Lesson what are the properties of water? Choose the correct answer

SECRETS OF THE ATMOSPHERE

1. Weather moves. Air masses and their fronts usually don’t stand but move across the

country.

2. The moving air takes along its weather.

3. The air in the lower strata of the atmosphere usually moves at a speed of 40-50 kilometers per hour while in the upper strata the speed increases up to 100-200 kilometers per hour.

4. So to forecast weather for Moscow one day in advance it is necessary to get a lot of information on the air which is at the present moment 1,000-2,000 kilometers away from the city.
5. The information includes the following: air temperature, speed of the wind, wind direction, humidity, and cloud formation and so on.

6. To make a forecast 2-3 days in advance it is necessary to get a picture of the state of the atmosphere over the entire Northern hemisphere at least.

7. The weather, however, is dependent not only on the movement of the air, but also on huge bodies of water, the Sun, the Earth’s rotation, mountains, volcanic activities, forest fires and even supersonic airplanes whose flight in the stratosphere causes condensation of water vapor.

8. How are all these factors measured and compared in order to determine the weather for any given area of the Earth?

9. The scientists turn to mathematics. Mathematical modeling of natural processes and phenomena has helped the weathermen to understand many things and to see them in a new light.

10. Today, in several minutes they can calculate the weather one day ahead due to electronic computers.

11. Are these forecasts true? Only one in 10 is incorrect. It is much more difficult to compute a forecast for a week, month or even more ahead, and they are, of

course, less accurate.

12. But in spite of it long-range forecasts are very important for the country’s economy.

13. The weather depends on natural conditions, so knowledge of the amount of snow accumulated in winter will permit to calculate the volume of the spring flow of rivers.

14. This is of much importance in planning the hydro resources for irrigation and transport.

15. The meteorologists obtained many new data by means of rockets and sputniks which “observe” vast areas of the globe from above and transmit back to the Earth data on the physical phenomena in the higher strata of the atmosphere and in the ionosphere.