Modeling Climate and Deep Water Sensitivity to Changes in Deglacial Meltwater Flux and Location Using a Fully-Coupled Ocean-Atmosphere GCM

该奖项支持一个项目，该项目将使用一个同步耦合的海洋-大气大气环流模式(O-A GCM)来研究千禧年尺度的快速气候变化事件的动力学起源，这些事件打断了最后的冰期和非冰期。重点将放在深层环流和地表气候对海洋去冰川融化水供应和输入位置的规定变化的反应。本提议中使用的NASA GISS O-A GCM是独一无二的，因为：1)它不需要通量修正来维持现实的大西洋深水循环，因此整个气候系统可以自由调整以适应变化的边界条件；2)地表径流被组织在41个单独的河流排水系统中，允许点源淡水注入海洋；3)海洋模型真正地(每小时)与完整的大气模型相耦合，以及4)该模型支持氧同位素分馏和示踪代码来监测格陵兰冰成分的结果变化。将涉及三个研究重点：1)描述与控制模式中深水产量高低有关的海洋-大气模式气候特征；2)量化深层环流对输入到海洋的去冰川融水的通量和位置变化的敏感性；3)青年仙女木模拟：12,000-9,000年前不同的去冰川径流量和输入地点的影响。

Abstract ATM-9612684 deMenocal, Peter Columbia University Title: Modeling Climate and Deep Water Sensitivity to Changes in Deglacial Meltwater Flux and Location Using a Fully-Coupled Ocean- Atmosphere GCM This award supports a project that will use a synchronously-coupled ocean-atmosphere general circulation model (O-A GCM ) to examine the dynamical origins of rapid, millennial-scale climate change events which punctuate the last glacial and deglacial periods. Focus will be on deep circulation and surface climate responses to prescribed changes in the supply and input location of deglacial meltwater to the ocean. The NASA GISS O-A GCM used in this proposal is unique because: 1) it does not require flux corrections to sustain realistic Atlantic deep water circulation so the entire climatic system is free to adjust to changed boundary conditions, 2) surface runoff is organized in 41 separate river drainages allowing for point-source freshwater injection to the ocean, 3) the ocean model is truly synchronously-coupled (every hour) to a full atmospheric model, and 4) the model supports oxygen-isotopic fractionation and tracer code to monitor resulting changes in Greenland ice composition. Three research foci will be addressed: 1) characterize the ocean-atmosphere model climate signatures associated with high and low deep-water production in the control model; 2) quantify deep circulation sensitivity to changes in the flux and location of deglacial meltwater input to the ocean; and 3) Younger Dryas simulation: effects of variable deglacial runoff volumes and input locations between 12,000-9,000 years ago.