Climate Class 9
We as a layman often confuse between climate and weather and use these words synonymously, however, these have different meanings. Let’s look at these brief notes on Climate Class 9 to understand the concept in its literal sense.
Weather is the state of atmosphere recorded at any given point of time. It can change every moment and varies throughout the day. Whereas, the Climate of a place is the sum of average weather conditions of 30 years, in short, the climate is a sum total of the weather conditions of a place, assertively a large one for a comparatively longer period of time. It can take millions of years for the climate of a place to change.
The Elements of Climate and Weather are same, which are:
- Temperature
- Atmospheric Pressure
- Wind
- Humidity
- Precipitation
Note: According to the monthly atmospheric conditions of a place a year is divided into three seasons, namely- Summer, Winter, Rainy.
The Climatic conditions of any place depend on the following common factors:
- Latitude
- Altitude
- Distance from the sea
- Pressure and wind systems
- Ocean Currents
- Relief Features
In particular to a country like India, the factors that are considered to affect the climatic conditions are- Latitude, Altitude, Pressure, and Winds, which means it is influenced by pressure and surface winds, upper air circulation, western cyclonic disturbances and tropical cyclones.
Quick Facts About Indian Climate
- The climate of India is described as the “Monsoon” type of climate which is most prevalent in South and South East Asia. This is because the climate of India is influenced by the monsoon winds, which is basically a seasonal reversal in the wind through the year
- Tropic of cancer passes through the middle of India from Rann of Kutch to Mizoram. When the sun is directly overhead on the Tropic of cancer which is June 21, it marks the beginning of summer in the Northern hemisphere
- Temperature and precipitation are the elements which are taken into consideration to ascertain the varying climatic condition from place to place and season to season
- The Himalayas prevent the cold Katabatic winds from entering the Indian sub-continent
- Jet streams are fast flowing and narrow air currents which flow at a high altitude of about 12000 feet in the troposphere
- Coriolis Force is an apparent force caused by the earth’s rotation. Due to this force, the winds are deflected towards the right in the northern hemisphere and towards the left in the southern hemisphere, this mechanism is known as ‘Ferrel’s Law’
- The western cyclonic disturbances are weather phenomena of the winter months brought in by the westerly flow from the Mediterranean region, which influences the weather of the north and north-western regions of India.
- A broad trough of low pressure in equatorial latitudes is known as Inter-Tropical Convergence Zone (ITCZ), where the northeast and southeast trade winds converge
- The east to west region in the Northern plains experiences decrease in rainfall
- Ocean currents influence the climate of coastal regions
- Indian climatic region also experiences the concept of continentality which means that the people residing far away from the sea experiences extreme weather conditions
The Temperature and Precipitation Affects the Climate of India
Temperature
- Some parts of Rajasthan experiences temperature as high as 50 degrees in summer, this is the reason why houses in Rajasthan have houses with thick walls and flat roofs because thick walls do not allow heat to get into the house and flat roofs retains the little water Rajasthan deserts receive as rainfall. As compared to such a high temperature in Rajasthan places like Pahalgam in Jammu and Kashmir experiences a temperature of 20 degrees at the same time of the year. Thereby, explaining how climatic conditions varies from one place to another
- The temperature varies not only from place to place but it also varies during different hours of the day at the same place. For example, Thar Desert experience a temperature as high as 50 degress during the day but this is the same place which experiences a temperature as low as 15 degrees during the night of the same day.
Precipitation
- While precipitation takes the general forms of rain, snow, sleet, hail. India mostly experiences it in the form of rain while in the upper part of Himalayas it is in the form of snow
- Most part of the country receives rainfall during the month of June to September, whereas some parts like Tamil Nadu receives its share of rainfall during October and November
Quick Facts About Indian Monsoon
- Influenced by the monsoon winds the monsoon mechanism is based on the differential heating and cooling of the land and water which creates low pressure on the land while the seas around experiences a high pressure
- Indian monsoons are also affected by the shift in the position of Inter Tropical Convergence Zone in summer over the Ganga plain
- The high pressure of east Madagascar over Indian Ocean also affects the monsoons
- Mawsynram receives the highest rainfall
Onset and Withdrawal of Monsoon
The onset of Indian monsoon is recorded approximately around the first week of June at the southern tip of the Indian peninsula. The withdrawal of monsoon begins from early September starting from the northern part of India and gradually it is completely withdrawn by the month of December.
Seasons
The four types of seasons are
- Cold weather Season – It begins from mid-November to February. Northeast trade winds blow from land to sea during this period, making it a dry season where days are warm and nights are cold.
- Hot weather Season – During this season which begins from March to May the temperature increases from south to north with the temperature remaining lower in peninsular India. It experiences hot dry winds, ‘Loo’ in May and June along with rising temperature with falling air pressure (in the northern part). While Kerela & Karnataka receives pre-monsoon showers, West Bengal and Assam are affected by northwesterly winds
- Advancing monsoon Season- It begins from June to September and during this season north-western region of the country receives the maximum rainfall
- Retreating monsoon Season is also known as the withdrawing monsoon – please refer to the above section of onset and withdrawal of monsoon.
Also check out our article on Science notes Class 9 here.
