نتایج جستجو برای: synoptic type

تعداد نتایج: 1346527  

Journal: :Journal of environmental quality 2003
Karen G Wayland David T Long David W Hyndman Bryan C Pijanowski Sarah M Woodhams Sheridan K Haack

The relationship between land use and stream chemistry is often explored through synoptic sampling of rivers at baseflow conditions. However, baseflow chemistry is likely to vary temporally and spatially with land use. The purpose of our study is to examine the usefulness of the synoptic sampling approach for identifying the relationship between complex land use configurations and stream water ...

Journal: :The Journal of the Acoustical Society of America 1980

2013
Adriaan M. Dokter Judy Shamoun-Baranes Michael U. Kemp Sander Tijm Iwan Holleman

At temperate latitudes the synoptic patterns of bird migration are strongly structured by the presence of cyclones and anticyclones, both in the horizontal and altitudinal dimensions. In certain synoptic conditions, birds may efficiently cross regions with opposing surface wind by choosing a higher flight altitude with more favourable wind. We observed migratory passerines at mid-latitudes that...

2002
Somnath Baidya Roy Roni Avissar

[1] A high-resolution mesoscale model was used to investigate the impact of deforestation in Amazonia. Coherent mesoscale circulations were triggered by the surface heterogeneity; synoptic flow did not eliminate the circulations but advected them away from the location where they were generated. This was substantiated by satellite-derived cloud images. These circulations affected the transport ...

2007
K. Wyat Appel Alice B. Gilliland Golam Sarwar Robert C. Gilliam

This study examines ozone (O3) predictions from the Community Multiscale Air Quality (CMAQ) model version 4.5 and discusses potential factors influencing the model results. Daily maximum 8-h average O3 levels are largely underpredicted when observed O3 levels are above 85 ppb and overpredicted when they are below 35 ppb. Using a clustering approach, model performance was examined separately for...

2004
JAMES J. BENEDICT SUKYOUNG LEE STEVEN B. FELDSTEIN

This article investigates the synoptic characteristics of individual North Atlantic Oscillation (NAO) events by examining the daily evolution of the potential temperature field on the nominal tropopause (the 2-PVU surface). This quantity is obtained from the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis dataset for the winter seaso...

2003
JASON C. KNIEVEL RICHARD H. JOHNSON

The authors employ data from the NOAA Wind Profiler Network to present a scale-discriminating vorticity budget for a mesoscale convective vortex (MCV) that was generated by a mesoscale convective system (MCS) in Oklahoma and Kansas on 1 August 1996. A spatial bandpass filter was used to divide observed wind into mesoscale and synoptic components. Then the authors sought sources and sinks of vor...

2005
Maki Miyake Hiroyuki Akama Masanori Nakagawa

It is well known that some techniques have already been developed to automatically subdivide texts into multiparagraph subtopic passages, such as TextTiling methodology proposed by Hearst. However, an additional algorithm is needed to perform a similar task for parallel or variant texts, because ambiguous and complicated traces of cross citation among them might often generate some sinuous patt...

2006
RUSS S. SCHUMACHER RICHARD H. JOHNSON

This study examines the characteristics of a large number of extreme rain events over the eastern two-thirds of the United States. Over a 5-yr period, 184 events are identified where the 24-h precipitation total at one or more stations exceeds the 50-yr recurrence amount for that location. Over the entire region of study, these events are most common in July. In the northern United States, extr...

Journal: :Environmental Health Perspectives 2001
P Kassomenos A Gryparis E Samoli K Katsouyanni S Lykoudis H A Flocas

We investigated the short-term effects of synoptic and mesoscale atmospheric circulation types on mortality in Athens, Greece. The synoptic patterns in the lower troposphere were classified in 8 a priori defined categories. The mesoscale weather types were classified into 11 categories, using meteorologic parameters from the Athens area surface monitoring network; the daily number of deaths was...

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