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Meteorological Phenomena (meteorological + phenomenon)

Distribution by Scientific Domains
Engineering42%

Selected Abstracts

The LEAD Portal: a TeraGrid gateway and application service architecture

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6 2007
Marcus Christie
Abstract The Linked Environments for Atmospheric Discovery (LEAD) Portal is a science application portal designed to enable effective use of Grid resources in exploring mesoscale meteorological phenomena. The aim of the LEAD Portal is to provide a more productive interface for doing experimental work by the meteorological research community, as well as bringing weather research to a wider class of users, meaning pre-college students in grades 6,12 and undergraduate college students. In this paper, we give an overview of the LEAD project and the role that LEAD portal is playing in reaching its goals. We then describe the various technologies we are using to bring powerful and complex scientific tools to educational and research users. These technologies,a fine-grained capability based authorization framework, an application service factory toolkit, and a Web services-based workflow execution engine and supporting tools,enable our team to deploy these once inaccessible, stovepipe scientific codes onto a Grid where they can be collectively utilized. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Measurement of atmospheric water vapour on the ground's surface by radio waves

HYDROLOGICAL PROCESSES, Issue 11 2001
Tokuo Kishii
Abstract Water vapour in the atmosphere and various meteorological phenomena are essential to the understanding of the mechanism of the water cycle. However, it is very difficult to observe water vapour in the atmosphere because the quantities are usually observed at a single point not over long intervals or in a specific plane or volume. Accordingly, the use of radio waves is considered to be necessary to observe water vapour. Radio waves can be transmitted over long intervals and across large areas, and generally speaking, the characteristics of radio waves change due to material in the atmosphere, especially water vapour. Usually absorption is used to observe the quantity of water vapour. But the relationship between absorption and the quantity of water vapour is not linear, so we try to utilize the phase difference between two radio waves as an alternative method. First, the relationship between the phase delay and the water vapour was induced by a physical equation and the resulting phase delay was found to be proportional to the quantity of water vapour. Furthermore, the phase difference between two separate points was observed by use of two radio waves in the field, specifically 84 GHz and 245 GHz. For reference and comparison, water vapour density in the atmosphere was simultaneously observed by meteorological observation. As a result, the density of the water vapour was found to be proportional to the phase difference between the two radio waves. The result also shows that this method is able to measure the diurnal changes in water vapour density in each season. Copyright © 2001 John Wiley & Sons, Ltd. [source]

W-band physical layer design issues in the context of the DAVID,DCE experiment,

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2004
Claudio Sacchi
Abstract This paper aims at focusing on the aspects concerning the physical layer design for an innovative satellite communication experiment. Such an experiment, denoted by the acronym DAVID,DCE (Data and Video Interactive Distribution,Data Collection Experiment) is based on the exploitation of the W-band (75,110 GHz) for high-bit-rate satellite transmission. The potential advantages of using of the W-band are mainly related to the great bandwidth availability, and to the absence of interference. Moreover, an expected result of the experiment is a substantive improvement in the communication system's performances in the presence of meteorological phenomena (e.g. rain) as compared with the more conventional Ka-band satellite transmission. On the other hand, problems to be faced concern the non-ideal behaviours of hardware devices employed for high-frequency digital transmission. In particular, carrier recovery and timing recovery are the most crucial signal-processing tasks to be carefully considered in the design of the physical level of the system, because they considerably suffer from hardware impairments. The purpose of this work is to illustrate the proposed solutions in terms of the most critical modulation, demodulation and synchronization design issues, together with the effects of non-ideal behaviours of hardware components on BER performances. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Satellite Precipitation Measurements for Water Resource Monitoring,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2009
Chris Kidd
Abstract:, Satellites offer an unrivaled vantage point to observe and measure Earth system processes and parameters. Observations of meteorological phenomena permit a more holistic view of the weather and climate that is not possible through conventional surface observations. Precipitation (rain and snow) in particular, benefit from such observations since precipitation is spatially and temporally highly variable: conventional gauge and radar measurements tend to be land-based with variable coverage. This paper provides an overview of the satellite systems that provide the observations, the techniques used to derive precipitation from the observations, and examples of the precipitation products available for users to access. [source]

Adverse meteorological phenomena associated with low-level baric troughs in the Alagoas State, Brazil, in 2003

ATMOSPHERIC SCIENCE LETTERS, Issue 3 2010
Luis Ricardo Lage Rodrigues
Abstract Baric troughs were studied over the Alagoas State, Brazil, in 2003. The relationship between these synoptic systems, weekly sea surface temperature anomaly and adverse meteorological phenomena in the Alagoas State, was analyzed. The maximum trough frequency occurred at low levels during the wetter and colder season in the investigated region (June and July). Most of the troughs were observed at 1200 UTC. It was also noted that 87% of the troughs was associated with wavy disturbance in the trade winds on the northwestern periphery of the subtropical South Atlantic High. These troughs were associated with meteorological phenomena in a stable and an unstable atmosphere. Copyright © 2010 Royal Meteorological Society [source]