A topographic map depicting terrain can include clues to the area's climate.
Without statistics of precipitation, temperature and other meteorological measures, a topographic map has limited use in determining the portrayed area's climate. But the map's depiction of terrain and land cover can suggest some climatic characteristics.
Vegetation Shading
Many topographic maps, including the widely used publications of the U.S. Geological Survey, indicate forest cover and other general vegetation types with shading. You therefore can extrapolate basic levels of rainfall: a landscape dominated by grasses suggests semi-aridity, for example.
Wetlands and Waterways
The USGS topographic maps also reveal wetlands like swamps and marshes, which also suggest at least moderate precipitation. Ephemeral streams -- those that dry up part of the year -- are common in semi-arid and arid climates, and these maps distinguish these from year-round drainages.
Erosion
The degree and nature of erosion of a given landscape, shown by topographic maps, reflects the climate. A density of V-shaped drainages dissecting a mountainous tract -- as in parts of Hawaii or the Pacific Northwest -- often reflects a relatively wet climate with vigorous stream-cutting.
Glaciers, Snowfields and Elevation
The presence of glaciers or permanent snowfields on maps indicates areas that are colder and receive heavy snowfall. Elevation contours suggest climatic characteristics, too, as temperatures are cooler at higher elevations, hotter the closer to sea level -- or below -- you go.
Tags: topographic maps, area climate, climatic characteristics
