Crop Yield and Temperature Changes in North China during 601–900 AD
Figure 2
(a) Annual crop yield of North China from 601 to 900 AD (The straight line represents the negative trend of crop yield) and (b) real part-time frequency distribution of Morlet wavelet transform (shading denotes insignificance at confidence level of 95%) and (c) global power spectrum (dashed line denotes threshold value at confidence level of 95%).
