Q. 33.5( 4 Votes )

Answer the following questions in about 150 words.

(i) How do the latitude and the tilt in the axis of rotation of the earth affect the amount of radiation received at the earth’s surface?

(ii) Discuss the processes through which the earth-atmosphere system maintains heat balance.

(iii) Compare the global distribution of temperature in January over the northern and the southern hemisphere of the earth.

Answer :

(i) The amount of insolation a place receives depends upon the inclination of the rays. This depends on the latitude of the place. The higher the latitude, the less is the angle they make with surface of the earth resulting in slant sun rays. The area covered by vertical rays is always less than the slant rays. If more area is covered, the energy gets distributed and the net energy received per unit area decreases. Moreover, the slant areas are required to pass through greater depth of the atmosphere resulting in more absorption, scattering and diffusion.

The axis of the earth is tilted at an angle of 23.5°. So the sun’s rays are different in both the hemispheres at the same time. The sun’s rays fall vertically on the tropic of cancer from 1st March to 21st July and on Tropic of Capricorn from 23rd September to 22nd December. As we go towards the poles, the temperature keep decreasing as the earth is tilted. Therefore the latitude and tilt in the axis of rotation of the Earth affect the amount of radiation received at the earth’s surface.


(ii) The sun’s energy reaches the earth’s surface by the process of radiation. The earth maintains the temperature by absorbing the rays and reflecting the terrestrial radiation. Of the total energy radiated by the sun, some amount of energy is reflected, radiated and absorbed. Out of the remaining part, 35 units are reflected back to the space before reaching the earth’s surface. Of these 27 units are reflected back from the top of the clouds and 2 units from the snow and ice –covered areas of the earth. The remaining 65 units are absorbed, 14 units within the atmosphere and 51 units by the earth’s surface. The earth radiates back 51 units in the form of terrestrial radiation. Of these 17 units are radiated to space directly and the remaining 34 units are absorbed by the atmosphere. 48 units absorbed by the atmosphere are also radiated back into space. Thus, the total radiation returning from the earth and the atmosphere respectively is 65 units which balance the total of 65 units received from the sun. This is known as the heat balance of the earth’s surface.


(iii) In general the effect of latitude on latitude is well pronounced on the map as the isotherms are generally parallel to the latitude. The deviation from this general trend is more pronounced in January than in July especially in the northern hemisphere. In the northern hemisphere the land surface area is much larger than in southern hemisphere. Hence the effects of land mass and ocean currents are well pronounced. In the January the isotherms deviate to the north over the ocean and to the south over the continent. This can be seen in the Atlantic Ocean. The presence of warm ocean currents, gulf streams, and North Atlantic drift make the Northern Atlantic Ocean warmer and the isotherms bend towards the north. Over the land the temperature decreases sharply and isotherms bend south in Europe. The effect of ocean is well pronounced in the southern hemisphere. Hence the isotherms are more or less parallel to the latitudes and the variation in temperature is more gradual than in the northern hemisphere. The isotherm of 20°C, 10°C and 0°C runs parallel to 35°S, 45°S and 60°S latitudes respectively.


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
PREVIOUSAnswer the following questions in about 30 words.(i) How does the unequal distribution of heat over the planet earth in space and time cause variations in weather and climate?(ii) What are the factors that control temperature distribution on the surface of the earth?(iii) In India, why is the day temperature maximum in May and why not after the summer solstice?(iv) Why is the annual range of temperature high in the Siberian plains?NEXTSelect a meteorological observatory located in your city or near your town. Tabulate the temperature data as given in the climatological table of observatories:(i) Note the altitude, latitude of the observatory and the period for which the mean is calculated.(ii) Define the terms related to temperature as given in the table.(iii) Calculate the daily mean monthly temperature.(iv) Draw a graph to show the daily mean maximum, the daily mean minimum and the meantemperature.(v) Calculate the annual range of temperature.(vi) Find out in which months the daily range of temperature is the highest and the lowest.(vii) List out the factors that determine the temperature of the place and explain the possible causes for temperature variation in the months of January, May, July and October.ExampleObservatory: New Delhi (Safdarjung)Latitude: 28°35°’ NBased on observations: 1951 - 1980Altitude above mean sea level: 216 mDaily mean monthly temperatureJanuary May Annual range of temperatureMean Max. Temperature in May - Mean Temperature in JanuaryAnnual range of temperature = 32.75°C – 14.2°C = 18.55°C
Related Videos
Heat Transfer - 01 | Mastering important conceptsHeat Transfer - 01 | Mastering important conceptsHeat Transfer - 01 | Mastering important concepts40 mins
Learn how to balance Redox ReactionsLearn how to balance Redox ReactionsLearn how to balance Redox Reactions63 mins
Enthalpy & Heat CapacityEnthalpy & Heat CapacityEnthalpy & Heat Capacity65 mins
Enthalpy & Heat Capacity | Interactive QuizEnthalpy & Heat Capacity | Interactive QuizEnthalpy & Heat Capacity | Interactive Quiz55 mins
Heat Transfer -02 | Mastering important conceptsHeat Transfer -02 | Mastering important conceptsHeat Transfer -02 | Mastering important concepts49 mins
Calorimetry - 02 | Mastering important conceptsCalorimetry - 02 | Mastering important conceptsCalorimetry - 02 | Mastering important concepts39 mins
Kinetic Theory of GasesKinetic Theory of GasesKinetic Theory of Gases46 mins
Isothermal process | Master important conceptsIsothermal process | Master important conceptsIsothermal process | Master important concepts33 mins
Thermal Expansion | Master important conceptsThermal Expansion | Master important conceptsThermal Expansion | Master important concepts53 mins
Calorimetry - 01 | Mastering important conceptsCalorimetry - 01 | Mastering important conceptsCalorimetry - 01 | Mastering important concepts45 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses