High-resolution climate projections for the Philippines: Methodology

[摘要] Climate change has been recognized as one of the greatest challenges facing our planet, not only for the environment, but also for economic development, with changes occurring in the physical, ecological and socio-economic systems. Likely outcomes are changes to weather patterns and sea-level rise, with impacts on ecosystems, water resources, agriculture, forests, fisheries, industries, urban and rural settlements, energy usage, tourism and health (IPCC, 2013).The Philippines are located in South East Asia, with a tropical monsoon climate and a coastline of more than 35000 km. It is one of the most disaster-prone countries in the world, with most of the disasters related to weather and climate. Consequently, climate change and climate variability are likely to pose increasing threats to its inhabitants in the near and long-term future.Regional climate models (RCMs) have become important tools for the prediction of climate variability and change in the regions of southern and eastern Asia. In a study using the Conformal Cubic Atmospheric Model (CCAM) nested within the 2.5 degree NCEP reanalyses, Nguyen and McGregor (2009) demonstrated that the model could simulate the main features of the Asian monsoon, a major influence on weather and climate in the Philippines, including seasonal shifts of the precipitation throughout the year.To assist the Philippines in its efforts to better understand the impacts of climate change and prioritise its adaptation measures, the detailed climate change projections at 10 km resolution produced for the High-resolution Climate Projections for Vietnam (HCPV) project (Katzfey et al., 20141) were extracted for the Philippine region. The stretched-grid of the downscaling model used in the HCPV project allowed for the extraction of the projections over the Philippines (see section 2.3 for more description of the downscaling process and grid).To address the inherent uncertainty in future climate change projections, a range of global climate models (GCMs) and emission scenarios were used for the downscaled simulations, as well as analysis techniques such as ensemble statistics to ensure that a broad range of plausible changes to the climate was evaluated.The aims of this project were to:- Incorporate new climate science information released by the Intergovernmental Panel on Climate Change.- Improve understanding of potential future climate changes in the region with reduced uncertainty.- Integrate past and current research for a more complete assessment of the potential effects of climate change.- Produce regional climate change projections to help identify the people and sectors at risk at the local level, where most impacts are felt.- Further climate science research and build capacity in the Philippines.- Provide information necessary for appropriate planning and investment to adapt to climate change.Data analysed for the project were based on output from six of the latest available GCMs from the Coupled Model Intercomparison Project Phase 5 (CMIP5) that were selected on the basis of their ability to realistically capture current climate and climate features such as El Niño-Southern Oscillation (ENSO) that have a large influence on the region. The global data was dynamically downscaled using a stretched-grid RCM to produce high-resolution simulations for current and future climate. Simulations were performed for historical (1970-2005) and future (to 2099) time periods using two representative concentration pathways: RCP4.5 and RCP 8.5 (Meinshausen et al. 2011).Section 2 gives details of the downscaling methodology for the ensemble simulations of future climate for the Philippines. Section 2.1 gives describes the procedures used for selection of the six GCMs to be dynamically downscaled to finer resolution. Section 2.2 describes the methodology used to correct the biases of the GCM Sea Surface Temperatures (SSTs) before they are used to drive the RCMs, followed by a description ...

[发布日期] 2015-12-14 [发布机构] CSIRO

[学科分类] 地球科学(综合)