MODIS 4 µm radiance in global megacities depends on seasonality, land cover, and view zenith angle

We explored variation in 4 μm radiance in and nearby eight global megacities using MODIS band 23 calibrated radiance. We found the linkage between MIR radiance seasonality and seasonal pattern of insolation, especially stronger/pronounced at higher latitude than at tropics zones. The meteorological parameter - precipitation was identified as an impact factor of MIR radiance attenuation. Similarity of MIR radiance from desert, bare soil areas, or areas with a little of crop cover to MIR radiance from urban areas makes the distinction of cover using only MIR information even impossible during the time when insolation is the highest. Also, the seasonal variations of MIR radiance are being affected by the heterogeneity of cover as different types of building and construction materials, and urban green spaces. Conceivably, additional data and MIR radiance with higher spatial resolution improve and refine/detail information about MIR radiance behavior for further investigation.