The correlation between the thickness of the troposphere (THK) and observed temperature over Iran is investigated. To achieve this goal, the monthly observed temperature data for the period between January 1, 1979 and December 31, 2013, from 42 meteorological stations throughout Iran were used. Atmospheric thickness, defined as the vertical distances between the 500, 700, 850 and 1,000 hPa pressure surfaces, is directly related to nearsurface air temperature. The results show that the magnitude of the correlation between near-surface air temperature and the THK vary in different months and from region to region. The strongest significant correlation was observed between December and March when air temperature is low. The correlation was particularly high in the eastern part of the study area at layer 1,000–850 hPa, while the strongest correlation was observed at layer 1,000–700 hPa in the mountainous western parts of the country. The study area’s average correlation co-efficient in March fluctuated between 0.900 at layer 1,000–500 hPa to 0.918 at layer 1,000–700 hPa. The magnitude of the correlation co-efficients and the spatial extent of the significant positive correlation gradually decreased with increasing air temperature, reaching a minimum during the summer. Low-level troposphere thickness (1,000–700 hPa) plays an important role in impacting near-surface temperature comparable with the effect of mid-level troposphere thickness.
