1. Ozone Radiometer at 142 GHz: Calibration Yasmine Calisesi

2. The Stratospheric Ozone Monitoring Radiometer SOMORA ● Developed by the IAP for MeteoSwiss ● Tuned to Ozone at 142.175 GHz ● Improved version of the GROMOS instrument ● Operated at the IAP since January 2000 ● Moved to Payerne in June 2002

3. Somora location in Payerne

4. SOMORA Quasi-Optics Rotating Planar Mirror Hot Load Cold Load Eccosorb CV-3 IF 7.1 Ghz T = 310 K T=77K

5. Fans PT 100 Heating Element Eccosorb CV-3 PT 100 Polystyrene Window SOMORA Hot Load

6. Eccosorb CV-3 SOMORA Cold Load Dewar Vessel Packaging Foam Material

7. Liquid N 2 Inlet Gaz-phase N 2 exhaust Expansion Vessel  P = 0.4 Bar

8. Total Power Calibration

9. Temperature Definitions ● Physical Temperature ● „Planck“ Brightness Temp.: ● In the RJ limit (h  kT):  P ÷ T  P can be replaced by T in RT model

10. Example: Planck and RJ emission curves at various frequencies Brightness Temperature [K]

11. Conclusions : ● SOMORA: Total power radiometer ● P ÷ T in considered T range  Total power calibration formula can be used ● T RJ ≠ T P  Radiative transfer computed in the units of P