Janko Drnovsek METROLOGY AND ENVIRONMENT gathering and sharing/Janko... · of Metrology and Quality...
Transcript of Janko Drnovsek METROLOGY AND ENVIRONMENT gathering and sharing/Janko... · of Metrology and Quality...
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Prof Janko Drnovšek and Laboratory of Metrology and Quality group
Faculty of Electrical EngineeringUniversity of Ljubljana
Bridging the GapResponding to Environmental Change: from Words to Deeds
14-16 May 2008, Portorož
Metrology and Environment
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Basic dilemmaHow to ensure appropriate environmental measurements and monitorenvironmental/climate changes?
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Definitions
Metrology – science of measurementmeasurement - process of empirical, objective, assignment of numbers to properties of objects or events of the real world in such a way as to describe them
Testing – action of carrying out teststest – technical operation that consists of determination of one or more characteristics of a given product, process or service according to a specified procedure
Monitoring – continuous observation (measurements and testing included)
Resolution - smallest difference between indications of a displaying device that can be meaningfully distinguished
Uncertainty - parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand
Sensitivity – change in the response of a measuring instrument divided by the corresponding change in the stimulus
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Main objectives for environmental measurements
1. Comparable and reliable measurement results in time and space
2. Sensitivity of the measurement method (fitness for purpose)
3. “Resolution” versus “uncertainty”
4. A complete measurement result, including correction and uncertainty, should correspond to the required precision of observation
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Copacabana, Rio de Janeiro, Brasil Portorož, Slovenia
TemperatureRelative humidity
Air pressureOzone concentration
…
TemperatureRelative humidity
Air pressureOzone concentration
…
InternationalIntercomparison
2008
1. Comparable and reliable measurement results in time and space
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Copacabana, Rio de Janeiro, Brasil Portorož, Slovenia
1. Comparable and reliable measurement results in time and space
TemperatureRelative humidity
Air pressure…
TemperatureRelative humidity
Air pressure…
InternationalIntercomparison
1930196019802008
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
10 years 20 years 30 years
10 m
100 m
300 m
1000 m
2000 m
5 m
sea
dept
h
comparabilitytime invariance
traceability
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Case study : Monitoring of seawater temperature changes - depth (vertical profile)
2. Sensitivity of the measurement method (fitness for purpose)
Required sensitivity = 5 °C/ 200 m = 0,025 °C/mRequired resolution = 0,020 °C
Uncertainty = 0,010 °C
Vertical profile (1 m)
Required sensitivity = 5 °C/ 200 m = 0, 25 °C/10mRequired resolution = 0,20 °C
Uncertainty = 0,1 °C
Vertical profile (10 m)
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Case study : Monitoring of seawater temperature changes - time (environmentalchanges)
2. Sensitivity of the measurement method (fitness for purpose)
Required resolution = 0,50 °C Uncertainty for ENTIRE time of observation = 0,10 °C
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
DEEP SEA PROBES
• depths to 1000 meters• uncertainty 0,1 °C • on buoys
Depth temperature profile measurements
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
INTERNATIONALCOMPARISONS
deep sea water temperature changes monitoring
NATIONALSTANDARDS
CALIBRATION LABORATORY
trac
eabi
lity
Uncertainty = 0,05 °C
Uncertainty = 0,010 °C
Uncertainty = 0,005 °C
diss
emin
atio
n
Uncertainty = 0,1 °C
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
time
temperature
resolution = 0.005 °C
uncertainty = 0.1 °Cupper limit
resolution is important!
definedalarmreal
alarm
Resolution of thermometer = 0.005 °C
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
time
temperature
resolution = 0.1 °C
uncertainty = 0.1 °Cupper limit
resolution is important!
definedalarmfalse
alarm
Resolution of thermometer = 0.1 °C
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
tem
pera
ture
t em
pera
ture
uncertainty = 1 °C
uncertainty = 0,1 °C
time10 years
10 years
30 years
30 yearstime
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
examples of different test result interpretation
WITHIN TOLERANCESOUTSIDE TOLERANCES OUTSIDE TOLERANCES
distribution ofmeasurements
real value ofmeasurement
real value ofmeasurement
upper limitlower limit
possibility of rejection ofan acceptableproduct/result
possibility of acceptance ofan unacceptableproduct/result
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
BIPM
Regional key interlaboratory comparisons
CIPM Key interlaboratory comparisons
National metrology institutes
= CIPM key-comparisons
= CIPM and Regional key-comparisons
= Regional key-comparisons
= BIPM key-comparisons = Bilateral key-comparisons
= MRA members
Regional key interlaboratory comparisons
Regional key interlaboratory comparisons
Interlaboratory intercomparison scheme
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Hierarchical structure of technical infrastructure
National measuring standards
National metrology infrastructure
Testing
Standardisation
Accreditation
Certification
International trade
Traceability
MetrologyTesting
Standardisation
Accreditation
Certification
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Acceptable measurement traceability
• VIM definition of traceability:Property of the result of a measurement or the value of standard whereby it can be related to stated
references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.
• Traceability in national accreditation bodies:- Traceability is always related to accredited calibration laboratories (certificates)- Calibration certificates without accreditation logo are not accepted
Measuring instrument
Measurement result?
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
influential parameters:• influential parameter0 (uncertainty of the thermometer),• influential parameter1 (resolution of thermometer),• influential parameter2 (hydrostatic pressure),• influential parameter3 (currents),• influential parameter4(hot-water sources),• influential parameter5 …
...rl_parameteinfluentiarl_parameteinfluentiarl_parameteinfluentia 23
22
21 ++=u
u - uncertainty of the measurement result
University of LjubljanaFaculty of Electrical Engineering
Laboratoryof Metrologyand Quality
Conclusions
! resolution IS NOT! uncertainty
! monitoring requires absolute accuracy in time and space
! absolute accuracy of measurement is the responsibility of national metrology infrastructure
• environmental monitoring and management depend on metrology !