Question 1
In Table-I, the average mean monthly temperatures and amounts of rainfall of 10 representative stations have been given. It is for you to study on your own and convert them into 'temperature and rainfall' graphs. A glance at these visual representations will help you to grasp instantly the similarities and differences between them. One such graph (Figure I) is already prepared for you. See if you can arrive at some broad generalisations about our diverse climatic conditions. We hope you are in for a great joy of learning. Do the following activities
| Stations | Latitude | Altitude (Metres) | Jan. | Feb. | Mar. | Apr. | May. | Jun. | Jul. | Aug. | Sep. | Oct. | Nov. | Dec. | Annual Rainfall |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temperature(°C) Bengaluru Rainfall(cm) | 20.5 | 22.7 | 25.2 | 27.1 | 26.7 | 24.2 | 23.0 | 23.0 | 23.1 | 22.9 | 18.9 | 20.2 | 88.9 | ||
| 12°58'N | 909 | ||||||||||||||
| 0.7 | 0.9 | 1.1 | 4.5 | 10.7 | 7.1 | 11.1 | 13.7 | 16.4 | 15.3 | 6.1 | 1.3 | ||||
| Temperature(°C) Mumbai Rainfall(cm) | 24.4 | 24.4 | 26.7 | 28.3 | 30.0 | 28.9 | 27.2 | 27.2 | 27.2 | 27.8 | 27.2 | 25.0 | 183.4 | ||
| 19°N | 11 | ||||||||||||||
| 0.2 | 0.2 | — | — | 1.8 | 50.6 | 61.0 | 36.9 | 26.9 | 4.8 | 1.0 | — | ||||
| Temperature(°C) Kolkata Rainfall(cm) | 19.6 | 22.0 | 27.1 | 30.1 | 30.4 | 29.9 | 28.9 | 28.7 | 28.9 | 27.6 | 23.4 | 19.7 | 162.5 | ||
| 22°34'N | 6 | ||||||||||||||
| 1.2 | 2.8 | 3.4 | 5.1 | 13.4 | 29.0 | 33.1 | 33.4 | 25.3 | 12.7 | 2.7 | 0.4 | ||||
| Temperature(°C) Delhi Rainfall(cm) | 14.4 | 16.7 | 23.3 | 30.0 | 33.3 | 33.3 | 30.0 | 29.4 | 28.9 | 25.6 | 19.4 | 15.6 | 67.0 | ||
| 29°N | 219 | ||||||||||||||
| 2.5 | 1.5 | 1.3 | 1.0 | 1.8 | 7.4 | 19.3 | 17.8 | 11.9 | 1.3 | 0.2 | 1.0 | ||||
| Temperature(°C) Jodhpur Rainfall(cm) | 16.8 | 19.2 | 26.6 | 29.8 | 33.3 | 33.9 | 31.3 | 29.0 | 20.1 | 27.0 | 20.1 | 14.9 | 36.6 | ||
| 26°18'N | 224 | ||||||||||||||
| 0.5 | 0.6 | 0.3 | 0.3 | 1.0 | 3.1 | 10.8 | 13.1 | 5.7 | 0.8 | 0.2 | 0.2 | ||||
| Temperature(°C) Chennai Rainfall(cm) | 24.5 | 25.7 | 27.7 | 30.4 | 33.0 | 32.5 | 31.0 | 30.2 | 29.8 | 28.0 | 25.9 | 24.7 | 128.6 | ||
| 13°4'N | 7 | ||||||||||||||
| 4.6 | 1.3 | 1.3 | 1.8 | 3.8 | 4.5 | 8.7 | 11.3 | 11.9 | 30.6 | 35.0 | 13.9 | ||||
| Temperature(°C) Nagpur Rainfall(cm) | 21.5 | 23.9 | 28.3 | 32.7 | 35.5 | 32.0 | 27.7 | 27.3 | 27.9 | 26.7 | 23.1 | 20.7 | 124.2 | ||
| 21°9'N | 312 | ||||||||||||||
| 1.1 | 2.3 | 1.7 | 1.6 | 2.1 | 22.2 | 37.6 | 28.6 | 18.5 | 5.5 | 2.0 | 1.0 | ||||
| Temperature(°C) Shillong Rainfall(cm) | 9.8 | 11.3 | 15.9 | 18.5 | 19.2 | 20.5 | 21.1 | 20.9 | 20.0 | 17.2 | 13.3 | 10.4 | 225.3 | ||
| 24°34'N | 1461 | ||||||||||||||
| 1.4 | 2.9 | 5.6 | 14.6 | 29.5 | 47.6 | 35.9 | 34.3 | 30.2 | 18.8 | 3.8 | 0.6 | ||||
| Temperature(°C) Thiruvananthapuram Rainfall(cm) | 26.7 | 27.3 | 28.3 | 28.7 | 28.6 | 26.6 | 26.2 | 26.2 | 26.5 | 26.7 | 26.6 | 26.5 | 181.2 | ||
| 8°29'N | 61 | ||||||||||||||
| 2.3 | 2.1 | 3.7 | 10.6 | 20.8 | 35.6 | 22.3 | 14.6 | 13.8 | 27.3 | 20.6 | 7.5 | ||||
| Temperature(°C) Leh Rainfall(cm) | -8.5 | -7.2 | -0.6 | 6.1 | 10.0 | 14.4 | 17.2 | 16.1 | 12.2 | 6.1 | 0.0 | -5.6 | 8.5 | ||
| 34°N | 3506 | ||||||||||||||
| 1.0 | 0.8 | 0.8 | 0.5 | 0.5 | 0.5 | 1.3 | 1.3 | 0.8 | 0.5 | — | 0.5 |
(2) Re-arrange the 10 stations in two different sequences:
(i) According to their distance from the equator.
(ii) According to their altitude above mean sea level.
(3)
(i) Name two rainiest stations.
(ii) Name two driest stations.
(iii) Two stations with most equable climate.
(iv) Two stations with most extreme climate.
(v) Two stations influenced by retreating monsoons.
(vi) The two hottest stations in the months of:
(a) February
(b) April
(c) May
(d) June
(4) Now find out
(i) Why are Thiruvananthapuram and Shillong rainier in June than in July?
(ii) Why is July rainier in Mumbai than in Thiruvananthapuram ?
(iii) Why are southwest monsoons less rainy in Chennai?
(iv) Why is Shillong rainier than Kolkata?
(v) Why is Kolkata rainier in July than in June unlike Shillong which is rainier in June than in July?
(vi) Why does Delhi receive more rain than Jodhpur?
(5) Now think why
- Thiruvananthapuram has equable climate?
- Chennai has more rains only after the fury of monsoon is over in most parts of the country?
- Jodhpur has a hot desert type of climate?
- Leh has moderate precipitation almost throughout the year?
- while in Delhi and Jodhpur most of the rain is confined to nearly three months, in Thiruvananthapuram and Shillong it is almost nine months of the year?
In spite of these facts see carefully if there are strong evidences to conclude that the monsoons still provide a very strong framework lending overall climatic unity to the whole country.
(1) The temperature and rainfall graphs for stations are shown below:
(2) The re-arranged stations:
(i) According to increasing order of their distance from the equator:
Thiruvananthapuram → Bangalore → Chennai → Mumbai → Nagpur → Kolkata → Shillong → Jodhpur → Delhi → Leh
(ii) According to increasing order of their altitude above mean sea level.
Kolkata → Chennai → Mumbai → Thiruvananthapuram → Delhi → Jodhpur → Nagpur → Bengaluru → Shillong → Leh
(3)
(i) Two rainiest stations — Shillong, Mumbai
(ii) Two driest stations — Leh, Jodhpur
(iii) Two stations with most equable climate — Mumbai, Kolkata
(iv) Two stations with most extreme climate — Leh, Jodhpur
(v) Two stations influenced by retreating monsoons — Chennai, Bengaluru
(vi) The two hottest stations in the months of:
(a) February — Thiruvananthapuram, Chennai
(b) April — Nagpur, Chennai
(c) May — Nagpur, Jodhpur
(d) June — Delhi, Jodhpur
(4)
(i) Thiruvananthapuram receives rainfall from the Arabian sea branch of the monsoon and Shillong receives rainfall from the Bay of Bengal branch of the monsoon in first week of June. Later these branches move ahead and these places receive less rainfall in July.
(ii) The Arabian sea branch hits Thiruvananthapuram on 1 June while it reaches Mumbai on 10 June. So, Thiruvananthapuram receives most of the rainfall in June but Mumbai gets most of rainfall in July.
(iii) The southwest monsoons has two branches: the Arabian sea branch and the Bay of Bengal branch. The Arabian sea branch brings rainfall on western Ghats. Chennai is situated on the leeward side of Western ghats and therefore get very less rainfall. The Bay of Bengal branch moves towards north-eastern states and bring heavy rainfall. Therefore, southwest monsoons are less rainy in Chennai.
(iv) Due to lofty Himalayas, the monsoon wind do not escape and remains near Shillong bringing heavy rainfall there. Therefore, Shillong is rainier than Kolkata.
(v) The Bay of Bengal branch of Monsoon reaches Shillong earlier than Kolkata. Therefore, Kolkata rainier in July than in June unlike Shillong which is rainier in June than in July.
(vi) Jodhpur is located to the west of Delhi. As the monsoon winds traverse Northern India from east to west, they gradually shed their moisture. Hence, when these winds reach Delhi, they retain more moisture and result in greater rainfall compared to Jodhpur.
(5)
Thiruvananthapuram has equable climate because it is situated near sea which has a moderating effect on its climate.
Chennai does not get rainfall from Southwest monsoons during June to september. It gets its share of rainfall from retreating monsoon and prevalent northwest trade winds that bring moisture from Bay of Bengal during October-November.
Jodhpur is situated in Thar desert. This area gets very less rainfall. The sand is heated up quickly during day and increases the temperature. Therefore, Jodhpur has a hot desert type of climate.
Leh has moderate precipitation almost throughout the year because it is situated on landlocked plateau and the place is dry due to low temperature.
Delhi and Jodhpur get rainfall mostly from monsoon and some from western disturbances. Thiruvananthapuram receives rainfall from monsoon as well as from local factors as it is situated near sea. Shillong is surrounded by lofty mountains that do not allow the rain bringing winds from Bay of Bengal to escape. Therefore, while in Delhi and Jodhpur most of the rain is confined to nearly three months, in Thiruvananthapuram and Shillong it is almost nine months of the year.
In spite of the above facts, we can say that monsoon unifies India as one because monsoon brings rainfall to most of India from north to south in span of 2-3 months. All the festivals and agricultural practices revolve around the monsoon rains.