Is difficult to detect in deep sea – since wavelength is high and wave height is low (thus less damage to ships in deep sea – since height is less) – but as it comes nearer to coast height increase – thus can cause heavy damage
Tropical cyclones
Are intense LP zones confined within 30 deg north and south
Conditions necessary for a tropical cyclone
1. Large and continuous supply of warm and moist air that can release enormous latent heat through condensation
2. Strong Coriolis force that can prevent filling of low pressure zone – near equator ( 0 to 5 deg) Coriolis force is weak thus no tropical cyclone is formed
3. Unstable conditions through troposphere that creates local disturbances around which cyclones develops
4. Absence of strong vertical wind wedge that disturbs the vertical transport of latent heat
Centre of storm is mostly warm and has low pressure – eye of storm
These originate both in bay of Bengal and Arabian sea
Originate close to 10 to 15 deg North and also close to 16 and 18 deg north and 92 deg East in bay of Bengal
Based on empirical data (observed data), genetic (underlying cause) and applied (actions)
Koeppen’s classification
Is based on temperature and precipitation data
Classified everything as capital and small letters – A,B,C ..e,f,g
A- Tropical – average temperature of coldest month is more than 18 C
B – Dry Climate – Potential evaporation exceeds precipitation
C – Warm Temperate - average temperature of coldest month is more than -3 C and less than 18 C
D – Cold snow forest climate - average temperature of coldest month is less than – 3 C
E – Cold climates - average temperature of all months is less than 10 C
H – High land – cold due to altitude
These are then subdivided
Tropical Humid Climate
Exists between tropic
Sun is overhead throughout the year and is in INTCZ (inter tropical convergence zone) – thus it is hot and humid
Temperature is high and precipitation is also high
Tropical group is divided into 3 – tropical wet climate, tropical monsoon climate and tropical wet and dry climate
Tropical wet climate – near equator – Amazon basin, tropical dense evergreen forest with dense canopy is found
Tropical monsoon – India, Northern Australia, NE South America – Summer is wet and winters are dry
Tropical wet and dry climate – it occurs in north and south of Tropical wet climate, deciduous and tree shredded grasslands can be found
Dry Climate
Very low rainfall
Can be found from 15 to 60 deg N and S of equator
In low latitudes (15 to 30) – this type is seen on coast land more as compared to inner lands
Whereas in high latitudes (30 to 60) – it is seen more on inner lands – where maritime air winds cannot reach
Subtropical steppe climate and sub-tropical desert – rainfall is less, steppe has more rainfall than the desert type – ex. Libya
Warm temperate – between 30 to 50 deg – mainly seen on eastern and western margins of continents
4 types of Warm temperate –
1. humid sub-tropical – (dry in winter and hot in summer) closer to tropics – ex. North Indian plains, South China interior plain, winters are warm
2. Mediterranean climate – near Mediterranean sea, 30-40 deg, ex – central California, central chile, south eastern and south western Australia,- summer is hot and dry – winter –rainy
3. Humid subtropical – (no dry season and mild winter) on the eastern parts of continent – rainfall is use throughout the year – eastern USA, southern and eastern China, southern japan, eastern coast of Australia
4. Marine west coast climate – is on west coast of continents above Mediterranean climate zone – NW Europe, West USA, SE Australia, NewZealand
Cold Snow Forest Climates (D)
40 to 70 deg North
Europe, Asia, North America
Types 2
1. Cold climate with humid winter – above marine west coast climate zone
2. Cold climate with dry winter – NE Asia,
Polar Climates (E)
Beyond 70 deg
2 types
1. Tundra – vegetation –low growing mosses, flowering plants, - region of permafrost (sub-soil is permanently frozen). During summer – days are very long
2. Ice cap climate – inner Greenland and Antarctica. Very little precipitation
Global warming
The gases that absorb long wave radiations are called as green house gases
Gases- CO2, O3, CFCs, CH4, N2O – gases like CO and NO also affects
Effectiveness of these gases depend upon – concentration, lifetime in atmosphere and wavelength of radiation it absorbs
