Very Short Answer Type Questions
1. Define the word weather.
Solution:
Weather denotes the atmospheric conditions of weather elements at a particular place and time.
2. What are basic elements of weather?
Solution:
The weather elements include temperature, pressure, wind, humidity and cloudiness.
3. How is relative humidity calculated?
Solution:
In simple words, we can say that relative humidity is expressed in ratio or percentage of total moist absorbing capacity of air.
It is calculated by using following formula:
For example, if humidity at a place is 5 gm while it has the capacity of absorbing 10 gm humidity at that temperature. Then we can say that relative humidity is 50%.
4. What are weather maps?
Solution:
A weather map is the representation of weather phenomena of the earth or a part of it on a flat surface. It depicts conditions associated with different weather elements such as temperature, rainfall, sunshine and cloudiness, direction and velocity of winds, etc. on a particular day.
5. What is the utility of weather charts?
Solution:
Weather charts provide the primary tools for weather forecasting. They help in locating and identifying different air ‘ masses, pressure systems, fronts and areas of precipitation.
6. When and why was first weather map drawn?
Solution:
First of all need for weather map was felt by boatmen. N 1688, Admond Hally drew first weather map for 30° North and 30° South latitude.
7. What are three levels for recording meteorological observations worldwide?
Solution:
Globally, meteorological observations are recorded at three levels, viz. surface observatories, upper air observatories and space-based observation platforms. The World Meteorological Organization (WMO), a specialised agency of the United Nations, coordinates these observations.
8. What is aneroid barometer?
Solution:
Aneroid barometer gets its name from the Greek word, aneros in which ‘a’ means ‘not’, neros means moisture, hence aneroid means without liquid. It is a compact and portable instrument. It consists of a corrugated metal box made up of a thin alloy, sealed completely and made airtight after partial exhaustion of air.
9. Explain about rain gauge.
Solution:
The amount of rainfall is measured with the help of a rain gauge. The rain gauge consists of a metal cylinder on which a circular funnel is fitted. The diameter of the funnel’s rim is normally 20 cm. The rain drops are collected and measured in a measuring glass. Normally, rainfall is measured in the units of millimetres or centimetres. Snow is also measured in a similar manner by turning it into liquid form.
10. On what elements of weather does INS AT provide observations?
Solution:
The Indian National Satellite (INSAT) provides valuable observations of temperature, cloud cover, wind and associated weather phenomena.
Short Answer Type Questions
1. How is weather forecasting useful for different groups?
Solution:
Weather forecasting is very important for all groups:
- Weather forecasts help in taking safety measures in advance in case of the likelihood of bad weather.
- It reduces the likely loss from natural calamities. Had tsunami been predicted in advance, the loss that happened could be minimized to a great extent.
- Predicting weather a few days in advance may prove very useful to farmers and to the crew of ships, pilots, fishermen, defence personnel, etc.
2. Explain in short about Wind Vane.
Solution:
Purpose: Wind vane is a device used to measure the direction of the wind. Structure: The wind vane is a light-weight revolving plate with an arrowhead on one end and two metal plates attached to the other end at the same angle. This revolving plate is mounted on a rod in such a manner that it is free to rotate on a horizontal plane. It responds even to a slight blow of wind.
Important Aspect: The arrow always points towards the direction from which the wind blows.
3. Explain in short about Anemometer.
Solution:
An anemometer is an instrument that measures wind speed and wind pressure. Anemometers are important tools for meteorologists, who study weather patterns. They are also important to the work of physicists, who study the way air moves. The most common type of anemometer has three or four cups attached to horizontal arms. The arms are attached to a vertical rod. As the wind blows, the cups rotate, making the rod spin. The stronger the wind blows, the faster the rod spins. The anemometer counts the number of rotations, or turns, which is used to calculate wind speed. Because wind speeds are not consistent—there are gusts and lulls-wind speed is usually averaged over a short period of time.
A similar type of anemometer counts the revolutions made by windmill-style blades. The rod of windmill anemometers rotates horizontally. Other anemometers calculate wind speed in different ways. A hot-wire anemometer takes advantage of the fact that air cools a heated object when it flows over it.
4. How do Weather observatories work in India?
Solution:
Each day weather maps are prepared for that day by the Meteorological Department from the data obtained from observations made at various weather stations across the world. In India, weather-related information is collected and published under the auspices of the Indian Meteorological Department, New Delhi, which is also responsible for weather forecasting.
The Indian Meteorological Department (IMD) was established in 1875, with its headquarters at Calcutta. The IMD headquarters are presently located at New Delhi.
5. Write a short note on Stevenson Screen.
Solution:
The Stevenson screen is designed to protect thermometers from precipitation and direct sunlight while allowing air to circulate freely around them. Formation: It is made from wood with louvered sides to allow free and even flow of air. It is painted white to reflect radiation. It stands on four legs and is about 3 feet 6 inches above the level of the ground. The legs must be sufficiently rigid and be buried sufficiently in the ground to prevent shaking.
The front panel is hinged at the bottom to form a door, which allows for maintenance and reading of the thermometers. The door of Stevenson screen is always towards the north in the northern hemisphere and towards the south in the southern hemisphere because direct sunrays also affect mercury.
Objective: The purpose of the Stevenson screen is to create a uniform temperature enclosure that closely represents the same temperature as the air outside.
6. What is aneroid barometer? How does it work?
Solution:
Aneroid barometer gets its name from the Greek word, aneros in which ‘a’ means ‘not’, ‘neros’ means ‘moisture’, hence aneroid means without liquid. It is a compact and portable instrument. It consists of a corrugated metal box made up of a thin alloy, sealed completely and made airtight after partial exhaustion of air.
It has a thin flexible lid, which is sensitive to changes of pressure. As the pressure increases, the lid is pressed inward, and this, in turn, moves a system of levers connected to a pointer, which moves clockwise over the graduated dial and gives higher reading. When the pressure decreases, the lid is pushed outward and the pointer moves counter clockwise, indicating lower pressure. Barograph works on the principle of aneroid barometer.
There are a number of vacuum boxes placed one above the other so that the displacement is large. A system of levers magnifies this movement which is recorded by a pen on a paper attached to a rotating drum. The readings of a barograph are not always accurate, and therefore, they are standardised by comparing them with a mercury barometer reading.
