Interpolated Climate Data
The interpolation program and map generation is based on the interpolation equation given below.
so is the station at which we are interpolating a value
do is the date for which we are interpolating a value
v (s, d) is the value at station s and date d
e (s) is the elevation at station s
d (si , s2) is the distance between s1 and s2
Current Interpolation Method:
Let S be the set of the 10 closest stations s to so for which v (s, do) is not null.
Then v (so, do) can be interpolated as follows:
∑ v(s, do) + λe (s)
d (s, so)
v(so, do)= -λ e(so)
s-S d (s, so)
where: λ is the lapse rate of the sensor being interpolated.
The previous interpolation method that was used before 2005 (Mott et al. 1994) was:
Let s1 be the closest station to so such that v(s1, do) is not null and there exist 25 dates δ for which both v(so, δ ) and v(si , δ) are not null, and let D be the set of the 25 most recent such dates.
Let b= ∑ v(si , δ), c=∑ v(si , δ)2 , d=∑ v(so , δ), and e=∑ v(so , δ) v(si , δ).
δ- D δ- D δ- D δ- D
Then v(so , do)=a1 v(si , do) +ao, where ao = , and ai =
Mott, Paul. T. W. Sammis and M. Southward. 1994. Climate data estimation using climate information from surrounding climate stations. ASAE Applied Engineering in Agriculture. Vol 10:1 pp414-537.