ESS210B
Prof. Jin-Yi Yu
What Does Each Harmonic Mean?
qAs an example, if the time series is the monthly-mean temperature
from January to December:
q N=12, Dt =1 month, and T=12´ Dt = 12 month = one year
q 1s harmonic (k=1) è annual harmonic (one cycle through the period)
q 2nd harmonic (k=2) è semi-annual harmonic (2 cycles through the period)
q Last harmonic (k=N/2) è the smallest period to be included.
Period = NDt = 12 months
Period = 0.5NDt = 6 months
Period = 2Dt = 2 months
Nyquist frequency
