A Climatology of Atmospheric Iron Inputs to the Atlantic Ocean
Lead Research Organisation:
University of East Anglia
Department Name: Environmental Sciences
Abstract
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.
Organisations
Publications
Baker A
(2013)
Estimation of atmospheric nutrient inputs to the Atlantic Ocean from 50°N to 50°S based on large-scale field sampling: Iron and other dust-associated elements
in Global Biogeochemical Cycles
Okin G
(2011)
Impacts of atmospheric nutrient deposition on marine productivity: Roles of nitrogen, phosphorus, and iron ATMOSPHERIC DEPOSITION TO OCEANS
in Global Biogeochemical Cycles
Schulz M
(2012)
Atmospheric transport and deposition of mineral dust to the ocean: implications for research needs.
in Environmental science & technology
Sholkovitz E
(2012)
Fractional solubility of aerosol iron: Synthesis of a global-scale data set
in Geochimica et Cosmochimica Acta
Description | 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 carried out 10 long-transect crossings of the Atlantic Ocean between the years 2000 and 2005, sampling the atmosphere for the iron content of aerosol and rain. This is a unique dataset and allows 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 were compared directly to the results of three separate dust transport models. This comparison showed that all of the models performed well for some of the substances that we measured, in some parts of the Atlantic, but none could reproduce all of the measurements over the whole Atlantic. In one case the lack of agreement between observations and model was due to an over-estimation of rainfall in the model. |
Exploitation Route | Development of models that simulate the atmospheric transport of dust and its direct and indirect impact on the Earth System is on-going. Comparison of our results to existing models has helped to highlight areas where models can be improved. The observational database established during our project will continue to be useful resource for the validation of such models in the future. |
Sectors | Environment |
Title | SOLAS Aerosol and Rainwater Chemistry Database |
Description | The database holds a collection of data on the concentrations of iron, nutrients, trace metals and other constituents in aerosols and rainwater obtained during sampling from ships in the remote ocean and from some marine land-based sites. The coverage of the data is global in extent. |
Type Of Material | Database/Collection of data |
Year Produced | 2009 |
Provided To Others? | Yes |
Impact | Data obtained from the database is currently being used to validate global models of atmospheric nitrogen deposition. |
URL | http://www.bodc.ac.uk/solas_integration/implementation_products/group1/aerosol_rain/ |