The contribution of power production from PV systems to the electricity supply is constantly increasing. An efficient use of the fluctuating solar power production will highly benefit from forecast information on the expected power production, as a basis for management of the electricity grids and trading on the energy market. We present and evaluate the regional PV power prediction system of University of Oldenburg and Meteocontrol GmbH providing forecasts of up to 2 days ahead with hourly resolution. The proposed approach is based on forecasts of the global model of the European Centre for Medium‐Range Forecasts (ECMWF). It includes a post‐processing procedure to derive optimised, site‐specific irradiance forecasts and explicit physical modelling steps to convert the predicted irradiances to PV power. Finally, regional power forecasts are derived by up‐scaling from a representative set of PV systems. The investigation of proper up‐scaling is a special focus of this paper. We introduce a modified up‐scaling approach, modelling the spatial distribution of the nominal power with a resolution of 1° × 1°. The operational PV power prediction system is evaluated in comparison to the modified up‐scaling approach for the control areas of the two German transmission system operators ‘transpower’ and ‘50 Hertz’ for the period 2.7.2009–30.4.2010. rmse values of the operational forecasts are in the range of 4–5% with respect to the nominal power for intra‐day and day‐ahead forecast horizons. Further improvement is achieved with the modified up‐scaling approach. Copyright © 2010 John Wiley & Sons, Ltd.

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The electron density in the edge, divertor and X-point regions of Alcator C-Mod [Proceedings of the IEEE 13th Symposium on Fusion Engineering (Institute of Electrical and Electronic Engineers, New York, 1990), Vol. 1, p. 13] has been measured using the Stark broadening of high-n (n=8 through 11) transitions of the Balmer series of deuterium. These measurements have been made during typical single null, diverted operation and during gas-puffing through capillaries located within the first wall and divertor. Electron densities up to 1.6×1021 m−3 have been measured in the X-point region and slightly lower densities (5−7×1020 m−3) have been measured in the divertor and edge regions. These results are factors of 2 to 5 larger than the density measurements from the CO2 laser interferometer system in the main chamber (3×1020 m−3) and comparable with probe measurements in the divertor. The ratios of the widths of adjacent lines within the Balmer series have been compared with ratios calculated for the Stark broadening of these lines. These transitions can be used to measure electron densities from 3×1019 to 2×1021 m−3 with a modest resolution spectrograph [(Δλinst=1 Å full width at half maximum)].

Abstract. During the TROCCINOX field experiments in February-March 2004 and February 2005, airborne in situ measurements of NO, NO y , CO, and O 3 mixing ratios and the J(NO 2 ) photolysis rate were carried out in the anvil outflow of thunderstorms over southern Brazil. Both tropical and subtropical thunderstorms were investigated, depending on the location of the South Atlantic convergence zone. Tropical air masses were discriminated from subtropical ones according to the higher equivalent potential temperature ( e ) in the lower and mid troposphere, the higher CO mixing ratio in the mid troposphere, and the lower wind velocity in the upper troposphere within the Bolivian High (north of the subtropical jet stream). During thunderstorm anvil penetrations, typically at 20-40 km horizontal scales, NO x mixing ratios were distinctly enhanced and the absolute mixing ratios varied between 0.2-1.6 nmol mol −1 on average. This enhancement was mainly attributed to NO x production by lightning and partly due to upward transport from the NO x -richer boundary layer. In addition, CO mixing ratios were occasionally enhanced, indicating upward transport from the boundary layer. For the first time, the composition of the anvil outflow from a large, long-lived mesoscale convective system (MCS) advected from northern Argentina and Uruguay was investigated in more detail. Over a horizontal scale of about 400 km, NO x , CO and O 3 absolute mixing ratios were significantly enhanced in these air masses in the range of 0.6-1.1, 110-140 and 60-70 nmol mol −1 , respectively. AnalysesCorrespondence to: H. Huntrieser (heidi.huntrieser@dlr.de) from trace gas correlations and a Lagrangian particle dispersion model indicate that polluted air masses, probably from the Buenos Aires urban area and from biomass burning regions, were uplifted by the MCS. Ozone was distinctly enhanced in the aged MCS outflow, due to photochemical production and entrainment of O 3 -rich air masses from the upper troposphere -lower stratosphere region. The aged MCS outflow was transported to the north, ascended and circulated, driven by the Bolivian High over the Amazon basin. In the observed case, the O 3 -rich MCS outflow remained over the continent and did not contribute to the South Atlantic ozone maximum.

We present a complete calculation of the electroweak O(α 3 αs) corrections to three-jet production and related event-shape observables at electron-positron colliders. The Z-boson resonance is described within the complex-mass scheme, rendering the calculation valid both in the resonance and off-shell regions. Higher-order initial-state radiation is included in the leading-logarithmic approximation. We properly account for the corrections to the total hadronic cross section and for the experimental photon isolation criteria. To this end we implement contributions of the quarkto-photon fragmentation function both in the slicing and subtraction formalism. The effects of the electroweak corrections on various event-shape distributions and on the three-jet rate are studied. They are typically at the few-per-cent level, and remnants of the radiative return are found even after inclusion of appropriate cuts.

Detailed measurements and transport analysis of divertor conditions inAlcator C-Mod [Phys. Plasmas 1, 1511 (1994)] are presented for a range of line-averaged densities, 0.7 < fie < 2.2 x 1020 M-3 . Three parallel heat transport regimes are evident in the scrape-off layer: sheath-limited conduction, high-recycling divertor and detached divertor, which can coexist in the same discharge. Local cross-field pressure gradients are found to scale simply with local electron temperature. This scaling is consistent with classical electron parallel conduction being balanced by anomalous cross-field transport (XI -0.1 m 2 s-1) proportional to the local pressure gradient. 60 to 80% of divertor power is radiated in attached discharges, approaching 100% in detached discharges. Detachment occurs when the heat flux to the plate is low and the plasma pressure is high (Te -5 eV). High neutral pressures in the divertor are nearly always present (1 -20 mTorr), sufficient to remove parallel momentum via ion-neutral collisions.

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Large-scale grid integration of photovoltaic (PV) power requires forecast information on the expected PV power for all levels of electricity supply systems. Regional PV power forecasts provide the basis for grid management and trading of PV power on the energy market. On the local scale, smart grid applications define a sector with increasing need for PV power forecasting. Here, we present and evaluate new and enhanced features of the regional PV power prediction system of the University of Oldenburg and Meteocontrol GmbH. The basic approach to predict regional PV power with an hourly resolution of up to 2 days ahead is based on global model forecasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) and includes explicit physical modelling steps to convert the predicted solar irradiance into PV power. The proposed new, empirical approach aims at improving PV power predictions during periods of snow cover, where the original forecasts usually show a strong overestimation of the power production. The approach integrates measured PV power production data and additional meteorological forecast parameters. The new approach for power forecasting has been evaluated against the operational forecasts for the control area of the German transmission system operator '50Hertz Transmission GmbH' for a 1-year period. The root mean square error (rmse) of the forecasts could be reduced from 4.9% to 3.9% for intra-day forecasts, and from 5.7% to 4.6% for day-ahead forecasts. The largest improvement was found during January, where the rmse could be reduced by more than half by applying the proposed algorithm for snow detection.