Homogenisation of Daily Climate Data and Analysis of Climate Extremes in Pacific Island Nations

Many people living in the Pacific Islands Countries and East Timor report their climate is changing. Despite the high vulnerability that these countries face, there is only very limited scientific information available to these countries about the nature and significance of climate trends. A recent report published by the Pacific Climate Change Science Program (PCCSP) found that collectively, the Pacific region indicates a climate in transition, driven by both natural and human influences, with large nearly monotonic warming, sea level rise and shift in rainfall patters.

Pacific Island nations are highly vulnerable to changes not only in mean climate but also in climate extremes. Research in the Pacific Australian Climate Change Science and Adaptation Program (PACCSAP) has focused on enhancing tools for the analysis of historical climate extremes in 15 Pacific Island Countries and East Timor. Data was collected for partner countries from various sources and quality controlled during the development of a new set of homogenised daily rainfall and temperature data for Pacific Island Countries.

This research then utilised a suite of indices that define a range of climate extremes, which have been developed by the WMO Expert Team on Climate Change Detection and Indices (ET-CCDI). Indices describing temperature and precipitation extremes have been calculated and trends analysed. In this way the current research fits in to an existing global framework, building on an international effort to improve understanding of climate variability and trends, and includes the latest in a series of workshops dedicated to building our understanding of climate extremes and capacity building in regional areas. Preliminary results highlight large shifts in extreme events, including a dramatic increase in warm nights and hot days, a decline in cool extremes, and significant shifts in rainfall.