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  • 11
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    Berlin Dahlem precipitation time-series 2001-2013 (2017)
    PANGAEA
    In:  Supplement to: Ritschel, Christoph; Ulbrich, Uwe; Névir, Peter; Rust, Henning (2017): Precipitation extremes on multiple timescales - Bartlett-Lewis rectangular pulse model and intensity-duration-frequency curves. Hydrology and Earth System Sciences, 21(12), 6501-6517, https://doi.org/10.5194/hess-21-6501-2017
    Details
    Publication Date: 2023-01-13
    Description: For several hydrological modelling tasks, precipitation time-series with a high (i.e. sub-daily) resolution are indispensable. This data is, however, not always available and thus model simulations are used to compensate. A canonical class of stochastic models for sub-daily precipitation are Poisson-cluster processes, with the Bartlett-Lewis rectangular pulse model (BLRPM) as a prominent representative. The BLRPM has been shown to well reproduce certain characteristics found in observations. Our focus is on intensity-duration-frequency relationship (IDF), which are of particular interest in risk assessment. Based on a high resolution precipitation time-series (5-min) from Berlin-Dahlem, BLRPM parameters are estimated and IDF curves are obtained on the one hand directly from the observations and on the other hand from BLRPM simulations. Comparing the resulting IDF curves suggests that the BLRPM is able to reproduce main features of IDF statistics across several durations but cannot capture singular events (here an event of magnitude 5 times larger than the second larges event). Here, IDF curves are estimated based on a parametric model for the duration dependence of the scale parameter in the General Extreme Value distribution; this allows to obtain a consistent set of curves over all durations. We use the BLRPM to investigate the validity of this approach based on simulated long time series.
    Keywords: Berlin, Germany; Berlin-Dahlem_BotGarden; DATE/TIME; ORDINAL NUMBER; Precipitation; Tipping bucket; Weather station/meteorological observation; WST
    Type: Dataset
    Format: text/tab-separated-values, 113952 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 12
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    Earth system model results by the MPI-ESM-LR of the MiKlip Decadal climate prediction experiment improved by ocean ensemble dispersion filtering, links to NetCDF files (2017)
    PANGAEA
    In:  Supplement to: Kadow, Christopher; Illing, Sebastian; Kröner, Igor; Ulbrich, Uwe; Cubasch, Ulrich (2017): Decadal climate predictions improved by ocean ensemble dispersion filtering. Journal of Advances in Modeling Earth Systems, https://doi.org/10.1002/2016MS000787
    Details
    Publication Date: 2023-01-13
    Description: 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.
    Keywords: File content; File format; File name; File size; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 20 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 13
    Electronic Resource
    Electronic Resource
    The effect of a regional increase in ocean surface roughness on the tropospheric circulation: a GCM experiment (1993)
    Springer
    Climate dynamics 8 (1993), S. 277-285 
    Details
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The sensitivity of the atmospheric circulation to an increase in ocean surface roughness in the Southern Hemisphere storm track is investigated in a paired general circulation model experiment. Such a change in sea roughness could be induced by ocean waves generated by storms. Two extended permanent-July runs are made. One with standard sea surface roughness, the other with ten times as a large surface roughness over open sea poleward of 40° S. The regional increase in ocean surface roughness significantly modifies the tropospheric circulation in the Southern Hemisphere. The strongest effect is the reduction of tropospheric winds (by 2 m/s or 10%) above the area with increased roughness. The poleward eddy momentum flux is reduced in the upper troposphere and the meridional eddy sensible heat flux is reduced in the lower troposphere. Zonal mean and eddy kinetic energy are consistently reduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209667
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    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Ester von (Hydroxymethyl)diorganylsilanen: Synthese und thermisch induzierte Umlagerung (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 591-605 
    Details
    ISSN: 0009-2940
    Keywords: (Hydroxymethyl)diorganylsilanes, esters of ; Rearrangement, thermally induced ; Kinetics ; DSC ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Esters of (Hydroxymethyl)diorganylsilanes: Synthesis and Thermally Induced RearrangementTwenty silanes of the type R1R2Si(H)CH2OR3 (A) were synthesized [R1, R2 = Me, Ph, 1-naphthyl, PhCH2,Me3SiCH2; OR3 = OC(O)Me, OC(O)Ph, OC(O)CF3, OS(O)2CF3, OP(O)Ph2, OC(O)Cl] and studied for their thermal behaviour. The silanes A undergo a thermally induced rearrangement to give the corresponding silanes R1R2Si(OR3)Me (B). For compounds with OR3 = OC(O)Cl, an additional decarboxylation takes place to yield the chlorosilanes R1R2Si(Cl)Me. Except for the derivatives with OR3 = OC(O)Cl, the energetic (reaction enthalpy) and kinetic data (reaction order, frequency factor, enthalpy and entropy of activation) of these reactions were studied by means of differential scanning calorimetry (DSC). In addition, the kinetics of all reactions were investigated by 1H-NMR spectroscopy. The transition state of the rearrangement was investigated by an ab initio study based on the model compound H3SiCH2OC(O)H [→ MeH2SiOC(O)H]. The theoretical data and the experimentally obtained energetic and kinetic data are discussed in terms of mechanistic aspects of the rearrangement reaction A → B.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250310
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    Paper (German National Licenses)
    Fulltext
  • 15
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    Quantifying the extremity of windstorms for regions featuring infrequent events (2017)
    Wiley
    In:  Atmospheric Science Letters, 18 (7). pp. 315-322.
    Details
    Publication Date: 2020-02-06
    Description: This paper introduces the Distribution-Independent Storm Severity Index (DI-SSI). The DI-SSI represents an approach to quantify the severity of exceptional surface wind speeds of large scale windstorms that is complementary to the SSI introduced by Leckebusch et al. While the SSI approaches the extremeness of a storm from a meteorological and potential loss (impact) perspective, the DI-SSI defines the severity in a more climatological perspective. The idea is to assign equal index values to wind speeds of the same singularity (e.g. the 99th percentile) under consideration of the shape of the tail of the local wind speed climatology. Especially in regions at the edge of the classical storm track, the DI-SSI shows more equitable severity estimates, e.g. for the extra-tropical cyclone Klaus. In order to compare the indices, their relation with the North Atlantic Oscillation is studied, which is one of the main large scale drivers for the intensity of European windstorms.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1002/asl.758
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 16
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    Discontinuous Daily Temperatures in the WATCH Forcing Datasets (2015)
    American Meteorological Society
    In:  Journal of Hydrometeorology, 16 (1). pp. 465-472.
    Details
    Publication Date: 2020-07-23
    Description: The Water and Global Change (WATCH) forcing datasets have been created to support the use of hydrological and land surface models for the assessment of the water cycle within climate change studies. They are based on 40-yr ECMWF Re-Analysis (ERA-40) or ECMWF interim reanalysis (ERA-Interim) with temperatures (among other variables) adjusted such that their monthly means match the monthly temperature dataset from the Climatic Research Unit. To this end, daily minimum, maximum, and mean temperatures within one calendar month have been subjected to a correction involving monthly means of the respective month. As these corrections can be largely different for adjacent months, this procedure potentially leads to implausible differences in daily temperatures across the boundaries of calendar months. We analyze day-to-day temperature fluctuations within and across months and find that across-months differences are significantly larger, mostly in the tropics and frigid zones. Average across-months differences in daily mean temperature are typically between 10% and 40% larger than their corresponding within-months average temperature differences. However, regions with differences up to 200% can be found in tropical Africa. Particularly in regions where snowmelt is a relevant player for hydrology, a few degrees Celsius difference can be decisive for triggering this process. Daily maximum and minimum temperatures are affected in the same regions, but in a less severe way.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1175/JHM-D-14-0123.1
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 17
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    The central European floods of August 2002: Part 1 – Rainfall periods and flood development (2003)
    Wiley-Blackwell
    In:  Weather, 58 (10). pp. 371-377.
    Details
    Publication Date: 2020-04-28
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1256/wea.61.03A
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 18
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    The central European floods of August 2002: Part 2 - Synoptic causes and considerations with respect to climatic change (2003)
    Wiley-Blackwell
    In:  Weather, 58 (11). pp. 434-442.
    Details
    Publication Date: 2020-04-28
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1256/wea.61.03B
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 19
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    Evaluating decadal predictions of northern hemispheric cyclone frequencies (2014)
    Taylor & Francis
    In:  Tellus A: Dynamic meteorology and oceanography, 66 . p. 22830.
    Details
    Publication Date: 2015-11-25
    Description: Mid-latitudinal cyclones are a key factor for understanding regional anomalies in primary meteorological parameters such as temperature or precipitation. Extreme cyclones can produce notable impacts on human society and economy, for example, by causing enormous economic losses through wind damage. Based on 41 annually initialised (1961–2001) hindcast ensembles, this study evaluates the ability of a single-model decadal forecast system (MPI-ESM-LR) to provide skilful probabilistic three-category forecasts (enhanced, normal or decreased) of winter (ONDJFM) extra-tropical cyclone frequency over the Northern Hemisphere with lead times from 1 yr up to a decade. It is shown that these predictions exhibit some significant skill, mainly for lead times of 2–5 yr, especially over the North Atlantic and Pacific. Skill for intense cyclones is generally higher than for all detected systems. A comparison of decadal hindcasts from two different initialisation techniques indicates that initialising from reanalysis fields yields slightly better results for the first forecast winter (month 10–15), while initialisation based on an assimilation experiment provides better skill for lead times between 2 and 5 yr. The reasons and mechanisms behind this predictive skill are subject to future work. Preliminary analyses suggest a strong relationship of the model’s skill over the North Atlantic with the ability to predict upper ocean temperatures modulating lower troposphere baroclinicity for the respective area and time scales.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.3402/tellusa.v66.22830
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 20
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    An analysis of uncertainties and skill in forecasts of winter storm losses (2016)
    Copernicus Publications
    In:  Natural Hazards and Earth System Sciences, 16 . pp. 2391-2402.
    Details
    Publication Date: 2019-02-01
    Description: This paper describes an approach to derive probabilistic predictions of local winter storm damage occurrences from a global medium-range ensemble prediction system (EPS). Predictions of storm damage occurrences are subject to large uncertainty due to meteorological forecast uncertainty (typically addressed by means of ensemble predictions) and uncertainties in modelling weather impacts. The latter uncertainty arises from the fact that local vulnerabilities are not known in sufficient detail to allow for a deterministic prediction of damages, even if the forecasted gust wind speed contains no uncertainty. Thus, to estimate the damage model uncertainty, a statistical model based on logistic regression analysis is employed, relating meteorological analyses to historical damage records. A quantification of the two individual contributions (meteorological and damage model uncertainty) to the total forecast uncertainty is achieved by neglecting individual uncertainty sources and analysing resulting predictions. Results show an increase in forecast skill measured by means of a reduced Brier score if both meteorological and damage model uncertainties are taken into account. It is demonstrated that skilful predictions on district level (dividing the area of Germany into 439 administrative districts) are possible on lead times of several days. Skill is increased through the application of a proper ensemble calibration method, extending the range of lead times for which skilful damage predictions can be made.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.5194/nhess-16-2391-2016
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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