Reconstruct and Average SD/Max Calculated Column

This type of calculated data column combines two speed SD or speed Max data columns by averaging them, with special treatment of tower-shaded values.

Tip: The Combine Anemometers automatically creates SD and Max columns of this type for each pair of colocated anemometers that you combine using the reconstruct-and-average option.

This calculated column type behaves exactly the same as a standard average of two data columns, except in time steps in which one value is missing or flagged to exclude, and the other value is flagged as tower shaded. Standard default flag filtering rules dictate that such a time step remain empty, since both values are flagged to exclude. But this type of calculated column will be equal to that tower-shaded value in such a time step.

If we are combining data column A and data column B, for example, then in a time step in which A is missing or flagged to exclude, with some flag other than the special tower shading flag, and B is flagged with the tower shading flag, then the calculated column will take on the value of B, despite the fact that it is affected by tower shading.

This calculated column type behaves this way because of how the related Reconstruct and Average calculated column behaves. In a time step like the one described above, the Reconstruct and Average calculated column will reconstruct a valid A value using the shaded B value, so it will not report a gap in that time step. The Reconstruct and Average SD/Max calculated column therefore aims to avoid a gap in this time step as well, so it uses the shaded SD or Max value.