weather circulation patterns play a main role in the occurrence of environmental phenomena especially in middle latitude. occurrence of dry and wet spells is in relation to synoptical system repetitions and types of weather. in this research first by using of standard precipitation index (spi), extensive droughts in the province were identified. then by using principal component analysis (pca) ...

the quality of pressure distribution over the atmosphere of the sea level and geopotential altitude at different atmosphere layers affect on many climate and meteorology phenomena of the earth surface. one of the important meteorology phenomenon is the occurrence of frost phenomenon especially late spring frost. in this surrey, occurring late spring frost days and minimum temperature during the...

drought is a natural hazard that have in arid and semiarid areas more frequency. so the study and identify synoptic patterns affecting this phenomenon seems to be necessary. by using peripheral circulation approach, drought periods during the 30-year (2011-1982) in the six synoptic stations provinces of kerman, yazd and isfahan, which have a long-term cooperative period were calculated with usi...

Mechanisms of global warming impacts on regional tropical precipitation are examined in a coupled atmosphere–ocean general circulation model (ECHAM4/OPYC3). The pattern of the regional tropical precipitation changes, once established, tends to persist, growing in magnitude as greenhouse gases increase. The sulfate aerosol induces regional tropical precipitation anomalies similar to the greenhou...

The seasonal footprinting mechanism (SFM) is thought to be a pre-cursor to the El Nino Southern Oscillation (ENSO). Fluctuations in the North Pacific Oscillation (NPO) impact the ocean via surface heat fluxes during winter, leaving a sea-surface temperature (SST) ‘‘footprint’’ in the subtropics. This footprint persists through the spring, impacting the tropical Pacific atmosphere–ocean circulat...

Any system designed to simulate the earth's atmosphere general circulation, must necessarily be based on the spatial-or temporal average conditions. Irregularities in the profiles of air motions that we observe on daily weather maps often make lose any real meaning to the general circulation. As complicated and inconsistent that is the daily traffic of air particles, it is interesting to define...

[1] The ability of general circulation models (GCMs) to reproduce the observed strong correlations of Eurasian snow extent in the fall to wave activity and Northern Annular Mode anomalies in the following winter is studied. The observed correlations have been hypothesized to involve two parts: a Rossby wave pulse generated in the troposphere in response to snow-forced surface cooling and a coup...

This paper presents an analysis of the frequency and spatial distribution of droughts in Argentina during the 20th century. Special attention is given to the mean monthly atmospheric circulation associated with dry conditions in the Pampas during the second half of the century. A reduction in the number of dry cases is found throughout the century, especially during the warm season (October to ...

Early Springs (ES), March and April in particular, have been extremely dry Central Europe recent years, particularly from 2003 onwards. This is causing substantial impacts, foremost to agriculture, which heavily dependent on sufficient moisture supply at the beginning growing season. However, drivers of ES droughts are still not well understood. In this article, we investigate temporal evolutio...

Atmosphere and ocean model assimilated products, in conjunction with observed precipitation and ocean model estimates of Indonesian Throughflow (ITF) transport and barrier layer thickness, are analyzed to elucidate the role of external (ENSO and ITF) and internal (monsoon) factors in the initiation of the Indian Ocean Zonal Mode (IOZM). The diagnostics show that there exists a natural mode of c...