spell_length_of_days_with_air_temperature_at_or_below_threshold day
Change Date: 4 Jun 2026, 2:52 p.m.
spell_length_of_days_with_air_temperature_at_or_below_threshold day [UTAA] Air temperature is the bulk temperature of the air, not the surface (skin) temperature. A spell is the number of consecutive days on which the condition X_strictly_above_threshold|X_strictly_below_threshold|X_at_or_above_threshold|X_at_or_below_threshold is satisfied. A condition of the form strictly_above|below means the threshold value itself is excluded (strict inequality). A condition of the form at_or_above_threshold|at_or_below_threshold means the threshold value itself is included. A variable whose standard name has the form spell_length_of_days_with_X relative to a threshold condition must have a coordinate variable or scalar coordinate variable with the standard name of X to supply the threshold(s). It must have a climatological time variable, and a cell_method entry for within days which describes the processing of quantity X before the threshold is applied. A spell_length_of_days is an intensive quantity in time, and the cell_methods entry for over days can be any of the methods listed in Appendix E appropriate for intensive quantities e.g. "maximum", "minimum" or "mean".