Data assimilation for volcanic ash plumes using a satellite observational operator: A case study on the 2010 Eyjafjallajokull volcanic eruption

Guangliang Fu, Fred Prata, Hai Xiang Lin, Arnold Heemink, AJ Segers, Sha Lu

Research output: Contribution to journalArticleScientificpeer-review

13 Citations (Scopus)
52 Downloads (Pure)

Abstract

Using data assimilation (DA) to improve model forecast accuracy is a powerful approach that requires available observations. Infrared satellite measurements of volcanic ash mass loadings are often used as input observations for the assimilation scheme. However, because these primary satellite-retrieved data are often two-dimensional (2-D) and the ash plume is usually vertically located in a narrow band, directly assimilating the 2-D ash mass loadings in a three-dimensional (3-D) volcanic ash model (with an integral observational operator) can usually introduce large artificial/spurious vertical correlations.

In this study, we look at an approach to avoid the artificial vertical correlations by not involving the integral operator. By integrating available data of ash mass loadings and cloud top heights, as well as data-based assumptions on thickness, we propose a satellite observational operator (SOO) that translates satellite-retrieved 2-D volcanic ash mass loadings to 3-D concentrations. The 3-D SOO makes the analysis step of assimilation comparable in the 3-D model space.

Ensemble-based DA is used to assimilate the extracted measurements of ash concentrations. The results show that satellite DA with SOO can improve the estimate of volcanic ash state and the forecast. Comparison with both satellite-retrieved data and aircraft in situ measurements shows that the effective duration of the improved volcanic ash forecasts for the distal part of the Eyjafjallajökull volcano is about 6 h.
Original languageEnglish
Pages (from-to)1187-1205
Number of pages19
JournalAtmospheric Chemistry and Physics
Volume17
Issue number2
DOIs
Publication statusPublished - 25 Jan 2017

Keywords

  • Satellite data
  • data assimilation
  • Ensemble Kalman filter
  • ensemble square root filter
  • aircraft data
  • satellite observational operator
  • OA-Fund TU Delft

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