Description: Das Projekt "Scientific Support for Regional Downscaling of Precipitation and Temperature Data for Climate Change Impact Assessment in the Nile Equatorial Lakes Region" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Wasserbau durchgeführt. The goal of this study was to enable a prognosis on the future rainfall conditions of the Nile Equatorial Lakes regions by delivering time-series of monthly rainfall sums for the time-period from 2021 to 2050 that can be used for all kinds of applications. One example might be the dimensioning of hydraulic structures. In these very long lasting investments, future climatic conditions have to be considered during present planning and construction.The principal sources of information on future climate conditions are General Circulation Models (GCMs). These are physically based atmospheric models that resemble a numerical weather prediction system but on a much coarser scale. This forecast cannot be perfect. Especially, it cannot predict single values, e. g. if January 2050 will be rather wet or dry, but only climatic references, i.e. state, if Januaries in general will become wetter or dryer in the future. Even if the predictions of a GCM were perfect, its output could not be used directly for hydrological purposes, due to its coarse resolution. The monthly precipitation values that are provided by the GCM present the spatially averaged precipitation over a grid cell of several thousand square kilometres. This 'block rainfall' can differ significantly from rainfall measured at the ground. Rain gauges are influenced by local effects like micro climatic conditions or orographic effects of mountain ranges that GCMs are not able to resolve.This study combined the information from different data sources. As global trend information, monthly precipitation values from two GCMs (ECHAM5 and HadCM3) were used. Three CO2-emission scenarios (A1b, A2 and B1) were considered in this data. As local ground reference observed monthly rainfall sums from several rain gauges in East Africa as well as from three reanalysis projects (Climate Research Unit, University of Delaware and GPCC) were used.At each rain gauge or observation point in the reanalysis a technique called 'Quantile-Quantile-Transformation' was applied to establish a relationship between the Cumulative Distribution Function (CDF) of the GCMs and that of the ground references during the calibration period from 1961-1990. The CDFs were fitted by non-parametric Kernel-Smoothing. To account for potential shifts in the annual cycles of GCMs and ground references, the transformations was done separately for each month.Assuming that the relation between Global Model and local response will be constant in the future, the global predictions of the GCM can be downscaled to local scale, leading to future rainfall scenarios that are coherent with observed past rainfall.Combining the data from three CO2-emission scenarios of two GCM with three reanalysis data sets, an ensemble of 18 different rainfall time-series was created for each observation point. The range of this ensemble helps to estimate the possible uncertainties in the prognosis of future monthly precipitation sums from 2021 to 2050.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Stuttgart ? CO2-Emission ? Seen ? Delaware ? Buchhaltung ? Kalibrierung ? Klimatologie ? Pflanzensamen ? Brunnen ? Regen ? Gebäude ? Kind ? Regenwasser ? Orographie ? Szenario ? Temperatur ? Prognose ? Wirkung ? Ackerrandstreifen ? Nil ? Ostafrika ? Globales Klimamodell ? Wirkung ? Klimaforschung ? Atmosphärenmodell ? Berg ? Bewertung ? Daten ? Globalmodell ? Klimamodell ? Regen ? Studie ? Technik ? Wasserbau ? Wettervorhersage ? Wirkungsanalyse ? Zelle ? Afrika ? Messung ? Klimafolgen ? Bauelement ? Hydrologie ? Investition ? Klima ? Niederschlag ? Fahrradfahren ? Standortbedingung ? Planung ? Gebiet ? Gebirge ? Globale Aspekte ? Staat ? EIN ? REFERENZ ? FUNKTION ? BEISPIEL ? Verwertung ? GEBRAUCHT ? BEREICH ? GEGENWART ? GEMISCHT ? WERT ? ZEITRAEUME ? GEMITTELT ? ZWECKBESTIMMUNG ? BEWERTEN ? DATENSATZ ? GITTERNETZ ? Hydraulische Bemessung ? See [Binnengewässer] ? VERANTWORTUNG ? INFORMATIONSQUELLE ? DAUER ? VERHAELTNIS ? AEQUATORIAL ? DAUERHAFT ? KONNEX ? Kapitalanlage ? LAENDER ? POTENZIAL ? ANGEPASST ? VERTEILUNG ? PRAEZIPITATION ? PROJEKT ? ANGEWANDT ?
Region: Baden-Württemberg
Bounding box: 9° .. 9° x 48.5° .. 48.5°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2010-11-01 - 2011-04-30
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