Example of GSRN log with uncertainties

The log file reports an example of post-processed data product for temperature measurements at climatological reference stations, according to the findings of this project and now specified by the GCOS Surface Reference Network - GSRN

Column A reports the date and time, while in column B temperature are directly converted from Ohm to degree Celsius, being the standard recommended sensor for climate reference stations is a PT 100. Data in column B already takes into account the correction due to the sensor calibration and is therefore the main value for this data file.

According to the findings of this project, now accepted as recommendations for the climatological stations of the GSRN, accurate air temperature measurements require the evaluation of the correction and/or uncertainty contributions due to several other associated quantities of influence (AQI): Direct Solar radiation (W/m^2), Reflected Solar radiation (W/m^2), Wind direction (degree), Wind speed (m/s), Precipitation, rain temperature. These are measured at the same time at the station by means of other instruments, but are not recorded at reference level (they are used for the temperature correction due to the influence of each environmental factor).

From column J to column Q the uncertainty components are reported.

Column j reports the “system uncertainty” (According to the WMO MQCS), being the instrumental component due to the thermometer calibration, drift, resolution, logger etc. This is the key uncertainty components, required to be within the limits of the WMO prescriptions (0.2 °C in K=2). The following columns reports the uncertainty associated to each AQI, which at present are just an attempt to quantify the several contributions. Studies are still required for completing the thermodynamic models and quantifying each uncertainty contributions: such process is strictly linked to the specific instrumentation used (thermometer, screen, sensor) and need to be evaluated case by case.