Work

Effect of Sun Glints from Ice Clouds on MODIS Data Products

Year: 2026

Type: article

Abstract: This paper examines the way sun glints from horizontally oriented ice crystals that occur in clouds impact atmospheric data products provided by the Moderate-Resolution Imaging Spectroradiometer (MODIS). For this, the paper presents a statistical analysis of two years of MODIS data from all tropical land regions. The results indicate only weak glint effects on cloud amount and height, as these values are obtained using mainly observations of (inherently glint-free) thermal infrared radiation. In contrast, glints are found to cause a roughly 10% increase in mean retrieved cloud optical thickness, and 10% decreases in mean particle size and in the prevalence of ice cloud phase. Moreover, glints from undetected ice clouds are found to cause roughly 5% increases in mean aerosol optical depth and coarse mode fraction, and positive and negative biases comparable to the magnitude of the seasonal cycle in total column ozone and precipitable water vapor amounts, respectively. Given the modest size of glints, the effects are most important to consider in studies that use data from a limited range of viewing zenith angles (e.g., around nadir). The results are relevant to MODIS and to other satellite imagers that use similar retrieval algorithms, and thus likely experience similar glint effects.

Source: Remote Sensing

DOI: 10.3390/rs18203488

Authors: Tamás Várnai, Alexander Marshak, Alexander Kostinski

Institutions: Goddard Space Flight Center, University of Maryland, Baltimore County, Michigan Technological University

Language: English

Topic: Atmospheric aerosols and clouds

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,258