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Weather and Climate
Weather and Climate PH vocabulary
Term | Definition |
---|---|
weather | The condition of earth's atmosphere at a particular time and place. |
atmosphere | The layer of gases that surrounds the planet. |
ozone | A form of oxygen that has three oxygen atoms in each molecule instead of three. Ozone layer, located in the stratosphere protects us from ultraviolet radiation. |
water vapor | Water in the form of a GAS...NOT steam, which is tiny droplets of LIQUID water. |
density | The amount of mass in a given volume (D=M/V). In weather, this refers to the amount of mass in a given volume of AIR; the denser the air, the greater the air pressure |
altitude | or elevation, is the distance above sea level. |
air pressure | The result of the weight of a column of air pressing down on an area. Air pressure decreases as altitude increases (inverse relationship...one goes up and the other goes down) |
troposphere | The layer of the atmosphere in which we live; the lowest layer of the atmosphere; weather occurs here. |
stratosphere | Extends from the top of the troposphere. The upper portion of the stratosphere contains the ozone, which protects us from ultraviolet radiation. |
mesosphere | The layer above the stratosphere; middle layer, meteors burn up here; m.m.m. |
thermosphere | The outermost layer of the atmosphere; very low density of atmospheric gases; divided into two sub-layers (ionosphere, exosphere) |
ionosphere | The lower layer of the thermosphere; aurora borealis occurs here. |
exosphere | The outer layer of the thermosphere; satellites orbit here, and our TV and cell phone signals traveled to the exosphere and back to earth. |
ultraviolet radiation | A form of energy from the sun that is blocked (somewhat) by the ozone layer. |
conduction | The transfer of heat from one object to another by direct contact. |
convection | the transfer of heat by the movement of fluid. In weather, convection occurs among air masses of different temperatures. |
wind | The horizontal movement of air from an area of high pressure to an area of low pressure. All winds are caused by differences in air pressure. |
anemometer | An instrument that measures air speed. |
global wind | Winds that blow steadily from SPECIFIC directions and over LONG distances. Caused by unequal heating of earth's surface over LARGE areas. |
local wind | Winds that blow over SHORT distances and can CHANGE directions. Caused by unequal heating of earth's surface over SMALL areas, often on land that is next to a large body of water. |
jet stream | Bands of high speed winds that blow from west to east that wander north and south along a wavy path. Jets traveling east save fuel by traveling in the jet stream. |
cumulus | Clouds that look like fluffy piles of cotton; usually indicate fair weather. |
condensation | When molecules of water vapor become liquid water. |
humidity | A measure of the amount of water vapor in the air. |
stratus | Clouds that form in flat layers and usually cover all or most of the sky; may produce drizzle, rain, or snow. |
relative humidity | The percentage of water vapor in the air compared to the maximum amount the air could hold. |
cirrus | Wispy, feathery clouds that form at high levels and are made of ice crystals. |
precipitation | Any form of water that falls from clouds and reaches earth's surface. |
air mass | A huge body of air that has similar temperature, humidity, and air pressure. |
maritime tropical | Warm, humid air masses that form over oceans near the tropics. In summer, they may bring showers and thunderstorms; in wither, they may bring heavy rain or snow. |
continental polar | Cool/cold, dry air masses that form over land near polar regions. In winter, they bring clear, cold, dry air; in summer, storms may develop where cP air meets mT air. |
continental tropical | Hot, dry air masses that form only in summer over land near the tropics. They bring hot, dry weather. |
maritime polar | Cool, humid air masses that form over cold N. Pacific and N. Atlantic oceans. They bring fog, rain, and cool temps to the West Coast. |
isobar | Lines joining places on a weather map that have the same air pressure. Lines are labeled with pressure readings in inches of mercury or in millibars. |
isotherm | Lines joining places on a weather map that have the same temperature. Lines are labeled with temperature in degrees Fahrenheit, Celsius, or both. |
prevailing westerlies | Global winds that blow from west to east; great effect on weather of the U.S. |
lake-effect snow | Cold, dry air blows across warmer water picking up water vapor. The (humid) air reaches land and cools, producing lake-effect snow. |
front | The area where air masses meet and do not mix; this is where weather occurs. |
occluded front | A warm air mass is caught between two cooler air masses and pushed up where it is cut off from earth's surface. The warm air condenses at a higher elevation and produces cloudy, rainy, snowy weather. |
cold front | A fast-moving cold air mass overtakes a warm air mass; the warm air is pushed upwards, condenses, and produces rain or snow. Heavy thunderstorms are associated with cold fronts. Once the front passes, the temperatures are cooler. |
warm front | A fast-moving warm air mass moves over a slow-moving cool air mass. Produces rainy, foggy, cloudy weather for days and days since warm air masses move more slowly than cool air masses. Temps are warmer behind the front. |
stationary front | When a cold air mass and a warm air mass meet but neither one has enough energy to move the other, there is a 'standoff.' Brings several days of clouds and precipitation. |
storm | A violent disturbance in the atmosphere involving sudden changes in air pressure that cause rapid air movements. |
tornado | A rapidly whirling, funnel-shaped cloud that reaches down from a storm cloud to touch earth's surface. |
doldrums | The area near the equator with little or no wind. |