Section 12.3Gathering Weather Data

Gathering Weather DataSection 12.3

Data from Earth’s Surface

A thermometer measures temperature.

A barometer measures air pressure.

Gathering Weather DataSection 12.3

Gathering Weather DataSection 12.3

An anemometer measures wind speed.

A hygrometer measures relative humidity.

Data from Earth’s Surface

Gathering Weather DataSection 12.3

Data from the Upper Atmosphere

Radiosonde - instrument used for gathering upper-atmosphere data.

A radiosonde’s sensors measure the air’s temperature, pressure, and humidity.

Gathering Weather DataSection 12.3

Weather Observation Systems

A weather radar system detects specific locations of precipitation.The Doppler effect is the change in pitch or frequency that occurs due to the relative motion of a wave, as it comes toward or goes away from an observer.

Weather radar

Gathering Weather DataSection 12.3

Analysis of Doppler radar data can be used to determine the speed and direction at which precipitation moves.

Weather radar

Gathering Weather DataSection 12.3

Some weather satellites use infrared imagery to measure thermal energy at night to map cloud cover or surface temperature.

Some satellites use cameras that require visible light to photograph Earth and its clouds

Weather satellites

Gathering Weather DataSection 12.3

A 3rd type of satellite imagery is called water-vapor imagery that shows moisture in the atmosphere, not just clouds.

Weather satellites

Section 12.4Weather Analysis and Prediction

Weather Analysis and PredictionSection 12.4

Surface Weather Analysis

Weather Analysis and PredictionSection 12.4

A station model is a record of weather data for a particular site at a particular time.

Station models

Weather Analysis and PredictionSection 12.4

Meteorological symbols are used to represent weather data in a station model.

Weather Analysis and PredictionSection 12.4

To plot data nationwide and globally, meteorologists use lines that connect points of equal or constant values.

Plotting station model data

Weather Analysis and PredictionSection 12.4

Isobars - lines of equal pressure

Isotherms - lines of equal temperature

Plotting station model data

Weather Analysis and PredictionSection 12.4

The weather map shows isobars and air pressure data

Interpreting station model data

Weather Analysis and PredictionSection 12.4

Using isobars, isotherms, and station model data, meteorologists can analyze current weather conditions for a particular location.

Interpreting station model data

Weather Analysis and PredictionSection 12.4

Types of Forecasts

Digital forecast - created by applying physical principles and mathematics to atmospheric variables to make a prediction.

Digital forecasts

Analog forecast - comparison of current weather patterns to similar weather patterns from the past.

Weather Analysis and PredictionSection 12.4

Analog forecasts

Short-Term Forecasts

Weather Analysis and PredictionSection 12.4

Short-Term - most accurate and detailed forecasts because weather systems change directions, speeds, and intensities over time.

Long-Term Forecasts

Long-Term are less reliable than short-term forecasts.