ER-2 Radars During RADEX/OLYMPEX G. Heymsfield/GSFC March 21, 2017 High-altitude Imaging Rain and Wind Airborne Profiler (HIWRAP) Ku- and Ka-Band Cloud Radar System (CRS) W-Band ER-2 X-band Radar (EXRAD) X-Band CRS and HIWRAP radars funded by NASA Aerosol Chemistry Ecosystem (ACE) Decadal Mission Formuation Study. Precipitation research funded by NASA PMM.

RADEX ER-2 Radar Parameters Changes for RADEx (from IPHEx): CRS moved to left side of plane along with HIWRAP New Ku transceiver 4 X power Improved range side lobes for CRS Dual-pol (LDR) at W-band To Note: Unmatched beams although HIWRAP Ka and Ku share same antenna 3 radars have separate alignment

ER-2 Radar Flight Summary Date Description ER-2 EXRAD HIWRAP CRS Issues 10-Nov-16 Ridge condition with little precip over mountains   Y 18-Nov-16 Shallow post-frontal convection with an overrrunning altostatus ice layer 1759-0033 N  CRS: Missing data in the middle of the flight due to datasystem overheating. 23-Nov-16 Wide zone of precip in an approaching weak trough and collapsing frontal system 1402-2214 24-Nov-16 Part 2 of dying frontal system, weak snow at hurriane ridge, postfrontal clouds 1508-2216 CRS: navigation file corrupted, low resol. aircraft nav used. 1-Dec-16 Weak trough and front with extensive stratiform modified by topography 2103-0208 3-Dec-16 Complex baroclinic system with orographically enhanced rain & GPM overpass 1408-1733 4-Dec-16 Post frontal convection over the ocean and mountains 1305-2006 Calibration change (~10 dBZ) after ~18:00 5-Dec-16 Broad frontal cloud system with strong wind shear 1359-1757 Lose cable, occasional stripes 8-Dec-16 Orographic enhancement of an "Atmospheric River" 1827-~0030 Lose cable 10-Dec-16 Occlulded front and post-frontal convection 1434-1702 12-Dec-16 Precipitation associated with an occluded front and warm sector 1800-2206 CRS canister lost pressure; inoperative 13-Dec-16 Convection following the passage of an occlusion 1603-0002 CRS pressure issues. *EXRAD: Sensitivity in both nadir and scanning beams degraded significantly (9dBZ nadir; 18 dBZ scanning) due to front-end switch problem. *HIWRAP Ku-band LDR RFI from D3R much of the time.

5 Dec 2015

Pulse Compression CRS and HIWRAP Used to achieve higher sensitivity with low peak power transmitters. Illustration of the CRS Frequency Diversity Waveform. Two pulses and a chirp are transmitted in a train at slightly offset frequencies, then all three frequencies are received simultaneously. ____________________________________________ References: Li, L., G. Heymsfield, J. Carswell, D. Schaubert, M. McLinden, M. Vega, M. Perrine, 2016. Development of the NASA High-Altitude Imaging Wind and Rain Airborne Profiler. IEEE. McLinden, M., J. Carswell, G. Heymsfield, A. Emory, J. Cervantes and L. Tian, 2012. Utilizing versatile transmission waveforms to mitigate pulse compression range sidelobes with the HIWRAP radar. IEEE

Calibration External Calibration Ocean surface for Ku-band based on TRMM NRCS @~10 deg incidence angle Ka, W, and X calibrations tied to Ku-band Internal Calibration During Flight HIWRAP and EXRAD Cal. signal injected at beginning of each pulse. In-flight temperature and other day-to-day and flight-to-flight biases removed in reflectivity calculation. Inter-channel (pulse, chirp) calibration dealt with well CRSLose cable, occasional stripes Calibration signal injected periodically during flight as commanded from ground. Calibration of pulse and chirp channels fairly stable during campaign.

ER2 and DC8 radar data comparison 3 December 2015 Provided by Lin Tian

ER2 and DC8 radar data comparison 23 November 2015 Provided by Lin Tian

3 Dec 2015 Zoom SW of Mtns

Dual-Freq Ratio’s & LDR RFI in Ku-LDR HIWRAP Ku-band transmitted at 13.904, 13.916, 13.886, 13.886, 13.898, 13.898, 13.912, 13.912 GHz D3R Ku-band transmitted at 13.895 and 13.925 GHz APR-3 Ku-band 13.405 GHz.

Data Status Great data sets from ER-2! The radar sets are complicated so always ask questions. Reflectivity quick looks are on “har” web site (http://har.gsfc.nasa.gov) Level 1B (calibrated reflectivity, unfolded Doppler, etc.) version 1 in OLYMPEX archive. Current version v01b which has changes to calibration (lower ~1 dB) and improvements in noise subtraction and pulse/chirp blending near surface. Not yet distributed. In progress: LDR calibration; improved processing algorithms; scanning beam.

Questions?

ER-2 Payload ACE ACE GMI ACE DPR ACE Airborne Multi-angle SpectroPolarimeter Imager (AirMSPI) or ER-2 X-band Radar (EXRAD) ACE Cloud Physics Lidar (CPL) ACE GMI Advanced Microwave Precipitation Radiometer (AMPR) High-altitude Imaging Wind & Rain Airborne Profiler (HIWRAP) ACE ACE DPR Enhanced MODIS Airborne Simulator – Infrared (eMAS-IR) Cloud Radar System (CRS) EXRAD and AirMSPI interchanged depending on flight goals