Articles | Volume 9, issue 7
Atmos. Meas. Tech., 9, 3193–3203, 2016
Atmos. Meas. Tech., 9, 3193–3203, 2016

Research article 21 Jul 2016

Research article | 21 Jul 2016

Comparison of MODIS and VIIRS cloud properties with ARM ground-based observations over Finland

Moa K. Sporre1, Ewan J. O'Connor2,3, Nina Håkansson4, Anke Thoss4, Erik Swietlicki1, and Tuukka Petäjä5 Moa K. Sporre et al.
  • 1Department of Physics, Lund University, Lund, Sweden
  • 2Department of Meteorology, University of Reading, Reading, UK
  • 3Finnish Meteorological Institute, Helsinki, Finland
  • 4Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
  • 5Department of Physics, University of Helsinki, Helsinki, Finland

Abstract. Cloud retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the satellites Terra and Aqua and the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard the Suomi-NPP satellite are evaluated using a combination of ground-based instruments providing vertical profiles of clouds. The ground-based measurements are obtained from the Atmospheric Radiation Measurement (ARM) programme mobile facility, which was deployed in Hyytiälä, Finland, between February and September 2014 for the Biogenic Aerosols – Effects on Clouds and Climate (BAECC) campaign. The satellite cloud parameters cloud top height (CTH) and liquid water path (LWP) are compared with ground-based CTH obtained from a cloud mask created using lidar and radar data and LWP acquired from a multi-channel microwave radiometer. Clouds from all altitudes in the atmosphere are investigated. The clouds are diagnosed as single or multiple layer using the ground-based cloud mask. For single-layer clouds, satellites overestimated CTH by 326 m (14 %) on average. When including multilayer clouds, satellites underestimated CTH by on average 169 m (5.8 %). MODIS collection 6 overestimated LWP by on average 13 g m−2 (11 %). Interestingly, LWP for MODIS collection 5.1 is slightly overestimated by Aqua (4.56 %) but is underestimated by Terra (14.3 %). This underestimation may be attributed to a known issue with a drift in the reflectance bands of the MODIS instrument on Terra. This evaluation indicates that the satellite cloud parameters selected show reasonable agreement with their ground-based counterparts over Finland, with minimal influence from the large solar zenith angle experienced by the satellites in this high-latitude location.

Short summary
Satellite measurements of cloud top height and liquid water path are compared to ground-based remote sensing to evaluate the satellite retrievals. The overall performance of the satellite retrievals of cloud top height are good, but they become more problematic when several layers of clouds are present. The liquid water path retrievals also agree well, and the average differences are within the estimated measurement uncertainties.