MICRU: an effective cloud fraction algorithm designed for UV–vis satellite instruments with large viewing angles

Sihler, Holger; Beirle, Steffen; Dörner, Steffen; Gutenstein-Penning de Vries, Marloes; Hörmann, Christoph; Borger, Christian; Warnach, Simon; Wagner, Thomas

doi:https://doi.org/10.5194/amt-14-3989-2021

Articles | Volume 14, issue 6

https://doi.org/10.5194/amt-14-3989-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-14-3989-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 14, issue 6

Research article

|

02 Jun 2021

Research article |

| 02 Jun 2021

MICRU: an effective cloud fraction algorithm designed for UV–vis satellite instruments with large viewing angles

Holger Sihler, Steffen Beirle, Steffen Dörner, Marloes Gutenstein-Penning de Vries, Christoph Hörmann, Christian Borger, Simon Warnach, and Thomas Wagner

Data sets

MICRU effective cloud fractions from GOME-2A Holger Sihler and Thomas Wagner https://doi.org/10.17617/3.59

MODIS/Terra Snow Cover 8-Day L3 Global 0.05Deg CMG, Version 6, 2007-2013 D. K. Hall and G. A. Riggs https://doi.org/10.5067/MODIS/MOD10C2.006

Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 1, NSIDC-0051, 2007-2013 D. J. Cavalieri, C. L. Parkinson, P. Gloersen, and H. J. Zwally https://doi.org/10.5067/8GQ8LZQVL0VL

Global 30 Arc-Second Elevation (GTOPO30) USGS https://doi.org/10.5066/F7DF6PQS

Global Self-consistent Hierarchical High-resolution Geography (GSHHG), Version 2.3.7 NOAA https://www.ngdc.noaa.gov/mgg/shorelines/

GOME-2A Absorbing Aerosol Index MSC (R1) - Metop AC SAF https://doi.org/10.15770/EUM_SAF_O3M_0003

GOME-2A Absorbing Aerosol Index PMD (R1) - Metop AC SAF https://doi.org/10.15770/EUM_SAF_O3M_0004

Short summary

MICRU is an algorithm for the retrieval of effective cloud fractions (CFs) from satellite measurements. CFs describe the amount of clouds, which have a significant impact on the vertical sensitivity profile of trace gases like NO₂ and HCHO. MICRU retrieves small CFs with an accuracy of 0.04 over the entire satellite swath. It features an empirical surface reflectivity model accounting for physical anisotropy (BRDF, sun glitter) and instrumental effects. MICRU is also applicable to imager data.