1. 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.

2. 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

3. 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 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
24-Nov-16
Part 2 of dying frontal system, weak snow at hurriane ridge, postfrontal clouds
CRS: navigation file corrupted, low resol. aircraft nav used.
1-Dec-16
Weak trough and front with extensive stratiform modified by topography
3-Dec-16
Complex baroclinic system with orographically enhanced rain & GPM overpass
4-Dec-16
Post frontal convection over the ocean and mountains
Calibration change (~10 dBZ) after ~18:00
5-Dec-16
Broad frontal cloud system with strong wind shear
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
12-Dec-16
Precipitation associated with an occluded front and warm sector
CRS canister lost pressure; inoperative
13-Dec-16
Convection following the passage of an occlusion
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.

4. 5 Dec 2015

5. 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, 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, Utilizing versatile transmission waveforms to mitigate pulse compression range sidelobes with the HIWRAP radar. IEEE

6. Calibration External Calibration
Ocean surface for Ku-band based on TRMM 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.

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

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

11. 3 Dec 2015 Zoom SW of Mtns

12. Dual-Freq Ratio’s & LDR
RFI in Ku-LDR
HIWRAP Ku-band transmitted at , , , , , , , GHz
D3R Ku-band transmitted at and GHz
APR-3 Ku-band GHz.

13. 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 (
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.

14. Questions?

15. 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