GLOBEC 2000: Nested Interdisciplinary Models for the Gulf of Alaska

作为正在进行的globecc资助的阿拉斯加沿海湾跨学科建模工作的一部分，本研究包括以下技术目标：用于区域环流建模的更高空间分辨率和嵌套网格能力，嵌套中尺度大气建模和区域风和浮力强迫，以及为现有沿海NPZ模型提供边界条件的深海NPZ模型。目前这些模型的单年模拟将扩展到连续的多年积分，旨在为幼鲑鱼的个体模型提供循环和猎物场。这些耦合模型将共同用于探索物理场的年际/年代际变化影响GLOBEC目标浮游动物物种的生产和CGOA幼鱼摄食的机制。这些模型的生态系统动力学将与在GLOBEC下为加利福尼亚洋流系统开发的模型进行比较。核心科学问题包括：1)“最优稳定性窗口”假说，Gargett提出阿留申低地的变化通过影响CGOA和CCS系统中水柱的稳定性来影响鲑鱼。通常，在靠近CGOA的亚北极环流中观察到高营养但低光照条件，而在靠近CCS的亚热带环流中观察到低营养但高光照条件。2) CGOA的营养来源，即阿拉斯加海岸湾，几乎全年都是一个下流系统。如此产生的逆压梯度应该会对大陆架深层营养物质的供应产生不利影响，无论该大陆架是光滑笔直的，还是被海底峡谷打断的（就像CGOA的情况一样）。这些比较将有助于阐明两个系统在年代际时间尺度上观察到的鲑鱼（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.