A new tropopause definition, based on a flow-dependent blending of the traditional thermal tropopause with one based on potential vorticity, has been developed. The benefits of such a blending algorithm are most apparent in regions with synoptic scale fluctuations between tropical and extratropical airmasses. The properties of the local airmass determine the relative contributions to the locati...

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...

In the present work the Black Sea wave climate is assessed using a total of 38 years of data (1979–2016). As a first step, the long-term variations of the main wave parameters were evaluated using data provided by the European Center for Medium-Range Weather Forecasts (ECMWF). Based on these values, the nearshore and offshore conditions from the Black Sea were evaluated. Moreover, the Sea of Az...

با توجه به رشد بالای جمعیت در جهان و نیاز اطمینان از امنیت غذایی، افزایش تولید واحد سطح محصولات زراعی به‌منزلة راهبردی اساسی حل مسئلة تأمین غذا به‌شمار می‌رود. سوی دیگر، وجود محدودیت زیرکشت پایین‌بودن میانگین عملکرد برخی کشاورزی مانند گندم کشور، محصول می‌تواند راهکاری عملی پاسخ کشور محسوب شود. یکی مهم‌ترین بیماری‌های فوزاریوم است که، نقش پیش‌بینی این بیماری جلوگیری کاهش بهره‌وری محصول، مدل‌هایی...

a Météo France, Centre National de Recherches Météorologiques (CNRM/GAME), URA CNRS 1357, Toulouse, France b Centre d’Etude Spatiale de la Biosphère (Cesbio), Toulouse, France c Institut de Recherche pour le Développement (IRD), Toulouse, France d European Centre for Medium-Range Weather Forecasting (ECMWF), Reading, United Kingdom e Centre Européen de Recherche et de Formation Avancée en Calcu...

To evaluate the scalar ocean surface wind speeds obtained from the Special Sensor Microwave Imager (SSM/I) we compare them over the time period from July 1987 through December 1997 with those from two global analyses: the NCEP/NCAR Annual Reanalysis and the ECMWF TOGA Global Surface Analysis. We perform a statistical analysis for the whole globe and present time series analyses for selected geo...