Difference between revisions of "Growing Degree Day"

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Each plant species  has  its  own  lower  air  temperature  threshold  and  upper
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air temperature threshold. It is assumed that no growth occurs outside of this
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range. This temperature range varies for each plant.
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Growing  degree  day  units  are  calculated  by  using  the  maximum  daily  air
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temperature,  the  minimum  daily  air  temperature  and  the  crop’s  lower
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temperature  threshold. 
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Different methods exist for calculating heat units. The method most commonly used in the U.S. for determining heat unit accumulation relative to corn phenology is the formula first suggested by the National Oceanic and Atmospheric Administration. The “modified growing degree day formula” calculates daily accumulation of GDD’s as the average daily temperature minus 50° F.
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Calculate [http://en.wikipedia.org/wiki/Growing_degree_day Growing Degree Day (GDD)] for each hive and add to database.
 
Calculate [http://en.wikipedia.org/wiki/Growing_degree_day Growing Degree Day (GDD)] for each hive and add to database.
  

Revision as of 11:19, 25 November 2018


Each plant species has its own lower air temperature threshold and upper air temperature threshold. It is assumed that no growth occurs outside of this range. This temperature range varies for each plant.

Growing degree day units are calculated by using the maximum daily air temperature, the minimum daily air temperature and the crop’s lower temperature threshold.

Different methods exist for calculating heat units. The method most commonly used in the U.S. for determining heat unit accumulation relative to corn phenology is the formula first suggested by the National Oceanic and Atmospheric Administration. The “modified growing degree day formula” calculates daily accumulation of GDD’s as the average daily temperature minus 50° F.



Calculate Growing Degree Day (GDD) for each hive and add to database.


Centigrade
Tbase = 10
Tmax  = 30


SET @gdd_total:=0;
SELECT
  q1.doy,
  q1.gdd,
  round(@gdd_total := @gdd_total + q1.gdd) as gdd_tot
FROM
 (SELECT DAYOFYEAR(DATE_FORMAT(`hive_observation_time_local`, '%Y-%m-%d')) AS doy,
  (least(greatest(max(wx_temp_c),10),30) - least(greatest(min(wx_temp_c),10),30))/2 AS gdd
  from HIVE_DATA 
  where hive_id=10 group by DATE_FORMAT(`hive_observation_time_local`, '%Y-%m-%d') ) AS q1



SELECT hive_id, DAYOFYEAR(DATE_FORMAT(`hive_observation_time_local`, '%Y-%m-%d')) AS doy,
  (least(greatest(max(wx_temp_c),10),30) - least(greatest(min(wx_temp_c),10),30))/2 AS gdd
  from HIVE_DATA group by DATE_FORMAT(`hive_observation_time_local`, '%Y-%m-%d'), hive_id