The logarithm-linear relationship of the occurrence frequency to the duration of sand-dust storms: Evidence from observational data in China

The sand-dust storm data compiled by the China State Meteorological Bureau for the period of 1960-2000 have been analyzed to find the distribution of the sand-dust storm occurrence frequency against the duration time. It is found that there exists a universal relationship of log10N=a-bt, where N is the number of sand-dust storm occurrence frequency with the duration time greater than t, a and b are constants that may be associated with the sand-dust storm occurrence conditions at a given site. It is also shown that the constant b is related with surface conditions for the sand-dust storm occurrence with larger value of b less favorable for the occurrence of the sand-dust storm at that site. In fact, the large value of b is found in the Gobi and high-mountainous regions whereas the small value of b is found in the sand and dry loess regions.