This acquisition mode records only the incoming electromagnetic radiation emitted from the Earth. Radiometer instruments conduct passive microwave imaging. The energy budget of emitted radiation (from Earth) is significantly smaller than from instrument-generated, transmitted electromagnetic waves, used in the active microwave imaging mode. Hence, the signal to noise ratio is significantly worse for passive microwave imaging forcing a longer intergration time for robust signal recording. This results in a coarse spatial resolution of radiometer images (in the order of kilometers).