نتایج جستجو برای: پایگاه ecmwf

تعداد نتایج: 10960  

2002
MOZHENG WEI ZOLTAN TOTH

Most existing ensemble forecast verification statistics are influenced by the quality of not only the ensemble generation scheme, but also the forecast model and the analysis scheme. In this study, a new tool called perturbation versus error correlation analysis (PECA) is introduced that lessens the influence of the initial errors that affect the quality of the analysis. PECA evaluates the ense...

Journal: :Remote Sensing 2018
Stefano Zecchetto

This paper aims to illustrate and test a method, based on the Two-Dimensional Continuous Wavelet Transform (2D-CWT), developed to extract the wind directions from the Synthetic Aperture Radar (SAR) images. The knowledge of the wind direction is essential to retrieve the wind speed by using the radar-backscatter versus wind speed algorithms. The method has been applied to 61 SAR images from diff...

2014
Wen-Hao Yeh Cheng-Yung Huang Tsen-Chieh Chiu Ming-Quey Chen Jann-Yenq Liu Yuei-An Liou

A three-dimensional ray tracing model with aiming algorithms for global positioning system (GPS) signal is proposed to make simulations conform to the realistic radio occultation (RO) signal propagation. The two aiming algorithms used in this study ensure the initial and end point ray trajectories are located in the prescribed region. In past studies, the ray tracing techniques applied to the R...

2005
Xianglei Huang Brian J. Soden Darren L. Jackson

[1] We use a 20-year record of HIRS radiance measurements to evaluate the fidelity of interannual co-variability of tropical humidity and temperature in the reanalyses and GFDL AM2 simulations. Large inconsistencies between the NCEP and ECMWF reanalyses are found as are disagreements between the reanalyses and AM2 simulations. The largest discrepancies occur in the middle and upper troposphere ...

2003
S. Noël

Global water vapour column amounts have been derived for the first time from measurements of the SCanning Imaging Absorption spectroMeter for Atmospheric CHar-tographY (SCIAMACHY) on the European environmental satellite ENVISAT. For this purpose, two different existing retrieval algorithms have been adapted, namely the Air 5 Mass Corrected Differential Absorption Spectroscopy (AMC-DOAS) which w...

2004
C. Marsigli A. Montani F. Nerozzi T. Paccagnella

Abstract. The limited-area ensemble prediction system COSMO-LEPS has been running operationally at ECMWF since November 2002. Five runs of the non-hydrostatic limited-area model Lokal Modell (LM) are available every day, nested on five selected members of three consecutive 12-h lagged ECMWF global ensembles. The limited-area ensemble forecasts range up to 120 h and LM-based probabilistic produc...

2015
A. C. Spessa R. D. Field F. Pappenberger A. Langner S. Englhart U. Weber T. Stockdale F. Siegert J. W. Kaiser

Large-scale fires occur frequently across Indonesia, particularly in the southern region of Kalimantan and eastern Sumatra. They have considerable impacts on carbon emissions, haze production, biodiversity, health, and economic activities. In this study, we demonstrate that severe fire and haze events in Indonesia can generally be predicted months in advance using predictions of seasonal rainfa...

2002
Aiguo Dai Kevin E. Trenberth

New estimates of freshwater discharge from continents were derived using stream-flow records from the world's largest 921 rivers, supplemented with estimates of discharge from unmonitored areas based on the ratios of runoff and drainage area between the unmonitored and monitored regions. The farthest downstream river-flow data were extrapolated to the river mouth using river transport model sim...

2006
Kerstin Geißler Elena Masciadri

In this paper we present the characterization of all the principal meteorological parameters (wind speed and direction, pressure, absolute and potential temperature) extended up to 25 km from the ground and over two years (2003 and 2004) above the Antarctic site of Dome C. The data set is composed by ’analyses’ provided by the General Circulation Model (GCM) of the European Center for Medium We...

1999
Peter Janssen Jean-Raymond Bidlot

This document is partly based on Chapter III of "Dynamics and Modelling of Ocean Waves" by Komen et al, 1994. For more background information on the fundamentals of wave prediction models this book comes highly recommended. Here, after a historical introduction, we will describe the basic evolution equation, including a discussion of the parametrization of the source functions. This is then fol...

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