Weather
Weather is composed of a number of
elements such as the temperature and humidity of the air, atmospheric pressure,
the speed and direction of the wind, air visibility and of special phenomena
such as fog, storms and others.
Pilots need the information about weather
conditions along the route of flight and at the destination aerodrome. The
object of the meteorological service is to contribute to safety, efficiency and
regularity of air traffic.
There exist some sources of aviation
weather information: surface observation, radar observation, automatic
meteorological observation, pilot reports and others.
At every airport there is a meteorological
station which is equipped with special instruments recording all changes in the
atmosphere. They indicate air pressure and temperature, record wind speed and
direction as well as the movements of clouds. All the observations are summed
up on special weather charts. The observations at the airports are made every
30 minutes and every 15 minutes if the weather suddenly gets worse or better.
Preparing for the flight the pilot is to
get the latest weather information and weather forecasts along the planned
route and at the point of destination and the alternates.
At a great number of met. stations situated along the
airways complete weather observations are made and then transmitted to weather
forecast centres by telephone, telegraph, radio and thousands of miles of
teletype circuits. Thus, the pilot has a complete picture of the weather.
20-30 minutes before entering the
aerodrome area the controller gives the pilot full information about the
terminal weather. At many airports the information helpful for landing and take
off is continuously broadcast on a navigational aid frequency. Prior to descent
the pilot requests the actual weather and aerodrome conditions for the airport
he is going to land.
It is considered that landing
of an aircraft is probably the most difficult operation which a pilot has to
perform and the standards of visibility required are higher than for any other
phase of flight.
It is known that fog, rain
and clouds often affect the aircraft operation. For many decades attempts were
made to make flying independent of weather conditions or, in other words, to
allow an aircraft to land under very low or zero visibility.
Now there exist several
categories set up by ICAO:
Category I - 200 ft ceiling
and 1/2 mile visibility;
Category II- 100 ft ceiling
and I/4 mile visibility;
Category III - landing under
zero-zero conditions.
Met. services for aviation require much
work to collect data and prepare weather charts. This work is especially
difficult for long-distance flights over vast areas with different climatic
conditions.
Nowaday met. services for aviation are
almost fully automated. Automated Surface Weather Systems are installed at the
airports of many countries. The System provides for the measurements,
processing and display of the following meteorological parameters: wind
direction and speed, air temperature and dew point t°, runway visual range,
minimum cloud height, barometric pressure.
The use of lazers makes it possible to
give pilots all the necessary information when they land under low visibility
conditions. The introduction of these systems has greatly increased the reliability
and safety of flights.
Satellite
meteorology has become an independent area of science. Weather forecasts based
on information from outer space make forecasts more accurate and help to save a
great sum of money annually.
At present the work of meteorologist becomes easier
thanks to computers which make calculations quicker and due to them the weather
forecast service is becoming more reliable. The use of satellites and computers
greatly increases the accuracy of weather forecasts.
Exercises
I.
Ответьте на
вопросы:
- What
elements are included in weather report?
- What
is the object of meteorological service?
- How
often is weather observation made at the airport?
- What
do the instruments at the meteorological stations indicate?
- What
weather information does the pilot get before the flight?
- Do
the pilots obtain weather information while in flight?
- When
does the controller give the pilot full information about the terminal
weather?
- What
phase of flight does especially depend on weather conditions?
- What
weather phenomena affect the aircraft operation?
- What
categories are set up by ICAO?
- What
does Automated Surface Weather System provide?
- When
do lazers help the pilots?
- What
is the advantage of satellite meteorology?
- What
other instruments make weather forecast service more reliable?
II.
Найдите в тексте
эквивалент следующим словосочетаниям:
сводки погоды, погодные условия, давление воздуха,
скорость ветра, направление ветра, нижняя граница облачности, прогноз погоды,
центр прогнозирования погоды, прогностические карты, станция обеспечения
полета, погода аэродрома посадки
III.
Переведите на
английский язык:
- Погода состоит из таких элементов как температура и влажность
воздуха, атмосферное давление, скорость и направление ветра, видимость.
- Дождь, гроза, туман, шторм и другие явления опасны для полета.
- Перед полетом пилот идет в метеобюро, чтобы получить сводку погоды
и прогноз не только по своему маршруту, но и в пункте назначения.
- В каждом аэропорту есть метеостанция со специальными приборами,
регистрирующими все изменения в атмосфере.
- Имея все данные о погоде, синоптики составляют погодную карту.
- Во многих аэропортах информация о погоде непрерывно транслируется
на определенной частоте.
- Посадка самолета – самая трудная операция.
- Стандарты видимости для посадки выше, чем для любой другой фазы
полета.
- Сейчас большинство метеостанций почти полностью автоматизированы.
- Автоматическая система погоды показывает скорость и направление
ветра, температуру воздуха, точку росы, дальность видимости на полосе, высоту
облачности.
- Прогноз погоды, полученный со спутников, делает его точнее.
- Использование спутников и компьютеров повышает точность прогноза
погоды.
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