Search Results

You are looking at 1 - 10 of 1,318 items for :

  • Journal of Atmospheric and Oceanic Technology x
  • All content x
Clear All
A. J. Bennett, C. Gaffard, J. Nash, G. Callaghan, and N. C. Atkinson

sensor sites over Europe receiving between 5 and 15 kHz, centered at 9.8 kHz ( Lagouvardos et al. 2009 ). ZEUS previously included seven additional sensors in Africa, but these operated independently from the European subnetwork to avoid system overload. ZEUS has also been used in combination with sensors in Brazil and Africa [Sferics Timing and Ranging Network (STARNET)]. Given that the ATD technique involves correlation of the whole waveform, the time differences retrieved will be sensitive to any

Full access
Jovan Bojkovski, Janko Drnovšek, Drago Groselj, Joško Knez, and Gaber Begeš

:2005 standard for calibration and testing laboratories, ILC should be regularly performed at least once per five years as crucial element for confirming quality of measurement results. This ILC was organized by the laboratory in the Slovenian Environment Agency (ARSO) from the Regional Instrument Centre (RIC) in Regional Association (RA) VI in Europe, which acted as the coordinator and reference laboratory for pressure, temperature, and humidity. The University of Ljubljana, Faculty of Electrical

Open access
Katja Friedrich, Urs Germann, and Pierre Tabary

many fruitful discussions regarding polarimetry. The authors thank Kim DoKhac of Météo-France for assisting in the acquisition of the radar data. Clarity and understanding of the analysis have been improved by many fruitful comments and suggestions made by the four anonymous reviewers to whom we also express our thanks. This research is part of the collaboration between Switzerland and France in the INTERREG IIIa project Radar de Franche-Comté. It is cofunded by the European Union, the French

Full access
Magnus Hieronymus, Jenny Hieronymus, and Fredrik Hieronymus

1. Introduction Global sea level rise is perhaps the most severe consequence of the ongoing climate change. The global mean sea level rise today is around 3 mm yr −1 , and it is projected to increase fourfold or more until the end of the century in the RCP8.5 scenario ( Church et al. 2013 ; DeConto and Pollard 2016 ). The economic consequences for Europe in terms of flood damage from such a scenario were recently estimated by Vousdoukas et al. (2018) . They estimated that, unless coastal

Full access
Adam Krężel and Marcin Paszkuta

Development in Warsaw, Poland, Project 0423/R/T02/2008/04; Polish Ministry of Science and Higher Education Project 2816/B/P01/2009/36; and the European Union through the European Regional Development Fund Project Satellite Monitoring of the Baltic Sea Environment (SatBaltyk) POIG 01.01.02-22-011/09. REFERENCES Di Vittorio, A. , and Emery W. , 2002 : An automated, dynamic threshold cloud-masking algorithm for daytime AVHRR images over land . IEEE Trans. Geosci. Remote Sens. , 40 , 1684 – 1694

Full access
Brett F. Thornton, Axel Horst, Daniel Carrizo, Henry Holmstrand, Per Andersson, Patrick M. Crill, and Örjan Gustafsson

Abstract

A system was developed for collecting from the ambient atmosphere the methyl halides CH3Cl and CH3Br in quantities sufficient for chlorine and bromine isotope analysis. The construction and operation of the novel cryogenic collection system (cryosampler) and sample purification system developed for this task are described. This study demonstrates the capability of the cryosampler by quantifying the CH3Cl and CH3Br collected from atmospheric samples and the nonfractionating bromine isotope fingerprint of CH3Br from synthetic air samples of controlled composition. An optimized cryosampler operation time of 4 h at a flow rate of 15 L min−1 is applied to yield the nearly 40 ng required for subsequent δ81Br-CH3Br analyses. The sample purification system is designed around a packed column gas chromatography–quadropole–mass spectrometry (GCqMS) system with three additional cryotraps and backflushing capacity. The system's suitability was tested by observing both the mass recovery and the lack of Δ81Br isotope fractionation induced during sample purification under varying flow rates and loading scenarios. To demonstrate that the entire system samples and dependably delivers CH3Br to the isotope analysis system without inducing isotope fractionation, diluted synthetic air mixtures prepared from standard gases were processed through the entire system, yielding a Δ81Br-CH3Br of +0.03‰ ± 0.10‰ relative to their starting composition. Finally, the combined cryosampler–purification and analysis system was applied to demonstrate the first-ever δ81Br-CH3Br in the ambient atmosphere with two samples collected in the autumn of 2011, yielding −0.08‰ ± 0.43‰ and +1.75‰ ± 0.13‰ versus standard mean ocean bromide for samples collected at a suburban Stockholm, Sweden, site.

Full access
Ad Stoffelen

1. Introduction It is not simple to obtain an accurate absolute calibration for a scatterometer. For the calibration of the European Remote Sensing Satellite (ERS) scatterometers ( Attema 1991 ), the European Space Agency (ESA) planned to perform the absolute calibration by a controlled radar return to the scatterometer from transponders when the transponders are illuminated by one of the three scatterometer radar beams. In addition, an interbeam comparison was planned over the rain forest

Full access
Sven-Erik Enno, Graeme Anderson, and Jacqueline Sugier

1. Introduction High-quality real-time lightning data are increasingly important for severe weather monitoring and forecasting. Most of the European countries are covered by a lightning location system (LLS), either operated by the national meteorological service or by a private company or other organization. There is a trend toward international cooperation of ground-based and satellite-based (geostationary) lightning detection. For example, in 2001 several countries started a cooperation

Full access
E. Obligis, L. Eymard, N. Tran, S. Labroue, and P. Femenias

1. Introduction The European satellite Envisat was launched from Kourou (French Guyana) on 1 March 2002. It is equipped with many instruments dedicated to the observation of the earth environment. Among them, the Radar Altimeter (RA)-2 is used over sea to determine the ocean topography, thus supporting the research of sea level and ocean circulation. To correct the altimeter range for water vapor path delay over ocean, a nadir-looking microwave radiometer has been added to the mission, as for

Full access
S. Caires and A. Sterl

1. Introduction The European Centre for Medium-Range Weather Forecasts (ECMWF) has recently completed the computations of the 40-yr ECMWF Re-Analysis (ERA-40) dataset, a reanalysis of global variables, among which ocean surface wind waves from September 1957 to August 2002 (45 yr) are included. The reanalysis was produced by ECMWF’s Integrated Forecasting System, which uses variational data assimilation. In terms of sea state data, this reanalysis was the first in which an ocean wind–wave model

Full access