Teleconnection of local droughts in Isiolo County in Kenya to el-nino southern oscillation and associated Atmospheric circulation anomalies

Kenya Agricultural and Livestock Research Organization (KALRO)

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Abstract: The study was based on monthly gridded temperature dataset at 0.5o × 0.5o spatial resolution from Climate Research Unit, CRUTS4.03, Climate Hazard Group Infrared Precipitation with Station Monthly Precipitation Datasets (CHIRPSv2) at spatial resolution of 0.05 (5.3 km). The climatological data on available water holding capacity of the soil (AWHC) from Oak Ridge National Laboratory Distributed Active Archive Center at a spatial resolution of 1ox1o. The National Center for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) re-analyzed global observation network of weather parameters (wind, geo-potential height omega). Temporal resolution of all datasets was from 1980-2018. The study showed that there was weak to moderate relationship between ENSO and local drought events in Isiolo County. The maximum Empirical Orthogonal Functions loadings were observed in the eastern zones and minimum to the western zone with the leading modes accounting for over 80% of the total variability. A comparison between the 2 phases of ENSO revealed easterly and westerly lower tropospheric winds over the Indian Ocean basin during El-Nino and La-Nina respectively, with negative and positive 500hPa geo-potential anomalies in El-Nino and La-Nina phases. The drought cycles had periodicity of 3-9 years and 5-10 years during OND and DJF, respectively.