1
The “U.S. Climate Reference Network” Developments
Presentation for the
Office of Federal Coordinator for Meteorology
Dr. Sharon LeducNOAA/NESDIS
National Climatic Data Center
October 24, 2003
2
How has the climate of the U.S. changed over the past 50 years on national,
regional and local levels?
An observing system that 50 years from now can, with the highest degree of confidence, answer the
question…
3
T1
T2
T3
Primary Instrumentation
Two precipitation gauges inside a double windshield
Three temperature sensors, T1, T2, & T3
4
Precipitation Gauge & Small DFIR w/Single Alter
5The National Climatic Data Center
Standard Measurements Primary Sensors• Air Temperature (3 separate aspirated sensors)• Precipitation (4 separate sensors)
Secondary Sensors• Wind Speed• Global Solar Radiation• Ground Surface (Skin) Temperature
• Power AC/DC– Solar panels & Wind power (optional)
• Extended Range Operating Envelopes
6The National Climatic Data Center
Ten climate Principles1. Management of Network Change2. Parallel Testing3. Meta Data4. Data Quality and Continuity5. Integrated Environmental Assessment6. Historical Significance7. Complementary Data8. Climate Requirements9. Continuity of Purpose10. Data and Meta Data Access
7The National Climatic Data Center
Network Characteristics
• Benchmark Network for temperature and precipitation
• Anchor points for USHCN and full COOP network
• Long-Term Stability of Observing Site (50+ years) likely to be
free from human encroachment
• Sensors Calibrated to Traceable Standards
• Planned redundancy of sensors and selected stations
• Network Performance Monitoring - Hourly and Daily
• Strong Climate Science & Research Component
8The National Climatic Data Center
USCRN Program Documentation
– Incorporates 10 climate Principles
– Defines standards, procedures
– Provides long-term program continuity
– Under configuration management
– On-line accessible
9The National Climatic Data Center
• Functional Requirements Document – Systems - parameters, ranges, accuracies, resolutions, expandability,
design life, maintainability – Program - number of systems, cost and schedule targets,
communications
• Commissioning Plan– Defines decision point – when data are official – Sustained operation, data from each site 95% of the time within one
hour and/or successful entry into the archives within 30 days
• Configuration Management Plan – Change management of hardware and software items, metadata
management – responsibilities and procedures for CCB
10The National Climatic Data Center
Test and Evaluation Phase Completed
• Conducted by Evaluation Team
• Reviewed by Ad Hoc Science Working Group
• Six areas Evaluated– Site Selection– Site Installation– Field Equipment and Sensors– Communications– Data Processing and Quality Control– Maintenance
• 30 sites in varied climate regimes
11The National Climatic Data Center
CRN Station Sit Selection Standards
• Site Density methodology• Michel Leroy basis for site classification• Objective site scoring• Trained site surveyors• Exceeds WMO standards• Possible OFCM standard for climate monitoring
stations
12The National Climatic Data Center
Site Density
Statistical analysis for network to maximize the reduction in uncertainty of the change in the climate signal– 300 stations; 2.5-degree grid– 100 stations; 5-degree grid– Minor deviations from the grid to capture
climatic regimes
13The National Climatic Data Center
Michel Leroy Method
Methods used as basis for site classification exceeds the WMO standards
Method of classification presented at: AMS conference
Tenth Symposium on Meteorological Observations and Instrumentation, Phoenix, AZ, January 11-16, 1998
14The National Climatic Data Center
WMO Standards
WMO Guide to Climatological Practices "The Siting of Climatological Stations" Chapter 4 paragraph 2.4, pages 45-50
15The National Climatic Data Center
Objective Site Scoring
An objective scoring sheet was developed based on the Leroy method. The score for a station becomes part of the metadata for the station
Re-scoring of stations is part of the annual maintenance visit; allows tracking time change in representativeness of station meteorology
16The National Climatic Data Center
Trained Site Surveyors
Regional Climate Centers (RCCs) Responsible for site surveys of potential CRN sites Trained on the objective scoring systemComplete the scoring sheet as part of the site survey
processScore becomes part of the station metadata.
17The National Climatic Data Center
Possible OFCM Standard
NCDC believes that the siting standards used in the USCRN program should be considered by the OFCM as the standard for locating climate monitoring stations
Could also be adopted as a standard for other networks (COOP, etc.)
18The National Climatic Data Center
Siting Standards Documents
• Network Plan• CRN Site Acquisition Plan• Site Information Handbook• CRN Site Survey Plan• Site Survey Handbook• Site Survey Checklist• Site Acquisition Checklist
19
Data Management Documented Ingest to Access
Access to Data & Metadata
Ingest
Automatic
Manual
ATS
Maintenance
Quality Assurance/Control
Raw
Flagged
Metadata
Users
20The National Climatic Data Center
QA/QC • Quality Assurance of Instruments
– Documented in Anomaly Tracking System Users Manual– Reports of Incidences collected, evaluated, maintenance as needed– Metadata records updated
• Quality Control Data
– Documented in Data Management – Ingest to Access– Data ingest
• Tests for proper message form, communication errors, etc.– Automated
• Limits - Gross limits check• Variance - Limits for individual parameters• Redundancy - Data inter-comparison relies on multiple sensors
– Manual -- Handbook of Manual Monitoring
21The National Climatic Data Center
QA/QC (Continued)
• Integration of QC– Health of the Network
• Instrument and equipment records• Documented Metatdata Management – Survey to Operations• Post analysis of measurement records
– TempVal PrecipVal• CRN data used in validation of coop data
– Transfer functions
22
Metadata ManagementSurvey to Operations
23The National Climatic Data Center
Status
• Successfully Completed Demonstration Test and Evaluation phase
– January-June 2003
• In “pre-commissioning” phase– July-December 2003
• Data and Metadata for all sites on-line restricted access
• Network commissioning announcement at AMS
24
Location of 100-station USCRNSeptember 2005 (100* stations)
* Includes 2 in Alaska
Installed Paired LocationsInstalled Single Locations
25
Regional Impact
Preliminary analysis (Dr. Bomin Sun)Significance level of a linear temperature trend (1951-2002) Red: upward trend Blue: downward trend
26
RAWS Site
Proposed CRN Site
COOP Site
Dinosaur National Monument CRN Site
27
Network Integration
28The National Climatic Data Center
7-Yr Vision• Sufficient CRN stations deployed ( ~ 300) for capture of CONUS National & Regional Climate Signals
• Inter-network (Coop, SCAN, SNOTEL, RAWS) transfer functions give increased, homogeneous spatial
coverage.
• Inter-database (HCN, some Coop, NADP) transfer functions extend high-confidence Length-of-Record Observations.
• Sufficient CRN data stream & confidence supports broad scientific analyses of climate trends.
• CRN data on-line within one hour of receipt at NCDC.
• CRN data and metadata public access