Chapter 8 Notes

Chapter 8 Notes - Chapter 8: Weather Weather Essentials o...

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Chapter 8: Weather Weather Essentials o Weather – short term, day to day condition of the atmosphere, contrasted with climate, which is long term average of weather conditions and extremes in a region. Temperature Air Pressure Relative Humidity Wind Speed and Direction Seasonal Factors Insolation Receipt Daylength Sun Angle o Meteorology – scientific study of the atmosphere Meteorologists study: Atmospheres physical characteristics and motions Related chemical, physical, and geologic processes Complex linkages of atmospheric systems and weather forecasting Advanced Weather Interactive Processing System Allows forecasters to integrate meteorological, hydrological, satellite, and radar data at a computer workstation. Doppler Radar Using backscatter from two radar pulses it detects the direction of moisture droplets toward or away from the radar, indicating wind direction and speed. Air Masses – distinctive body of air with specific conditions of temperature, humidity, and stability. o Air Masses Affecting North America Air masses are generally classified according to the moisture and temperature characteristics of their source regions: Moisture – designated m for maritime (wet) and c for continental (dry). Temperature – designated A (arctic), P (polar), T (tropical), E (equatorial), and AA (Antarctic). Continental Polar Form only in the Northern Hemisphere Most developed in winter when they dominate cold weather conditions Major players in middle and high latitude weather The cold dense cP air lifts moist, warm air in its path, producing lifting, cooling, and condensation. Greater temperature difference between this cold air mass and warmer air masses, the more dramatic is the weather produced. Area covered by cP air in winter experiences cold, stable air, clear skies, high pressure, and anticyclonic wind flow. Maritime Polar Exist northwest and northeast of the North American continent over the northern oceans. Cool, moist, unstable conditions prevail throughout the year. Aleutian and Icelandic subpolar low pressure cells reside within these mP air masses, especially in their well-developed winter pattern. Two maritime tropical air masses influence North America: o mT Gulf/Atlantic Creates the humidity experienced in the East and Midwest. Particularly unstable and active from late spring to early fall. o mT Pacific Stable to conditionally unstable and generally lower in moisture content and available energy. Creates lower average precipitation than rest of United States in the west. o Air Mass Modification As air masses migrate from their source regions, their temperature and moisture characteristics modify and slowly take on the characteristics of the land over which they pass. Atmospheric Lifting Mechanisms
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Chapter 8 Notes - Chapter 8: Weather Weather Essentials o...

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