GLOBEC 2000: Nested Interdisciplinary Models for the Gulf of Alaska

作为正在进行的由GLOBEC资助的阿拉斯加湾沿岸跨学科模拟工作的一部分，这项研究包括以下技术目标：用于区域环流模拟的更高的空间分辨率和嵌套网格能力，嵌套的中尺度大气模拟和区域风和浮力强迫，以及为现有的沿海NPZ模式提供边界条件的深海NPZ模式。目前对这些模型的一年模拟将扩展到连续的数十年积分，旨在为基于个体的幼鲑鱼模型提供循环场和捕食场。这些耦合模式将被用来探索物理场的年际/年代际变化对GLOBEC目标浮游动物物种的生产和CGOA中鲑鱼幼鱼摄食的影响的机制。这些模型的生态系统动力学将与GLOBEC为加州海流系统开发的模型进行比较。中心科学问题包括：1)“最佳稳定窗口”假说，其中Gargett提出，阿留申低压的变化通过影响CGOA和CCS系统的水柱稳定性来影响鲑鱼。通常，在与CGOA相邻的亚北极环流中观察到高营养但弱光条件，与之相反，在与CCS相邻的副热带环流中观察到低营养但强光条件。2)CGOA的营养物质来源，即阿拉斯加海湾沿岸，几乎全年都是一个下流系统。由此产生的不利压力梯度应该不利于向大陆架供应深层营养物质，无论大陆架是平坦笔直的还是(就像CGOA中的情况一样)被海底峡谷点缀。这些比较将有助于解释在十年时间尺度上观察到的两个系统中鲑鱼的(逆)协方差。

As part of an ongoing GLOBEC-funded interdisciplinary modeling effort for the Coastal Gulf of Alaska, this study includes the following technical objectives: higher spatial resolution and nested grid capabilities for regional circulation modeling, nested mesoscale atmospheric modeling and regional wind and buoyancy forcing, and a deep-ocean NPZ model to provide boundary conditions for an existing coastal NPZ model. Present single-year simulations of these models will be expanded to continuous multi-decadal integrations, designed to provide circulation and prey fields to an individual-based model of juvenile salmon. Together, these coupled models will be used to explore the mechanisms by which interannual/interdecadal variability of physical fields affect the production of GLOBEC target zooplankton species and the feeding of juvenile salmon in the CGOA. The ecosystem dynamics of these models will be compared with those developed under GLOBEC for the California Current System. Central scientific issues include: 1) The "optimal stability window" hypothesis where Gargett has suggested that variations in the Aleutian Low affect salmon through their impact on water column stability in the CGOA and CCS systems. Typically, high nutrient but low light conditions are observed in the subarctic gyre adjacent to the CGOA, in contrast to low nutrient but high light conditions in the subtropical gyre adjacent to the CCS. And 2) The source of nutrients of the CGOA, i.e., the Coastal Gulf Alaska is a downwelling system for nearly all of the year. The adverse pressure gradient so produced should work against the supply of deep nutrients to the shelf, whether that shelf is smooth and straight or (as is the case in the CGOA) punctuated by submarine canyons. These comparison will help elucidate the observed (inverse) covariance of salmon in the two systems on decadal time scales.