Table 1: Some features of atmospheric annual precipitable water of Iran during the three periods of upper-air reanalyzed data retrieved from NCEP/NCAR. (Q means Quartile).

Distributions Statistical Specifications 1948-1957 1958-1978 1979-2012
Central index mean 15.02 14.6 13.03
mode 8.41 7.7 7.2
Dispersion index range 14.7
15.2 14.2 Variance 15.03
14.06 14.4 Std 3.87
3.75 3.79 Coefficient variation 25.5
26.4 9.7 distribution index skewness 0.123
0.124 0.184 Kurtosis -0.837
-0.625 -0.647
Thresholds Q1 11.5 11.4
10.5 Q2 14.6 14.3
13.6 Q3 17.9 16.6
15.9 Maximum 23.1 22.9