Presentation on theme: "8.10 Weather Forecasts Objectives:"— Presentation transcript:
18.10 Weather Forecasts Objectives: Identify instruments used to measure weather variables.Interpret weather maps.Explain how weather models are used to predict the weather.
2Measuring WeatherMeteorologists use special instruments to measure conditions in the atmosphere.Thermometer to measure the variable temperatureBarometer, air pressurePsychrometer, relative humidityAnemometer, wind speed
3Surface and Upper-Air Reports A surface report describes a set of weather measurements made on Earth’s surface.Measured at a weather stationAn upper-air report described wind, temperature, and humidity conditions above the Earth’s surface.Measured by a collection of weather instruments called a radiosonde.On a weather balloon many kilometers above the ground.
4Satellite and Radar Images From km aboveVisible light shows cloudsInfrared gives thermal energy images.Information: cloud height and atmospheric temperature.
5Satellite and Radar Images (continued) Radar measures precipitation when radio waves bounce off raindrops and snowflakes.Doppler radar is a specialized type of radar that can detect precipitation as well as the movement of other small particles, which can approximate wind speed.This doppler radar image of Hurricane Dolly as it hit Texas was made by pulsing microwave radiation and measuring the time of arrival of the pulses.
6Weather MapsWeather maps are tools for simplifying a huge amount of weather data.The Station ModelDisplays data from many measurements for a specific location.
8Mapping Temperature and Pressure (continued) Isobars are lines that connect all places on a map where pressure has the same value.Can give information on wind speed: Wind speeds are stronger when isobars are closer together.Isotherms (not shown on the next slide) are lines that connect places that have the same ____?___.Fronts are represented with lines with symbols on them.
9Predicting the Weather Weather forecasts are made with the help of computer models.Computer models are detailed computer programs that solve a set of complex mathematical formulas.Formulas predict weather conditions.Forecasts made available to public through TV, radio, newspapers and Internet.