Detection of inhomogeneities and breaks in climate in India and southern South America

ADRIÁN YUCHECHEN

Montevideo

Conferencia; WCRP Conference for Latin America and the Caribbean: Developing, linking and applying climate knowledge; 2014

World Climate Research Programme

Aimed at detecting inhomogeneities and possible breaks in climate, a method presented in the mid-2000s that was initially developed to be applied on annual time series was implemented on series of monthly means for mandatory levels ranging from 850 to 10 hPa. Two regions were included in the analysis, covering the Indian subcontinent and southern South America. The time series analyzed span the period 1973−2011. The method provides flexibility in the width of the time window to be used, but only a 120-month timespan, i.e. 10 years, is discussed here. When both height and temperature are considered, there exist two different points of reference at which there have been shifts in the corresponding means that lasted at least 10 years: one starting between December 1982 and April 1983, with changes in regime mainly taking place at stations along the southern South American Atlantic coast, and another one taking place within a narrower period centered at May 1999, for which the break has taken place at stations located mostly in Western India. In both cases, these shifts have been detected at all mandatory levels within the troposphere. Given that the summer Indian monsoon commences in May in the Arabian Sea and the southern Indian Ocean, i.e. the western coast of India, and that the southern Atlantic coast is a cyclogenetic region during the austral summer, further insights on the effects these changes had in their corresponding regions can be provided with the analysis of the circulation patterns before and after they took place.