CLIMATE
State of Environment Report of Tripura for the year of 2002

3.0 Introduction

The State of Tripura experiences Humid Sub-tropical type of climate. The features of climate, however, vary between its different parts of the State. There are only two Meteorological Observatories at Agartala and Kailasahar in Tripura having the facility to record temperature and other weather information. Some of the important features of regional variation of climate with regard to temperature, rainfall, humidity and wind speed are described below.

3.1 Temperature

The normal temperature at Agratala and Kilasahar is 25.2C and 25.0C respectively. The temperature shows a declining trend from west to east. The daily maximum temperature and minimum mean temperatures are 30.70C and 19.50C respectively during summer months. The cold weather starts from about the end of November when the temperature of both day and night decreases steadily. January is the coldest month when mean daily minimum temperature is only 8.9C and maximum temperature is 25.2C. Average temperature in different years is given in Table-15.

Table- 15 : Average temperature in different years (in C)

Year

Agratala

Kailasahar

Highest

Lowest

Highest

Lowest

1987

33.9

16.7

NA

NA

1988

33.4

16.3

NA

NA

1989

33.3

16.5

NA

NA

1990

34.1

16.1

NA

NA

1991

33.6

15.5

NA

NA

1992

33.2

16.0

NA

NA

1993

32.9

15.6

NA

NA

1994

33.4

15.9

NA

NA

1995

34.0

15.4

NA

NA

1996

34.2

14.8

NA

NA

1997

32.8

14.9

33.1

16.25

1998

32.1

16.7

33.3

17.5

1999

33.7

17.2

34.1

17.3

2000

NA

NA

NA

NA

[Source: Meteorological Centre, Guwahati]

  3.2 Rainfall

A more sensitive element of climate is the variation in rainfall. It varies not only from place to place or from year to year, but also between seasons. Variation of rainfall between the districts over some years is shown in Table-16. Annual rainfall ranges from 1922 mm to 2855 mm. The rainfall generally increases from south-west to north-east. There is a big gap in the rainfall content in southern central part around Amarpur, which is surrounded by 1500 mm. isohytes. The north-eastern part of the state around Dharamnagar gets maximum rainfall.

Most of the rain comes during the months April-June and July to September.  This period is generally referred to as the Kharif season this is the major agricultural season of the whole State. The variation of Kharif rainfall between the districts as also shown in Table -17 & Fig.-6.

The Factors governing rainfall are the seasonal changes in the direction of wind and the presence of cool upper air current over the given parts of the State. During the Kharif season, large depressions develop over one or the other parts of the State.

Table-16 : Average rainfall in different years (in centimeter)

District

1987

1988

1989

1999

1991

1992

1993

1994

1995

1996

West Dist.

271.6

333.0

200.7

254.6

297.5

172.8

269.1

146.3

207.8

192.2

North Dist.

228.8

325.3

255.1

260.8

337.6

226.8

373.4

226.6

223.8

222.5

South Dist.

249.7

337.8

230.5

313.5

373.8

173.8

372.6

182.4

251.1

209.4

Dhalai Dist.

NA

NA

NA

NA

NA

NA

NA

NA

323.7

285.5

Tripura

250.0

332.0

228.8

276.2

336.2

191.1

338.4

185.1

251.6

227.4

[Source: Directorate of Agriculture, Govt. of Tripura]

 

Table-17 : Quarterly average rainfall in different district in 1996 (in Centimeter)

District

January- March

April-June

July-September

October-December

West District

11.4

88.2

69.6

23.0

North District

22.9

86.4

97.6

15.6

South District

11.1

92.2

77.9

28.2

Dhalai District

16.3

130.5

122.8

15.9

Tripura

15.4

99.3

92.0

20.7

[Source: Directorate of Agriculture, Govt., of Tripura]


 

3.3 Humidity

Humidity is generally high throughout the year. In the summer season the relative humidity is between 50 percent to 74 percent whereas in the rainy season it is over 85 percent.

3.4 Wind Speed

The mean wind speed is 7.1 km per hour, with maximum of 13.1 km per hour in May and minimum of 3 km per hour in December.

3.5 Climate and Agriculture

The relationship between rainfall, temperature and farming is suitable to grow paddy crops in the plains, and bamboo trees and jhum cultivation on hills along with the scope for plantation of rubber, coffee, cashewnut, coconut and other evergreen and deciduous plants on the hilly and tilla land.

The state represents hypothermic soil temperature regime. On the basis of variation in rain fall, potential and actual evapotranspiration and length of crop growing period and their interrelationship, the state of Tripura has been divided into eight agroecological zones (Table-18).


Table-18 : Agroecological Zones in Tripura

Climate

Physiography

Soil Type

AWC

LGP

Moisture

Perhumid Hyperthermic

North eastern hills/Purvachal

Red & Lateritic

150-199 mm/m

>300 days

 

Humid Hyperthermic

North eastern hills/Purvachal

Red & Lateritic

150-199 mm/m

>300 days

 

Humid Hyperthermic

North eastern hills/Purvachal

Red & Lateritic

150-199 mm/m

>300 days

80-100%

Humid Hyperthermic

North eastern hills/Purvachal

Red & Lateritic

150-199 mm/m

>300 days

60-80%

Humid Hyperthermic

As above with high structural hills

Red & Lateritic

150-199 mm/m

>300 days

 

Humid Hyperthermic

Northeastern hills/Purvachal

Red & Lateritic

150-199 mm/m

>300 days

40-60%

Humid Hyperthermic

Northeastern hills/Purvachal

Red & Lateritic

250 mm/m

<300 days

 

Humid Hyperthermic

As above with high structural hills

Red & Lateritic

250 mm/m

<300 days

 

 

 
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