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Heat/cold degree days and Chill hours: Difference between revisions
Heat/cold degree days and Chill hours (view source)
Revision as of 11:34, 3 January 2013
, 3 January 2013→Chill Hours: Clarify re Air Frost days in View menu
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m (→Chill Hours: Clarify re Air Frost days in View menu) |
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So if for the whole of November, there was just one hour at one degree below the threshold, two hours at five degrees below, and three hours at seven degrees below; the total for the month would be (1*1)+(2*5) +(3*7) hours reported as 32 degree days.
==Chill Hours and/or Air Frost==
A related measure, also reported by Cumulus counting the ''hours'' below a (different) configurable temperature threshold for the 12 month period starting on the 1st day of a configurable month, is Chill Hours.
The traditional way of calculating the accumulation of Chill Hours is the number of hours the temperature is below 45F or 7.5C for the period of 1st October to 30th April in the Northern Hemisphere. On Cumulus that threshold, and start date are the default, so you simply observe the reported value on 30 April. The current figure is viewable on the 'This Year' screen accessed from the View menu (only when the current year is selected), and is available via web tag <#chillhours> to be added to a web page template of your design.
The main applicability is to stone and seed fruit as their exposure to low temperatures during the winter months will have a significant effect on the following harvest. Too few cold hours can result in poor quality and quantity of the crop. Fruit tree varieties prefer a Chill Hour rating from below 200 hours to around 1500 hours.
However, the way it can be configured on Cumulus will allow you to track air frost hours, ground frost hours or any other below the threshold parameter.
To see the number of Air Frost days, use the View menu to select 'This Month', 'This Year' or 'This Period' and choose the precise period of interest using the drop down selectors. (As at build 1058, there are no web tags to give air frost counts).
[[User:Sfws|Sfws]] 10:53, 1 December 2012 (UTC) (with thanks to Randy who raised Enhancement Request #117 and supplied some of the above text)
==Cold Degree Days==
You may have a thermostat that makes a cooling system come on when the temperature rises above a threshold.
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