NASA/GPM Radar Assets

NPOL Suspect Data and System Information

Date Period	Notes
06/26/2018	N2 waveguide purge. Power test indicated H and V forward channels were in phase.
04/30/2018	N2 waveguide purge. Power test revealed H and V forward channels are out of phase.
03/29/2018	N2 waveguide purge.
03/14/2018 --> 03/18/2018	Suspect data due to faulty modulator and power fluctuations.
01/31/2018	N2 waveguide purge.
11/29/2017	N2 waveguide purge.
08/08/2017 --> 08/09/2017	Radar computer change -- offsets not correct. Data should not be used.
06/26/2017	N2 waveguide purge.
05/22/2017 --> 06/26/2017	Zdr data are questionable for science due to moisture in the waveguide resulting in bias fluctuations.

NPOL Zh Bias Table

* RCA Method reflects absolute bias beginning December 2013. RCA baseline data: Feb 13, 2014.

Date	RCA Method* Negative = cold	Self Consistency Negative = cold	2DVD-NPOL Z Difference Positive = cold	Notes
11/27/2013	-2.0	-2.0 --> -2.5	2.5	Newark, MD; Optimal NPOL comparison elevation near 1.0 deg due to blockage at lower elevations. NPOL data approx. 0.8 km above disdrometers at 40 km range.
12/09-10/2013	-3.5	-4.5 --> -5.5	5.6	Newark, MD
12/23/2013	+0.5	+1.5 --> + 2.0	0.3	Newark, MD
12/29/2013	+0.5	+1.3	0.0	Newark, MD
01/11/2014	-0.5	+1.1	0.2	Newark, MD; Self-Consistency result from early stratiform.
01/14/2014	-0.5		0.6	Newark, MD; Dynamic event with convection.
02/13-14/2014	+0.5	+1.5 --> +1.8	-2.3	Newark, MD; *SUSPECT CASE* Widespread stratiform after change from snow. Rain with strong wind influencing DSD. 2DVD optics became wet -- disdrometer shutdown.
02/21/2014	+0.5		0.3	Newark, MD; Squall line with brief heavy rain and trailing stratiform. Light wind within rain.
03/07/2014	+0.5	precip too light	0.3	Newark, MD; Light stratiform with sustained NE wind 18mph. Low melting level near 1.0 km.
Jul 2014	+0.38	no good cases	0.11	Newark, MD; Events combined; Limited data for RCA - used Aug value
Aug 2014	+0.38	0.0-->+0.18	0.19	Newark, MD; Events combined
Sep 2014	+0.42	-0.55	0.27	Newark, MD; Events combined
Oct 2014	+0.43	0.0 --> +0.3	0.42	Newark, MD; Events combined for 2DVD comparison; Self Cons 1016 and 1022.
Nov 1-3 2014	+0.41	---	0.42	Newark, MD; Event on Nov 1 (using N2) combined with October results.
Nov 4-30 2014	+1.16	-0.14 --> -0.59	0.06	Newark, MD; Events using O2 with dehydrator combined; Zdr issues entire month. Self-cons. results are reasonably close considering Zdr fluctuation issues.
Dec 2014	+1.26	+0.95 --> +1.65	0.21	Newark, MD; Events combined (except 141224 0000-0903 UTC). Zdr jump issues between events.