【中文介绍】

         人类活动对气候系统的影响日益显著，气候模式是认识气候系统并预测预估其未来变化的主要工具。自1990年以来，联合国政府间气候变化专门委员会（IPCC）发布了系列评估报告，主要内容之一是在给定的温室气体和气溶胶排放情景和土地利用土地覆被条件下，使用多个气候模式来共同预估未来气候变化，旨在为适应和减缓气候变化提供科技支撑。30多年已经过去，这些模式对全球和区域尺度气候变化预估的信度如何是一个重要科学问题，特别是模式预估在中国地区是否可信并不知晓。

        为此，课题组使用IPCC第三（TAR）、第四（AR4）和第五次（AR5）评估报告中的多模式多情景试验数据，研究了气候模式对中国温度变化预估的信度，发现尽管还存在着一定程度的偏差，模式能提前几年到十几年较好预估出2002−2018年中国温度气候态变化和温度变化趋势，尤其是气候态。他们还比较了多模式等权重和不等权重集合平均的结果，指出两种方法的预估结果没有明显差别，但根据模式能力加权平均之后预估结果的不确定性范围明显缩小。另外，在研究时段内，预估的温度气候态变化不依赖于排放情景，但温度变化趋势在不同排放情景之间有较大差别。

        区域气候变化对我们的生存环境和生产生活等诸多方面均有着重要影响，并且适应和减缓气候变化以及相关的决策制定主要是在区域尺度上进行，因此我们需要特别重视对区域气候变化预估水平的检验。该项研究成果为中国气候变化短期预估的可靠性提供了科学依据。

  【英文介绍】

  Climate change has attracted significant attention due to its increasing impacts on various aspects of the world, and future climate projections are of vital importance for associated adaptation and mitigation, particularly at the regional scale. However, the skill level of the model projections over China in the past more than ten years remains unknown. In this study, we retrospectively investigate the skill of climate models within the Third (TAR), Fourth (AR4), and Fifth (AR5) Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC) for the near-term projections of near-surface (2 m) air temperature changes in China. Those models are revealed to be skillful in projecting the subsequent climatology and trend of the temperature changes in China during 2002–2018 from several to ten years ahead, with higher scores for the climatology than for the trend. The model projections display cold biases against observations in most of China, while the nationally averaged trend is overestimated by TAR models during 2002–2018 but underestimated by AR4 models during 2008–2018. For all emission scenarios, there is no obvious difference between the equal- and unequal-weighted averages based on the arithmetic averaging and reliability ensemble averaging method respectively, however the uncertainty range of projection is narrowed after weighting. The near-term temperature projections differ slightly among various emission scenarios for the climatology but are largely different for the trend.

      The crucial responses and policy decisions for climate change are mainly aimed at specific regions, and thus particular emphasis should be given to assessments of the skill of regional climate change projections. This retrospective investigation is very important to continually strengthen our confidence in the near-term projections of regional climate changes that prominently affect our environment and ultimately our lives.

  【关键图表】

  【引用格式】       

  Hu, D., D. Jiang*, Z. Tian, and X. Lang, How skillful was the projected temperature over China during 2002−2018? Science Bulletin, 2022, 67(10), 1077−1085.