Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 12, 933-941, 2008
http://www.hydrol-earth-syst-sci.net/12/933/2008/
doi:10.5194/hess-12-933-2008
© Author(s) 2008. This work is distributed
under the Creative Commons Attribution 3.0 License.
 
20 Jun 2008
Empirical Mode Decomposition on the sphere: application to the spatial scales of surface temperature variations
N. Fauchereau1, G. G. S. Pegram2, and S. Sinclair2 1Department of Oceanography, University of Cape-Town, Cape Town, South Africa
2Civil Engineering, University of KwaZulu-Natal, Durban, South Africa
Abstract. Empirical Mode Decomposition (EMD) is applied here in two dimensions over the sphere to demonstrate its potential as a data-adaptive method of separating the different scales of spatial variability in a geophysical (climatological/meteorological) field. After a brief description of the basics of the EMD in 1 then 2 dimensions, the principles of its application on the sphere are explained, in particular via the use of a zonal equal area partitioning. EMD is first applied to an artificial dataset, demonstrating its capability in extracting the different (known) scales embedded in the field. The decomposition is then applied to a global mean surface temperature dataset, and we show qualitatively that it extracts successively larger scales of temperature variations related, for example, to topographic and large-scale, solar radiation forcing. We propose that EMD can be used as a global data-adaptive filter, which will be useful in analysing geophysical phenomena that arise as the result of forcings at multiple spatial scales.

Citation: Fauchereau, N., Pegram, G. G. S., and Sinclair, S.: Empirical Mode Decomposition on the sphere: application to the spatial scales of surface temperature variations, Hydrol. Earth Syst. Sci., 12, 933-941, doi:10.5194/hess-12-933-2008, 2008.
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