Spatiotemporal Variations of Drought in the Arid Region of Northwestern China during 1950–2012

Figure 6

(a–c) Wavelet transformation and (d–f) wavelet variance of the SPI, SPEI, and SC-PDSI, and (g–i) wavelet coefficient during the 8a, 17a, and >20 a oscillation period in the ARNC from 1950 to 2012.

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(b)

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(i)