The MODIS Cloud Optical and Microphysical Products: Collection 6 Updates and Examples From Terra and Aqua

Abstract

The MODIS Level-2 cloud product (Earth Science Data Set names MOD06 and MYD06 for Terra and Aqua MODIS, respectively) provides pixel-level retrievals of cloud-top properties (day and night pressure, temperature, and height) and cloud optical properties (optical thickness, effective particle radius, and water path for both liquid water and ice cloud thermodynamic phases-daytime only). Collection 6 (C6) reprocessing of the product was completed in May 2014 and March 2015 for MODIS Aqua and Terra, respectively. Here we provide an overview of major C6 optical property algorithm changes relative to the previous Collection 5 (C5) product. Notable C6 optical and microphysical algorithm changes include: (i) new ice cloud optical property models and a more extensive cloud radiative transfer code lookup table (LUT) approach, (ii) improvement in the skill of the shortwave-derived cloud thermodynamic phase, (iii) separate cloud effective radius retrieval datasets for each spectral combination used in previous collections, (iv) separate retrievals for partly cloudy pixels and those associated with cloud edges, (v) failure metrics that provide diagnostic information for pixels having observations that fall outside the LUT solution space, and (vi) enhanced pixel-level retrieval uncertainty calculations. The C6 algorithm changes collectively can result in significant changes relative to C5, though the magnitude depends on the dataset and the pixel's retrieval location in the cloud parameter space. Example Level-2 granule and Level-3 gridded dataset differences between the two collections are shown. While the emphasis is on the suite of cloud optical property datasets, other MODIS cloud datasets are discussed when relevant.

Observations of Local Positive Low Cloud Feedback Patterns and Their Role in Internal Variability and Climate Sensitivity

“…Here the sum of low and midlevel cloud fraction is used to better represent the true total low cloud fraction (Yuan et al, 2016). Aqua MODIS level‐3 monthly products are also used to derive low cloud fraction (Platnick et al, 2016). MODIS onboard Aqua is well calibrated.…”

Earth Observations from DSCOVR EPIC Instrument

“…Over the years, cloud products from LEO satellites, such as Terra, Aqua, and the NOAA satellites (e.g., Parkinson 2003;Platnick et al 2017;Heidinger and Pavolonis 2009) and from geostationary-Earth-orbiting (GEO) satellites, such as GOES (e.g., Schmit et al 2008Schmit et al , 2017, constitute the main global cloud property database. With the launch of DSCOVR, the EPIC instrument provides new opportunities for cloud-related studies, since it covers almost the entire sunlit half of the Earth.…”

“…By incorporating the Goddard Earth Observing System Model, version 5 (GEOS-5), forecasted atmospheric profiles, the CEP is converted to CEH. 3) The EPIC COT product is produced using the operational MODIS cloud retrieval infrastructure (Platnick et al 2017). The MODIS system provides simultaneous two-channel retrievals of COT and cloud effective radius (CER), and cloud phase retrievals using a variety of spectral tests.…”

Comparing Airborne and Satellite Retrievals of Optical and Microphysical Properties of Cirrus and Deep Convective Clouds using a Radiance Ratio Technique

“…The MODIS cloud product MYD06_L2 (Platnick et al, 2003(Platnick et al, , 2017 provides three different r eff which are retrieved using different near-infrared wavelengths centered at λ = 1640 nm, 2130 20 nm, and 3700 nm (so-called r eff,1640 , r eff,2130 , and r eff,3700 ). However, the quality of r eff,1640 is limited due to problems of the detectors of MODIS-Aqua band 6.…”