Time delay evaluation on thewater-leaving irradiance retrieved from empirical models and satellite imagery

Peter Otto, Ramiro Vallejo-Rodríguez, Saskia Keesstra, Elizabeth León-Becerril, José de Anda, Leonel Hernández-Mena, Jorge del Real-Olvera, José de Jesús Díaz-Torres*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Temporal delays and spatial randomness between ground-based data and satellite overpass involve important deviations between the empirical model output and real data; these are factors poorly considered in the model calibration. The inorganic matter-generated turbidity in Lake Chapala (Mexico) was taken as a study case to expose the influence of such factors. Ground-based data from this study and historical records were used as references. We take advantage of the at-surface reflectance from Landsat-8, sun-glint corrections, a reduced NIR-band range, and null organic matter incidence in these wavelengths to diminish the physical phenomena-related radiometric artifacts; leaving the spatio-temporal relationships as the principal factor inducing the model uncertainty. Non-linear correlations were assessed to calibrate the best empirical model; none of them presented a strong relationship (<73%), including that based on hourly delays. This last model had the best predictability only for the summer-fall season, explaining 71% of the turbidity variation in 2016, and 59% in 2017, with RMSEs < 24%. The instantaneous turbidity maps depicted the hydrodynamic complexity of the lake, highlighting a strong component of spatial randomness associated with the temporal delays. Reasonably, robust empirical models will be developed if several dates and sampling-sites are synchronized with more satellite overpasses.

Original languageEnglish
Article number87
JournalRemote Sensing
Volume12
Issue number1
DOIs
Publication statusPublished - Jan 2020

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Keywords

  • Empirical model
  • Lake Chapala
  • Landsat-8
  • NIR reflectance
  • Shallow lake
  • Spatial randomness
  • Subtropical zone
  • Temporal delay
  • Turbidity

Cite this

Otto, P., Vallejo-Rodríguez, R., Keesstra, S., León-Becerril, E., de Anda, J., Hernández-Mena, L., ... de Jesús Díaz-Torres, J. (2020). Time delay evaluation on thewater-leaving irradiance retrieved from empirical models and satellite imagery. Remote Sensing, 12(1), [87]. https://doi.org/10.3390/RS12010087