Term | Definition |
UTC TIme | A 24 hr clock used to determine time around the world. 0:00 time at England. PA is -5 at standard time and -4 at daylight savings. |
Line of Latitude | Connect point of equal distance to the equator. Span from 0*-90*. Denoted as North (N) or South (S). |
Line of Longitude (Meridians) | Run from pole to pole. Span from 0*-180*. 0* passes through the British Royal Observatory in Greenwich (Prime Meridian). Denoted as East (E) or West (W). |
Tropics | The region of the earth surrounding the equator. They go as far south as the Tropics of Capricorn and as far north as the Tropic of Cancer. |
SubTropics | The location between the Tropic of Cancer to the 38th parallel in the northern hemisphere and between the Tropic of Capricorn and the 38th parallel in the southern hemisphere. |
Mid-latitudes | The location between 38th parallel and the arctic in the northern and southern hemisphere. |
Polar Regions | The location between the Arctic Circle and the North/South Pole. |
Temperature | a measure of the kinetic energy of its molecules. |
SI units for Mass | kg or kilograms |
SI units for Time | s or seconds |
SI units for length | m or meters |
SI units for temperature | K or Kelvin |
Spatial Scale | Measure of distance. Consists of a microscale, a mesoscale, and a synopic scale. |
Temporal Scales | Measure of time from seconds to months. |
Climate | The long-term average of atmospheric elements over months, years, or even longer. |
Weather | The atmospheric conditions over a short period of time. |
The three most prominent permanent gases in the atmosphere | Nitrogen, Oxygen, and Argon |
What a 60% percent chance of precipitation means | There is a 6 in 10 chance that somewhere in the forecast region will her measurable rain. |
Climatology | The collection of a location's climate data. This can predict the amount of precipitation/snowfall a certain area will receive. |
Isotherm | Isoplething temperature |
Isobar | Isoplething pressure |
Isotach | Isoplething wind speed |
Radiosondes | Measures temperature, relative humidity, pressure and are launched at 00Z and 12Z. |
Solar Radiation | Both the visible and invisible radiation emitted by the sun. In the visible light wavelength for its peak in radiation. 0.5 microns |
Terrestrial Radiation | What the earth emits from absorption of solar radiation and radiation emitted by the atmosphere. In the infrared wavelength for its peak in radiation. 10 microns |
What does radiation come from? | Both a spectrum and a wavelength |
Correlation of Temperature to wavelength | The higher the temperature of an object, the more energy it emits. It will have shorter wavelengths of radiation it emits and the shorter wavelength at which its peak emissions occur. |
Absorption of Radiation | the fraction of energy absorbed. This depends on color. Darker-colored surfaces absorb more visible radiation that lighter-colored surfaces. Snow scatters more radiation than grass. |
Transmission of Radiation | When radiation passes through an object. |
Scattering of Radiation | When an objects molecules interact with radiation such that radiation goes in all directions, |
Back-scattering of Radiation | When incident radiation gets scattered back in the general direction of the source. |
Correlation of sun angle and radiation | In northern hemisphere, there will be the same length of radiation to hit the earth's surface. In January, it will hit at a smaller angle causing a larger area to be covered by radiation. Vice Verse for July. |
Radiative Balance | Objects that absorb more radiation than they emit warm up. Objects that emit more radiation than they absorb cool. |
Albedo | The amount of radiation reflected by earth is the 30% of the solar radiation. |
Kirchoff's Law | A good absorber at a certain wavelength is also a good emitter at those wavelengths. |
Greenhouse Gases | Water and Carbon Dioxide tht produce heating through absorbing terrestrial radiation and emitting it back into the planet. |
Conduction | Energy transfer through contact. Air in contact with the ground heats up if the ground is warmer than the air. |
Convection | Energy transfer of heat by vertical mixing. Boiling water is an example. |
Eddies | Turbulent swirls of air. |
Nocturnal Inversions | At night, the ground does not absorb solar radiation, but still can emit it can cool. Because cooler air is denser than warmer air at constant pressure, cooler air can sit under warmer air. Conduction can cool the air if there is wind. |
Winter in Northern Hemisphere | Earth to the left of the the sun. Sun facing South America and Europe. Starts December 21st. Earth rotating counter clockwise and spinning clockwise. Shortest dat of the year when sun is overhead at 23.5*S. |
Summer in Northern Hemisphere | Earth to the right of the sun. Sun facing North America. Starts June 21st. Earth rotating counter clockwise and spinning clockwise. Longest day of daylight because the sun is directly overhead at 23.5*N. |
Spring in Norther Hemisphere | Earth in front of sun, facing away from sun. Begins March 20th. Earth rotating counter clockwise and spinning clockwise. Vernal equinox where sun is located over the equator |
Fall in Northern Hemisphere | Earth behind the sun, facing toward the sun. Begins September 22nd. Earth rotating counter clockwise and spinning clockwise. Autumnal Equinox, sun over the equator. |
Heat Capacity | Water is slow to cool or heat because water has this. This is what causes the water to take time to heat up and to cool down |
Correlation of Water Proximity and the Seasons | This is what causes average temperature to be the highest in July or August because the max solar radiation happens during these months and heats the water. |
Diurnal Temperature Changes | The change in temperature from the day time to the night time. Lower diurnal changes will happen around bodies of water due to capacity and higher inland. |
Average Environmental Lapse | Temperature that decreases with height because in the troposphere the heating comes from the Earth's surface. |
Tropopause | The transition zone between the troposphere and the stratosphere. |
Troposphere | The lowest level of the earth's atmosphere where all f the weather occurs. |
Air Mass | A large blob of air with fairly uniform properties of temperature and humidity. |
cP air mass | continental polar |
cT air mass | continental tropical |
mP air mass | Maritime polar |
mT air mass | Maritime tropical |
cA air mass | Continental arctic |
Cold Front | Cold air advancing. Represented on map with blue triangles facing the direction the front is moving toward |
Warm Front | Cold air retreating. Represented on map with red semi circles facing the direction the front is moving towards. |
Stationary Front | Cold air nearly stationary. Represented on map with alternating blue triangles and red semi circles pointed in the direction it is heading. |
Front | Boundaries between air masses |
Density of warm air vs. cold air | Cold air is denser than warm air at constant pressure |
Frontal Passages effects | Wind direction will usually change. The temperature and dew point will significantly drop and equal out to each other. |
Warm Air Advection | If wind advects warm air your way |
Cold Air Advection | If a cold front is advancing your way |
Persistence Forecast | A forecast that the current weather condition will persist and that future weather will be the same as the present |
Hydrologic Cycle | Evaporation and precipitation dominate in terms of volume of water transported. |
Evaporation | Water molecules break their bonds and escape to the air as gas |
Transpiration | Plants releasing water vapor to the air |
Sublimation | Ice changing directly to water vapor |
Humidity | The amount if water vapor in the air |
Evaporation/Condensation and Temperature | Evaporation is making the temperature warmer and more humid. Condensation will cool the temperature (gives off heat) |
Dew Point | The temperature to which the air must cool for condensation to occur. |
Net Condensation | condensation rates exceeding evaporation rates. |
Net Evaporation | when the rate of evaporation exceeds the rate of condensation. |
Rain and Temperature | Surface air temperature often decreases when it starts raining. |
Vapor Pressure | The part of total air pressure exerted by water vapor. |
Equilibrium Vapor Pressure | The vapor pressure at which evaporation and condensation rates are equal. |
Equilibrium Pressure and Temperature | It is a function of temperature. Water vapor content of the air over warm water is higher than over cooler water. |
Vapor Pressure Gradients | The difference in vapor pressure between the air and water interface. |
Vapor Pressure Gradients and Evaporation | When there is a lot of water vapor in the air net evaporation is reduced. On humid days sweat evaporates less quickly than on dry days. |
Relative Humidity | Ratio of the actual vapor pressure and the equilibrium vapor pressure multiplied by 100 to give a percent. |
CCN (Cloud Condensation Nuclei) | microscopic particles on which water vapor condense. They are hygroscopic meaning they attract water. |
Three things to make a cloud | Pressure, water vapor, and a cooling agent |
Temperature change with rising air | When air rises, it expands and cools and both density and pressure decrease |
Orographic Lifting | Air can be lifted by terrain |
Rain Shadow | When a precipitation minimum occurs on the leeward (opposite side of the one facing the wind) side of the mountain |
Ground Fog | Comes from radiative cooling |
Mixing Clounds | Occur when warm, moist air mixes with cooler, dry air |
Three Way to Change Humidity | changes in temperature, moisture advection, and mixing of dry air down. |
Cirrus Clouds | Latin for hair, stringy clouds |
Cumulus Clouds | Latin for heap, puffy clouds. |
Remote sensing | Observation without direct contact with observed medium |
In-suit Obervation | Comes from direct contact with the medium. |
Geostationary Satellites | GOES-East and GOES-West. Satellites do not move with respect to earth. |
Polar Orbitor | Satellites move with respect to earth. |
Visible Satellite Image | The earth doesn't absorb visible light well so there are used to monitor clouds in the atmosphere. |
Atmospheric Window | wavelengths of the electromagnetic spectrum that can be transmitted through the earth's atmosphere. |
Infrared Satellite Radiation | You can see water, land and clouds, mostly clouds. We can't see the the ultraviolet spectrum so weather satellites pick up the temperature and show warm areas with dark grey and cold areas with white. Used mostly for determining where clouds are in sky |
6.7 Microns | Water vapor absorbs at this amount of radiation so remote sensing of water vapor from space means only sensing upper level water vapor. |
Water Vapor Satellite | Used to determine what is happening in the atmosphere. |
Radar | Radio Detection and Ranging. Used to detect precipitation. |
How Radars work | They send short pulses of EM radiation which
strike raindrops, snow, hail, birds, insects and
then receive a back-scattered signal |
Reflectivity and dBZ | dBZ is used to determine what type of precipitation. Larger objects back scatter more radiation. 20-50 dBZ for rain and 55-70 dBZ for hail |
Doppler Effect | The frequency of a wave changes depending on whether it is moving towards or away from an observer. |
Air Pressure | the force exerted on you by the weight of tiny particles of air. Although air molecules are invisible, they still have weight and take up space. |
14.7 psi | Average sea level pressure. |
Pressure and Density | These decrease with altitude. Air is compressible. |
Gas Law | Temperature, pressure, and density are related by this equation. |
Ridges | Elongated areas of high pressure |
Troughs | Elongated areas of low pressure |
Pressure Gradient Force | the force which results when there is a difference in pressure across a surface. Determines wind direction and strength. |
Coriolis Force | Pushes objects in the atmosphere to the right. |
Wind and low pressure | Circulation around a surface low in the Northern Hemisphere is counterclockwise with air moving slightly towards the low |
Wind and high pressure | Circulation around a surface high in the Northern Hemisphere is clockwise with air moving away from the high. |
Friction | Over land wind crosses isobars at 30*, over oceans it is smaller. |
Surface High and Low | With a low, the air will rise. With a high, the air will sink. |
Characteristics of High Pressure | The air is sinking, it spirals outward and counterclockwise, and if the sinking air becomes warmer. |
How to find front our trough | Isotherms, isodrosotherms, isobars, and wind |