This is the zone of convergence of the northeast trade winds and the southeast trades. These winds move toward the equatorial trough where the air converges and rises into the atmosphere as part of the Hadley cell circulation. In January, an intense high-pressure system, the Siberian High, forms in central Asia due to the extreme cold. In July, the Siberian High is replaced by the Asiatic Low centred over the strongly heated lands of the Middle East. This seasonal change in pressure and the latitudinal movement of the ITCZ create the reversing wind pattern that underlies the monsoon climate of Asia.