MWR and MWR3C data during MAGIC

1. MWR and MWR3C data during MAGIC M. P. Cadeddu Argonne National Laboratory First MAGIC Science Workshop, May 5-7, 2014, Brookhaven National Laboratory, Upton, NY, 11973

2. OVERVIEW • Overview of MWR and MWR3C instruments • Data availability • Instrument calibration • Retrievals • Summary

3. MWR and MWR3C MWR3C rain sensor MWR MWR3C

4. MWR 2- frequencies: 23.8 and 31.4 GHz No azimuth scanning Time resolution ~ 1/20 s in LOS mode and ~1/50s in tip mode Calibration performed using ‘tip curves’ Measurements: Sky brightness temperatures Physical quantities: Retrieved precipitable water vapor and liquid water path MWR3C 3- frequencies: 23.834, 30, 89 GHz Time resolution ~ 1/20 s - Azimuth scanning possible Calibration performed using ‘tip curves’ Measurements: Sky brightness temperatures Physical quantities: Retrieved precipitable water vapor and liquid water path. Increased sensitivity to small amounts of liquid water. Embedded accelerometer for accurate pointing readings

5. MWR DATA AVAILABILTIY MWR3C: No data until 2012/11/15

6. CALIBRATION The MWR and MWR3C use the cloudless sky as a reference to calibrate the noise diode. Calibration is achieved by plotting airmass vs. opacity and extrapolating the line to airmasszero. Bilateral scan to collect points at different airmasses. The radiometer needs to be leveled and the pointing accuracy needs to be know within fractions of degrees.

7. MWR CALIBRATION (continued…) Mounting the radiometer on a ship causes multiple negative effects due to: Ship listing Ship movement (pitch, roll) Listing cannot be easily corrected but its effect can be minimized by frequently checking the alignment of the radiometer. Its effect is a deterioration in the calibration. Expected pointing during calibration scan Actual pointing during calibration scan

8. CALIBRATION (continued…) • Pitch and roll can be corrected if navigation data are available. • New calibration software was developed to post-processed the data when the navigation data were available. • Because the MWR needs to scan to low angles we couldn’t use the small angle approximation (θ=p2+r2). Z y Vo V 0 ε0  Y o p r X

9. MWR CALIBRATION (continued…) v=YPRv0 Y=0 Equivalent zenith brightness temperature difference between two sides of the scan

10. RETRIEVALS ARM provides statistical and physical retrievals of LWP and PWV Statistical retrievals available in real-time. • MWR linear regression • MWR3C neural network Physical retrievals MWRRET (not yet available for MAGIC)

11. PWV RETRIEVALS MWR STAT MWR3C NN-Archive MWR3C NN-reproc

12. LWP RETRIEVALS-ALL MWR STAT MWR3C NN-Archive MWR3C NN-reproc

13. LWP RETRIEVALS CLEAR SKY MWR STAT MWR3C NN-Archive MWR3C NN-reproc

14. RAIN MITIGATION

15. RAIN MITIGATION (continued)

16. SUMMARY MWR and MWR3C data available through most of the deployment Calibration was corrected for the MWR the MWR3C has embedded accelerometer MWR statistical retrievals (mwrlos) have high uncertainty (flagged yellow) MWR3C NN neural network retrievals will be reprocessed with new NN coefficients

17. Physical retrievals MWRRET are not yet available for MAGIC (may be available upon request from PI) Care should be used when data are used during rain For questions or any concern with the data email me mcadeddu@anl.gov For details on ARM microwave radiometer: M.P. Cadeddu, J.C. Liljegren, D.D. Turner: The Atmospheric Radiation Measurement (ARM) program network of microwave radiometers: instrumentation, data, and retrievals, Atmos, Meas. Tech., 6, 2359-2372, 2013. THANK YOU