Climatology of the ITCZ derived from ERA Interim reanalyses

The intertropical convergence zone (ITCZ) is usually analyzed in terms of the precipitation field. This study presents a new climatology of the ITCZ based on winds from ERA Interim reanalyses for the period 1990–2009. The central latitude of the ITCZ is defined as the zero crossing of the meridional wind averaged over 10 model levels below 900 hPa. Results of the zonal averaging of the meridional wind and wind convergence are compared with the zonally averaged precipitation from the ERA Interim and TRMM data sets. Collocation properties of precipitation maxima and the central latitude of the ITCZ are discussed for different land and ocean regions. It is found that the location of the ITCZ in wind and precipitation fields coincides over the Atlantic and east Pacific. Over other regions and especially over the tropical continents, the fields on average do not coincide. Key Points ERA Interim reanalyses provide good description of tropical surface winds Comparison between ITCZ defined by precipitation and winds is performed Collocation is found in East Pacific and Atlantic only