to doing this research daily interpolated temperature data from asfezari data base have been used. in order to recognition extreme cold days, the normalized temperature deviation index (ntdi) applied. then the index sorted according to extensive and severity and first 500 days selected for analysis. the geopotential height data extracted from www.esrl.noaa.gov data base. the thickness anomaly c...

The evolution of the mesoscale flow and precipitation distribution are investigated for a small mesoscale convective system (MCS) that evolved in a nearly barotropic environment exhibiting moderate instability and weak wind shear. Observations primarily from a single Doppler radar detail the growth of the MCS from the merger of several clusters and lines of vigorous convective cells into a matu...

Variability of Mexican hydroclimate, with special attention to persistent drought, is examined using observations , model simulations forced by historical sea surface temperature (SST), tree ring reconstructions of past climate and model simulations and projections of naturally and anthropogenically forced climate change. During the winter half year, hydroclimate across México is influenced by ...

In this study, a new index based on the potential vorticity (PV) framework is proposed for quantification of Tibetan Plateau (TP) surface thermodynamic and dynamic forcing. The results show that derived TP PV (SPV) includes topographical effect, near-surface absolute vorticity, land–air temperature differences. climatological annual cycle SPV suggests transitions from cooling to heating source ...

Precipitation extremes driven by the El Niño–Southern Oscillation (ENSO) are one of critical ways in which ENSO impacts global climate, specifically tropical Pacific, where they have potential to cause extreme weather conditions. However, existing approaches struggle effectively identify evolution ENSO-related precipitation anomalies that change rapidly spatial distribution. To address this cha...

[1] Atmospheric fronts are important for the day-to-day variability of weather in the midlatitudes, particularly during winter when extratropical storm-tracks are at their maximum intensity. Fronts are often associated with heavy rain, and strongly affect the local space-time distribution of rainfall. A recently developed objective front identification method that distinguishes between cold, wa...