Climate Implications of the Messinian Desiccation of the Mediterranean Basin: General Circulation Model (GCM) Simulations and Process Model Studies

该奖项提供资金，使用一套气候模型来模拟梅西尼亚干旱，包括单柱模型、简化的驻波模型和大气环流模型。在大约550万年前(Ma)的中新世的梅西尼期，现今直布罗陀海峡附近的构造活动导致地中海被孤立。在这种孤立的高度，地中海的蒸发似乎使地中海盆地内的海平面下降了1500米至2000米。这导致了地中海盆地周围丰富的盐矿沉积，以及流入地中海的主要河流对深峡谷的侵蚀。研究人员坚持认为，无论是深而广泛的空中盆地对大气一般环流的影响，还是发生干燥的物理过程，都没有使用复杂的大气模型来处理。因此，研究人员的目标是在物理上一致地重建深盆地内的气候条件，并评估这种盆地的存在对区域气候的影响。这种影响将通过深层盆地与大气环流的直接物理相互作用以及地中海干化引起的水蒸气、尘埃和盐分输送的变化来检验。该项目将包括使用为NCAR社区气候系统模式(CCSM)大气模块开发的新的灵活网格光谱元素动力核心。使用这一新的核心，以及标准的CCSM大气模块，对与目前地中海地形截然不同的地形进行建模研究，将涉及到在远离标准气候的表面边界条件下进行模型。这可能有助于暴露隐藏的弱点，从而改进模型设计。这个项目提供了一个机会来模拟地球历史上一个使整个海洋盆地暴露在蒸发中的独特事件。这可能会导致一些不同寻常的发现，并将为研究生提供一个独特的研究机会。

This award provides funds to model the Messinian desiccation using a suite of climate models, including a single column model, simplified stationary wave model, and general circulation model. During the Messinian period of the Miocene Epoch about 5.5 million years ago (Ma), tectonic activity near the present Straits of Gibraltar resulted in the isolation of the Mediterranean Sea. At the height of this isolation, evaporation of the Mediterranean Sea appears to have reduced the sea level within the Mediterranean basin by 1500 meters to 2000 meters. This resulted in abundant salt deposits around the Mediterranean basin, and in the erosion of deep canyons by the major rivers flowing into the Mediterranean. The researcher maintains that neither the impact of a deep, extensive subaerial basin on the general circulation of the atmosphere, nor the physical process by which the desiccation occurred has been treated using a sophisticated atmospheric model. As a consequence, the researcher aims to produce a physically consistent reconstruction of the climatic conditions within a deep basin and an assessment of the impact of the existence of such a basin on the regional climate. This impact will be examined by direct physical interaction of the deep basin with the atmospheric circulation, and by changes to transports of water vapor and dust and salt from the desiccation of the Mediterranean Sea. The project will include the use of a new flexible-grid spectral element dynamical core developed for the NCAR Community Climate System Model (CCSM) atmospheric module. The use of this new core, as well as the standard CCSM atmospheric module for a modeling study of topography so radically different from present Mediterranean topography, will involve the models under surface boundary conditions far from the standard climate in which they were developed. This may help expose hidden weaknesses, thereby allowing improvements in model design. This project provides an opportunity to model a singular event in Earth history that exposed an entire sea basin to evaporation. This could lead to some unusual findings and will provide a unique opportunity in research for a graduate student.