Geographic differences in the vertical structure of the MJO from IGRA radiosonde data

Composite vertical structures of MJO temperature, wind, and specific humidity anomalies are constructed based on once- or twice-daily radiosonde data from 50+ tropical stations in the Integrated Global Radiosonde Archive (IGRA). Geographic differences in vertical structures as MJO precipitation (brightness temperature) maximizes (minimizes) over each station are analyzed. Multiple stations in each geographic region - Africa, Indian Ocean, Maritime Continent, western and eastern Pacific, South America, and Atlantic - are utilized, and are further classified into oceanic, island, and continental stations. A fixed MJO index keyed to MJO initiation in the Indian Ocean is then used to construct maps of temperature, wind, and humidity fields as MJO initiation occurs, based only on radiosonde data. Results are compared to reanalysis and model MJO initiation composites.