Climatology

Answer : The earliest classification of climatic types was made by the Greek geographers. However, of the several schemes of climatic classification in modern times, the one devised by Wladimir Koppen,a German botanist and climatologist, still remains the most widely known descriptive system. It is a quantitative as well as empirical classification of climates.

Koppen proposed his first classification in 1900, using the world vegetation map of de Candolle, French plant physiologist. He revised his scheme in the ....

Answer : German climatologist Koppen presented his 1st empirical scheme of climatic classification in 1900.

Based on vegetation he gave 5 symbols—

1. Mega therm -Tropical Evergreen
2. Xerophytic-Desert/Semi arid
3. Mesotherm-Grassland
4. Micro therm-Taiga
5. Hekistotherm-Tundra

In 1918 classification, he used mean monthly and annual temperature, mean monthly and annual precipitation, seasonal variationinstead of extremetemperature and precipitation.

In the second level, he used f, m, s, w with A, C, and D type of climate.

• f- precipitation well distributed throughout the year
• m- 70% of annual rain in 3-4 months
• s- ....

Answer : The concept of potential Evapotranspiration (PE)was given by Thornthwaite in 1948. PE is the amount of transfer of both moisture and heat to atmosphere from soil and vegetation

• I = sum of 12 months (t/5)^1.514
• t = temp in °C

Based on this concept, he developed 4 induces—

(1) Moisture index =(100 S-60D)/PE

• S = Monthly supply of moisture
• D = deficit of moisture

Based on this index he identified humidity provinces.

A-Per humid C₂-Moistsub humid

• B₄- ....

Answer : Frontogenesis is the genesis of front near 60^th parallel and is related to the convergence of cold polar airmass and warm tropical airmass under the effect of polar winds and westerlies.

As the air masses converge, warm air starts rising leading to conditional instability.

Weather effectivity is related to 4 fronts.

1. Stable front—weather conditions are largely transitional type that denotes the begining of turbulent circulation.
2. Warm front—conditions ....

Answer : The modern school envisages a three cell model of meridional circulation of atmosphere wherein it is belived that there is cellular circulation of air at each meridian (longitude).

Surface winds blow from high pressure areas to low pressure areas but in the upper atmosphere the general direction of air circulation is opposite to the direction of surface winds.

Thus each meridian has 3 cells of ....

Answer : The regional and seasonal winds-monsoon, was identified by Arab scholars as seasonal reversal of wind pattern. The monsoon regions of the world are precisely confined to east tropical land with Indo-China peninsula and India forming the prominent examples.

To interpret the characteristics and origin of these regional -seasonal winds two distinctive approaches are taken into consideration:

(a) Classical concepts (b) Modern concepts

Classical concept: Classical concept (Thermal concept of sir Headley) postulates that differential heating of land and ....

Answer : In technical terms, a thunderstorm is said to develop when the atmosphere becomes “unstable to vertical motion.” Such instability can arise whenever relatively warm; light air is overlain by cooler, heavier air. Under such conditions the cooler air tends to sink, displacing the warmer air upward. If a sufficiently large volume of air rises, an updraft (a strong current of rising air) will be produced. If the updraft is moist, the water will condense and ....

Answer : A biome is a large ecosystem where plants, animals, and people all live together. Mountain biomes are found all over the planet and are generally found in large groups called chains or ranges. Mountain (Alpine) biomes are very cold and windy, with larger mountains being the coldest and windiest, and also having less oxygen closer to the top. The types of wildlife and plants found on mountain biomes depend on the elevation and location of ....

Answer : The dew point is the temperature below which the water vapor in air at constant barometric pressure condenses into liquid water (dew). The dew point is a water-to-air saturation temperature. The dew point is associated with relative humidity. It is the temperature at which water is completely saturated.

Forms of condensation-

1. Frost: When the temperature of air falls below 0°C before the dew point is reached, the water vapour is directly converted into crystals of ice, ....

• Gujarat agro-climatic zone includes Gujarat plains and hilly regions. It includes Kathiawad and fertile valleys of Sabarmati and Mahi rivers. It is an arid and semi arid region with annual rainfall of 50-100 cm and temperature 26-42°C. The plateau region has regur soil, coastal region has alluvial soil and Jamnagar region has red and yellow soil.
• Crops in this region are dependent on monsoon. Few crops such as groundnut, cotton, tobacco, oil seeds, rice, wheat, millet are produced by this region. ....

Answer : Cryosphere means vast ice shells spread over the earth surface. These cold regions include the Arctic and Antarctic region and impact the global climate significantly. The impact of cryosphere on climate is in the form of release of methane gas and absorption of insolation. This creates problem of global warming.

• Methane gas is released in environment from soil of these regions which is exposed after melting of glacier. Methane being greenhouse gas causes global warming
• Glacier ....

Answer : Airmass is known as that portion of atmosphere which has uniform temperature and humidity horizontally at different altitudes. Airmass is generated when atmospheric condition over vast planar surface exists for sufficient time. To classify the airmasses, it is necessary to keep in mind the characterstics related to airmasses. These characterstics can be areas of origin, weather condition, thermodynamic and mechanical changes in way. Bergeron had classified airmasses into two categories - physical and thermodynamic. Physical ....

Answer : Due to climate change, the average global atmospheric temperature has increased by 0.74°C between 1906-2009. The increase in CO2 level, CH4, NO2, etc. are responsible for this. The intensity and duration of rainy period have also reduced drastically over the time. The frequency of flood in some areas of low rain fall has increased. There is also evidences of depleting ground water in many areas of the country. The level of water in perennial rivers ....

Answer : Different forms of precipitation e.g. rain fall, hailstorm, etc. depend on the stability and instability of the atmosphere. The air without vertical movement is called stable air while air moving upward and downward is unstable air. An air mass ascends and become unstable when it becomes warmer than the surrounding air. This instability of air mass depends upon the relationship between normal lapse rate and adiabatic change of temperature. When the temperature of the atmosphere ....

Answer : Urban environment is largely man made in which microclimate has been altered. The urban climate structures create a totally different environment in the cities.

The characteristics of urban environment which affect the urban and make it different from the surrounding areas are-

• Here concrete, asphalt and glass replace the natural vegetation.
• Vertical buildings replace the horizontal structures.
• Here large amounts of energy is imported and combustion of these energy creating pollution.
• In comparison to surrounding areas, there is continuously rising ....

Answer : Climate like any other physical phenomenon is not static but rather a dynamic kind of thing. In greater or less in degree it is ever changing. The term climate change has been defined as the climatic variations in historical time over the span of a few thousand years. There are various indicators of climate change of past historic periods. Such as morphological evidences, (e.g.-glacial features erratics, denudation, cirques, arête, etc.). Fossil evidences, lithogenic evidences, Agricultural ....

Answer : As monsoons have become better understood, the term monsoon has been broadened to include almost all of the phenomena associated with the annual weather cycle within the tropical and subtropical land regions of the earth.

The monsoons, which help balance global temperatures and sustain life on earth, affect a vast area of the globe - from Africa across Asia to the Pacific; northern China and the Himalayas to north Australia; and even Mexico and parts of ....

Answer : The weather of any place is always the result of interplay among many climatic and geographical factors. The local winds, though narrow in scope, bring considerable influence upon the local weather conditions. The major factors that play important role inthe development of local winds are temperature, rainfall, proximity to sea, relief, direction of winds, aspect of sun etc. The importance and role of these factors vary from place to place.

Development of Winds: Wind is the ....

Answer : The cyclones are closed air circulation around a low pressure centre having steep barometric gradient and an associated revolving storm, accompanied by cyclonic rain. In a cyclone winds circulate blowing inwards in anti-clockwise direction in the Northern Hemisphere and in clockwise direction in the Southern Hemisphere. They are mainly of two types based on their latitudinal location - Tropical cyclone and Temperate cyclone. A comparative study is made under the following heads:

I. Origin And Development:

Tropical ....

Answer : Temperature differences produced by the varying amount of insolation received at the earth’s surface account for the density differences that drive the atmosphere in three-dimensional motion on global scale. The distribution pattern of temperature, pressure and the resultant winds depend basically on the distribution of insolation and the orbit of our planet around the sun. Besides the geography of earth and the constituent of atmosphere also determine the general circulation pattern.

The old concept of the ....

Answer : Thornthwaite, an American climatologist, presented his first classification in 1931 in which, he considered natural vegetation of a region as the indicater of climate of that region. He accepted the concept that the amount of precipitation and temperature had paramount control on vegetation but he also pleaded for inclusion of evaporation as important factor. Hence, precipitation effectiveness and temperature effectiveness were the chosen criteria for demarcation of the climatic regions.

After making sizeable modification, Thornthwaite presented ....

Answer : Precipitation has been defined as water in liquid or solid form falling to the earth. According to Foster, precipitation is deposition of atmospheric moisture and is perhaps the most important phase of the hydrologic cycle. The first step in precipitation is condensation. The process of condensation involves a change from water vapour to liquid, while the process of precipitation involves the falling of water as rain, snow, hale or some other form.

Precipitation Types: The three ....

Answer : Cs type of climate as per Koeppen’s classification:

• In Koeppen's scheme of climatic classification, C represents warm temperate (mid-latitude Mesothermal) climates with mild winters 'S' letter in his classification represents summer dry season meaning thereby winter is the wet season. The climate characterised by such features in temperate region is Mediterranean type of climate. It is found between 30° to 45° N and S on the west coast of each continent.
• Areas: The countries bordering the Mediterranean ....

Answer : The air, sea, and land constitute the major portions of four great material realms or spheres, that comprise the total global environment. Three of these realms are inorganic, (i) Atmosphere, (ii) Hydrosphere and (iii) Lithosphere. The fourth realm the biosphere, encompasses all living organisms of the earth. All these realms are in the figure given below:

Of the three inorganic spheres the atmosphere is ....

Answer : C.W.Thornthwaite, an American climatologist, induced two climatic classifications. One in 1931 and other in 1948. His most significant concept is that of “Potential evapo-tranpiration” on which he based his 1948 classification. This concept has been applied in practical studies of water balance to solve the problems of water-use. Let us explain some of the basic criteria used in his climatic classification.

Criteria:

1. Potential Evapo-transpiration: Represents the amount of moisture that would be transferred to the atmosphere by ....