A Climatology of Atmospheric Iron Inputs to the Atlantic Ocean

沙漠尘埃可以被强风卷起，并通过大气层输送很远的距离，有时甚至数千公里。这个过程对我们星球的气候有一些有趣的影响。铁只占灰尘的一小部分，对于生活在海洋中的植物(浮游植物)来说，这种元素往往供不应求。在一些海洋地区，被风吹来的尘埃可能是这些生物铁的重要来源，因此尘埃的供应可能与浮游植物的生长和由此导致的大气中碳的吸收有关。在大气中，尘埃也改变了辐射被地球吸收或反射的方式。因此，在地球气候系统的模型中包括尘埃传输是很重要的，但我们目前对这种传输的了解相当差。一个特别的困难是缺乏可用来帮助约束和开发此类模型的测量方法。一些长期监测点提供了关于粉尘输送随时间变化的信息，但这些监测点太少，而且分布太广，不能提供关于空间变异性的充分信息。UEA小组最近进行了10次大西洋长断面穿越，对大气中气溶胶和雨水中的铁含量进行了采样。这是一个独特的数据集，将使我们能够第一次根据现场数据直接评估大气中向大西洋输入的铁。我们的研究结果将直接与哈德利中心和Quest地球系统科学计划的模型师分享，这样我们就可以确保这些额外信息的好处直接传递给模型界。

Desert dust can be picked up by strong winds and transported great distances, sometimes thousands of kilometres, through the atmosphere. This process has some interesting effects on the climate of our planet. Iron makes up a small portion of the dust and this element is often in short supply for the plants (phytoplankton) that live in the ocean. Wind-blown dust can be an important source of iron to these organisms in some ocean regions and so dust supply can be linked to phytoplankton growth and the uptake of carbon from the atmosphere that this causes. While in the atmosphere, dust also alters the way that radiation is absorbed or reflect by the planet. It is therefore important to include dust transport in models of the Earth's climate system, but our current understanding of this transport is rather poor. One particular difficulty is the lack of measurements available to help constrain and develop such models. Some long-term monitoring sites provide information on changes in dust transport over time, but they are too few and too widely spaced to give adequate information on spatial variability. The UEA group has recently carried out 10 long-transect crossings of the Atlantic Ocean, sampling the atmosphere for the iron content of aerosol and rain. This is a unique dataset and will allow us to assess the atmospheric input of iron to the Atlantic directly, based on field data, for the first time. The results of our study will be shared directly with modellers at the Hadley Centre and the QUEST Earth System Science programme, so that we can ensure that the benefit of this extra information is passed directly to the modelling community.