objectives state the importance of accurate weather data. summarize the instruments used to collect...

ObjectivesState the importance of accurate weather data.

Summarize the instruments used to collect weather data from Earth’s surface.

Analyze the strengths and weaknesses of weather radar and weather satellites.

Gathering Weather DataSection 12.3


Review Vocabulary

temperature: the average thermal energy of the particles that make up a substance

Accurate measurements of atmospheric properties are a critical part of weather analysis and prediction.

New Vocabulary


thermometer

barometer

anemometer

hygrometer

radiosonde

Doppler effect

Data from Earth’s Surface


Two important factors in weather forecasting are the accuracy of the data and the amount of available data.


A thermometer measures temperature using either the Fahrenheit or Celsius scale.

A barometer measures air pressure.


Temperature and air pressure



An anemometer measures wind speed.

A hygrometer measures relative humidity.

Wind speed and relative humidity



The Automated Surface Observing System (ASOS) gathers data in a consistent manner, 24 hours a day, every day. It provides essential weather data for aviation, weather forecasting, and weather-related research.

Automated Surface Observing System


Data from the Upper Atmosphere

The instrument used for gathering upper-atmosphere data is a radiosonde.

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

Also wind speed and direction( by its movement)


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, such as sound or light, as it comes toward or goes away from an observer.

Weather radar



Analysis of Doppler radar data can be used to determine the speed at which precipitation moves toward or away from a radar station.

Doppler radar

Difference between radar and Doppler radar.Radar Doppler radar

detects specific locations of precipitation.

speed at which precipitation moves toward or away from a radar station.



1. Infra red, 2. visible light, 3.water vapor imagery.

Some satellites use cameras that require visible light to photograph Earth.

These digital photos are sent back to ground stations, and their data are plotted on maps. Unlike weather radar, which tracks precipitation but not clouds, satellites track clouds but not necessarily precipitation.

Weather satellites -3 types of imaging



Some weather satellites use infrared imagery to make observations at night.

Objects radiate thermal energy at slightly different frequencies. Infrared imagery detects these different frequencies, which enables meteorologists to map either cloud cover or surface temperatures.

Weather satellites track clouds and water vapor.



Another type of satellite imagery that is useful in weather analysis and forecasting is called water-vapor imagery.

Water-vapor imagery is a valuable tool for weather analysis and prediction because it shows moisture in the atmosphere, not just cloud patterns.

Weather satellites

Difference between weather radar and weather satellite

Radar Satellite

Tracks precipitation Tracks clouds and moisture.

ObjectivesAnalyze a basic surface weather chart.

Distinguish between digital and analog forecasting.

Describe problems with long-term forecasts.

Weather Analysis and PredictionSection 12.4

Review Vocabulary

model: an idea, system, or mathematical expression that represents an idea


Several methods are used to develop short-term and long-term weather forecasts.

New Vocabulary

station model

isobar

isotherm

digital forecast

analog forecast

Surface Weather Analysis


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

Station models



Meteorological symbols are used to represent weather data in a station model. Advantages: universal language, more info in less space.

Station models



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

Plotting station model data



Lines of equal pressure are called isobars.

Lines of equal temperature are called isotherms.

Plotting station model data



The weather map shows isobars and air pressure data for the continental United States.

Interpreting station model data



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

Interpreting station model data


Types of Forecasts

A digital forecast is created by applying physical principles and mathematics to atmospheric variables and then making a prediction about how these variables will change over time.

Digital forecasts

An analog forecast is based on a comparison of current weather patterns to similar weather patterns from the past.


Types of Forecasts

Analog forecasts

Differences between digital and analog forecasts.

Digital Analog

By analyzing current weather data By comparing current weather patterns with similar patterns from the past.

Short-Term Forecasts


The most accurate and detailed forecasts are short term because weather systems change directions, speeds, and intensities over time.


Long-Term Forecasts

Because it is impossible for computers to model every variable that affects the weather at a given time and place, all long-term forecasts are less reliable than short-term forecasts.

Short term forecasts are more reliable.

CH

Accurate measurements of atmospheric properties are a critical part of weather analysis and prediction.

To make accurate weather forecasts, meteorologists analyze and interpret data gathered from Earth’s surface by weather instruments.

Section 12.3 Gathering Weather Data

Study Guide Key Concepts

CH

A radiosonde collects upper-atmospheric data.

Doppler radar locates where precipitation occurs.

Weather satellites use infrared, visible-light, or water-vapor imagery to observe and monitor changing weather conditions on Earth.

Section 12.3 Gathering Weather Data


CH

Several methods are used to develop short-term and long-term weather forecasts.

A station model is used to plot different weather variables.

Meteorologists plot lines on a map that connect variables of equal value to represent nationwide and global trends.

Section 12.4 Weather Analysis and Prediction


CH

Two kinds of forecasts are digital and analog.

The longer the prediction period, the less reliable the weather forecast.

Section 12.4 Weather Analysis and Prediction


CH

Which weather instrument is used to measure wind speed?

a. barometer

b. thermometer

c. anemometer

d. hygrometer

12.3 Section Questions

Meteorology

CH

Doppler radar data show that the return echo from one side of a storm has a shorter wavelength than the emitted wave. What can be concluded about the reflecting particles?

a. They are very small.

b. They are very large.

c. They are moving toward the station.

d. They are moving away from the station.


Meteorology

CH

Why are weather satellites important to forecasters?


Meteorology

CH


Answer: Satellites can monitor weather conditions over large regions of Earth using a variety of wavelengths. The satellites provide information about cloud cover, moisture, atmospheric circulation, and more, which can be used together to provide current and rapid forecasts.

Meteorology

CH

What is an isobar?

a. a line of constant altitude

b. a line of constant temperature

c. a line of constant pressure

d. a line of constant moisture


Meteorology

CH

Which weather forecast is usually the most accurate?

a. one-day forecast

b. three-day forecast

c. seven-day forecast

d. thirty-day forecast


Meteorology

CH

How are digital forecasts made?


Possible answer: Digital forecasts are made by using computers to model future weather conditions based on current weather data.

Meteorology

CH

What characteristics describe a continental tropical air mass?

a. cool and dry

b. hot and dry

c. mild and humid

d. hot and humid

Chapter Assessment Questions

Meteorology

CH

A high-pressure system has moved directly over a region. What weather condition most likely exists in this region?

a. fair weather

b. steady rain

c. high winds

d. thunderstorms


Meteorology

CH

Which type of wave is transmitted by weather radar units?

a. X rays

b. sound waves

c. radio waves

d. infrared waves


Meteorology

CH


Examine the isobar map. From approximately which direction is the wind blowing in central Ohio?

a. southwest

b. southeast

c. northwest

d. northeast

Meteorology

CH

A warm, moist air mass is currently over a region. What changes will occur as a strong cold front advances over this region?


Meteorology

CH

Answer: The front has a high temperature contrast across it and a supply of moisture in front of it. As the cold front advances, uplift of moisture-laden air will occur and thunderstorms will probably develop. Some of these storms could be severe.


Meteorology

CH

Which type of air mass forms over the Gulf of Mexico and Caribbean Sea?

a. continental polar

b. continental tropical

c. maritime polar

d. maritime tropical

Standardized Test Practice

Meteorology

CH

A frigid, winter air mass is moving south across the central United States. Which feature can most modify the characteristics of this air mass?

a. a large lake

b. tree-covered hills

c. snow-covered plains

d. a lowland area


Meteorology

CH

a. polar easterlies

b. westerlies

c. trade winds

d. jet streams

Which winds converge and rise at the intertropical convergence zone?


Meteorology

CH

How is the path of a moving current of air in the southern hemisphere affected by Earth’s rotation?


a. It curves to the right.

b. It curves to the left.

c. It curves upward.

d. It curves downward.

Meteorology

CH


How does the polar jet stream affect weather in the midlatitudes?

Meteorology

CH


Possible answer: The jet stream marks the boundary between colder polar air and warmer subtropical air. Undulations in the jet stream move cold air to warmer latitudes and warm air to colder latitudes. Surface high- and low-pressure systems also form and move along the jet stream, so the jet stream guides weather across the midlatitudes.

Meteorology

objectives state the importance of accurate weather data. summarize the instruments used to collect...

Documents

essential weather data

weather radar slide

weather satellites

weather forecasting

weather analysis

weather radar system

weaknesses of weather

available data