Energy from the Sun
A great quantity of heat reaches the Earth from the Sun, through the layers of the atmosphere. Only a part of solar radiation reaches the Earth’s surface: 34% of solar radiation is reflected into space by the atmosphere, by clouds and by the Earth’s surface itself. Of the remaining 66%, 19% is absorbed by water vapour, by clouds and by the ozone layer and only 47% on average is absorbed by the Earth’s surface. Solar energy reaches the ground largely in the form of ultraviolet rays, that pass through the atmosphere easily and are subsequently absorbed by the ground. On getting heated, the ground releases the energy in the form of infrared radiation which has a longer wavelength but is more calorific. Infrared radiation is in turn absorbed by the atmosphere, that gets heated: in practise, therefore, the atmosphere behaves like the glass of a greenhouse that allows ultraviolet rays to pass but detains the infrared ones.
Special reports
-
29 April 2020
Lightning
Man has always been afraid of lightning, in fact in the past lightning was considered a sign of the anger…
10 February 2020
Coral turns pale!
The coral reef is one of the ecosystems with the richest biodiversity...
-
15 November 2021
How did Cop26 end?
On Saturday afternoon in Glasgow, representatives of more than 200 countries attending the COP26 United Nations climate change conference reached…
5 November 2021
Cop26, the calendar for the climate conference
1 November was the first day of the summit, the opening ceremony of which began with a speech by British…
25 August 2021
Geo-engineering: a contribution to mitigate climate change?
Geo-engineering, the science to moderate global warming...
-
29 April 2020
Lightning
Man has always been afraid of lightning, in fact in the past lightning was considered a sign of the anger…
5 August 2019
Summer wind
A sixteen-year-old Swedish girl is braving the wind, cold and rain to take her protest against the changing climate onto…
17 July 2018
Tornadoes and waterspouts: phenomena that (also) occur in Italy
When we talk about tornadoes, our thoughts immediately go to the immense American plains and the area known as “tornado…
-
29 April 2020
Lightning
Man has always been afraid of lightning, in fact in the past lightning was considered a sign of the anger…
-
10 February 2020
Coral turns pale!
The coral reef is one of the ecosystems with the richest biodiversity...
15 November 2021
How did Cop26 end?
On Saturday afternoon in Glasgow, representatives of more than 200 countries attending the COP26 United Nations climate change conference reached…
-
5 November 2021
Cop26, the calendar for the climate conference
1 November was the first day of the summit, the opening ceremony of which began with a speech by British…
25 August 2021
Geo-engineering: a contribution to mitigate climate change?
Geo-engineering, the science to moderate global warming...
-
29 April 2020
Lightning
Man has always been afraid of lightning, in fact in the past lightning was considered a sign of the anger…
-
10 February 2020
Coral turns pale!
The coral reef is one of the ecosystems with the richest biodiversity...
From the Multimedia section
Facts
-
Radars in meteorology
Radar (acronym for radio detection and ranging) monitoring techniques are used to...
-
7 April 2011
Weather over the Mediterranean Sea
The weather in the Mediterranean areas is generally...
-
13 May 2011
Meteorological satellites
Meteorological observations from satellites are at present the most...
-
7 April 2011
GOES meteorological satellites
The numerous civil and military satellites orbiting around us...
-
13 May 2011
Meteorological satellites
Meteorological observations from satellites are at present the most...