IONOSPHERE

IN NEWS:

• Scientists of Indian Institute of Geomagnetism (IIG), an autonomous institution of the Department of Science and Technology, have studied the signatures of recent large earthquakes into the ionosphere with an ambitious aim to derive the seismic source characteristics from the ionosphere.

IONOSPHERE:

• The ionosphere is the layer of the Earth's atmosphere that is ionized by solar and cosmic radiation. It lies 75-1000 km (46-621 miles) above the Earth.
• The ionosphere is composed of three main parts: the D, E, and F regions
  • The electron density is highest in the upper, or F region. The F region exists during both daytime and nighttime.
  • D region disappears during the night compared to the daytime, and the E region becomes weakened.

ROLE IN COMMUNICATION:

• Because of the high energy from the Sun and from cosmic rays, the atoms in this area have been stripped of one or more of their electrons, or ‘ionized’. Therefore, they are positively charged.
• These ionized gases refract high frequency radio waves. Hence, the ionosphere can reflect radio waves directed into the sky back toward the Earth. This was utilized for telecommunication in the 20^th century.
• But this communication method is variable and unreliable and has been replaced by satellite communication systems.

PRELIMS QUESTION:

Q. Which of the following statements regarding the ionosphere are correct:

1. It lies above the Mesosphere

2. It completely disappears during night due to lack of solar radiation

Choose the correct answers from the codes given below:   

a. 1 only

b. 2 only

c. Both 1 and 2

d. Neither 1 nor 2

 Answer to Prelims question