On the spatio-temporal representativeness of observations

Nick Schutgens, Svetlana Tsyro, Edward Gryspeerdt, Daisuke Goto, Natalie Weigum, Michael Schulz, Philip Stier

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The discontinuous spatio-temporal sampling of observations has an impact when using them to construct climatologies or evaluate models. Here we provide estimates of this so-called representation error for a range of timescales and length scales (semi-annually down to sub-daily, 300 to 50 km) and show that even after substantial averaging of data significant representation errors may remain, larger than typical measurement errors. Our study considers a variety of observations: ground-site or in situ remote sensing (PM2. 5, black carbon mass or number concentrations), satellite remote sensing with imagers or lidar (extinction). We show that observational coverage (a measure of how dense the spatio-temporal sampling of the observations is) is not an effective metric to limit representation errors. Different strategies to construct monthly gridded satellite L3 data are assessed and temporal averaging of spatially aggregated observations (super-observations) is found to be the best, although it still allows for significant representation errors. However, temporal collocation of data (possible when observations are compared to model data or other observations), combined with temporal averaging, can be very effective at reducing representation errors. We also show that ground-based and wide-swath imager satellite remote sensing data give rise to similar representation errors, although their observational sampling is different. Finally, emission sources and orography can lead to representation errors that are very hard to reduce, even with substantial temporal averaging.

Original languageEnglish
Pages (from-to)9761-9780
Number of pages20
JournalAtmospheric Chemistry and Physics
Volume17
Issue number16
DOIs
Publication statusPublished - 21 Aug 2017

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remote sensing
sampling
orography
black carbon
lidar
satellite data
extinction
timescale
in situ
emission source

Cite this

Schutgens, N., Tsyro, S., Gryspeerdt, E., Goto, D., Weigum, N., Schulz, M., & Stier, P. (2017). On the spatio-temporal representativeness of observations. Atmospheric Chemistry and Physics, 17(16), 9761-9780. https://doi.org/10.5194/acp-17-9761-2017
Schutgens, Nick ; Tsyro, Svetlana ; Gryspeerdt, Edward ; Goto, Daisuke ; Weigum, Natalie ; Schulz, Michael ; Stier, Philip. / On the spatio-temporal representativeness of observations. In: Atmospheric Chemistry and Physics. 2017 ; Vol. 17, No. 16. pp. 9761-9780.
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Schutgens, N, Tsyro, S, Gryspeerdt, E, Goto, D, Weigum, N, Schulz, M & Stier, P 2017, 'On the spatio-temporal representativeness of observations' Atmospheric Chemistry and Physics, vol. 17, no. 16, pp. 9761-9780. https://doi.org/10.5194/acp-17-9761-2017

On the spatio-temporal representativeness of observations. / Schutgens, Nick; Tsyro, Svetlana; Gryspeerdt, Edward; Goto, Daisuke; Weigum, Natalie; Schulz, Michael; Stier, Philip.

In: Atmospheric Chemistry and Physics, Vol. 17, No. 16, 21.08.2017, p. 9761-9780.

Research output: Contribution to JournalArticleAcademicpeer-review

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