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This icon extracts values from complex BUFR messages where coordinate descriptors are required to locate particular data. Briefly, when a BUFR element descriptor described as F'XX'YYY has an F of 0 and an XX of less than 10, it is a 'coordinate descriptor', which means that it retains its current value until redefined. In this way, a set of observations 'inherit' the same value for such a descriptor without it appearing explicitly for each observation. The purpose of this icon is to extract data that can only be described by using coordinate descriptors; for more complete BUFR data extraction, it can be used with BUFR output from the Observation Filter icon. The output is a geopoints file.

The macro language equivalent is bufr_picker().

The Bufr Picker Editor

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To specify a parameter enter its unique BUFR descriptor value (a numerical code). Geographical Polar Vectors and Geographical X Y Vectors require two descriptors, separated by a slash (/). The descriptor value is of the form XXYYY, where XX defines the class (e.g. 12 = Temperature class) and YYY the parameter within that class (e.g. 12004 = Dry bulb Temperature at 2m). These descriptor values are different from the ones of the GRIB format. If you do not know the descriptor value, click-left on the assist button to obtain a check list of parameters and associated descriptors. This list only contains the most common parameters. If the one you need is not on the list you can use the BUFR Examiner (right-click, Examine the BUFR file) to see what is there, or up its descriptor value in the "BUFR Reference Manual" (available fromhttp://www.ecmwf.int/products/data/software/bufr.html#description BUFRDC Home) - see "BUFR Table B", pages 6-19. The significance of code and flag values for non-quantitative parameters are given in the same manual, in "BUFR code table", pages 22-70.

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