Earth surface reflectance climatology from 3 years of OMI data

Abstract

Global maps of the Earth's surface Lambertian equivalent reflectance (LER) are constructed using 3 years of Ozone Monitoring Instrument (OMI) measurements obtained between October 2004 and October 2007 at 23 wavelengths between 328 and 500 nm. The maps are constructed on a 0.5° by 0.5° longitude‐latitude grid for each calendar month using an algorithm based on temporal histograms of the observed LER values per geophysical location. The algorithm allows seasonal effects related to vegetation, snow, and ice but excludes statistical outliers. The maps show typical features like open ocean regions with high reflectivity indicative of low phytoplankton levels, coastal waters with high reflectance caused by silt, and oceanic regions with low reflectance correlated with chlorophyll. Open oceans in general have a higher reflectivity than does land up to 420 nm. The highest reflectivity values of oceans occur at 380 nm. Good agreement is found with a similar LER map based on data from the Total Ozone Mapping Spectrometer (TOMS) at 331, 340, 360, and 380 nm, which is 0.015 lower on average. The comparison with data from the Global Ozone Monitoring Experiment (GOME) at 335, 380, 440, and 494 nm is also satisfactory, being 0.005 lower on average. The LER derived from OMI data is approximately 0.02 higher than the black sky albedo as derived from the Moderate Resolution Imaging Spectroradiometer at 470 nm, which is partly related to viewing geometry effects of the bidirectional reflectance distribution function of the surface. The data set presented contains residual cloud features over tropical rain forest regions, has a higher spatial resolution than those created using TOMS and GOME data, and includes more wavelengths.

Accounting for the effects of surface BRDF on satellite cloud and trace-gas retrievals: a new approach based on geometry-dependent Lambertian equivalent reflectivity applied to OMI algorithms

“…In contrast, the climatological LERs currently used in OMI algorithms, from either the Total Ozone Mapping Spectrometer (TOMS) or OMI, are derived by correcting only for Rayleigh scattering and thus include aerosol effects (see details in Herman and Celarier, 1997;Kleipool et al, 2008). Therefore, the use of the geometry-dependent LER product in trace-gas algorithms over heavily polluted regions may also require an explicit account of aerosols (Lin et al, 2015).…”

“…Surface reflectivity climatologies used in most current algorithms are typically gridded monthly Lambertian equivalent reflectivities (LERs) that have been derived from satellite observations (e.g., Herman and Celarier, 1997;Kleipool et al, 2008;Russell et al, 2011;Popp et al, 2011). These climatologies generally have no dependence on the observation geometry.…”

Sulfur dioxide retrievals from TROPOMI onboard Sentinel-5 Precursor: algorithm theoretical basis

“…A typical uncertainty on the albedo is 0.02 (Kleipool et al, 2008). This translates to an error on the air mass factor after multiplication by the slope of the air mass factor as a function of the albedo (Eq.…”

“…For the surface albedo dimension, we use the climatological monthly minimum Lambertian equivalent reflector (minLER) data from Kleipool et al (2008) at 328 nm for w1 and w2, and 376 m for w3. This database is based on OMI measurements and has a spatial resolution of 0.5 • × 0.5 • .…”

Towards the retrieval of tropospheric ozone with the Ozone Monitoring Instrument (OMI)

“…The surface albedo is also fitted in the retrieval and the OMI surface albedo climatology (Kleipool et al, 2008) is used as an initial value for the surface underneath the atmosphere. If the cloud fraction taken from the dedicated OMI cloud product (OMCLDO2; Acarreta et al, 2004) is lower than 0.2, surface albedos are fitted.…”