Meteorology Objectives: Differentiate between weather & climate Sun & latitudes effect on temperatures. How to categorize air masses Source region’s effect on temperature Characteristics of various source regions

Causes Of Weather Meteorology is the study of atmospheric phenomena (the weather). Weather is the current state of the atmosphere. Climate is the long-term weather variations of a particular area. Climate is averaged over 30 years time.

Role of the Sun Since the Earth rotates at an angle, not every place on Earth receives the same intensity of sunlight. High Angle: More heating, warmer temperatures. Low Angle: Less heating, lower temperatures.

Balancing Heat Because of the angle of Earth, regions maintain a constant average temperature. Movement of air also balances temperatures

Air Movement Air moves constantly and is redistributed around the Earth. This results in the changing of temperatures in various areas.

Air Masses Large body of air that takes on the characteristics of the area over which it forms. Where the air mass forms is its source region.

How to Categorize Air Masses Surface of Source Regions: Land: Continental (c); Dry Water: Maritime (m); Humid/Wet Temperature of Source Regions: Warm: Tropical (T) Cold: Polar (P) VERY Cold: Arctic (A)

Air Masses Arctic: Very cold, dry Maritime Polar: (mP) Cold, humid Continental Polar: (cP) Cold, dry Maritime Tropical: (mT) Warm, humid Continental Tropical: (cT) Warm, dry

Maritime Tropical Results from the warm waters of oceans and in the Gulf of Mexico Lower Latitudes Mostly in S.E. United States (N.C!) Temps in the 80-90’s in the summer, 70-80’s in the winter. High dew points: Lots of moisture Majority of U.S. thunderstorms

Maritime Polar Source is cold ocean currents or high latitude ocean waters. Can produce widespread rain and snow, fog, drizzle, and cloudy weather. Temperature range from just above freezing to 70 degrees. Mostly in the Pacific Northwest and Northeast A high dew point.

Continental Polar Source from Alaska and Northwest Canada Low dew point and cold temperature Dense air Light precipitation due to dryness Modifies rapidly when moving south Temperature increases slightly but dew point remains low.

Continental Tropical Source region is the desert Southwest and Mexico Low dew points Warm to hot afternoon temperatures, mild night time temperatures Severe thunderstorms can form at the edge of this air mass.

Arctic Source from northern Canada It is the same characteristics as cP but with even colder temperatures -30 to –40 degrees! This air spreads into southern Canada and northern U.S.

Modification Air masses move from one area to another and thus they change (or modify) to become a different type of air mass They take on the characteristics of the land they travel over Ex. Could change temperature or dew point.