The intensity of European heatwaves is connected to specific synoptic atmospheric circulation. 5Given the relatively small number of observations, estimates of the connection between the circulation 6 and temperature require ad hoc statistical methods. This can be achieved through the use of analogue 7 methods, which allow to determine a distribution of temperature conditioned to the circulation. 8The computation of analogues depends on a few parameters. In this article, we evaluate the influence of 9 the variable representing the circulation, the size of the domain of computation, the length of the dataset, 10 and the number of analogues on the reconstituted temperature anomalies. We tested the sensitivity of to investigate European summer heatwaves. We found that Z500 is better suited than SLP to simulate 14 temperature anomalies, and that rather small domains lead to better reconstitutions. The dataset length 15 has an important influence on the uncertainty. We conclude by a set of recommendations for an optimal 16 use of analogues to probe European heatwaves.

Abstract. Statistical downscaling is widely used to overcome the scale gap between predictors from numerical weather prediction models or global circulation models and predictands like local precipitation, required for example for medium-term operational forecasts or climate change impact studies. The predictors are considered over a given spatial domain which is rarely optimised with respect to the target predictand location. In this study, an extended version of the growing rectangular domain algorithm is proposed to provide an ensemble of near-optimum predictor domains for a statistical downscaling method. This algorithm is applied to find five-member ensembles of near-optimum geopotential predictor domains for an analogue downscaling method for 608 individual target zones covering France. Results first show that very similar downscaling performances based on the continuous ranked probability score (CRPS) can be achieved by different predictor domains for any specific target zone, demonstrating the need for considering alternative domains in this context of high equifinality. A second result is the large diversity of optimised predictor domains over the country that questions the commonly made hypothesis of a common predictor domain for large areas. The domain centres are mainly distributed following the geographical location of the target location, but there are apparent differences between the windward and the lee side of mountain ridges. Moreover, domains for target zones located in southeastern France are centred more east and south than the ones for target locations on the same longitude. The size of the optimised domains tends to be larger in the southeastern part of the country, while domains with a very small meridional extent can be found in an east-west band around 47 • N. Sensitivity experiments finally show that results are rather insensitive to the starting point of the optimisation algorithm except for zones located in the transition area north of this east-west band. Results also appear generally robust with respect to the archive length considered for the analogue method, except for zones with high interannual variability like in the Cévennes area. This study paves the way for defining regions with homogeneous geopotential predictor domains for precipitation downscaling over France, and therefore de facto ensuring the spatial coherence required for hydrological applications.

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Considering the Mediterranean as a region of high evaporation and low precipitation, evaluations of sinks and sources of moisture and precipitation in the Mediterranean basin have been carried out within the frame of the CIRCE (Climate Change and Impact Research: the Mediterranean Environment) project. Besides these evaluations, residence time and stagnation/ventilation analyses have been carried out to investigate transport to and from the Mediterranean basin and in the basin itself. A Lagrangian moisture diagnosis method calculating budgets of evaporation minus precipitation was applied to a 5.5 year (October 1999–April 2005) trajectory data set and evaluated for eight representative Mediterranean Regions Of Interest (ROI). The Mediterranean basin has been identified as a major source of moisture and precipitation to the surrounding land area and to the basin itself. Main regions of stagnation, i.e. the Po basin, have been defined on a seasonal basis through residence time analysis. Evaluation of the transport to and from the basin shows that the Mediterranean is a crossroad of airstreams where air enters mainly from the northwest and continues in two separate streams, one going southwest over North Africa into the trade wind zone and the other one to the northeast through Central Asia

these figures, we can see that the return loss is better than 19.5 dB, the gain is between 8.1 and 9.36 dB, and the axial ratio is between 2.30 and 4.41 dB. CONCLUSION AND DISCUSSIONSWe are in the process of designing an economical electronicallyscanned antenna array with quasi-hemispheric coverage for Inmarsat mobile communications. In this paper, we have presented the design of an electromagnetically-coupled patch antenna with circular polarization for such an array application. The Ensemble CAD tool has been used to simulate the antenna. Compared with similar antennas reported, this antenna covers a wider bandwidth from 1.525 to 1.661 GHz. We have chosen a simpler feeding structure in order to save the otherwise limited space for the beam-forming networks. Further, the feeding circuit and antenna are on the same side of the ground plane, which in the array situation leaves the volume underneath the antenna array for the power predivider, the duplexer, and the LNA. The return loss is better than 19.5 dB, the gain is between 8.1 and 9.36 dB, and the axial ratio is between 2.30 and 4.41 dB.The highest axial ratio is about 1.7-dB higher than the highest axial ratio of Karmakar and Bialkowski's sample antenna, which is 2.7 dB at 1.525 GHz. This can lead to at most a 0.3-dB difference in the polarization-mismatch factor. The lowest gain in the operation band is also 0.5-dB lower. A possible reason for this is the different material used. In our case, the dielectric constant is higher and therefore the patch is slightly smaller. The loss tangent of our material might be higher as well. Both cases will cause the gain to decrease. We will consider using a different substrate in our future designs. ACKNOWLEDGMENTPart of this work was finished in Laval University, Quebec, Canada. We would like to thank Prof. Michel Lecours and Mr. Claude Vergnolle for their help. INTRODUCTIONThe boundary conditions which electric and magnetic fields have to satisfy on the surfaces of the object play an important role in electromagnetic scattering problems. One of these conditions is called as the impedance boundary condition (IBC), which gives a relation between tangential electric and magnetic field vectors on a given surface in terms of a coefficient called a surface impedance. Leontovich [1] and Wait [2] used this type of boundary condition firstly. The simplest form of the IBC is the standard impedance boundary condition (SIBC), which is used to model coatings and lossy dielectrics [3]. Generally, the surface impedance appearing in the SIBC is assumed to be independent of the location and associated with a constant coefficient [3,4]. On the other hand, when a more accurate SIBC is considered, the surface impedance may be a function of location [5]. For example, when the inhomogeneous earth surface composed of different parts, such as rocky soil, sand, forest, sea, and so forth, it is modeled by an SIBC. Scattering from canonical structures whose surface satisfy inhomogeneous SIBC have been proposed in [6 -8] and scattering from i...

Analyses of extreme weather events and their impacts often requires big data processing of ensembles of climate model simulations. Researchers generally proceed by downloading the data from the providers and processing the data files "at home" with their own analysis processes. However, the growing amount of available climate model and observation data makes this procedure quite awkward. In addition, data processing knowledge is kept local, instead of being consolidated into a common resource of reusable code. These drawbacks can be mitigated by using a web processing service (WPS). A WPS hosts services such as data analysis processes that are accessible over the web, and can be installed close to the data archives. We developed a WPS named 'flyingpigeon' that communicates over an HTTP network protocol based on standards defined by the Open Geospatial Consortium (OGC) [23], to be used by climatologists and impact modelers as a tool for analyzing large datasets remotely.

Statistical downscaling is widely used to overcome the scale gap between predictors from Numerical Weather Prediction (NWP) models or General Circulation Models (GCMs) and predictands like local precipitation, required for example for medium-term operational forecasts or climate change impact studies. The predictors are considered over a given spatial domain which is rarely optimised with respect to the target predictand location. In this study the geopotential predictor domains used by an analogue downscaling method are optimised for 608 target zones covering France. An extended version of the growing rectangular domain algorithm provides an ensemble of five near-optimum domains for each target zone. All five near-optimum domains are consistently equally skillful based on the Continuous Rank Probability Score. Relevance maps calculated for selected target zones first reveal high skill geopotential regions with specific shapes for locations in south-eastern France compared to the rest of the country. In all cases, the optimised domains tend to include the most relevant area on the relevance maps. The domain centers of the optimised domains are mainly distributed following the geographical location of the target location, but there are apparent differences between the windward and the lee side of mountain ridges. Moreover, domains for target zones located in south-eastern France are centered more east and south than the ones for target locations on the same longitude. The size of the optimised domains tends to be larger in the southeastern part of the country, while domains with a very small meridional extent can be found in a east-west band around 47° N. Sensitivity tests on the archive length for the analogue method show a general robustness except for zones with high interannual variability like in the Cévennes area. Moreover, results appear to be rather unsensitive to the starting point of the optimisation algorithm except for zones located in the transition area north of the zones having optimized domains with a small meridional extent. This study paves the way for defining regions with homogeneous geopotential predictor domains for precipitation downscaling over France