Natural modes of variability and their teleconnections over the Pacific-North American region in CMIP3 and CMIP5 models
Abstract
Natural climate variability will continue to be an important modulator of future regional climates. It is therefore crucial to examine the performance of climate models in simulation of natural modes of variability and their teleconnections. This aspect is especially important for extreme events analysis, such as impact of climate change on drought, heat waves, and floods. The CMIP5 generation of climate models is yielding significant improvements in simulations of the key Pacific climate modes and their teleconnections to North America, compared to earlier CMIP3 simulations. The performance of fourteen models with simulations from both CMIP3 and CMIP5 experiments in this regard have been assessed using singular value decomposition analyses of simulated (and observed) Pacific sea-surface temperatures (SSTs) and winter precipitation over the contiguous United States. Overall most of the models reproduced the basic features of the natural modes and their teleconnection, albeit with important regional deviations from reality, both in SST and precipitation. On average, eleven models show improvement of 17.5% from CMIP3 to CMIP5, while three models show an average degradation of 2% in performance. Increasing horizontal resolution is found to be an important factor responsible for improvements, with higher resolution models tending to be most skillful. However, there are two models that show greater improvement in skill without improving the resolution, which conveys models resolution is not the only factor responsible for improvement in skill. Additionally, models that better represent observed spatial patters of overall variance of precipitation and SST are generally also more skillful in their representation of ENSO/PDO.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.A51I..06P
- Keywords:
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- 1616 GLOBAL CHANGE / Climate variability;
- 1637 GLOBAL CHANGE / Regional climate change