The World - Temperatures in July

Climate elements
978-3-14-100890-6 | Page 19 | Ill. 2
The World | Temperatures in July | Climate elements | Karte 19/2

Overview

The two maps show the average temperatures in January and July. The map drawing is done with the help of a coloured area signature, which ranges in steps of ten degrees Celsius from below -50 °C to above 30 °C. In addition, both maps show the respective 0° and 20° isotherms on the sea surface.

Comparing both climate maps

The maps can be used from grade 7 upwards in connection with the global delimitation of climate and landscape zones. First, students should look for the regions with the highest and lowest temperatures in January and July. In doing so they should note and observe that Antarctica is not shown on the maps.

Then they compare respective temperature values of specific regions of the world in January and July: In January, the highest temperatures (> 30 °C) are reached in Australia and East Africa, while the coldest regions (< -40 °C) are Siberia, Greenland and the islands in the Arctic Ocean. The highest temperatures in July (> 30 °C) are in the Great Basin in the USA, in the Sahara, on the Arabian Peninsula, in the highlands of Iran and in the lowlands of the Indies, the lowest temperatures (0 to -20 °C) in Greenland, the Andes, the Himalayas and the Tian Shan. The warm Gulf Stream moderates winter temperatures in Europe. This can be seen clearly from the 0° isotherm on the sea surface, which extends much further north in the eastern than in the western Atlantic Ocean.

Due to the right-angled solar radiation, the highest temperatures are reached in the area around the equator. In contrast, the two Polar Zones have the lowest temperatures due to the flat angle of the Sun's rays. To illustrate the correlation between latitude and solar radiation, an experiment can be carried out: A torch shines on a globe or a ball. The light source is at the height of the equator. There, the light rays travel a short distance and reach the globe at a right angle. At the poles, on the other hand, the rays travel a much longer distance and hit the Earth's surface at a flat angle. As a result, less energy, and thus heat, reaches the Earth's surface at the poles than it does at the equator.

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Intensity of solar radiation

The emergence of summer and winter and thus the occurrence of different temperatures in January and July can be explained with the help of the marginal figures. Alternatively, the seasons can also be illustrated with an experiment: An ellipse is drawn on a piece of cardboard. In the middle of the ellipse, a light bulb or other light source represents the Sun. The Earth is a on a wooden stick, on which the equator and the two tropics are marked. The Earth's axis, i.e. the stick, is placed on a solid block of polystyrene at an angle of 23.5°. By moving of this construction over the ellipse, the different illumination lighting conditions within a year and thus the development of the seasons becomes apparent and visible.

In Sekundarstufe II, the two maps are used in connection with atmospheric processes and as a basis for climate classifications. They can be used together with the maps on precipitation in January and July (18.3 and 19.4).

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