The Affect of Altered Ocean Heat Transports on Climate: Feedback Potential During Periods of Atmospheric Trace Gas Increase

ATM-9320372 Chandler，Mark A.Martinson，David Gornitz，Vivien M.Rind，David H.哥伦比亚大学标题：改变的海洋热量输送对气候的影响：大气微量气体增加期间的反馈潜力本项目的目标是在数值气候变化模拟中研究海洋热量输送的十年至世纪尺度的影响。该项目使用戈达德空间研究所的大气环流模型，再加上包括海洋经向热量传输的海洋模型，直接测试海洋热传输的变化是否可以增强或改善痕量气体引起的全球变暖的影响。该项目设计为三年两个阶段的研究：在第一阶段，将使用来自GCM实验的表面热通量诊断来计算与历史(20世纪)海表面温度和海冰范围异常相关的潜在海洋热输送。SST和海冰异常将从现有的最全面的数据集获得，包括：COADS、海军/NOAA、沃尔什、ESMR、SMMR和SMM/I，所有这些数据目前都在内部。此外，将根据GCM模拟和来自小冰期(约公元1700年)和末次冰盛期(约18-2lky BP)的替代数据计算海洋热输送，以便获得可能更接近系统潜在可变性的热通量的更大变化。该项目的第二阶段侧重于模拟海洋热输送变化的气候影响，并结合瞬时痕量气体增加的情景。计划进行10个100年的模拟，其中第一阶段计算的海洋热值将用于扰乱与大气痕量气体增加相关的气候变化的正常模式。根据对运行在IBM RS/6000-580工作站上的GISS 4ox50 GCM当前计算效率的估计，第二阶段的模拟将需要大约两年的时间完成。将以每三个月一次的速度完成和分析个别的瞬变实验。该项目的主要目标是确定与大气/海洋/冰系统的可变性有关的气候变化模式，并估计可能伴随大气痕量气体增加引起的气候变化而产生的潜在海洋能量反馈。对这种气候模式进行指纹识别将提高我们发现海洋引起的气候变化迹象的能力，并可以提高我们区分自然变化和人为气候变化的能力。此外，它将为我们提供对海洋能力的定量评估，通过能源运输反馈，改变气候敏感性和全球气候变化对未来气候变化的预测。这些实验取代了在不久的将来不太可能达到可靠预测能力的完全耦合的大气-海洋-冰模型，而是为测量海洋改变GCM未来气候诊断的能力提供了现实的替代方案。该项目由USGCRP NSF气候建模、分析和预测计划资助。

Abstract ATM-9320372 Chandler, Mark A. Martinson, David Gornitz, Vivien M. Rind, David H. Columbia University Title: The Affect of Altered Ocean Heat Transports on Climate: Feedback Potential During Periods of Atmospheric Trace Gas Increase The objective of this project is to investigate the decadal to century-scale affects of ocean heat transports in numerical climate change simulations. The project uses the Goddard Institute for Space Studies atmospheric general circulation model, coupled to an ocean model that includes meridional transport of heat by the oceans, to test directly whether changes in ocean heat transport could enhance or ameliorate the effects of trace-gas-induced global warming. The project is designed as a three year, two phase study: In the first phase, surface heat flux diagnostics from GCM experiments will be used to calculate the potential ocean heat transport associated with historical (20th century) anomalies in sea surface temperatures and sea ice extent. The SST and sea ice anomalies will be acquired from the most comprehensive data sets available including: COADS, Navy/NOAA, Walsh, ESMR, SMMR, and SMM/I, all of which are currently in-house. In addition, ocean heat transports will be calculated from GCM simulations and proxy data from the Little Ice Age (ca. 1700 AD) and Last Glacial Maximum (ca. 18-2lky BP) in order to obtain larger variations of heat fluxes that may be closer to the potential variability of the system. The second phase of the project focuses on simulations of the climatic effects of altered ocean heat transports in conjunction with transient trace gas increase scenarios. Ten 100- year simulations are planned in which the ocean heat values, calculated in phase one, will be used to perturb the normal pattern of climate change associated with the atmospheric trace gas increase. The simulations in phase two will take approximately two years to complete, based on estimates of the current comput ational efficiency of the GISS 4ox5o GCM running on IBM RS/6000-580 workstation. Individual transient experiments will be completed and analyzed at the rate of one every three months. The primary objective of this project is to identify patterns of climate change that are associated with variability in the air/sea/ice system and to estimate the potential ocean energy feedbacks that may accompany climate changes induced by atmospheric trace gas increase. Fingerprinting of such climate patterns will improve our ability to detect the signs of ocean-induced climate change and can improve our ability to distinguish between natural variability and anthropogenic climate change. Furthermore, it will provide us with a quantitative assessment of the oceans ability, through energy transport feedbacks, to alter the climate sensitivity and GCM predictions of future climate change. In lieu of fully coupled atmosphere-ocean-ice models, which are unlikely to reach a reliable predictive capacity in the near future, these experiments provide the realistic alternative for gauging the ability of the oceans to alter GCM future climate diagnoses. This project is funded under the USGCRP NSF Climate Modeling, Analysis and Prediction program.