Effect of ITCZ migration on the surface air temperature trends in Middle East and North
Africa
G. L. Stenchikov
King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
We analyze the surface air temperature change in the Middle East and North Africa (MENA) and
the adjacent Mediterranean region during the last three decades. We compare the results from
station observations, NCEP and ECMWF/ERA-40 reanalyses, and from the newly developed
Geophysical Fluid Dynamics Laboratory atmospheric general circulation model that runs with grid
spacing of 25 km and captures the observed warming patterns. The temperature trends since middle
1970s largely exceed the global mean value, in many regions including the Arabian Peninsula. The
spatial distributions of annual, and especially summer trends, over the MENA and Mediterranean
regions exhibit a pronounced latitudinal structure with strong warming in Northern Africa, Eastern
Mediterranean, Northern and Central Arabia, and cooling in the South, in Sahel and Southern
Arabia. The process analysis, conducted using model output and available observations, suggests
that observed warming pattern is consistent with the northward shift of the Intertropical
Convergence Zone (ITCZ) in Summer that is associated with increase of cloudiness and radiative
cooling in Sahel and Southern Arabia, demonstrating the important link between regional climate
response and changes of global-scale circulation patterns.