Geometry‐Dependent Surface Lambertian‐Equivalent Reflectivity (GLER) Climatology for the TEMPO Mission
Weizhen Hou, Christopher Chan Miller, Gonzalo González Abad, Xiong Liu, Peter Zoogman, Kelly Chance, Caroline R. Nowlan, Heesung Chong, Huiqun Wang, John C. Houck, Junsung Park, Wenhan Qin, Zachary Fasnacht, Joanna Joiner, Nickolay A. Krotkov, Alexander P. Vasilkov, Robert J. D. SpurrAbstract
We describe a Geometry‐dependent surface Lambertian‐Equivalent Reflectivity (GLER) climatology developed to support operational retrievals for the Tropospheric Emissions: Monitoring of Pollution (TEMPO) mission. This data set provides monthly and hourly surface reflectance for snow‐free land, snow‐covered land, and oceanic regions. The set is constructed by integrating MODIS MCD43C1/C2 bidirectional reflectance distribution function (BRDF) parameters, snow cover information, and radiative transfer simulations. A Factor‐Analysis spectral reconstruction method, constrained by spectral priors from the USGS spectral library and the SCIAMACHY LER data set, was applied to extend discrete MODIS four‐band reflectance over land to a near‐continuous spectral range (335–900 nm), covering most of the spectral range of TEMPO. The ocean climatology GLER was simulated using a Cox–Munk surface slope distribution model coupled with the VLIDORT model. Preliminary comparisons with the TROPOMI directionally dependent LER (DLER) empirical data set demonstrate strong seasonal consistency at a local solar time of 13:30. Summer mean differences generally remain within ±0.01, while larger winter biases (up to 0.03) are primarily attributed to extreme solar geometries, sub‐pixel residual snow, and adjacency pixel effects. This GLER climatology currently serves as a crucial input for TEMPO Level 2 operational algorithms, supporting retrievals for nitrogen dioxide, formaldehyde, and ozone, as well as cloud parameter estimations.