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Régis Borde, Marie Doutriaux-Boucher, Greg Dew, and Manuel Carranza

semitransparent and/or multilayer clouds ( Roebeling et al. 2013 ). It is also the parameter that most impacts the quality of the AMVs, and therefore their role in NWP assimilation. Several methods are used to set the AMV altitude, depending on the type of target tracked. For opaque clouds the measured window channel IR10.8 brightness temperature is matched against a collocated temperature profile obtained from NWP model forecast data. Specific methods are applied for low-level AMVs that include setting the

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Masami Sakamoto and John R. Christy

section, we briefly describe JRA-25 and ERA-40, focusing on their differences. We then provide a review of the microwave-based observational products. This will provide readers with a basic knowledge of the datasets. [Details are found in Onogi et al. (2007) , Uppala et al. (2005) , Christy et al. (2003) , and Mears et al. (2003) .] a. Observations and forecast/data assimilation systems in JRA-25 and ERA-40 1) Observations JRA-25 was constructed using the operational numerical weather prediction

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James D. Means and Daniel Cayan

improve operational forecasting and possibly result in more accurate forecasts of incipient flooding situations. Acknowledgments We thank Mary Tyree and Peng Fang for their computing assistance in the preparation of these results, and Yehuda Bock and the Scripps Orbit and Permanent Array Center for providing the zenith delays. We would also like to thank the anonymous reviewers for taking the time and effort to make this a better paper. This work was supported by a grant from the California Energy

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Anthony C. L. Lee

630 JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY VOLUME3An Operational System for the Remote Location of Lightning Flashes Using a VLF Arrival Time Difference Technique ANTHONY C. L. LEEMeteorological O.~ce, Bracknell, Berkshire, RG12 2SZ, United Kingdom(Manuscript received 29 October 1985, in final form 27 April 1986)ABSTRACT An operational system for the remote location of lightning flashes at ranges of thousands

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Laurent Menut and Bertrand Bessagnet

photochemical reactions are thus difficult to constrain), particulate matter mass (the aerosol speciation is often missing), or aerosol optical depth (an estimate of the radiative impact but without information about the chemical composition or the altitude of the layers). Today, numerous systems exist and, as recent examples, there is the Prévisions et Observations de la Qualité de l’Air en France et en Europe (PREV’AIR) system (the first European operational air quality forecast; Honoré et al. 2008 ) and

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Andrea Storto, Paolo Oddo, Elisa Cozzani, and Emanuel Ferreira Coelho

1. Introduction Satellite altimetry has revolutionized our knowledge of the ocean dynamics since more than two decades through systematic provision of information on both eddy and finescale dynamics ( Fu et al. 2010 ; Morrow et al. 2017 ) and large basin-scale circulation ( Stammer 1997 ). Consequently, the impact of altimetry observations has proven dramatic in both global ( Verrier et al. 2017 ) and regional ( Pujol et al. 2010 ) operational analysis and forecast systems, representing a

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Ross N. Hoffman, Christopher Grassotti, and S. Mark Leidner

.1 dB using spatially and temporally collocated QuikSCAT and SeaWinds measurements, and both National Centers for Environmental Prediction (NCEP) and European Centre for Medium-Range Weather Forecasts (ECMWF) operational surface analyses. b. WSI NEXRAD precipitation data The WSI NEXRAD data used in this study are named the NOWrad SPECIAL precipitation product, which we routinely download and archive in near–real time by a dedicated WSI ground station. These data are produced on a regular ≈2 km × 2

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R. Pacione and F. Vespe

since the timeliness requirement is 1–2 months. In order to perform an operational weather forecast, it is required that 75% of the observations are available within 1 h, 45 min. Therefore, a fast and reliable data flow from GPS observations to ZTD estimation has to be set up (see Fig. 1 ), and predicted GPS orbits can be used. The IGS UltraRapid orbits, delivered twice a day, have enough accuracy (∼25 cm or better; Springer and Hugentobler 2001 ) for meteorological application, although “bad

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M. Benkiran and E. Greiner

production during melting are parameterized ( Greiner et al. 2006 ). The daily surface forcing comes from the ECMWF operational outputs. The 12–24-h forecasts from the ECMWF 0-h run are cumulated with the 12–24-h forecasts from the 12-h run in order to have the best balanced daily wind stress, heat flux, precipitation, and evaporation. Hence, there is no diurnal signal in this configuration. Thirty-two climatological runoffs (including the Baltic outflow) are input at the surface. There is no restoring

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Mario Adani, Srdjan Dobricic, and Nadia Pinardi

carried out for the time period of 1985–2007 using all of the available historical in situ and satellite data and the operational forecasting model calibrated and validated over the past 10 yr ( Pinardi et al. 2003 ; Tonani et al. 2008b ). The Mediterranean Sea is a semienclosed sea located between 5°E and 36°W and between 32° and 46°N with average depth of 1500 m. It communicates with the Atlantic through the Strait of Gibraltar and with the Marmara Sea through the Dardanelles. The Mediterranean

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