1. NPOL Olympex Located 47.2772N/-124.211 W, 157 m ASL
S-band, dual-polarization, Doppler Radar
Beam width 0.95°
Vaisala/SIGMET processor
Strategy: PPI, RHI_land, RHI_ocean, Birdbath. Full sequence required 21 minutes. Scans were run continuously with no deviations for targets of opportunity except for Nov 14 RHIs over Chahelis River Basin for DC-8 support.
PPI: 0.5, 1.5, 2.5 deg elevation
RHI land sector (16 azimuths separated by 2 deg): 30 deg --> 60 deg.
RHI oceanic sector (40 azimuths separated by 3 deg): 210 deg --> 326 deg.
BB: 2 revolutions

2. NPOL Data Processing Multiple step process
Removal of non-precipitating echo
Reflectivity Calibration
Differential reflectivity calibration
Calculation of KDP (DROPS2; Chandra)
DSD and rain rate retrievals
ZZ Uncorrected reflectivity
CZ Corrected reflectivity
rHV Correlation coefficient
ZDR Differential reflectivity
FDP Differential phase
KDP Specific differential phase (DROPS2)
SW Spectrum Width
SQI Signal quality index
VR Radial velocity
FH Hydrometeor ID (Dolan)
DM Mass weighted mean diameter
NW Normalized intercept parameter using DM
D0 Median volume diameter
N2 Normalized intercept parameter using D0
RR Rain rate (DROPS2; Chandra)
RP Rain rate PolZR (Bringi et al. 2007)
RC Rain rate (Cifelli 2002)
Final output is Universal Format (UF)

3. ZDR Monitoring & Calibration
ZDR Calibration monitored via use of hourly birdbath scans. Steady throughout campaign.
Final post-campaign adjustment of -0.2 dB
13 Jan 2016
12 Nov 2015
rHV ZH
ZDR

4. Reflectivity Calibration Stability
Stability of reflectivity calibration tracked by Relative Calibration Adjustment (RCA: Silberstein et al. 2007; Wolff et al. 2013)
RCA tracks the stability of the 95th percentile of clutter area reflectivity.
Left panel shows the hourly PDF and CDF of clutter area reflectivity. Note that significant precipitation on this day does not effect the 95th percentile.
Olympex time-series shows very stable calibration with daily standard deviation of less than 0.1 dB!

5. Absolute Reflectivity Calibration Self-Consistency (Ryzhkov et al
Limited cases due to Kdp at S-band with very small drops.
Data were selected from km range and 1.5 degree elevation
QC and Zdr bias correction applied.
Dec 4, 2015: dB hot
Dec 6, 2015: dB hot

6. Absolute Reflectivity Calibration
Comparison to GPM DPR using Validation Network (VN) architecture*
Cf. Schwaller and Morris, 2011

7. Absolute Reflectivity Calibration
Reflectivity difference (2DVD - NPOL) from all OLYMPEX events combined show
NPOL reflectivity is approximately 0.8 dB higher than 2DVD (SN35, SN36, SN38).
NPOL data are above terrain blockage and below the melting level. 2DVD data are
from rain events without melting level or ice contamination.

8. Absolute Reflectivity Calibration Comparisons to 2DVD
ZH - NPOL vs 2DVD
Bias (dB)
Abs.Bias (dB)
Sample Size
OLYMPEx
1.13
4.34
2173
ZH - NPOL vs 2DVD
Bias (dB)
Abs.Bias (dB)
Sample Size
sn35
1.03
3.64
732
sn36
0.81
4.38
677
sn38
1.50
4.98
764

9. NPOL Quality Control Dual-pol QC as described by Pippitt et al. (2015)
Modified for Olympex to handle mountain and sea clutter

10. Data Access and Status Current version of data sent to
Total Data Volumes
Raw: 218 GB (16-bit data uncompressed)
Processed UF: 90 GB (compressed)
Browse products: 20 GB
We retrieve three separate rain rate product: DROPS2 (RR), PolZR (RP) and Cifelli (RC); however, due to an issue with DROPS2, RHI scans are being reprocessed to obtain better rain rates

11. Case Studies 39 GPM overpass cases 21 with widespread stratiform
4 with post-frontal convection
14 with scattered showers
17 Nov 2015 Narrow Cold Frontal Rainband (NCFR)

12. Backup Slides

13. D3R Specifications Scanning strategy
Olympex_survey (PPI: 0.5, 1.5, 2.5 deg elevation; azimuth limits were 220 to 130 deg -- clockwise)
Olympex_rhi_A (36 azimuths from deg; 3 deg separation )
Olympex_birdbath: 2 revolutions
Olympex_rhi_B, (16 azimuths from deg; 2 deg separation )
21 minutes to finish a full scan cycle.