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THE NERC MST RADAR FACILITY AT ABERYSTWYTH
MST RADAR VERSION-3 RELIABILITY DETAILS
MST radar radial and Cartesian data products produced from version-3
processing typically have an associated reliability flag variable and a
reliability details variable.
The reliability flag variable
A flag value of 0 implies that the associated data products are NOT reliable.
A flag value of 1 implies that the associated data products ARE reliable.
The reliability flag has the same dimensions (click here for an explanation of netCDF nomenclature) as the data product(s) it represents. For the radial files, there is only one reliability flag (signal_component_is_reliable) which covers the variables signal_power, radial_velocity, spectral_width, first_velocity_bin_number, final_velocity_bin_number, and peak_smooth_psd_to_noise. The netCDF attributes are as follows:
The reliability flag values are determined from the results of a number of tests which are coded bitwise into a 16-bit signed integer. Typically these individual tests can be ignored. However, under extreme atmospheric conditions, e.g. associated with convective activity, data products may fail individual tests causing them to be flagged as being unreliable overall. The availability of results from the individual tests can be used to consider data points which would otherwise be ignored. Not all data products use all tests.
Treating the reliability details value as a 14-bit unsigned integer (it only ever contains positive values, including zero), bit 00 is the least significant bit. Consequently the result (either a 0 or a 1) of a particular test can be determined from an operation of the form:
The contents of individual bits are as follows:
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Last updated 8th November 2006