IEM Daily Feature
Friday, 21 October 2016
Friday, 21 October 2016
Freezing Time
Posted: 21 Oct 2016 05:34 AM
The featured chart presents an analysis of duration and strength of the first fall periods at
or below freezing for Des Moines based on one minute interval temperature observations
since fall 2000. Each event represents a sequential fall date during which the low
temperature reached 32 degrees or colder. For example, event three would be the third
day during the fall season at or below 32. The time duration is the period between when the
temperature hit 32 degrees and rose back above 32. The maximum duration period for
each date was used in cases of multiple periods on a given date. The box and whisker
plots represent the spread of duration. A strength metric is also calculated and is simply
the temperature difference from 32 multiplied by time. So what is the moral of the story
here? The initial dips below freezing are brief (1.5 hours on average) and shallow. Both
the duration and "depth" increase with sequential event with more noise than signal
appearing after the fourth or fifth event.
Voting:
Good = 7
Bad = 2
Tags: freeze fall
Voting:
Good = 7
Bad = 2
Tags: freeze fall