spell_length_of_days_with_air_temperature_below_threshold

new

Created: 4 Jun 2026

Proposer: Lars Bärring

Proposed Date: 2026-04-28

308 #26.

Standard names: Standard names for climate indicators based on thresholds

Change Date: 4 Jun 2026, 2:53 p.m.

spell_length_of_days_with_air_temperature_below_threshold day [UTAA] P07 id: CFV13N23
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_below|above_threshold is satisfied. A variable whose standard name has the form spell_length_of_days_with_X_below|above_threshold 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".

Change Date: 4 Jun 2026, 2:55 p.m.

spell_length_of_days_with_air_temperature_below_threshold day [UTAA] P07 id: CFV13N23
This standard name is deprecated in favor of similar names containing the phrase "strictly_below_threshold" or "at_or_below_threshold" depending on which is most suitable for data being newly created. Use of the more precisely defined names is recommended to avoid ambiguity as to whether the threshold value itself is included when calculating the value of the quantity. For cases where the inclusion of the threshold is unknown, or is unlikely to significantly affect the value of the quantity, it is recommended to use the name containing "strictly_below" which is generally applicable to high-precision (floating point) data. This name has not been made into an alias of the more precisely defined names to avoid unintentionally changing the meaning of existing data. 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_below|above_threshold is satisfied. A variable whose standard name has the form spell_length_of_days_with_X_below|above_threshold 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".