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Diese Diplomarbeit untersucht die Güte eines globalen Datensatzes (IA), der die monatliche Ausdehnung der terrestrischen Oberflächengewässer für den Zeitraum von 1993 bis 2004 beinhaltet. IA ist aus komplementären, räumlich geringauflösenden Satellitendaten generiert. Die Wasserausdehnungen werden als prozentuale Flächenanteile von 0,5°-Gitterzellen angegeben. IA wäre durch seine monatliche Dynamik zur Kalibrierung und Validierung eines globalen Modells von temporären Überflutungsgebieten geeignet. Im Rahmen dieser Diplomarbeit werden die Wasserbedeckungen aus IA in einzelnen 0,5°-Zellen zu mehreren Zeitpunkten mithilfe von räumlich hochauflösenden Satellitenbildern des Enhanced Thematic Mapper Plus (ETM+) validiert. Aus Gründen der Effizienz (Minimierung des Speicheraufwands und der Verarbeitungszeit) wird nur ein einziger ETM+ Kanal im mittleren Infrarot zur Bestimmung der Wasserbedeckung verwendet: Band 5. Durch überwachte Klassifikationen wird der Anteil der Wasserflächen an der Gesamtfläche der 0,5°-Zellen ermittelt. Insgesamt werden 262 Klassifikationen in vier Untersuchungsgebieten durchgeführt. Zwischen den prozentualen Wasserbedeckungen aus IA und den ETM+ (Band 5)-Validierungsdaten werden häufige und unregelmäßige Abweichungen festgestellt. Die maximalen absoluten Abweichungen betragen mehr als 60%. Aufgrund dieser Ergebnisse sind die IA-Wasserausdehnungen nur sehr begrenzt als Validierungsdaten für die Modellierung von temporären Überflutungsgebieten geeignet.
Die vorliegende Diplomarbeit beschäftigt sich mit dem Vergleich des ASTER GDEM und SRTM, zweier kostenlos verfügbarer, digitaler Geländehöhenmodelle mit nahezu globaler Abdeckung. Die Untersuchungsgebiete befinden sich im Kleinwalsertal (Österreich) und in Südhessen (Deutschland). Der Vergleich der Geländehöhendaten erfolgt durch die Ermittlung der Höhenabweichung zu Referenzhöhen, die aus hochauflösenden amtlichen Geländemodellen ermittelt wurden. Die Höhenabweichung wurde zudem für bestimmte geomorphologische Oberflächenformen und Landbedeckungen ermittelt. Des Weiteren werden die Geländehöhendaten auf ihre Eignung für geomorphometrische und hydrologische Analysen bewertet.
Nach dem Reaktorunfall in Fukushima im März 2011 und dem darauf folgendem Beschluss in Deutschland, den Atomausstieg zu vollziehen, wird dort – sowohl auf nationaler, als auch auf regionaler Ebene – über eine alternative Energieversorgung diskutiert. Für die vorliegende Arbeit stellten sich die Fragen, wie die energiepolitische Ausgangssituation in Hessen aussieht und welche Potenziale erneuerbarer Energien in Hessen vorhanden sind. Mit einer Politikfeldanalyse wurde untersucht, welche Akteure am Ausbau erneuerbarer Energien beteiligt sind, wie diese interagieren, welche Instrumente zur Förderung erneuerbarer Energien in Hessen existieren und welche Erfolgsbedingungen und Restriktionen sich daraus ergeben. Ferner wurde anhand der jeweiligen Energiekonzepte die Frage verfolgt, welche Zukunftspotenziale für erneuerbare Energien die relevanten Akteure sehen und welche energiepolitischen Maßnahmen getroffen werden müssen, um den Ausbau zu forcieren. Bei einem Vergleich des Bundeslandes Hessen mit den Ländern Niedersachsen, Nordrhein-Westfalen und Sachsen-Anhalt wurde festgestellt, welche energiepolitischen Maßnahmen in diesen Bundesländern erfolgreich waren und auf Hessen übertragbar sind. Einerseits wurde aufgezeigt, dass Bemühungen den Ausbau erneuerbarer Energien zu forcieren erkennbar sind. Anderseits konnten ebenso die restriktiven Rahmenbedingungen dargestellt werden, die einen durchschlagenden Erfolg des Ausbaus erneuerbarer Energien bisher behindern. Die Untersuchung der Energiekonzepte hat ergeben, dass die Akteure die Zukunftspotenziale erneuerbarer Energien sehr unterschiedlich sehen und gewichten – sowohl was das zeitliche Ausbauziel als auch die Potenziale der jeweiligen erneuerbaren Energieträger betrifft.
Forty two samples of the Late Eocene Kiliran oil shale, Central Sumatra Basin, Indonesia were collected from a 102 m long drill core. Palynofacies and geochemical analyses have been carried out to reconstruct the paleoenvironmental conditions and paleoecology during deposition of the oil shale. Amorphous organic matter (AOM) is very abundant (>76%). B. braunii palynomorph is present (3-16%) as the only autochtonous structured organic matter and generally more abundant in middle part of the profile. The stable carbon isotopic composition of organic matter (δ13C) varies from -27.0 to -30.5‰ and is generally more depleted in middle part of the profile. The ratio of total organic carbon to sulfur (TOC/S), used as salinity indicator, ranges from 2.5 to 15.8 and shows variations along the profile. Relatively less saline environments are observed in the middle part profile. Fungal remains are generally present only in middle part of the profile with distinct peak of abundances. The presence of fungal remains is regarded as an indication for a relatively warmer climate during deposition of middle part of the profile. The warmer climate is thought to influence the establishment of a thermocline, limiting the supply of recycled nutrients to the epilimnion. Consequently, the primary productivity in the Kiliran lake decreased during deposition of the middle part of the profile as indicated by the relatively depleted δ13C and the blooming of B. braunii. The chemocline was also shoaling during deposition of the middle part of the profile according to the higher abundance of isorenieratene derivatives of green sulfur bacteria origin. The warmer climate affected also to increase of water supply and thus less saline environments.
Tectonic subsidence is also thought to be a significant factor for the development of the Kiliran lake. The Zr/Rb ratio, an indicator for grain size, ranges from 0.4 to 1.3 and generally increases upwards along the profile. Three sudden decreases of the ratio are observed, indicating rapid change to finer grain size. These decreases are interpreted to indicate rapid deepening events of the lake due to mainly periodic subsidence. During deposition of lower part of the profile, the subsidence rates might have been relatively higher than sediment and water supply rates, resulting in a higher autochtonous fraction in the oil shale. During deposition of middle part of the profile, the sediment and water supply rates were relatively higher promoting distinct progradational sedimentation. Subsequently, the lake became more shallow and smaller during deposition of the upper part of the profile, leading to a relatively higher terrigenous input to the oil shale.
Norneohop-13(18)-ene and neohop-13(18)-ene derived from methanotrophic bacteria are the dominant hopanoid hydrocarbons. The sum of their concentrations varies from 40.6 to 360.0 μg/g TOC. The δ13C of these compounds are extremely depleted (-45.2 to -50.2‰). The occurrence of abundant bacteria including methanotrophic bacteria was responsible for the recycling of carbon below the chemocline of the lake. The effect of the recycling of carbon is observed by the presence of a concomitant depletion (about 7-9‰) in 13C of some specific biomarkers derived from organisms dwelling in the whole phototrophic zone.
4-Methylsterane and 4-methyldiasterene homologues occur in the oil shale as the predominant biomarkers. The sum of the concentrations of all homologues are about 40.3-1,009.2 μg/g TOC with generally higher values in uppermost and lower parts of the profile. Ca accounts as the predominant element in the oil shale, ranging from 5.0 to 16.7%. This element shows generally parallel variation with the 4-methylsterane homologues along the profile. This suggests that the 4-methylsteranes were derived from biological sources favoring more alkaline and more trophic environments. On the other hand, these compounds were less abundant in middle part of the profile which is consistent with less alkaline and less trophic environments promoting B. braunii to bloom.
The 4-methylsterane homologues are considered to originate from Dinoflagellates. Alternation between Dinoflagellates and B. braunii in Paleogene lake systems due to water chemistry changes are known from previous studies. Moreover, freshwater Dinoflagellates have been frequently reported to occur in the basin depocenters. In the present case, distinct alternation between B. braunii abundances and concentrations of 4-methylsterane homologues along the studied oil shale profile suggest that the 4-methylsterane homologues were derived from freshwater Dinoflagellates although dinosterane is not present in the sediment extracts. Water alkalinity and trophic level changes were most likely responsible for the alternation of Dinoflagellates and B. braunii blooming.
We present the analysis of the impact of convection on the composition of the tropical tropopause layer region (TTL) in West-Africa during the AMMA-SCOUT campaign. Geophysica M55 aircraft observations of water vapor, ozone, aerosol and CO2 during August 2006 show perturbed values at altitudes ranging from 14 km to 17 km (above the main convective outflow) and satellite data indicates that air detrainment is likely to have originated from convective cloud east of the flights. Simulations of the BOLAM mesoscale model, nudged with infrared radiance temperatures, are used to estimate the convective impact in the upper troposphere and to assess the fraction of air processed by convection. The analysis shows that BOLAM correctly reproduces the location and the vertical structure of convective outflow. Model-aided analysis indicates that convection can influence the composition of the upper troposphere above the level of main outflow for an event of deep convection close to the observation site. Model analysis also shows that deep convection occurring in the entire Sahelian transect (up to 2000 km E of the measurement area) has a non negligible role in determining TTL composition.
In-situ measurements of ice crystal size distributions in tropical upper troposphere/lower stratosphere (UT/LS) clouds were performed during the SCOUT-AMMA campaign over West Africa in August 2006. The cloud properties were measured with a Forward Scattering Spectrometer Probe (FSSP-100) and a Cloud Imaging Probe (CIP) operated aboard the Russian high altitude research aircraft M-55 ''Geophysica'' with the mission base in Ouagadougou, Burkina Faso. A total of 117 ice particle size distributions were obtained from the measurements in the vicinity of Mesoscale Convective Systems (MCS). Two or three modal lognormal size distributions were fitted to the average size distributions for different potential temperature bins. The measurements showed proportionate more large ice particles compared to former measurements above maritime regions. With the help of trace gas measurements of NO, NOy, CO2, CO, and O3, and satellite images clouds in young and aged MCS outflow were identified. These events were observed at altitudes of 11.0 km to 14.2 km corresponding to potential temperature levels of 346 K to 356 K. In a young outflow (developing MCS) ice crystal number concentrations of up to 8.3 cm−3 and rimed ice particles with maximum dimensions exceeding 1.5 mm were found. A maximum ice water content of 0.05 g m−3 was observed and an effective radius of about 90 μm. In contrast the aged outflow events were more diluted and showed a maximum number concentration of 0.03 cm−3, an ice water content of 2.3 × 10−4 g m−3, an effective radius of about 18 μm, while the largest particles had a maximum dimension of 61 μm.
Close to the tropopause subvisual cirrus were encountered four times at altitudes of 15 km to 16.4 km. The mean ice particle number concentration of these encounters was 0.01 cm−3 with maximum particle sizes of 130 μm, and the mean ice water content was about 1.4 × 10−4 g m−3. All known in-situ measurements of subvisual tropopause cirrus are compared and an exponential fit on the size distributions is established in order to give a parameterisation for modelling.
A comparison of aerosol to ice crystal number concentrations, in order to obtain an estimate on how many ice particles result from activation of the present aerosol, yielded low activation ratios for the subvisual cirrus cases of roughly one cloud particle per 30 000 aerosol particles, while for the MCS outflow cases this resulted in a high ratio of one cloud particle per 300 aerosol particles.
Projections from coarse-grid global circulation models are not suitable for regional estimates of water balance or trends of extreme precipitation and temperature, especially not in complex terrain. Thus, downscaling of global to regionally resolved projections is necessary to provide input to integrated water resources management approaches for river basins like the Upper Danube River Basin (UDRB) and the Upper Brahmaputra River Basin (UBRB).
This paper discusses the application of the regional climate model COSMO-CLM as a dynamical downscaling tool. To provide accurate data the COSMO-CLM model output was post-processed by statistical means. This downscaling chain performs well in the baseline period 1971 to 2000. However, COSMO-CLM performs better in the UDRB than in the UBRB because of a longer application experience and a less complex climate in Europe.
Different climate change scenarios were downscaled for the time period 1960–2100. The projections show an increase of temperature in both basins and for all seasons. The values are generally higher in the UBRB with the highest values occurring in the region of the Tibetan Plateau. Annual precipitation shows no substantial change. However, seasonal amounts show clear trends, for instance an increasing amount of spring precipitation in the UDRB. Again, the largest trends for different precipitation statistics are projected in the region of the Tibetan Plateau. Here, the projections show up to 50% longer dry periods in the months June to September with a simultaneous increase of about 10% for the maximum amount of precipitation on five consecutive days. For the Assam region in India, the projections also show an increase of 25% in the number of consecutive dry days during the monsoon season leading to prolonged monsoon breaks.
Towards the goal to understand the role of land-surface processes over the Indian sub-continent, a series of soil-moisture sensitivity simulations have been performed using a non-hydrostatic regional climate model COSMO-CLM. The experiments were driven by the lateral boundary conditions provided by the ERA-Interim (ECMWF) reanalysis. The simulation results show that the pre-monsoonal soil moisture has a significant influence on the monsoonal precipitation. Both, positive and negative soil-moisture precipitation (S-P) feedback processes are of importance. The negative S-P feedback process is especially influential in the western and the northern parts of India.