Comparison of trends and frequencies of drought in central North China and sub-Saharan Africa from 1901 to 2010

This study compares the trends and frequencies of drought between central North China (CNC) and (SSA) for the periods 1901-2010 and 1951-2010. The Standardized Precipitation Evapotranspiration Index (SPEI) and Self-Calibrating Palmer Drought Severity Index (sc-PDSI) are used to assess the drought trends and frequencies. In general, the results exhibit downward trends of drought index values and upward trends of drought frequencies over CNC and SSA. A high rate of the trends' slopes for the drought index and a low rate of the frequencies' slopes is found over CNC with respect to SPEI and sc-PDSI. Furthermore, some abrupt changes are revealed after applying the sequential Mann-Kendall test to detect change points. These findings offer insight into the trends and frequencies of drought over the regions studied. Further analysis needs to be undertaken to understand the mechanisms underlying the occurrence of drought in these areas.