270 research outputs found
Ocean surface wave patterns on TerraSAR-X images and follow-on applications
The TerraSAR-X (TS-X) satellite provides images of wave patterns at the ocean surface which are of great scientific value. With the relatively low orbit of the platform, SAR specific non-linear imaging effects of the moving sea surface play a minor role. As a result, TS-X is able to image ocean waves down to around ~30 m length. Data on the ocean wavelength and wave direction are inferred directly from the image spectra, i.e. without inversion techniques.
In the Stripmap mode, TS-X image sequences may extend in length up to several hundred kilometres. Detecting the spatial variation of sea state parameters is the basis for different follow-on applications. We present selected use cases including the validation of sea state forecast models and a recent study on wave properties in the marginal ice zone. Another potential application included in our contribution, is the estimation of coastal bathymetry from ocean wavelength variations
Linear changes/trends in stratospheric O3 and BrO as seen by SCIAMACHY limb measurements during the decade 2002-2012
This thesis contributes to the understanding of the temporal evolution of stratospheric ozone as well as bromine monoxide, which is an ozone-depleting substance, during the decade 2002-2012. It is based on data from the satellite instrument SCIAMACHY on board of the European research satellite ENVISAT (2002-2012). Vertically resolved time series of ozone and bromine monoxide are investigated. A comprehensive trend analysis is performed using the concept of linear changes/trends. Long-term changes exhibited by the time series are identified and quantified. They are confirmed by instrument comparisons between SCIAMACHY and other measurements. Consistent with a decline of the stratospheric halogen load, decreases of BrO were found throughout the lower stratosphere. Increases of ozone in the upper stratosphere support the onset of an ozone recovery. In addition, an increase in the lower stratosphere as well as a pronounced decrease in the middle stratosphere were detected in tropical ozone. This co-occurrence of positive and negative changes was, until recently, a rather unexpected phenomenon
Seasonal and diurnal variations of dust storms in Martian Year 36 based on the EMM-EXI database
Peer reviewe
Comparing wavelengths simulated by the coastal wave model CWAM and TerraSAR-X satellite data
The accuracy of the high resolution coastal wave forecast model CWAM is validated on the basis of sea state information from satellite images of TerraSAR-X (TS-X). Employing 2-dimensional Fast Fourier Transformation, image spectra are derived from TS-X and locally varying
patterns of the peak wavelengths are provided. Subsequently, wavelength comparisons are performed between a typical set of TS-X scenes acquired in December 2013 over the German Bight and the model hindcasts. This results mostly in reasonable agreement. Potential wave modelling errors are discussed as well
Sea State from High Resolution Satellite-borne Synthetic Aperture Radar Imagery
The Sea Sate Processor (SSP) was developed for fully automatic processing of high-resolution Synthetic Aperture Radar (SAR) data from TerraSAR-X (TS-X) satellites and implemented into the processing chain for Near Real Time (NRT) services in the DLR Ground Station "Neustrelitz". The NRT chain was organised and tested to provide the processed data to the German Weather Service (DWD) in order to validate the new coastal forecast model CWAM (Coastal WAve Model) in the German Bight of the North Sea with 900 m horizontal resolution. The NRT test-runs, wherein the processed TS-X data were transferred to DWD and then incorporated into forecast products reach the best performance about 10 min for delivery of processed TS-X data to DWD server after scene acquisition.
To do this, a new empirical algorithm XWAVE_C (C = coastal) for estimation of significant wave height from X-band satellite-borne SAR data has been designed for coastal applications. The algorithm is based on the spectral analysis of subscenes and the empirical model function yields an estimation of integrated sea state parameters directly from SAR image spectra without transformation into wave spectra. To provide the raster coverage analysis, the SSP intends three steps of recognising and removing the influence of non-sea-state-produced signals in the Wadden Sea areas such as ships, buoys, dry sandbars as well as nonlinear SAR image distortions produced by e.g. short and breaking waves.
For the validation, more than 150 TS-X StripMap scene sequences with a coverage of ~30 km × 300 km across the German Bight since 2013 were analysed and compared with in situ Buoy measurements from 6 different locations. On this basis, the SSP autonomous processing of TS-X Stripmap images has been confirmed to have a high accuracy with an error RMSE = 25 cm for the total significant wave height
Kompetenzentwicklung für und in der digitalen Arbeitswelt
(1)Das digital-vernetzte Arbeitsleben erfordert neuartige und veränderte Kompetenzen, die sich in sechs Kompetenzfeldern differenzieren lassen: Personenbezogene Kompetenzen, soziale Kompetenzen, MMI-Kompetenzen, Prozess-Kompetenzen, Lösungs-Kompetenzen und Strategische Kompetenzen.
(2)Deren Förderung und Entwicklung im Unternehmenskontext darf nicht unabhängig von den gegebenen Kontextfaktoren (z.B. Organisation, Führung, Metrik etc.) gesehen werden; jeder Kontextfaktor beeinflusst den Prozess der Kompetenzentwicklung fördernd oder hemmend.
(3)Für jeden Kontextfaktor lassen sich individuell Ziel und Maßnahmen definieren, um zu einer Kompetenzentwicklung beitragen zu können.
(4)In Bezug auf die Kompetenzentwicklung beeinflussen sich die Kontextfaktoren gegenseitig, so dass die jeweiligen Ziele und Maßnahmen aufeinander abzustimmen sind.
(5)Die übergreifende, betriebswirtschaftliche, auf ein industrielles Arbeitssystem abgestimmte Metrik prägt zudem jeden einzelnen Kontextfaktor und beeinflusst somit den Prozess der Kompetenzentwicklung direkt und indirekt.
(6)Übergreifendes Ziel muss daher die Weiterentwicklung bzw. Anpassung der vorherrschenden, industriell geprägten Metrik als Instrument der Orientierung und als Rahmen für die digital-vernetzte Arbeitswelt sowie die Entwicklung der erforderlichen Kompetenzen für diese Arbeitswelt sein
Future Realized Return, Firm-Specific Risk and the Implied Expected Return
ArticleThis is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.In this paper, we propose a novel approach to derive a firm-specific measure of expected
return. It builds on recent accounting-based valuation models developed by Clubb (2013) and
Ashton and Wang (2013). The measure is intrinsically linked to commonly used financial
ratios including book-to-market, (forward) earnings yield, dividend-to-price as well as growth
and past returns. The empirical evidence shows that it is significantly positively associated
with future realized stock returns and also significantly correlates with commonly used risk
characteristics in a theoretically predictable manner. The results are likely to be of interest to
practitioners and managers in making capital allocation decisions and to academics in need of
proxies for firms’ discount rates and expected returns
Terminal valuations, growth rates and the implied cost of capital
This article is published with open access at Springerlink.comWe develop a model based on the notion that prices lead earnings,
allowing for a simultaneous estimation of the implied growth rate and the cost of
equity capital for US industrial sectors. The major difference between our approach
and that in prior literature is that ours avoids the necessity to make assumptions
about terminal values and consequently about future growth rates. In fact, growth
rates are an endogenous variable, which is estimated simultaneously with the
implied cost of equity capital. Since we require only 1-year-ahead forecasts of
earnings and no assumptions about dividend payouts, our methodology allows us to
estimate ex ante aggregate growth and risk premia over a larger sample of firms than
has previously been possible. Our estimate of the risk premium being between 3.1
and 3.9 % is at the lower end of recent estimates, reflecting the inclusion of these
short-lived companies. Our estimate of the long run growth is from 4.2 to 4.7 %
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