Authors
Angie Crews (University of Colorado Boulder)
Abstract
Passive microwave radiometers provide critical observations that are routinely assimilated into numerical weather prediction (NWP) systems. Because these sensors measure extremely weak naturally emitted microwave energy, they are inherently vulnerable to radio-frequency interference (RFI). Spectrum allocations for 5G services in frequency bands adjacent to those used by passive microwave sensors have increased concern that out-of-band emissions and harmonic signals could affect radiometer measurements. This work examines on-orbit observations from the Advanced Technology Microwave Sounder (ATMS) over urban regions with established 5G cellular infrastructure and compares the measurements with simulated reference data generated using the Community Radiative Transfer Model (CRTM). Observation-minus- background (O-B) biases are derived by comparing ATMS measurements with CRTM simulated brightness temperatures, followed by statistical evaluation of the resulting bias distributions. Independent 5G mmWave signal measurements are taken within urban study areas with SigCap, a data application used to collect detailed cellular metrics. These metrics are utilized to inform hypotheses regarding possible RFI levels. Results are presented for a case study of the Denver metropolitan area, together with an initial analysis of observations over Tokyo, Japan.