Spatial and Temporal Trends of Rainfall and Temperature in the Amboseli Ecosystem of Kenya

Abstract

This study investigated spatial and temporal trends of rainfall and temperature in the Amboseli ecosystem of Kenya. The analysis were based on historical Climate Hazards group InfraRed Precipitation with Station (CHIRPs) and Climate Hazards group InfraRed Temperature with Station (CHIRTs) data for the period 1960-2014 and the period 2006-2100 for the projections. This data was used due to limitations in the observed station data. Projections of rainfall and temperature were based on Regional Climate Models (RCM) from Coordinated Regional Downscaling Experiment (CORDEX) over the Amboseli ecosystem. The long-term annual and seasonal trends of rainfall and temperature were analyzed via Mann– Kendall’s statistical test and linear trend analysis. The annual and seasonal rainfall declined slightly between 1960 and 2014 though not significant. However the temperatures increased more in the annual minimum (1.23 °C) compared to the annual maximum (0.79 °C). The maximum temperatures for the October-November-December (OND) season had highest increases of 0.88 °C while the March-April-May (MAM) season showed an increase of 0.69 °C. The highest increase in minimum temperatures of 1.35 °C was recorded for the June-July-August-September season (JJAS), while the least increase was in MAM (1.04°C). Projected rainfall based on Representative Concentration Pathways (RCPs) for the periods 2006-2100 varied with RCP 2.6 showing a decline for the four seasons. RCP 4.5 and 8.5 project marginal increase in annual and OND with declines in the MAM and JJAS. Projected maximum and minimum temperature for RCP 2.6 indicate increments of less than 1 °C while for RCP 4.5 the maximum range is between 0.57 °C and 1.85 °Cand minimum is between 0.51 °C to 1.98 °C. RCP 8.5 projected maximum increase are the highest between 1.11°C and 4.34 °C and minimum is between 1.34 °C and 5.26 °C based on period – 2030, 2050 and 2070. The increase of temperatures and changes in rainfall can have large impacts on the resources in the savanna dry lands of East Africa especially on its livestock, agriculture, wildlife and pastoral and agro-pastoral communities. Index Terms— Climate change, dry lands, mitigation, Representative Concentration Pathways, temperature and rainfall.