Natalie M. Mahowald, Longlei Li, María Gonçalves Ageitos, Ronald L. Miller, Carlos Pérez García‐Pando, Paul Ginoux, Vincenzo Obiso, Philip G. Brodrick, Roger N. Clark, Karine Desboeufs, Robert O. Green, Gregory S. Okin, David R. Thompson, Sagar Rathod, Esteban Gazel, Adrian Hornby, Emile Journet, Maria Grazia Alaimo, C A Alves, Andres Alastuey, Paulo Artaxo, Alex R. Baker, Francisco Barraza, Silvia Becagli, Clifton S. Buck, Giulia Calzolai, Shankararaman Chellam, Ying Chen, P. Y. Chuang, David D. Cohen, Cristina Colombi, Evangelia Diapouli, Gaetano Dongarrà, Konstantinos Eleftheriadis, Johann Engelbrecht, Corinne Galy‐Lacaux, Cassandra Gaston, Darío Gómez, Yenny Gonzalez Ramos, J. L. Hand, R.M. Harrison, Barak Herut, P K Hopke, Zsófia Kertész, Katriina Kyllönen, Fabrice Lambert, Willam M. Landing, R. Losno, F. Lucarelli, Willy Maenhaut, Christopher Marsay, Hitoshi Matsui, Randall V. Martin, Yasser Morera‐Gómez, Adina Paytan, Joseph Prospero, Sergio Rodrı́guez, Géraldine Sarthou, Rachel Shelley, RL Siefert, Patricia Smichowski, Daniela Varrica
Abstract Atmospheric deposition of micro‐nutrients like Fe has been shown to be important for ocean biogeochemistry. The largest source of atmospheric Fe and other elements (e.g., Ca, Al, Si, and Ti) is desert dust, although there are significant non‐dust sources in some regions (e.g., combustion, sea salts, volcanoes). However, past estimates of these elements have been substantially uncertain due to limited information about the composition of the desert source regions. Here we use elemental distributions estimated from new Earth Surface Mineral Dust Source Investigation (EMIT) observations, which provide mineralogical composition at the surface of the Earth based on imaging spectroscopy measurements from the International Space Station. We focus on total elemental amounts, not on the soluble fraction. We add in other sources of these elements (anthropogenic and natural) and compare to a compilation of available surface concentration data from stations over land and from shipborne observations. The combined observational and model synthesis provides new information about the distribution and deposition of these elements. Our results suggest that the modeled distribution is similar to available observations, but discrepancies still exist in both natural desert dust regions as well as regions dominated by anthropogenic sources. Comparisons between the model estimated Ca/Al ratios and observations in some dust dominated regions suggest an underestimate of Ca/Al ratios. Global budgets for Ca, Al, Fe, Si, and Ti suggest that desert dust remains the dominant source, although volcanic and anthropogenic contributions are important in some regions. Changes in elemental distributions since preindustrial times were also estimated.