Table 2: 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).

Period Type Of Trend Coverage (%) Sig Level Coverage (%) Period Type Trend Coverage (%) Sig Level Coverage (%)
1951-1955 Decr 29.16 Sig 0 1988-2011 Decr 79.16 Sig 16.6
Not Signt 29.1 Not Signt 62.5
Incr 70.8 Sig 1.8 Incr 20.8 Sig 0
Not Sig 68.8 Not Sig 20.8
1956-1988 Decr 50 Sig 4.2 1951-2011 Decr 91.6 Sig 83.3
Not Sig 45.8 Not Sig 8.2
Incr 50 Sig 25 Incr 8.33 Sig 0
Not Sig 25 Not Sig 8.3