â â â  in this research, temporal and spatial behaviors of azores high pressure was studied at the level of 700 hpa. this study has been done using daily data of geopotential height at 12 gmt in ncep/ncar database with spatial resolution of 2.5*2.5 degree in a 55 years period including 20089 days from january, 1st, 1951(dey, 11th, 1329) to december, 31st,2005(dey, 10th,1384). at first, the mean...

Bayesian model averaging (BMA) and ensemble output statistics (EMOS) were used to improve the prediction skill of 500 hPa geopotential height field over northern hemisphere with lead times 1–7 days based on forecasts from European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers Environmental Prediction (NCEP), UK Met Office (UKMO) systems. The performance BMA EMOS compared e...

in this paper, the correlation between total ozone and upper air meteorological parameters such as heights of geopotential surfaces and temperatures for three stations of tehran, ankara and bet dagan located in the middle east, in cold period (jan, feb and march) of years of 2005, 2007 and 2008 has been investigated. data for upper air is taken from wyoming university and ozone data is from sat...

This study presents a classification of stratospheric extreme events during northern winter into events with or without a consistent downward propagation of anomalies to the troposphere. Anomalous strong and weak stratospheric polar vortex events are detected from daily time series of the polar cap averaged (60∘–90∘N) geopotential height anomaly. The method is applied to chemistry-climate model...

Obliquely rotated T-mode principal component analysis has been applied to the NCEP/NCAR geopotential height reanalysis data for winter months from 1958 to 1996 over the New Zealand region. A new set of ten representative weather types were identified, with two being the most dominant. The temporal characteristics of the ten synoptic weather types were anlayzed in relation to different phases of...

Abstract We analyze the seasonal evolution and trends of atmospheric blocking from 1979 to 2018 using a geopotential-height-based method over two domains, one located west (150°–90°W, 50°–70°S) other east (90°–30°W, Antarctic Peninsula. Spatial patterns geopotential heights on days with feature well-defined ridge axes much South America, most extreme (above 99th percentile) showed upper-troposp...