Development of a Dust-Iron Modeling System and a Benchmarking Regional Dust-Iron Budget Study

每年都有大量的灰尘沉积到海洋中，相关的铁供应在海洋表面生物质生产中起着至关重要的作用，而海洋生物质生产决定了海洋从大气中吸收的碳。然而，我们对海洋中尘铁沉积的定量估计存在着不确定性。我们非常依赖沙尘模型来生成沙尘-铁沉积模式，以研究海洋生物群落对气候变化的响应，并估计大气中二氧化碳浓度升高的海洋碳汇。现有的粉尘模型不能预测粉尘粒度分布，而这是确定尘铁迁移和沉积所必需的。在本项目中，我们计划通过开发一个新的区域尘铁模型系统来解决研究尘铁碳关系的最关键问题，该系统具有确定沙尘暴事件和零星弱尘事件的大小分辨尘铁排放和沉积的能力。粉尘参数化的方法将是全新的。该模拟系统将应用于澳大利亚的艾尔湖盆地，该盆地是南半球最大的风成尘-铁源，具有丰富的尘-铁观测和陆地表面特征。如果成功，该项目将首次提供详细的区域铁预算，用于模拟全球尘铁模式和海洋生物群落对铁供应的反应。

Large quantities of dust are deposited to the ocean each year and the associated iron supply plays an essential role in the surface-ocean biomass production which determines the ocean carbon uptake from the atmosphere. However, our quantitative estimates of dust-iron deposition to ocean are plagued with uncertainties. We very much rely on dust models to generate the dust-iron deposition patterns for studying the ocean biome response to climate change and to estimate the ocean carbon sink in an atmosphere with elevated CO2 concentration. Existing dust models cannot predict dust particles-size distributions which are necessary for determining dust-iron transport and deposition. In this project, we plan to tackle the most critical issues in studying the dust-iron-carbon relations by developing a new regional dust-iron modeling system with the capacity of determining size-resolved dust-iron emissions and depositions for both dust-storm events and sporadic weak dust events. The approach to dust parameterization will be completely new. The modeling system will be applied to the Lake Eyre Basin of Australia, which is the largest Aeolian dust-iron source in the southern Hemisphere and is rich in dust-iron observations and land-surface characterizations. If successful, this project will provide, for the first time, a detailed regional iron budget for benchmarking the simulations of global dust-iron patterns and ocean biome responses to iron supply.