Application of CALIOP Measurements to the Evaluation of Cloud Phase Derived from MODIS Infrared Channels Academic Article uri icon

abstract

  • Abstract In this study, Moderate Resolution Imaging Spectroradiometer (MODIS) infrared-based cloud thermodynamic phase retrievals are evaluated using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) retrievals for the 6 months from January to June of 2008. The CALIOP 5-km cloud-layer product provides information on cloud opacity, cloud-top height, midlayer cloud temperature, and cloud thermodynamic phase. Comparisons are made between MODIS IR phase and CALIOP observations for single-layer clouds (54% of the cloudy CALIOP scenes) and for the top layer of the CALIOP scenes. Both CALIOP and MODIS retrieve larger fractions of water clouds in the single-layer cases than in the top-layer cases, demonstrating that focusing on only single-layer clouds may introduce a water-cloud bias. Of the single-layer clouds, 60% are transparent and 40% are opaque (defined by the lack of a CALIOP ground return). MODIS tends to classify single-layer clouds with midlayer temperatures below 40C as ice; around 30C nearly equally as ice, mixed, and unknown; between 28 and 15C as mixed; and above 0C as water. Ninety-five percent of the single-layer CALIOP clouds not detected by MODIS are transparent. Approximately of transparent single-layer clouds with temperatures below 30C are not detected by MODIS and close to another are classified as ice, with the rest assigned as water, mixed, or unknown. CALIOP classes nearly all of these transparent cold clouds as ice.

published proceedings

  • JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY

author list (cited authors)

  • Cho, H., Nasiri, S. L., & Yang, P.

citation count

  • 25

complete list of authors

  • Cho, Hyoun-Myoung||Nasiri, Shaima L||Yang, Ping

publication date

  • October 2009