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FraRI: an algorithm to account for the discontinuity at 60 degrees N in MODIS temperature products

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • Luigi Sedda
  • David W. Morley
  • David Benz
  • G. R. William Wint
  • Zhengming Wan
  • David J. Rogers
<mark>Journal publication date</mark>2013
<mark>Journal</mark>International Journal of Remote Sensing
Issue number4
Number of pages14
Pages (from-to)1220-1233
Publication StatusPublished
Early online date2/10/12
<mark>Original language</mark>English


The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra and Aqua satellites conducts continuous monitoring of the Earth's land surface and oceans. Recently, a sharp discontinuity (averaging 1.9 degrees C) has been noticed at 60 degrees N in both MODIS daytime and night-time land surface temperature (LST) products. This linear artefact arises because the CO2 high cloud test in the operational code for the generation of the MODIS cloud mask product is used only in the non-polar region (between 60 degrees N and 60 degrees S). The resulting discontinuity clearly has negative implications for any statistical applications of these temperature data. In this technical note we present a new algorithm, which minimizes this discontinuity. The method uses edge detection and elimination based on a mixture of Sobel and non-linear Laplacian filters (edge detection and quantification), cubic splines (edge modelling), and a controllable power function for image restoration. The implementation of this algorithm is demonstrated on an image of average minimum night-time LST between 2001 and 2008.