A new tropopause definition involving a flow-dependent blending of the traditional thermal tropopause with one based on potential vorticity has been developed and applied to the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses (ERA), ERA-40 and ERA-Interim. Global and regional trends in tropopause characteristics for annual and solsticial seasonal means are presented here, ...

The homogeneity of the ECMWF 40-yr Re-Analysis (ERA-40) is assessed. This is done by comparing ERA40 data with results from the NCEP–NCAR reanalysis and also by investigating a known relationship between a modeled (latent heat flux) and an external (SST) quantity. The direct comparison between the two reanalyses reveals a lot of inhomogeneities. They occur mainly in the Southern Hemisphere and ...

Data mining is a valuable tool in meteorological applications. Properly selected data mining techniques enable researchers to process and analyze massive amounts of data collected by satellites and other instruments. Large spatial-temporal datasets can be analyzed using different linear and nonlinear methods. The Self-Organizing Map (SOM) is a promising tool for clustering and visualizing high ...

khānsār was one of the principal cities of isfahan district in qajar era. the city is mentioned repeatedly in historical texts and visited frequently by european travelers khānsār was celebrated in qajar era for presence of significant cultural and artistic figures in the city as well as production of various commercial products. the remnants of commercial monuments such as qajar bazar or kārva...

This work deals with the hypothesis that synoptically-driven heavy rains in the Mediterranean region are connected with the occurrence of synoptic-dynamic anomalies. We investigate this hypothesis by conducting a diagnostic study of a cyclogenesis event from 18–21 July 2001. Cyclogenesis started over the western Mediterranean Sea and was triggered by the approach of a pre-existing upper trough ...

[1] A global comparison of altimeter and ERA-40 mean wave period data is performed for the first time. Altimeter and ERA-40 mean wave period are shown to compare well in non-swell-dominated conditions. Triply collocated altimeter, buoy, and ERA-40 data show that the variance of the random errors is bigger for the ERA-40 data and smaller for the buoy data. A new expression is given to relate alt...

Nowadays, mobile terminal has become an indispensable element in people’s daily life as the advent of post-PC era, the security issue of these mobile platforms plays a pivotal role in this information technology era. As Android accounts for approximately 80% in the third quarter of 2013, the importance of its potential security risks cannot be neglected. This research started from the critical ...

The stratospheric mean-meridional circulation (MMC) and eddy mixing are compared among six meteorological reanalysis data sets: NCEP-NCAR, NCEP-CFSR, ERA-40, ERA-Interim, JRA-25, and JRA-55 for the period 1979–2012. The reanalysis data sets produced using advanced systems (i.e., NCEP-CFSR, ERA-Interim, and JRA55) generally reveal a weaker MMC in the Northern Hemisphere (NH) compared with those ...

The distribution of the daily wintertime North Atlantic Oscillation (NAO) index in the 40-yr ECMWF ReAnalysis (ERA-40) is significantly negatively skewed. Dynamical and statistical analyses both suggest that this skewness reflects the presence of two distinct regimes—referred to as ‘‘Greenland blocking’’ and ‘‘subpolar jet.’’ Changes in both the relative occurrence and in the structure of the r...