USCRN - OFCM Brief (24Oct03).PPT

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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

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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…

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T1

T2

T3

Primary Instrumentation

Two precipitation gauges inside a double windshield

Three temperature sensors, T1, T2, & T3

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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


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

marjorie.mcguirk

1.Management of Network Change: Assess how and the extent to which a proposed change could influence the existing and future climatology obtainable from the system, particularly with respect to climate variability and change. Changes in observing times will adversely affect time series. Without adequate transfer functions, spatial changes and spatially dependent changes will adversely affect the mapping of climatic elements. 2.Parallel Testing: Operate the old system simultaneously with the replacement system over a sufficiently long time period to observe the behavior of the two systems over the full range of variation of the climate variable observed. This testing should allow the derivation of a transfer function to convert between climatic data taken before and after the change. When the observing system is of sufficient scope and importance, the results of parallel testing should be documented in peer-reviewed literature. 3.Meta Data: Fully document each observing system and its operating procedures. This is particularly ijmportant immediately prior to and following any contemplated change. Relevant information includes: instruments, instrument sampling time, calibration, validation, station location, exposure, local environmental conditions, and other platform specifics that could influence the data history. The recording should be a mandatory part of the observing routine and should be archived with the original data. Algorithms used to process observations need proper documentation. Documentation of changes and improvements in the algorithms should be carried along with the data throughout the data archiving process. 4.Data Quality and Continuity: Assess data quality and homogeneity as a part of routine operating procedures. This assessment should focus on the requirements for measuring climate variability and change, including routine evaluation of the long-term, high-resolution data capable of revealing and documenting important extreme weather events. 5.Integrated Environmental Assessment: Anticipate the use of data in the development of environmental assessments, particularly those pertaining to climate variability and change, as a part of a climate observing system's strategic plan. National climate assessments and international assessments (e.g., international ozone or IPCC) are critical to evaluating and maintaining overall consistency of climate data sets. A system's participation in an integrated environmental monitoring program can also be quite beneficial for maintaining climate relevancy. Time series of data achieve value only with regular scientific analysis. 6.Historical Significance: Maintain operation of observing systems that have provided homogeneous data sets over a period of many decades to a century or more. A list of protected sites within each major observing system should be developed, based on their prioritized contribution to documenting the long-term climate record. 7.Complementary Data: Give the highest priority in the design and implementation of new sites or instrumentation within an observing system to data-poor regions, poorly observed variables, regions sensitive to change, and key measurements with inadequate temporal resolution. Data sets archived in non-electronic format should be converted for efficient electronic access. 8.Climate Requirements: Give network designers, operators, and instrument engineers climate monitoring requirements at the outset of network design. Instruments must have adequate accuracy with biases sufficiently small to resolve climate variations and changes of primary interest. Modeling and theoretical studies must identify spatial and temporal resolution requirements. 9.Continuity of Purpose: Maintain a stable, long-term commitment to these observations, and develop a clear transition plan from serving research needs to serving operational purposes. 10.Data and Meta Data Access: Develop data management systems that facilitate access, use, and interpretation of data and data products by users. Freedom of access, low cost mechanisms that facilitate use (directories, catalogs, browse capabilities, availability of meta data on station histories, algorithm accessibility and documentation, etc.), and quality control should be an integral part of data management. International cooperation is critical for successful data management.


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


USCRN Program Documentation

– Incorporates 10 climate Principles

– Defines standards, procedures

– Provides long-term program continuity

– Under configuration management

– On-line accessible


• 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


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


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


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


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


WMO Standards

WMO Guide to Climatological Practices "The Siting of Climatological Stations" Chapter 4 paragraph 2.4, pages 45-50


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


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.


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.)


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

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Data Management Documented Ingest to Access

Access to Data & Metadata

Ingest

Automatic

Manual

ATS

Maintenance

Quality Assurance/Control

Raw

Flagged

Metadata

Users


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


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

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Metadata ManagementSurvey to Operations


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

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Location of 100-station USCRNSeptember 2005 (100* stations)

* Includes 2 in Alaska

Installed Paired LocationsInstalled Single Locations

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Regional Impact

Preliminary analysis (Dr. Bomin Sun)Significance level of a linear temperature trend (1951-2002) Red: upward trend Blue: downward trend

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RAWS Site

Proposed CRN Site

COOP Site

Dinosaur National Monument CRN Site

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Network Integration


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

Technology

USCRN - OFCM Brief (24Oct03).PPT