GSICS Microwave Sub-Group/ Lunar Calibration Focus Group meeting 2026-07-03

Presentation

AWS Lunar Pointing Calculation, Hu (Tiger) Yang, NASA

Attendees

Niutao Liu (Fudan U.)

Shengli Wu (CMA)

Tiger Hu (UMD)

Martin Burgdorf (U Hamburg)

Yang Gou (CMA)

Tim Hewison (EUMETSAT)

Catalina Medina (U Bern)

Summary

This meeting focused on lunar calibration activities for the Arctic Weather Satellite (AWS). Martin presented his analysis of beam size measurements derived from lunar observations, while Tiger shared his work on calculating lunar pointing directions.

Martin showed that the AWS water vapor channels around 183 GHz have a larger field of view than indicated by ground test measurements. He also demonstrated excellent agreement between AWS and MHS brightness temperature measurements over a lunar phase angle range of approximately 30 degrees.

Tiger presented his calculations of lunar pointing angles and found that the attitude information contained in the dataset appears to be inaccurate. The calculated lunar positions did not align with the observed lunar intrusions in the space-view measurements, suggesting potential issues with the satellite attitude data.

Catalina, from the University of Bern, presented antenna pattern simulations to help explain the differences between nadir and space-view measurements. She also discussed the team’s work on retrieving reflector emissivity from spacecraft maneuver data.

The discussion highlighted ongoing challenges related to satellite attitude information and scan angle calculations. Both presentations emphasized that accurate attitude data are essential for reliable lunar pointing and calibration, making improvements in these datasets a key priority for future work.