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Quality management, calibration, testing and comparison of instruments and observing systems M. Leroy, CIMO Quality management, calibration, testing and comparison of instruments and observing systems M. Leroy, CIMO ET on SBII&CM

Quality management, some aspects § § Explicit identification of uncertainty objectives Representativeness of observations Quality management, some aspects § § Explicit identification of uncertainty objectives Representativeness of observations Calibration and maintenance Selecting instruments : knowing their characteristics – Testing – Intercomparisons § Composite observing systems § Value analysis § ISO 9001 -2000 is an international frame

Quality management process § § Setting and documenting objectives Defining associated indicators Regular survey Quality management process § § Setting and documenting objectives Defining associated indicators Regular survey of users’ (customers) needs and satisfaction. § Correcting and improving

Identification of uncertainty objectives § Identification of users of observation data – Forecasters and Identification of uncertainty objectives § Identification of users of observation data – Forecasters and climatologists – Few direct users of observation : special case is aeronautic users, with needs clearly defined in Annex 3 of ICAO. § Getting the users’ needs is not always easy – They are not always aware of the possible uncertainty and associated cost. – A value analysis is necessary to get a good compromise. § The CIMO guide (WMO doc n° 8) is a guide. – Annex 1 B indicates users’ needs and achievable measurements (best state of the art). § The measurement uncertainty must be demonstrated. So realistic choices must be done.

An example § For his proprietary Radome network, mainly dedicated for real-time observation, Météo. An example § For his proprietary Radome network, mainly dedicated for real-time observation, Météo. France has set up the following objectives; some are less ambitious than the achievable measurement uncertainty stated by the CIMO guide. – – – 0. 5 h. Pa for pressure 6% for relative humidity 0. 5°C for air temperature 10% for wind speed 5 -10% for precipitation amount 5% for daily amount of solar radiation.

§ For other objectives, additional care can be necessary § Example : US Climate § For other objectives, additional care can be necessary § Example : US Climate Reference Network – – Redundancy and cross check of measurements. 3 independent air temperature measurements. Dual fence rain gauge. Associated measurement of wind speed. § Such efforts cannot be made in each station of a climatological cooperative network.

Quality indicators § Availability of data in the (final) data base – Within a Quality indicators § Availability of data in the (final) data base – Within a given limit of time : example 95% of expected surface observations available within 10 minutes. – Availability of data in the climatological data base : example 98% for the Radome network. § Measurement uncertainty – % of sensors calibrated in a stated delay : example 12 months nominal, 15 months maximum, objective is more than 90%. – % of sensors found outside an Acceptable User Limit : example hygrometers found with one (or more) control point more than 5% from the reference. These sensors are flagged as having drifted. – % of sensors for which the periodicity of preventive maintenance is respected. – % of large errors when compared to numerical models (monitoring)

Some examples Some examples

Knowing the characteristics of an instrument § Technological survey : reading publications, participating to Knowing the characteristics of an instrument § Technological survey : reading publications, participating to conference and instrument exhibitions. § Testing of instruments : please, publish results and make them available. § Intercomparisons, WMO intercomparisons. § Read the manufacturers’ technical documentation, having in mind the common characteristics of instruments, for example, thru the CIMO guide.

Recent WMO intercomparisons § Radiosonde intercomparisons § WMO Laboratory Intercomparison of Rainfall Intensity gauges Recent WMO intercomparisons § Radiosonde intercomparisons § WMO Laboratory Intercomparison of Rainfall Intensity gauges § WMO Field Intercomparison of RI gauges : May 2007 -May 2008, Vigna di Valle, Italy § WMO Intercomparison of Thermometer Screens/Shields in conjunction with Humidity Measurements : 2007, Ghardaïa, Algeria

WMO Field Intercomparison of Rainfall Intensity Instruments § The laboratory Intercomparison was a first WMO Field Intercomparison of Rainfall Intensity Instruments § The laboratory Intercomparison was a first step, easier to handle than a field test. § Not all instrument types available on the market were tested in laboratory. § Looking for a possible site, Vigna di Valle, Italy (Italian Meteorological Service, Re. SMA) was selected. August 2007 August 2008

Field Intercomparison § Call for instruments (March 2006) § 24 instruments of different measuring Field Intercomparison § Call for instruments (March 2006) § 24 instruments of different measuring principles were selected (54 proposed !). § Reference based on a set of high quality devices, inserted in a pit gauge. § Draft Rec. 4. 2/2 : Procedure and reference instruments for field rainfall intensity intercomparisons

WMO Combined Intercomparison of Thermometer Screens/Shields, in conjunction with Humidity Measuring Instruments § Looking WMO Combined Intercomparison of Thermometer Screens/Shields, in conjunction with Humidity Measuring Instruments § Looking for a possible site in harsh conditions, Ghardaïa, Algeria was selected. § Desert region § Jan. 2007 Jan. 2008 § Instruments’ calibration before and after

Screens & Hygrometers Intercomparison § Call for instruments (March 2006) § 16 screens/shields’ types Screens & Hygrometers Intercomparison § Call for instruments (March 2006) § 16 screens/shields’ types (29 proposed) and 11 hygrometers’ types(17 proposed) were selected. § Reference : Thygan § Data analysis : – International Organizing Committee – ISO standard 17714 (draft)

Conclusion § There are many other subjects and actions concerning quality measurement : – Conclusion § There are many other subjects and actions concerning quality measurement : – Quality control directly at the level of the measurement systems. – Quality control using spatial and temporal cross-check. – Representativeness of observations, due to the nearby environment of the measuring site. – … § Quality management and ISO 9001 -2000 certification force us to explicit the objectives of observing networks and the proofs demonstrating their achievement.