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Time filter

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Tiana-Alsina J.,Polytechnic University of Catalonia | Gutierrez M.A.,Polytechnic University of Catalonia | Gutierrez M.A.,Catalonia Institute for Energy Research IREC | Wurth I.,University of Stuttgart | And 3 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015

This paper addresses a cardanic frame as mechanical-compensation device for a Doppler-wind lidar installed on a floating sea buoy as the 'moving' lidar. From the methodological point of view, the horizontal wind speed (HWS) measured by both a reference lidar (i.e., 'fixed') and a floating lidar (i.e., 'moving') with and without a cardarnic frame is cross-examined by using standard statistical indicators and a compound pendulum model. Performance results are analysed both at laboratory level using a pitch/roll motion-simulation platform and at a sea-test measurement-campaign level some 250-m offshore Barcelona coast. Finally, simulations of the proposed pendulum-based model enables to tune-in and optimize cardanic-frame design parameters. © 2015 IEEE. Source


Saeed U.,Polytechnic University of Catalonia | Rocadenbosch F.,Polytechnic University of Catalonia | Rocadenbosch F.,Institute for Space Studies of Catalonia IEEC | Crewell S.,University of Cologne
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015

A synergetic approach for estimation of the nocturnal stable boundary-layer (SBL) height is presented. Aerosol backscatter from a lidar ceilometer and potential temperature from a microwave radiometer (MWR) are combined by using an extended Kalman filter (EKF). While height-resolved spatial-variance from the ceilometer backscatter signal provides a signature for the stratification of aerosols in the SBL, temperature data from the MWR helps to correctly incorporate information about the thermodynamic stability of atmosphere. The method is applied to data from a Vaisala CT25K ceilometer and a Humidity-and-Temperature Profiler (HAT-PRO) MWR collected during the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany. © 2015 IEEE. Source


Saeed U.,Polytechnic University of Catalonia | Rocadenbosch F.,Polytechnic University of Catalonia | Rocadenbosch F.,Institute for Space Studies of Catalonia IEEC | Crewell S.,University of Cologne
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015

The nocturnal stable boundary-layer height (SBLH) is estimated from the backscatter lidar data by using an adaptive-filtering approach based on an Extended Kalman Filter (EKF). Height-resolved temporal variance of the lidar data is used as the observables for the processing along with the modelling of minimum-variance regions. The filter is initialized by SBLH estimate from a radio-sonde. The method is applied to the Vaisala CT25K ceilometer data collected during the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany. Results are compared with SBLH estimates from a collocated microwave radiometer (MWR) and a good degree of agreement is observed. © 2015 IEEE. Source


Gutierrez M.A.,Polytechnic University of Catalonia | Gutierrez M.A.,Catalonia Institute for Energy Research IREC | Tiana-Alsina J.,Polytechnic University of Catalonia | Bischoff O.,University of Stuttgart | And 3 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015

This paper departs from a preliminary near-shore measurement test campaign hold at El Pont del Petroli (PdP), Barcelona (Spain) where measurements from a Doppler wind-lidar buoy (the 'floating' lidar) are cross-examined against an on-shore reference lidar. From this framework the methodological analysis to intercompare two such lidars in terms of the retrieved Horizontal Wind Speed (HWS) - as key variable - is presented along with an overview of the signal-processing block diagram. Central to this work is to introduce the main error indicators (e.g., bias, RMSE, determination coefficient, absolute error and scatter plots) used to assess the performance of the floating lidar in the campaign. Finally, it is shown that even a basic smoothing procedure on the retrieved 1-s HWS time series is enough to enhance the determination coefficient against the reference lidar Turbulence Intensity (TI). © 2015 IEEE. Source


Fries A.,University of Barcelona | Fries A.,Institute for Space Studies of Catalonia IEEC | Fries A.,Institute of Cosmos science ICC | Castaneda J.,University of Barcelona | And 10 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Java is a commonly used programming language, although its use in High Performance Computing (HPC) remains relatively low. One of the reasons is a lack of libraries offering specific HPC functions to Java applications. In this paper we present a Java-based framework, called DpcbTools, designed to provide a set of functions that fill this gap. It includes a set of efficient data communication functions based on message-passing, thus providing, when a low latency network such as Myrinet is available, higher throughputs and lower latencies than standard solutions used by Java. DpcbTools also includes routines for the launching, monitoring and management of Java applications on several computing nodes by making use of JMX to communicate with remote Java VMs. The Gaia Data Processing and Analysis Consortium (DPAC) is a real case where scientific data from the ESA Gaia astrometric satellite will be entirely processed using Java. In this paper we describe the main elements of DPAC and its usage of the DpcbTools framework. We also assess the usefulness and performance of DpcbTools through its performance evaluation and the analysis of its impact on some DPAC systems deployed in the MareNostrum supercomputer (Barcelona Supercomputing Center). © 2011 SPIE. Source

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