GRGC: Modeling and Validating Cretaceous Climate and Ocean Circulation Based on New Boundary Conditions

小行星19405737 通常的做法是运行大气（AGCM）或海洋（OGCM）环流模式，并搜索可能被地质数据证实或拒绝的结果。 AGCM的输出描述了大面积的平均条件，但提供最佳气候记录的非海洋地质沉积很少在平均条件下沉积。 这种模型结果与可能用于验证的地质数据之间的不匹配一直是古气候研究中的一个主要问题。 一个新的AGCM，GENESIS，专为古气候研究，和一个新的方法来验证一个古气候模型的结果，代理形成模型（PFM），可以一起使用，使更逼真的模拟，可以通过比较验证与真实的数据。 一个经过验证的AGCM可以用来驱动OGCM来研究海洋环流。 GENESIS最初是CCM 1的一个重大修改版本，在处理水蒸气输送、地球表面的大气对流、与气溶胶有关的太阳辐射、云参数化、植被、土壤、雪和海冰方面与CCM 1不同。 它的海洋是一个平板，包括热容量和海洋热传输。 GENESIS具有独立的AGCM和地表网格，可以更好地表示地表古地理，植被和土壤条件。 PFM是气候模式数据和地质观测之间的定量联系。 PFM正在开发用于在已知气候条件下形成的沉积矿床。 1)铝土矿; 2）铝土矿和红土; 3）煤（泥炭）。 PFM规定了矿床所在地必须存在的边界条件。 这个额外的“网格点”被插入到气候模型中，计算出的环境参数（温度、湿度等）与形成存款所需的条件进行比较。 根据这项建议，我们会在 PFM的：1）沙漠; 2）沿海海冰; 3）山区冰川; 4）冰盖。 早白垩世和晚白垩世的气候是不同的，都不同于晚新生代的气候。 在白垩纪早期，有高纬度的海冰，强烈的中纬度季节性，以及“大西洋”变得缺氧的趋势。 在白垩纪晚期，没有高纬度的冰，季节性更少，海洋的含氧量更高（有两个短暂的明显例外）。 这些差异是对边界条件变化的响应：1）从早白垩世期间西特提斯-大西洋-印度海道与东特提斯-泛大洋的隔离到晚白垩世更开放的连接：2）大气中CO2含量从早白垩世的较低水平上升到晚白垩世的较高水平：（3）向极地的海洋热输送从早白垩世的低水平增加到晚白垩世的高水平;（4）海平面上升到晚白垩世的最高点。 地球在白垩纪的古地理学、古气候学能量平衡已经足够清楚，可以运行AGCM和随后的OGCM，这些都可以使用基于地质数据的PFM进行严格验证。

19405737 Hay It has been common practice to run an atmospheric (AGCM) or oceanic (OGCM) general circulation model and search for results that might be confirmed or rejected by geologic data. AGCM output describes average conditions over large areas, but the non-marine geologic deposits providing the best record of climate were rarely laid down under average conditions. This mismatch between the model results and the geologic data that might be used for their validation has been a major problem in paleoclimate studies. A new AGCM, GENESIS, designed specifically for paleoclimate research, and a new method for validating the results of a paleoclimate model, the Proxy Formation Model (PFM), can be used together to make more realistic simulations that can be validated by comparison with real data. A validated AGCM can then be used to drive an OGCM to investigate circulation of the ocean. GENESIS began as a heavily modified version of CCM1 and differs from it in treatment of water vapor transport, atmospheric convection from the earth's surface, solar radiation related to aerosols, cloud parameterization, vegetation, soil, snow and sea ice. Its ocean is a slab, with heat capacity and ocean heat transport included. GENESIS has independent AGCM and surface grids, allowing for much better representation of surface paleogeographic, vegetation, and soil conditions. The PFM is a quantitative link between climate model data and geologic observations. PFM's are being developed for sedimentary deposits that form under known climatic conditions. 1) evaporites; 2) bauxites and laterites; 3) coal (peat). The PFM prescribes boundary conditions that must have existed at the location where the deposits occur. This additional "grid point" is inserted into the climate model, and the calculated environmental parameters (temperature, humidity, etc.) are compared with conditions required for formation of the deposit. Under this proposal, we will develop 4 additional PFM's : 1) sand deserts; 2) coastal sea ice; 3) mountain glaciers; 4) ice sheets. The climates of the Early and Late Cretaceous were different from each other and both were different from Late Cenozoic climates. In the Early Cretaceous there was high-latitude sea ice, strong mid- latitude seasonality, and a tendency for the "Atlantic" to become anoxic. In the Late Cretaceous there was no high-latitude ice, less seasonality, and a more oxic ocean (with two brief notable exceptions). The differences were a response to changing boundary conditions: 1) from isolation of the western Tethys-Atlantic-Indian seaway from the eastern Tethys-Panthalassic Ocean during the Early Cretaceous to more open connections in the Late Cretaceous: 2) rise in the atmospheric content of CO2 from a lower level in the Early Cretaceous to a high level in the Late Cretaceous: 3) increase in poleward ocean heat transport form a low level during the Early Cretaceous to a high level in the Late Cretaceous: and 4) rise of sea level to a mximum in the Late Cretaceous. The paleogeography, paleoclimatology energy balance of the Earth in the Cretaceous are well enough known to run AGCM's and subsequently OGCM's that can be rigorously validated using PFM's based on geologic data.