Document Type : Research Paper

Authors

• Yousef Ghavidel Rahimi ¹
• Manochehr Farajzadeh Asl ²
• Daryoush Hatami Zarneh ³

¹ Water and Meteorology, Department of Geography, Tarbiat Modarres University

² Remote sensing and GIS, Tarbiat Modarres University

³ Hydrometeorological applications, Tarbiat Modarres University

Abstract

The NCP as one of the effective teleconnection patterns in level of
500 hpa have an important role in thermal and hydro-climatic
variability in East Mediterranean region. In this study to investigate
the correlation between the NCP and maximum temperature
fluctuations Iran for a 60 years period (1950-2010) have been studied.
Pearson correlation analysis as the main method used in this study
show an inverse relationship between maximum temperatures and
selected stations and NCP index. This shows decrease of temperature
in positive phase of the NCP and rise of temperature in negative
phase. In terms of time correlation coefficients were calculated and
showed a significant negative correlation between the temperature of
stations and the NCP in months of January, February, March and
almost direct relation most stations in August. At monthly interval in
the monthly correlation between stations with 0.342 were computed in
January. Seasonal correlation of shows a significant correlation of
maximum temperatures in winter to be -0.212. In terms of period, the
results indicate a strong correlation between cold period in most
stations and mentioned index. Atmospheric circulation in 500 hpa at
positive and negative phases showed in positive phase, settlement of
deep trough on the Caspian Sea, Iraq, Turkey and Iran, and also the
location of Iran in the eastern part of the trough axis on the other hand,
indicates establishment of a ridge on the North Sea and Europe which
leads to transfer of cold temperatures of northern Europe and its
adjacence of polar section to Iran. But on the negative phase
placement of Iran beneath the ridge axis leads to the creation of a
barotropic atmosphere with weak zonal wind and warm temperatures
to Iran. So with blowing warm air from Africa, Arabia and low
latitude Iran's temperature rises.

Keywords

• Maximum temperature
• Teleconnection
• NCP
• Iran

Main Subjects

• Climatology