Carmen García Izquierdo Centro Español de Metrología Proposal of traceable measurements of permafrost temperature by optical fiber Carmen García Izquierdo, CEM, Spain Head of Contact Thermometry

Carmen García Izquierdo, CEM, Spain Head of Contact Thermometry Carmen García Izquierdo Head of Contact Thermometry of CEM, 2001 Member: Euramet ENV TG BIPM-CCT ENV TG WMO-CIMO Expert team on instrument intercomparison The CENTRO ESPAÑOL DE METROLOGÍA is the Spanish National Metrology Institute responsible for the maintenance and dissemination of the national standards of the IS Units. The TEMPERATURE Division is responsible for the development, maintenance and dissemination of the unit of thermodynamic temperature: the kelvin, by means of the International Temperature Scale of 1990 (ITS-90). Nowadays, The Centro Español de Metrología realizes the ITS-90 from -189,3442 ºC (triple point of argon) up to 2200 ºC.

Contact Thermometry/primary laboratory: -Calibration of SPRT in fixed points: (T.P. Ar:-189 ºC, F.P. Ag: 961,78 ºC) -Calibration and study of CSPRT in fixed points -Calibration of water triple point cells -Assembly of mercury triple points cells (~ -39 ºC) Contact Thermometry/secondary laboratory: -Calibration by comparison: IPRT (Pt-100), digital thermometers, liquid in glass thermometers, thermistors, thermocouples -Calibration in fixed points: Nobel metal thermocouples -Characterization of calibration baths, climate chambers, furnaces Carmen García Izquierdo, CEM, Spain Head of Contact Thermometry

MeteoMet1. Air Temperature sensors: Study of the influence of the radiation shield in the calibration of thermometers Study of the drift of air temperature sensors under extreme salinity environments Carmen García Izquierdo, CEM, Spain Sensor failure

MeteoMet2 Leader of WP on land : the coordination of :14 NMI’s 151,8 men/month 43 deliverables Carmen García Izquierdo, CEM, Spain Technical activities: LAND -Study the behaviour of temperature sensors in extreme conditions of T and H.R. -Study the influence of the buildings in air temperature measurements -Calibration of Ultrasonic anemometer as a thermometer -Protocol for the instruments intercomparions. SEA, CSIC and UPC - Temperature Calibration of CTD seabirds -Design, built, calibration and use of fiber optics as thermometer: Determination of sea surface and sea profile temperature Study the drift of the CTD

Measurement of permafrost profile temperature by optical fiber Proposals, Future activities Current Techniques : -Pt-100, Thermistors - Invasive -Conduction errors in the temperature of active layer? -Wide cables -Light Radiation errors? Critical in the Arctic since the sun light is different in each season -Selfheating? - Drift? Fiber Bragg grating : -Are not affected by electromagnetic radiation -No transmitters of electromagnetic radiation, no temperature change -Little size and light: Non invasive -Remote control -Easy multiplexing in one device -No drift in short term Carmen García Izquierdo, CEM, Spain

Proposals, Future activities -Design a new optical sensor based in Fiber Bragg grating -Temperature measurement points in agreement with the experimental site -Traceable calibration of the designed device in wavelength and as thermometer -Experimental measurements -Evaluation of the sensor drift -Comparison of the current techniques with the optical fiber at INRiM device (Designed and characterized in MeteoMet2 project) - Establishment of model function and uncertainty evaluation

Other proposals: Proposals, Future activities -Comparison of snow surface temperature measured by contact and non contact methods. Uncertainties? -Quantities of influence in air temperature measurements. Direct sun radiation influence? -Sea temperature measurements. Definitions of SST? Model functions ? Uncertainties? -More ideas? More problems? Carmen García Izquierdo, CEM, Spain

Thank you Carmen García Izquierdo, CEM, Spain