berlin (Germany) has one of the longest climate records in the world (Cubasch and Kadow, 2011). In the 17th century mainly the family of the astronomer Kirch started measuring the temperature and wrote down general weather patterns. In the beginning of the 18th century the measurements became more regular including multiple measures per day. Over time, more inner city stations appeared but also disappeared. Therefore, this Berlin Climate Record is a moving station, but representable for the inner city of Berlin. With these datasets we reactivate the long inner city climate record in several variables. In this study, we digitized, analyzed, corrected, reconstructed, and provide the datasets on the very rare daily time frequency.

Beschreibung: Berlin has one of the longest climate records in the world (Cubasch and Kadow, 2011). In the 17th century mainly the family of the astronomer Kirch started measuring the temperature and wrote down general weather patterns. In the beginning of the 18th century the measurements became more regular including multiple measures per day. Over time, more inner city stations appeared but also disappeared. Therefore, this Berlin Climate Record is a moving station, but representable for the inner city of Berlin. Many approaches were combining these datasets including bias correction efforts. With this dataset from 1876-01-01 to 1908-12-31 we reactivate the long inner city precipitation record, related to Kadow et al. 2016. In this study, we digitized, analyzed, and corrected the precipitation data set on the daily time frequency. The dataset has been reconstructed from: "Das Klima von Berlin (III) Niederschlag, Luftfeuchtigkeit, Dampfdruck, Bewölkung, Sonnenscheindauer, Wind, Luftdruck - Abh. des Met. Dienstes der DDR Nr. 118, Band XV, Akademie-Verlag 1976".

Beschreibung: Decadal predictions by Earth system models aim to capture the state and phase of the climate several years in advance. Atmosphere-ocean interaction plays an important role for such climate forecasts. While short-term weather forecasts represent an initial value problem and long-term climate projections represent a boundary condition problem, the decadal climate prediction falls in-between these two timescales. In recent years, more precise initialization techniques of coupled Earth system models and increased ensemble sizes have improved decadal predictions. However, climate models in general start losing the initialized signal and its predictive skill from one forecast year to the next. Here we show that the climate prediction skill of an Earth system model can be improved by a shift of the ocean state towards the ensemble mean of its individual members at seasonal intervals. We found that this procedure, called ensemble dispersion filter, results in more accurate results than the standard decadal prediction. Global mean and regional temperature, precipitation, and winter cyclone predictions show an increased skill up to 5 years ahead. Furthermore, the novel technique outperforms predictions with larger ensembles and higher resolution. Our results demonstrate how decadal climate predictions benefit from ocean ensemble dispersion filtering towards the ensemble mean.

Beschreibung: Berlin has one of the longest climate records in the world (Cubasch and Kadow, 2011). In the 17th century mainly the family of the astronomer Kirch started measuring the temperature and wrote down general weather patterns. In the beginning of the 18th century the measurements became more regular including multiple measures per day. Over time, more inner city stations appeared but also disappeared. Therefore, this Berlin Climate Record is a moving station, but representable for the inner city of Berlin. Many approaches were combining these datasets including bias correction efforts. With this dataset from 01.01.1766 to 31.12.1934 we reactivate the long inner city temperature record. In this study, we digitized, analyzed, and corrected the data set on the daily time frequency. The dataset has been reconstructed from: "Das Klima von Berlin (II) Temperatur - Abh. des Met. Dienstes der DDR Nr. 103, Band XIII, Akademie-Verlag 1971"

Beschreibung: A German national project coordinates research on improving a global decadal climate prediction system for future operational use. MiKlip, an eight-year German national research project on decadal climate prediction, is organized around a global prediction system comprising the climate model MPI-ESM together with an initialization procedure and a model evaluation system. This paper summarizes the lessons learned from MiKlip so far; some are purely scientific, others concern strategies and structures of research that targets future operational use. Three prediction-system generations have been constructed, characterized by alternative initialization strategies; the later generations show a marked improvement in hindcast skill for surface temperature. Hindcast skill is also identified for multi-year-mean European summer surface temperatures, extra-tropical cyclone tracks, the Quasi-Biennial Oscillation, and ocean carbon uptake, among others. Regionalization maintains or slightly enhances the skill in European surface temperature inherited from the global model and also displays hindcast skill for wind-energy output. A new volcano code package permits rapid modification of the predictions in response to a future eruption. MiKlip has demonstrated the efficacy of subjecting a single global prediction system to a major research effort. The benefits of this strategy include the rapid cycling through the prediction-system generations, the development of a sophisticated evaluation package usable by all MiKlip researchers, and regional applications of the global predictions. Open research questions include the optimal balance between model resolution and ensemble size, the appropriate method for constructing a prediction ensemble, and the decision between full-field and anomaly initialization. Operational use of the MiKlip system is targeted for the end of the current decade, with a recommended generational cycle of two to three years.