How Topography Affects Climate
Sometimes a single feature--the direction mountains face, proximity to large bodies of water or humidity levels--affects a region's climate. At other times, an area's climate results from a complex set of geographical factors. Monitoring any regional climate is not simply a matter of checking local weather reports. Weather can vary considerably from one day to the next, but overall climate scarcely changes over time.
Time Frame
Mark Twain once said, "Climate is what we expect and weather is what we get." When meteorologists report the weather conditions (temperature, humidity, precipitation), their report covers the conditions present at a specific time and location. However, figuring out the climate for that location requires quantifying the weather data over a period of decades, and averaging the results.
Effects
Mountains are an example of a single feature affecting a climate. A mountain's windward slope faces into the wind, creating a constant uplift of air which produces large amounts of rain and snow. The mountain's leeward (sheltered) side is protected, so less precipitation occurs. Temperatures on the mountain are affected by sunshine or lack of it, with the warmest temperatures occurring on the sunny side. Elevation also drops temperatures as the altitude rises.
Types
The Earth is comprised of numerous climate categories. Tropical rain forest and tropical desert, wet coast land and marine, wet subarctic and ice cap, and urban climates, are just a few of these climate types. Each climactic region has a different set of environmental and geographical conditions affecting it.
Geography
Tropical rain forest climates straddle the equator and have high sun angles, creating warm temperatures and long days year-round, while their mountains face into the trade winds, increasing rain and humidity levels. In contrast, parched, scorching tropical deserts with low precipitation rates, are parked on a mountain's leeward side or near cold bodies of water. Their constant subtropical, high-pressure systems decrease humidity levels and leave rain or snow formation in short supply. The Earth's coldest temperatures are found at the ice caps, thanks to the extreme latitudes and the lack of sunshine for half of the year and their precipitation levels mimic that of deserts due to low humidity and precipitation levels. Concrete and buildings made of metal and glass raise temperatures in urban climates, like Houston, and the sheer quantity of skyscrapers create canyons that intensify wind speeds. Pollution from cars, trucks, and refineries -- among other things -- drive up the content of particulate matter in the air, which increases raindrops and friction in the clouds, thereby increasing lightning formation.
Expert Insight
Storms have always developed over Houston according to Richard Orville, an atmospheric scientist from Texas A&M, but they used to be caused only by nature. Now, he says, Houston's population (3 to 4 million) and half of the nation's petroleum refineries have affected this urban climate, producing stronger cumulus clouds and more powerful thunderstorms.
Tags: Affects Climate, bodies water, humidity levels, humidity precipitation, mountain leeward
