NOUS41 KWBC 211155
PNSWSH
Technical
Implementation Notice 13-4
National Weather
Service Headquarters Washington DC
656 AM EST Thu
Feb 21 2013
To: Subscribers
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather
Information Network
-NOAAPORT
-Other NWS Partners and Employees
From: Richard J. Vogt
Director, WSR-88D Radar Operations
Center
Subject: WSR-88D Software Build 14 Changes That May
Impact
WSR-88D Product
and Data Users starting January 2014
The NEXRAD
Program will implement software changes in Weather
Surveillance
Radar-1988, Doppler (WSR-88D) Radar Data
Acquisition/Radar
Product Generator (RDA/RPG) Build 14, that may
impact data/product users and user systems. Beta
testing of Build
14 will begin at
5 sites in October 2013. The software is
scheduled for release starting in January 2014. Three of the
changes will slightly change the format of Level 3
products and
Level 2
data. These changes are described below:
1. A new, dynamic scanning method called
Supplemental Adaptive
Intra-Volume
Low-Level Scan (SAILS) will be introduced. When
SAILS" is
selected by the radar operator, one supplemental "Split
Cut scan (lowest
elevation of the VCP, normally 0.5°) is inserted
into the "middle" of existing severe
weather VCPs 12 and 212. To
evenly space the time intervals between low-level
updates, the
"middle" of the VCP is determined each volume scan based
on the
termination angle assigned by the Automated Volume Scan
Evaluation and
Termination (AVSET) function. SAILS will extend
volume scan completion times by approximately 35
seconds and
double the number of low-level scans.
2. Radial-by-Radial Noise Estimation will be
introduced. Noise
can vary within elevation scans and over time.
The new
algorithm’s noise power estimate comes from radial data
rather
than the current separate test, resulting in a
unique noise value
for each radial. This change prevents over- or
under-estimation
of noise and improves signal recovery,
resulting in more accurate
Reflectivity,
Differential Reflectivity, Spectrum Width, and
Correlation
Coefficient values.
3. Base Products, Base Data, and General Status
Message (GSM)
changes in Build 14:
- Base Products: The RPG will support generating base products
DR (94), DV (99),
SDR (153), SDV (154), and SDW (155) from the
SAILS added Split
Cut. For these products, the volume scan
time/date fields will be set to the start time/date of
the added
Split Cut. The volume scan time/date fields for all other
products will continue to be the start time/date of
first radial
of the volume scan. While SAILS is active, the
supplemental
products N0Q(94/DR) and N0U(99/DV) will be provided
via the NWS
Radar Product
Central Data Collection Dissemination Service
(RPCCDS)
and NOAAPort.
- Level 2 Base Data: The legacy base moments
and Dual Pol
variables from SAILS supplemental scans will be in the
Level II
base data stream. Radial-by-Radial Noise
Estimation requires the
Horizontal and
Vertical channel dBZ0 values to be added to the
Radial Data Block
within Message Type 31, resulting in a Major
Version
change from 1 to 2.
- General Status Message (GSM): The GSM
length is increasing to
200
bytes. GSM Halfword 58, Bit 15 is set when AVSET is enabled,
Bit 14 will be
used to identify when SAILS is active, and Bit 13
will be set if a site-specific VCP is in use. Bit 14 is set when
SAILS is enabled
and a SAILS VCP is active and is not set all
other times. Bit 13 will only be set for the KLGX
(Langley Hill,
WA)
GSM.
The following
tools are available to assist user’s transition to
the Build 14 changes:
1. Draft Build 14 Interface Control Documents
(ICDs) describing
the new data format and data stream (RPG to
Class 1, RDA to RPG,
and Product Specification) are available at:
http://www.roc.noaa.gov/WSR88D/NewRadarTechnology/NewTechDefault.aspx
2. Dates/times of archived test Level 2 data
sets, available
from NCDC, using the new format and SAILS and/or
AVSET are
available at:
http://www.roc.noaa.gov/WSR88D/PublicDocs/NewTechnology/SAILS_AVSET_ON-OFF_Times.pdf
3. Real-time Level 2 data from the ROC test bed
WSR-88D (KCRI)
will be available during Build 14 Operations Test
at select
periods beginning in July. The ROC will issue
another TIN in June
with information on how to obtain the data from
the NWS Level 2
Data Collection
and Distribution network and when the data will
be available with SAILS and/or AVSET operating.
4. An early version of Build 14 Software,
executable and source
code, will be available from the NWS Common
Operations and
Development Environment
(CODE) beginning in June 2013 at:
http://www.nws.noaa.gov/code88d
More detailed
descriptions of AVSET and SAILS are available at:
http://www.roc.noaa.gov/WSR88D/NewRadarTechnology/NewTechDefault.aspx
If you have
questions concerning these changes, please contact:
Mike Istok
NWS Office of Science & Technology
or
Joe Chrisman
WSR-88D Radar Operations Center
National
Technical Implementation Notices are online at:
http://www.weather.gov/os/notif.htm
$$