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基于CMIP5的两类EINino及相关赤道降水在21世纪的预测


Francis建议我在香港时可以做的研究是:conducting AGCM experiment to test the idea that, for both CP and EP El Nino in the future climate based on CMIP5 simulations, the precipitation response will be stronger no matter whether the future El NInos (irrespective of the the type) is projected to be stronger or weaker (measured in terms of the anomalous SST in the tropical Pacific).

Xu, K., et al. (2017). “CMIP5 Projections of Two Types of El Nino and Their Related Tropical Precipitation in the Twenty-First Century.” Journal of Climate 30(3):

摘要

本文利用CMIP5(phase 5 of the Coupled Model Intercomparison Project)模式中用RCP8.5排放量模拟未来2050-2099的气候,发现在中部型EiNino没有明显变化时,未来东部型EiNino会变弱,且中部型向东部型转变的频率在未来如何变化无统一结论。

但是与两类EiNino相关的赤道大气环流及降水在全球变暖的情况下存在显著变化。

在全球变暖的情况下,与东部型EiNino相关的异常降水量级增加,表明西太平洋干燥加剧、中东太平洋潮湿加剧。此时,异常Walk环流减弱。

中部EiNnio,中东太平洋的异常干燥会在未来加剧,异常下沉作用增强

文章结构

  1. Introduction
  2. Datasets and methodology
  3. Simulations of two types of EiNino and their projected changes
    3.1 Evaluation of EiNino related SST variability in CMIP5 models
    3.2 Projected changes of EP and CP EiNino characteristics
  4. Robust changes of the tropical precipitation associated with EiNino
    4.1 EiNino related precipitation anomalies
    4.2 Atmospheric overturning circulations
  5. Summary and discussion

1. Introduction

CP EiNino 的触发机制目前还存在争议
目前大家都比较关注全球变暖对CP和EP型EiNino发生频率的影响,Yeh et al. (2009) 认为未来CP会发生的比较多而EP发生频率变化不大; Power et al. (2013) 认为在CMIP5中的众多模式结果对此的结论都不一致。

证据表明,在全球变暖的情况下,全球平均降雨量在以一个较小的速度缓慢增长。
常见的增长机制有两种:“wet get wetter”、“warmer get wetter”

以往的研究都关注在全球变暖的情况下,EP EiNino事件的变化预测及与其遥相关,很少有关注CP在未来的变化情况及相关的赤道降水变化。
本文先评估了CMIP5中31个模式对两类EiNino的模拟好坏并在此基础上探究模式预测的未来由两类EiNino引起的赤道降水和大气环流变化情况。

2. Datasets and methodology

All model output were first interpolated onto the same spatial grid of 18 3 18 horizontal resolution before analysis.

In addition, to assess the fidelity of the simulated ENSO variability, model SST data were compared to their observational counterpart at the same horizontal resolution from the Hadley Centre Sea Ice and Sea Surface Temperature (HadISST, version 1.1) analysis for the period of 1950–99.

Observed precipitation data were taken from the monthly analysis of the Global Precipitation Climatology Project, covering the period of 1979–2010 with a horizontal resolution of 2.58 3 2.58.

Monthly mean variables from models and observations were smoothed by taking 3-month running averages to suppress subseasonal variability.

该文还定义了intermodel consistency来衡量某一气候信号在许多模式中的稳定性,一个格点一个值,其值是该点符号同ensemble mean相同的模式个数与总模式个数之比。

3. Simulations of two types of EiNino and their projected changes

这里有一个spatial correlation coefficients不清楚是怎么算的

3.2 Projected changes of EP and CP EiNino characteristics

4. Robust changes of the tropical precipitation associated with EiNino

4.2 Atmospheric overturning circulations

5. Summary and discussion

bears the greatest resemblance with sth 与某物很像
its environmental and socioeconomic impacts
the atmospheric bridge mechanism
sth will be probed 什么将会被探索
The remainder of the paper is organized as follows.
state-of-the-art 最先进的,已经发展的


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