Relative Humidity

Annual and seasonal means and trends in region averaged RH of the six regions during the period of 1969-2012 is given in Table 2. Region averaged annual mean RH is the highest (77.3 %) in north-east and the lowest (55.4 %) in central India. Annual RH trends are statistically significant at the 95 % confidence level for all the regions except over north-east. The rate of change in region averaged annual RH is the highest (+1.09 % per decade) in north-west and the lowest (+0.11 % per decade) in north-east as shown in Fig. 5. It is clear from Table 2 that seasonal mean RH values averaged over the six regions are the highest in north-east for all the seasons. Similarly, the lowest seasonal mean RH values are in central India (winter, summer and post-monsoon) and in north-west India (monsoon). Seasonal trends in region averaged RH are significantly positive for winter and summer in all regions except the north-east region. Monsoon season RH has shown significant increasing trend over the south region. Post-monsoon season RH is significantly increasing in north-west, central, east and south regions while it is significantly decreasing in the north-east region (Table 2).

Table 2 Mean and trends in surface relative humidity averaged over the six regions of India during the period of 1969-2012

Region

Annual

Winter

Summer

Monsoon

Post-monsoon

Mean

Trend

Mean

Trend

Mean

Trend

Mean

Trend

Mean

Trend

North-west

58.27

1.09a

62.02

1.94a

41.60

0.98a

67.87

0.42

58.42

1.37a

Central

55.40

1.03a

52.90

1.55a

33.15

1.35a

72.90

0.29

57.45

1.27a

East

70.30

0.81a

66.18

1.56a

59.06

0.84a

80.45

0.16

72.98

0.95a

North-east

77.09

0.11

72.83

0.24

71.02

0.39

83.91

0

78.85

-0.34a

West

63.73

0.44a

54.37

0.89a

54.85

0.50a

78.61

0.06

61.23

0.52

South

68.75

0.57a

65.44

0.59a

61.37

0.78a

74.06

0.37a

74.21

0.70a

While mean relative humidity values are in %, trends are given in % per decade. Trends statistically significant at the 95 % significance level are marked ‘a’

 
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