You Are Here!
(Looking at Maps and Weather)
By Cynthia Butler
A map is a way of representing an object’s real-world location on an artificially created two-dimensional surface. Maps have been used by humans since about 1400 B.C. when they appear in the archaeological record of the ancient Egyptians. Later, as their cultures mixed, these early attempts were improved upon by the Greeks. In 150 A.D. Ptolemy (an Egyptian) added the first lines of latitude and longitude used on a map. Today typical references used for mapping include latitude, longitude, the location of the north and south poles, and the location of the equator.
Latitude and Longitude are lines superimposed on the surface of the earth. These lines create a grid coordinate system that is used to pinpoint locations on earth - each point on the globe is assigned an unique pair of longitude and latitude values so that it may be identified easily and accurately. Latitude lines (or parallels) run from east to west horizontally around the globe. Longitude lines (or meridians) run vertically from the North and South Poles. A prime meridian is a meridian, i.e. a line of longitude, at which longitude is defined to be 0°. An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and midway between the poles.
You will see weather forecasters on television using maps to indicate patterns of weather. For example, they will use maps to illustrate cold and warm fronts that are coming and leaving into the area.
In meteorology, an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of square miles, and adopt the characteristics of the surface below them. They are classified according to latitude and their continental or maritime source regions. Colder air masses are termed polar or arctic, while warmer air masses are called tropical. Continental and superior air masses are dry while maritime and monsoon air masses are moist.
Fronts are the boundaries between air masses of different temperature.
If warm air is moving toward cold air, it is a warm front. These are shown on weather maps as a red line with scallops on it.
If cold air is moving toward warm air, then it is a cold front. Cold fronts are always shown as a blue line with arrow points on it.
If neither air mass is moving very much, it is called a stationary front, shown as an alternating red and blue line.
An occluded front is formed when a cold front overtakes a warm front. When this occurs, the warm air is separated (occluded) from the cyclone center at the Earth's surface.
"Whether the weather is hot or whether the weather is cold'.........