Uncertainty tree diagram
An 'uncertainty tree diagram' is a concept developed for the second step of the QA4EO Five Steps. The aim is to show the traceability: how the measured quantity (here sea level anomaly and then global mean sea level) is calculated from raw data. Here we show only the parts of the uncertainty tree diagram that relate to the altimeter. The equations in boxes represent processing steps. Some of these are given as equations, others, where the processing is more complicated and may involve iterative processes, are given as functions of input quantities. Some sources of uncertainty are identified. More work is needed to identify all the sources of uncertainty.