View
213
Download
1
Category
Tags:
Preview:
Citation preview
Use of State and Local Government Differential GPS for Weather Forecasting
or How to Build a Low Cost
National GPS-Met Network for NOAA
Presented by
Seth I. Gutman Chief, GPS-MET Observing Systems Branch
NOAA Forecast Systems Laboratory Boulder, Colorado
• FSL is building a 200-station GPS-Met Demonstration Network using sites belonging to NOAA, other federal, state, and local government agencies, and universities.
• Dual-use of these other agency sites has allowed us to evaluate GPS-Met quickly and at low cost.
• Collaboration with state and local government agencies will help NOAA to expand the GPS-Met network and improve local-to-national scale Wx forecasts.
• Use of a DGPS site for Wx forecasting adds little to the cost of the site and has no adverse impact on it’s primary use: improved positioning and navigation.
Use of DGPS for Weather Forecasting
NOAA GPS-Met Demonstration Network Current & Planned Configuration SEAW
HKLO
NDSK
DQUA
WSMN
GDAC
VCIO
HVLK
HBRK
PRCO
RCM7
KYW1
EKY1
MOB1ENG1
GAL1
ARP3
NDBC
PLTC
JTNT
PATT
CCV3
WNFL
SIO3TCUN
MOR1
SHK1
900 km
LMNO
CHA1
WLCI
SYCN
CENA
TLKA GNAA
MBWW
MRRN
FBYN
NLGN
RWDN
SAV1
BLKV
EXPLANATION
DoT NDGPS SITES
NOAA GPS-IPW SITES
USCG DGPS SITES
Filled = Operational, Open = Planned
LTHM
CNWM
CLK1
AZCN
DSRC
BLMM
WDLMBLRW
SLAI
WNCI
CLGO
DRV1
USACE DGPS SITES
VIC1 MLF1
MEM2SAL1
KAN1 STL3
HTV1
LOU1
CHL1
RED1
DET1CHT1
POR4
BRU1
PNB1
YOU1
MIL1
RIS1
STP1
WIS1
SAG1
CHB1
PCK1
KEW1
OMH1
CHO1
STB1
OKOM
BARN
WHN2
DUCK
WHD1
RPT1
CME1
PBL1PPT1
VAN1
PLO3
FTS1
MC01
BIL1
FST1
PLS1SPN1
HDF1
MCN1
BARH
MCD1
NBR2
1000 km
ANN1
SUM1
MYT1
PUB1
KRT1
HAG1
HWK1
KLM1
EDN1
MDR1
BKR1
BRN1
GWEN
MAI1
NOAA GPS-MET SITES
Examples of Non-NOAA Sites Used for GPS-Met
Mesa County, CO DGPS
Local Government
Hartsville, TN NDGPS
U.S. DOT
La Jolla, CA
Scripps Institution of Oceanography
Montauk Pt., NY Maritime DGPS
U.S.Coast Guard
Dual-Use IPWV Data Comparison
Driver, VA: DOT NDGPS Site
Blacksburg, VA: NOAA FSL/NWS GPS-Met Site
RNK: NWS RAOBS
• The first collaborative use of DGPS for NOAA weather forecasting was with U.S. Coast Guard Maritime DGPS Program. It involved engineering evaluations, and solved system compatibility and interoperability issues.
• This was followed with agreements to use the DOT Nationwide Differential GPS (NDGPS) sites as part of the GPS-Met Demonstration Network.
• In 2000, FSL worked with Mesa County Colorado to integrate their Cooperative CORS site into the network.
• Future collaborations with state, and local government agencies will help NOAA expand the GPS-IPWV network and improve local-to-national scale Wx forecasts.
• Here’s an example / proof-of-concept.
Collaborative Dual-Use of DGPS
• FDOT is establishing about 45 DGPS sites all over Florida in the next few years.
• These sites will support statewide surveying for mapping, planning, design, construction, and use of transportation facilities.
• FDOT needed places to put their GPS receivers, and the Florida SOO’s are interested in GPS-Met, so Ronnie Taylor of NGS brought FDOT, Pat Welsh and the rest of the Florida SOO’s, and FSL together to form a project.
• We promised to work with FDOT and the SOO’s, and the WFO’s volunteered to host six systems.
• The fact that their GPS observations may also help improve NOAA Wx forecasts seems pretty cool* to FDOT.
Florida Department of Transportation
* Cool in this context is defined as consistent with their overall mission to protect life and property, and encourage commerce in the state.
FDOT Differential GPS Network
Perry
CCV3
MCD1
KYW1
MAI1
MOB1
Tallahassee Jacksonville
TampaMelbourne
Miami
Key West
ProposedCCAFS/KSC Micro-Net
EXISTING USCG DGPS SITE
POTENTIAL FDOT DGPS SITE
FDOT DGPS SITE at NOAA/NWS WFO
0 50 100 km
• FDOT will: Install the GPS receivers and communication systems at 45 sites and continuously retrieve the GPS data. Place the observations on a server in
Tallahassee.
• FSL will: FTP these observations to Boulder every 30
minutes. Add these sites to the GPS-Met Demonstration Network, calculate and monitor their positions, and calculate tropospheric signal delays in near real-time.
• Note that no surface met packages, normally required to parse the ZTD’s into their wet and dry components, will be installed at these sites. The ancillary pressure and temperature measurements will have to be derived some other way.
How This Will Work
• Suppose we know the difference in height between the GPS antenna and a model’s grid elevation.
• Given the analyzed pressure (altimeter) from the model, and accounting for any residual biases in an empirical manner, is it possible to estimate Psfc at the location of the antenna with an error 1 hPa?
• If so, we can expect IPWV retrieval accuracy roughly comparable to that achieved using standard NWS barometers and temperature sensors.
• Tm is not a problem, since estimates from the 40-km RUC model are already better than those estimated using Tsfc
measurements and a climate model.
• We need Psfc and Tm, valid at 15 and 45 minutes after the hour for near real-time data processing.
We Propose The Following Experiment
• If we can do this successfully, then there is no technical reason why we could not extend this strategy over the entire U.S.
• Lots of states beside Florida are starting to deploy DGPS networks.
• A coordinated outreach effort to the states will show them that sharing GPS and other data (e.g. mesonet observations) with NOAA is really in the best interests of the states’ residents.
• The local forecast offices should participate since they will be primary beneficiaries of these data and observations.
• Our work is cut out for us, but the cost & time savings to NOAA could be enormous.
Conclusion
Recommended