Drought and Grain Crop Yields over the East European Plain under Influence of Quasibiennial Oscillation of Global Atmospheric Processes

Figure 4

Linear regression coefficient of severe drought in the westward QBO phase ((a), (b)) and in the eastward QBO phase ((c), (d)) in May (left) and June (right) during the period 1991–2011 according to SPI.

(a)

(b)

(c)

(d)