Iranian surface air temperature periodicities and correlations with the North Atlantic and Indian Ocean sea surface temperature variations

• Published in: Meteorological Applications
• Main Authors: Abbasi, Madjid, Mashhadizadeh Maleki, Saeed
• Other Authors: Iran National Science Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2017
• Subjects: North Atlantic
• Online Access: http://dx.doi.org/10.1002/met.1625; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fmet.1625; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/met.1625

ABSTRACT Monthly mean surface air temperature data of synoptic meteorological stations in I ran have been analysed in order to detect probable periodicities and corresponding amplitudes. Statistically meaningful annual periodicity and its harmonics, quasi‐biennial (2–3 year), interannual (3–5 year) and quasi‐decadal (8–12 year) periodicities have been detected. The ensemble average of the spectra shows statistically meaningful harmonic components in 2.2, 2.5, 3.6, 4.0, 4.9, 8.0 and 9.9 years. The amplitude maps of these harmonic components show variations, with higher amplitudes in north and northwest I ran compared to the south and southeast (north of the P ersian G ulf and O man S ea). The cumulative amplitude map of detected periodicities indicates that the I ranian surface air temperatures have an average periodic oscillation of 0.8 ° C in a decade, from a minimum of 0.2 ° C in the southeast to a maximum of 1.4 ° C in the northwest of I ran. The influence of the I ndian O cean D ipole ( IOD ) and the A tlantic M ultidecadal O scillation ( AMO ), which are two major sea surface temperature variations in the I ndian and A tlantic O ceans, has been analysed by partial correlation analysis. This showed that the I ranian surface air temperature is mostly affected by the A tlantic O cean sea surface temperature variations rather than those of the I ndian O cean. The mean absolute values of the partial correlation for the IOD and the AMO are 30.8% and 49.6% respectively. In corresponding partial correlation maps, a regular and partitionable behaviour was not observed. However, a maximum influence of the AMO and a minimum influence of the IOD occur in the northwest of I ran.