Dynamic Power Spectral Analysis of Solar Measurements from Photospheric, Chromospheric, and Coronal Sources

An important aspect in the power spectral analysis of solar variability is the quasistationary and quasiperiodic nature of solar periodicities. In other words, the frequency, phase, and amplitude of solar periodicities vary on time scales ranging from active region lifetimes to solar cycle time scales. Here, researchers employ a dynamic, or running, power spectral density analysis to determine many periodicities and their time-varying nature in the projected area of active sunspot groups (S sub act). The Solar Maximum Mission/Active Cavity Radiometer Irradiance Monitor (SMM/ACRIM) total solar irradiance (S), the Nimbus-7 MgII center-to-wing ratio (R (MgII sub c/w)), the Ottawa 10.7 cm flux (F sub 10.7), and the GOES background x ray flux (X sub b) for the maximum, descending, and minimum portions of solar cycle 21 (i.e., 1980 to 1986) are used. The technique dramatically illustrates several previously unrecognized periodicities. For example, a relatively stable period at about 51 days has been found in those indices which are related to emerging magnetic fields. The majority of solar periodicities, particularly around 27, 150 and 300 days, are quasiperiodic because they vary in amplitude and frequency throughout the solar cycle. Finally, it is shown that there are clear differences between the power spectral densities of solar measurements from photospheric, chromospheric, and coronal sources

Influence of the isomeric composition of the acceptor on the performance of organic bulk heterojunction P3HT:bis-PCBM solar cells

We synthesized three isomeric subpopulations of bisadduct analogues of [6,6]-phenyl-C61-butyric acid methyl ester (bis-PCBM) via tether-directed control. Bulk heterojunction solar cells prepared using these isomers together with poly(3-hexylthiophene) (P3HT) resulted in an increase of Jsc from 72.4 to 79.6 A m-2, and an improvement in fill factor from 0.55 to 0.62, both with a Voc of 0.72 V resulting in an overall enhancement of the power conversion efficiency (PCE) from 2.9% to 3.5%, compared to conventional bis-PCBM.

Disasters and climate change: analyses and methods for projecting future losses from extreme weather

Vellinga, P. [Promotor]Aerts, J.C.J.H. [Promotor

Catalogue of programmes and policies related to regional development and infrastructure ("Baseline assessment")

A baseline assessment, an impact and vulnerability assessment of EU investments in infrastructure and a mitigation potential analysis shall help to generate policy options, which will be appraised in the subsequent phase of the project. In this report we set the stage for the further tasks. The report identifies critical questions and resulting implications concerning the assessment of impacts and vulnerability of infrastructure and infrastructure investments in the EU; describes EU Cohesion Policy; o details the current design of the Structural Funds; describes the issue of environmental and climate change mainstreaming from an EU perspective; presents an exploratory analysis of evidence for climate policy integration based on Member States National Strategic Reference Frameworks (NSRFs); and finally addresses the main research and knowledge gaps that will be addressed in subsequent research within this work package

Detecting the long-term impacts from climate variability and increasing water consumption on runoff in the Krishna river basin (India)

Variations in climate, land-use and water consumption can have profound effects on river runoff. There is an increasing demand to study these factors at the regional to river basin-scale since these effects will particularly affect water resources management at this level. This paper presents a method that can help to differentiate between the effects of man-made hydrological developments and climate variability at the basin scale. We show and explain the relation between climate, water consumption and changes in runoff for the Krishna river basin in central India. Runoff under climate variability and increasing water consumption for irrigation and hydropower is simulated for the last 100 years using the STREAM water balance model. Runoff under climate variability is shown to vary only by about 14–34 mm (6–15%). It appears that reservoir construction after 1960 and increasing water consumption has caused a persistent decrease in annual runoff of up to approximately 123 mm (61%). Variation in runoff under natural climate variability only would have decreased over the period under study, but we estimate that increasing water consumption causes about two thirds of the current runoff variability

Inundation scenarios for flood damage evaluation in polder areas

We present an approach for flood damage simulations through the creation of a comparatively large number of inundation scenarios for a polder area, using a high-resolution digital elevation model. In particular, the method could be used for detailed scenario studies of the impact of future socioeconomic and climatic developments on flood risks. The approach is applied to a case-study area in the south of the Netherlands along the river Meuse. The advantage of our approach is that a large number of potential flood events can be created relatively fast without hydrodynamical calculations, and that it can be applied to high-resolution elevation models and for large areas. The large number of flood scenarios and the high horizontal resolution reduces at least part of the uncertainties encountered in flood loss modelling. The approach with a low horizontal-resolution (100-m) for loss modelling results in an overestimation of losses by up to 22% for high density urban areas, and underestimation of 100% for infrastructure, compared to the high-resolution (25-m). Loss modelling at 5-m horizontal resolution shows that aggregate losses may be overestimated by some 4.3%, compared to the 25-m resolution. The generation of a large variety of inundation scenarios provides a basis for constructing loss probability curves. The calculated range and expected values of damages compare reasonably well with earlier independent estimates