Final answer:
Symbols on weather maps indicate heavier precipitation with denser shading or more closely packed lines corresponding to the intensity of rainfall or snowfall. Changes include darker colors for heavier precipitation and the use of different symbols to represent raindrops or snowflakes. Such patterns are changing due to climate-related increases in water vapor and evaporation rates.
Step-by-step explanation:
The symbols on weather maps change to indicate heavier precipitation by showing more dense and concentrated areas of precipitation such as denser shading or more tightly packed lines, indicating a greater intensity of rainfall or snowfall. Meteorologists use symbols like varying shades of blue for rain or white to gray gradients for snow to convey different intensities. Symbols may also include shapes like asterisks to indicate snow and dots for rain. These visual representations help to forecast future precipitation and storm events, which are expected to become more intense due to the increasing atmospheric water vapor content and higher evaporation rates caused by global warming. For instance, cities like New York, Bogotá, and Manila may face challenges due to an anticipated increase in annual average precipitation and more intense tropical storms. Furthermore, shifts in wind patterns and storm tracks moving towards the poles can also redistribute these precipitation events.
As an example of how these symbols may change, consider a weather map that initially displays light blue shading or spaced isobars to indicate light rain. Then, the weather map transitions to darker blue shading or closer isobars when heavier rain is expected. This indicates not only an increase in precipitation but also possible changes in weather conditions influenced by high (H) and low (L) pressure regions as depicted by isobars on such maps.
The shifts in precipitation patterns can be more finely illustrated in descriptive writing, where lighter precipitation may be described as 'dancing droplets on pavement,' whereas heavier rain might be 'pounding the pavement,' reflecting the intensity of the precipitation event.