Das Projekt "The predictability of atmospheric blocking in global ensemble prediction systems" wird vom Umweltbundesamt gefördert und von Deutscher Wetterdienst durchgeführt. Blocking is an atmospheric phenomenon which has major implications for local weather. It can lead to extremely high or low temperatures due to the long lasting almost stationary high pressure system. Furthermore, a block can exert a strong impact on upstream, in-situ and downstream synoptic weather patterns by disrupting the multitude westerly flow. Thereby, blocking can be the cause for severe precipitation anomalies in cut-off lows surrounding the high pressure system. The state of the art ensemble prediction systems (EPSs) which are part of the THORPEX Interactive Grand Global Ensemble (TIGGE) perform well in predicting the frequencies of Atlantic European and Pacific blocking but have difficulties in predicting the onset and the decay of blocking. The predictability of the onset is about 1 day worse than the predictability if the blocking is already specified in the initial conditions. Furthermore, the TIGGE ensemble prediction systems (EPSs) have problems in simulating the frequencies of Greenland and Ural blocking. This study is dedicated to investigate the dynamics of selected blocking events in the medium range, the monthly, and the seasonal ECMWF EPS. Two different clustering methods based on EOF/PC 3 analysis and one method based on ensemble analysis covariance will be applied to the EPSs. Links between different types of block formation or decay and large scale events like breaking Ross by waves or small scale diabetic processes like precipitation resulting from the advection of moist air masses will be investigated. Their roles in the life cycle of a blocking event will be compared. The same investigation methods will be applied to the TIGGE ensembles and to carry forward the results obtained for the medium range ECMWF EPS alone. Additionally, for two winter seasons and for a whole year scores and skill scores used at the ECMWF will be calculated and the predictive skill of the EPSs will be assessed with regard to blockings.
Das Projekt "CO2-Fußabdrücke im Alltagsverkehr - Datenauswertung auf Basis der Studie Mobilität in Deutschland" wird vom Umweltbundesamt gefördert und von infas Institut für angewandte Sozialwissenschaft GmbH durchgeführt. Die dieser Studie zugrundeliegende Sekundärauswertung erfolgt auf Basis der Ergebnisse aus 'Mobilität in Deutschland' und zielt darauf ab, im alltäglichen Personenverkehr Faktoren und Zusammenhänge aufzuzeigen, die besonders stark zu den CO2-Emissionen beitragen, um Ansatz-punkte zu identifizieren, politische Maßnahmen zielgerichteter und dabei den Mitteleinsatz effizienter zu gestalten. Dazu werden zum einen das Emissionsberechnungsmodell TREMOD (Transport Emission Model) in der Version 6.03 (01/2020) verwendet und zum anderen die Datensätze der Verkehrserhebung Mobilität in Deutschland (MiD) der Erhebungsjahre 2002, 2008 und 2017. In dieser Studie werden ausschließlich CO2-Emissionen betrachtet.
Unter Berücksichtigung dieser Festlegungen und Definitionen wurde auf Grundlage von TREMOD 6.03 eine Liste spezifischer Emissionswerte inklusive Vorkette nach Fahrzeugtyp und Verkehrsmittel in Gramm pro Personenkilometer bzw. pro Kilometer bereitgestellt. Jedem berichteten Weg innerhalb der MiD wird anhand dieser Liste ein CO2-Wert zugeordnet, der sich aus den verkehrsmittelspezifischen Emissionswerten multipliziert mit der Länge des Weges ergibt. Hierzu werden die Angaben für die Bezugsjahre 2002, 2008 und 2017 ausschließlich nach TREMOD 6.03 verwendet. Auf dieser Grundlage lassen sich anhand des Verkehrsaufkommens genaue Emissionsberechnungen durchführen, da in den CO2-Emissionswerten pro Weg die zugehörigen Distanzen und durchschnittliche Auslastungen als Information enthalten sind.
Mit den beschriebenen Verfahren lassen sich nun differenzierte Analysen der Emissionsmengen durchführen, um die Emissionsquellen und -ursachen zu benennen. Dabei werden drei analytische Perspektiven unterschieden: Längsschnittanalyse zum Vergleich der Erhebungsjahre und damit der zeitlichen Entwicklung, eine Betrachtung der Wegeebene und nach Personen im Querschnitt.
Das Projekt "Combined airborne lidar measurments of moisture transport and cirrus properties: HALO-LIDAR" wird vom Umweltbundesamt gefördert und von Ludwig-Maximilians-Universität München, Meteorologisches Institut durchgeführt. Humidity in and around cirrus clouds: Radiative effects of cirrus clouds are a major uncertainty in determining the climate cloud feedback. The variability of cirrus on different spatial scales is another major issue which complicates modelling of their radiative properties. Aerosol and water vapour measurements were performed with the DLR lidar system WALES in 2010 during the first mission with the new German research aircraft HALO. ECMWF temperature analyses are used to derive relative humidity inside and outside of cirrus clouds from the lidar water vapour observations. Comparisons with in situ measurements of humidity on the research aircraft Falcon flying inside the cirrus clouds confirm the high accuracy of the WALES system. The study shows the advantages of lidar cross sections to provide additional information about the vertical structure of the complex humidity field, also allowing for simultaneous statistical analyses in different cloud layers. Combined with accurate temperature measurements, the lidar observations have a great potential for detailed statistical cirrus cloud and related humidity studies. Future HALO missions will benefit from the findings and techniques developed here. HSRL aerosol classification: To better understand the effects of aerosols on the climate system it is important to obtain highly accurate information on the aerosol optical properties (e.g., extinction coefficient, single scattering albedo and phase function) as well as on their temporal and spatial distribution. The high spectral resolution lidar (HSRL) method based on an iodine absorption filter and a frequency doubled pulsed Nd:YAG laser, developed at DLR, has the capability to directly measure the extinction and backscatter coefficients of aerosols and clouds. Airborne HSRL data from four different field experiments are used in the frame of this project to build up an aerosol classification. The method is based on HSRL measurements of a set of intensive aerosol properties, in particular the lidar ratio, the particle linear depolarization ratio and the color ratio of backscatter. Applied to the HSRL measurements on ESA's EarthCARE mission it will provide the climate relevant properties extinction coefficient and aerosol optical depth, together with the global, verticallyresolved distribution of aerosols and clouds. Statistical characterization of humidity variability: The distribution of water vapour in the atmosphere shows variability on all spatial scales. An accurate representation of cloud processes in climate models with limited resolution relies on a statistical description of the unresolved structures. A compact description that can describe intermittent variability on many scales is multifractal scaling based on structure functions of different orders. This analysis method was applied to airborne water vapour lidar measurements from a number of field campaigns in midlatitude, polar and subtropical latitudes. The humidity was found to be charact
Das Projekt "Research application of the novel multi sensor dropsonde for HALO for investigation of cyclones and embedded convection causing high impact weather in the Mediterranean" wird vom Umweltbundesamt gefördert und von Karlsruher Institut für Technologie (KIT), Institut für Meteorologie und Klimaforschung, Department Troposphärenforschung durchgeführt. The new KITsonde multi-sensor dropsonde will have its first operational use aboard HALO for investigation of deep convection and cyclones causing High Impact Weather (HIW) in the Mediterranean during the Demonstration Mission NEPTUN in autumn 2012. Following a sequence of three days of the development of an upper tropospheric trough leading to deep convection, mesoscale convective systems, and a lower tropospheric cyclone with embedded convection, the KITsonde will be used on the one hand to detect the variability of wind temperature and humidity prior to the cyclogenesis upstream, combined with in-situ and lidar remote sensing instruments. On the other hand during the final stage of HIW development, KITsonde will provide high resolution in-situ measurements from the inside of convective cells and MCS, inaccessible for the aircraft and optical remote sensing instruments. This dataset will allow the analysis of the variability of wind, temperature and humidity in time and space on all affecting scales, responsible for vertical fluxes of energy, which themselves are decisive for the initiation of convection - an important trigger mechanism for HIW. The impact of additional high resolution profiles within convective systems on the forecast quality of the NWF model COSMO-DE will be investigated.
Das Projekt "The initiation, development, and predictability of Mediterranean weather on the synoptic and convective scale leading to extreme events (MED)" wird vom Umweltbundesamt gefördert und von Karlsruher Institut für Technologie (KIT), Institut für Meteorologie und Klimaforschung, Department Troposphärenforschung durchgeführt. The project focuses on the dynamics of Mediterranean cyclones and convection and on the factors that determine their predictability. The main goal is the early identification of cyclones and convective systems leading to high impact weather (storms, heavy precipitation, flash floods) in the west-ern Mediterranean basin. We aim at quantifying the sensitivity of Mediterranean weather to large-scale forcing due to upper-level PV anomalies relative to the regional-scale impact of (convective) moist processes and surface fluxes. The role of embedded convection and warm conveyor belts in the energy and water cycle of cyclones will be investigated by numerical modelling in order to distinguish between cyclones with and without potential for HIW. The impact of grid spacing, the method of convection parameterization, and convection resolving approaches on the initiation of convection and resulting interaction with larger (synoptic) scales will be investigated for selected cases with and without HIW events. Using the TIGGE data base the sensitivity of Mediterranean cyclones on changing initial conditions and their coupling on the upstream flow will be analyzed. With its model studies this project contributes to and benefits from the HYMEX project on the hydrological cycle in the Mediterranean.