Atmospheric pressure
force exerted b the gas molecules on some area of earths surface or on anyother body including yours
isobars
lines connnecting points of equal atmospheric pressure.
Milibars
most common units of measure for atmospheric pressure
ridge
is a elongated area of relativity
Ideal gas law
includes density, pressure, and temperature not inertness
Dynamic High
is a strongly descending air with high pressure
Thermal High
is very cold surface conditions
Dynamic Low
is ascending air at low pressure of surface.
Thermal Low
is hot surface conditions
Pressure Gradient Force
The movement of air from areas of high to low pressure.vthis acts at right angles to the isobars in the direction of the lower pressure.
The Coriolis Effect
curvature of global winds, ocean currents, and anything else that moves freely across the Earth's surface, due to the rotation of the Earth on its axis. It keeps the wind from flowing directly down a pressure gradient. It has a important influence on the
Wind
horizontal air movement, air in a hurry. Insolation is the ultimate factor in causing the generation of this.Wind speed is determined by the pressure gradient which is indicated by the spacing of isobars. When isobars are close pressure gradient is steep
Cyclone
Upper atmosphere convergence, descending air, surface divergence air moves counterclockwise in the Northern Hemisphere
Anticyclones
Surface convergence, ascending air, upper atmosphere divergence. is a high pressure center with wind that travels clockwise in the Northern Hemisphere
Geostrophic Wind
type of wind where coriolis effect and pressure gradient are in balance in the upper atmosphere, wind moves parallel to the isobars.
Subtropical High
big anticyclones develop from the descending air of the Hadley cells. they normally persist over the ocean basins throughout the year because temperatures and pressures there remain essentially constant. The weather is always clear within an STH is not co
Trade Winds
the sths major surface wind system thats located On the equatorward side of the subtropical highs.
Westerlies
the other major surface wind system of sth cover much of the earth and the reason they are less extensive then trade winds is because The globe is much smaller at the latitudes that encompass the westerlies.
horse latitudes
are High atmospheric pressure, Absence of wind, Diverging air near the margins of the region located in SThs because of an absence of wind in the center of an STH air is subsiding.
Doldrums
The zone where the air from the Northern Hemisphere and Southern Hemisphere meet is usually called the intertropical convergence zone or this. located in the general vicininty of the Equator, ( feeble and erratic winds, low pressure, high rainfall, and ri
Rossby Waves
giant meanders in high-altitude winds that are a major influence on weather. Can be thought of as separating cold polar air from warmer tropical air. When the polar front jet stream path is more directly west-east, there is a zonal flow pattern in the wea
Polar Highs
are high pressured cells situtated over both polar regions
Polar Front
the final surface component of the general pattern of atmospheric circulation is a zone of low pressure at about 50 to 60 degrees of latitude both Northern and Southern Hemispheres.
Monsoons
s seasonal reversal of winds, a general sea to land movement called onshore flow in summer and a general land to sea movement called offshore flow in winter. Heavy summer rains derived from the moist maritime air of the onshore flow and a pronounced winte
Sea Breezes
a common local wind system along tropical coastlines and to a lesser extent during the summer in the midaltitude coastal areas is During the day and during the night they are called Land Breezes.
El Nino
an episodic atmospheric and oceanic phenomenon of the equatorial pacific ocean, particularly prominent along the west coast of South America. during an el nino event abnormally warm water appears at the surface of the ocean off the west coast of South Ame
subsidence
The gradual caving in or sinking of an area of land.
Chapter 6
precipitation variability
is the expected departure from average percipitation in any given year, dry regions have greater variability than humid areas
3 things needed for precipitation
Collision and Coalescene of water droplets and ice crystal formation must grow heavy enough to fall through the air
Clouds
form when rising air, through expansion, cools to the point where some of the water vapor molecules "clump together" faster than they are torn apart by their thermal energy. Some of that (invisible) water vapor condenses to form (visible) cloud droplets o
Dew Point
is the temperature at which saturation is reached
Unlike relative humidity, which is a measure of how near the air is to being saturated, dewpoint temperature is a measure of the air's actual moisture content. High dew-point temperatures equate to moist a
Dry Adiabatic Rate
is the rate at which dry air changes its temperature as a result of expansion or compression. The dry adiabatic rate is 1.0o C/100 meters. Air rises and cools at the dry adiabatic rate up to the level of condensation where dew point temperature is reached
Saturated Adiabatic Rate
More commonly the "moist adiabatic lapse rate", it is the rate at which a parcel of air rises when it is saturated with moisture. Adiabatic means there is no exchange of heat with its surroundings, so the parcel only cools because the pressure is decreasi
Lifting Condensation Level
Lifting Condensation Level is altitude at which clouds begin in a rising parcel of air.
Lifting condensation level(LCL) can be said to be the level to which an unsaturated air parcel can be lifted adiabatically before it becomes saturated.Remember,this un
Relative Humidity
the relationship between temperature and relative humidity is one most important. As temperature increases, relative humidity decreases, as temp decrease relative increases.
Relative Humidity= Actual vapor density/saturation vapor density or capacity X 10
Specific Humidity
The mass of water vapor per unit mass of air, including the water vapor (usually expressed as grams of water vapor per kilogram of air).
rain shadow
nevada is the rain shadow of the Sierra Nevada mts of california.
Low precipitation
deserts and dry lands are associated most with low precipitation because they do not have much humidity or rain fall
Saturated Air
moist air in which the partial pressure of water vapour equals the vapour pressure of water at the existing temperature. This occurs when dry air and saturated water vapour coexist at the same dr -bulb temperature
air that contains the maximum amount of w
Atmospheric Lifting
Frontal is two dissimiliar air masses meet, and one forces the other aloft
orographic is an air mass is forced to rise when it encounters a topographic barrier.
Convergence is two similiar airmasses meet eachother and rise
Convectional is radiation of ene
Global precipitation pattern
1. seasonal shifting of major pressure and wind systems, shifting that follows sun, most in tropical regions, heavy rain
2. summers is the time of max precipitation over world, n hemis experienve rainfall in july
3. the most conspicuous variation in seaso
rain shadow
is a dry region of land that is leeward of a mountain range or other geographic feature, with respect to prevailing wind direction. The mountains block the passage of rain-producing weather systems, casting a "shadow" of dryness behind them.
Read more: ht
Glaze
is rain that turns to ice the instant it collides with a solid object
Hail
precipitation form with the most complex orgin which is consists of either small pellets or larger lumps of ice
Sleet
small raindrops that freeze during descent and reach ground as small pellets of ice
Stable Air
if a parcel of air resists uplift it is said to be stable. if stable air is forced to rise perhaps by coming up against a mountain slope it does so only as long as the force is applied.
Unstable Air
air is said to be unstable if it either rises without any external force other than the buoyant force or continuest to rise after such an external force has ceased to function.
Supercooled Water
water that persists in liquid form at temps below freezing is said to be supercooled. Important to condensation because they promoste the growth of ice particles in cold clouds by freezing around them or by evaporating into vapor form which water molecule
Evapotranspiration
the process where plants give up moisture through their leaves is called transpiration, and the combined process of water vapor entering the air from land sources is called evapotranspiration
Acid Rain
Acid rain is rainfall that has been acidified. Rain is acidified by oxides of sulfur and nitrogen. Acid rain usually has a pH of less than 5.6. Acid rain is formed when pollutants called oxides of sulfur and nitrogen, contained in power plant smoke, facto
Chapter 7 start
CHAPTER 7
Air Mass
is a huge body of air with similar temperature and moisture properties. The types of air masses formed on Earth are determined by their source region.
1. must be large 2. must have uniform properties in the horizontal dimmension, temp humid and stability
North America
North American continent is a prominent area of air mass interaction. The lack of mts trending east to west permists polar air to sweep southward and tropical air to flow northward unhindered by terrain, mostly over the eastern two thirds of the continent
Cold Front
forms where an advancing cold air mass meets warmer air., moves faster than warm fronts because the dense cold air mass easily displaces the lighter warm air.
Warm Front
forms where an advancing warm air mass meets colder air
Stationary Fronts
a front that does not move or barely do. fronts behave like warm fronts, but are more quiescent. Many times the winds on both sides of a stationary front are parallel to the front.
Typically stationary fronts form when polar air masses are modified signif
Occluded Front
Because cold fronts move faster than warm fronts, they can catch up to and overtake their related warm front. When they do, an occluded front is formed.
Occluded fronts are indicative of mature storm systems (i.e., those about to dissipate).
The most comm
Midaltitude Anticyclone
is an extensive migratory high pressure cell of the multialtitudes. Contain no front, the weather is clear and dry with little or no oppurtunity for cloud formation. Wind movement is limitied near the center of an anticyclone but increases outward
Tornado
is characterized by a deep low pressure cell surrounded by a violently whirling cylinder of wind. Most are in the U.S. due to optimum enviromental conditions, with the relatively flat terrain fo the central and se U.S. providing an unhindered zone of inte
Thunderstorm
a violent convective storm accompanied by thunder and lightning is usually localized and short lived. Associated with vertical air motion, considerable humidity and instability a combination tha tproduces a towering cumulonimbus cloud and always showery p
Tropical Cyclones
are intense low pressure disturbances that develop in the tropics and occasionally move poleward into the multialtitudes. Region where most deaths occur is low lying coastal areas
Hurricanes
Hurricanes are intense low pressure areas that form over warm ocean waters in the summer and early fall. Their source of energy is water vapor which is evaporated from the ocean surface. Winds must reach a speed of 64 knots for the storm to be officially
Mesocyclone
A storm-scale region of rotation, typically around 2-6 miles in diameter and often found in the right rear flank of a supercell (or often on the eastern, or front, flank of an HP storm). The circulation of a mesocyclone covers an area much larger than the
Eye
is a feature of a welldeveloped hurricane in the center of the storm. the winds do not converge to a central point but do at eye wall. no rain at eye and almost no clouds
Eye Wall
Winds reach their highest speed here, which is the edge of the eye
Dryline(dew point)
A dry line (also called dew point line, or Marfa front) separates moist air from the Gulf of Mexico (to the east) and dry desert air from the south-western states (to the west). The dry line is an important factor in severe weather frequency in the Great
El Nino
An El Ni�o is a temporary change in the climate of the Pacific ocean, in the region around the equator. You can see its effects in both the ocean and atmosphere, generally in Northern Hemisphere winter. Typically, the ocean surface warms up by a few degre
Source Region
An extensive area of the earth's surface characterized by essentially uniform surface conditions and so situated with respect to the general atmospheric circulation that an air mass may remain over it long enough to acquire its characteristic properties.
Typhoon
A typhoon is a violent cyclone that occurs in the northwest Pacific Ocean. Typhoons feature heavy rains and winds that maintain speeds equal to or greater than 74 miles (119 kilometers) per hour. Similar storms that occur in other parts of the world are c
Chapter 8********
CHAPTER 8************************
Climate Classification
we need a classification scheme to simplify, organize, and generalize a vast array of data. It can help us understand global climate patterns
Koppen Climate Classification System
(Precipitation and Temperature) is the most widely used modern climate classification system uses six letters to divide the world into six major climate regions, based on average annual precipitation, average monthly precipitation, and average monthly tem
Climograph
is a graphic representation of monthly temperature and precipitation for a specific weather station
Tropical Humid Climates
(Group A) occupy almost all the land area of Earth within the tropics.
Tropical Wet(Af) are equatorial found in east west astride equator(monotonous) a season less climate with endless repetition of the same weather day after day.
Tropical Savanna(Aw) mos
desert
is a dry, often sandy region of little rainfall, extreme temperatures, and sparse vegetation. Cool ocean currents(Deserts are very arid and steppes are semiarid)
Steppe
is a grassland without trees. It may be a semi-desert or covered with grass or shrubs. The term is also sometimes used to describe a climate that is to dry to support trees. A prairie can be considered (rainfall is greater and more reliable and temperatur
Subtropical desert
the distinctive climatic characteristic of deserts is lack of moisture, and 3 adj. scarce, unreliable, and intense
the association between the subtropical desert and the subtropical highs is the subsidence from the highs, cool ocean currents, and may be e
Mediterranean Climate(Csa, Csb)
distinctive characteristics of climate are subtropical high subsidence and stability in summer, westerly winds and cyclonic storms in winter. summers hot. Located at 35 degrees lat. on western sides of continents; limited east west extent except in Medite
Tropical Monsoon Climate(Am)
the one year record rainfall took place in this climate in India
The reason summer is not the hottest season is because the heavy cloud cover of the wet monsoon period shields out some of the insolation, resulting in slightly lower temperatures in summer
Marine West Coast Climate(Cfb,Cfc)
the mild temperatures are due to the year round cool maritime influence brought by the onshore flow of the westerlies leads to frequent cloudiness and high proportions of days with some precipitation, as well as an extraordinary temperate climate consider
Polar Climates(E)
being farthest from the equator, the polar climates receive too little insolation for any significant warming. The air is too dry and too stable for percipitation
Tundra
refers to the climate of the high altitude regions, long cold dar winters, and cool summers characterize the tundra
THe two types of polar climates(tundra and ice cap climate) are distinguished by summer temperature. Tundra has atleast one month with an a
Tropical Wet Climate
this climate has the smalles annual temperature range, is a seasonless climate, with endless repetition of the same weather day after day
Subtropical Desert CLimate(BWh)
this climate type has the greatest variability, low latitude location and lack of cloudiness permits a great deal of insolation summers are hot and winters. Weather is unusual and very unpredictable
The Atacama Desert
desert is located in the country of Chile (South America), right next to the Pacific Ocean It is known for being one of the driest places on Earth.
the double rain shadow is created by the presence of these two thingsoist winds from the east are kept out
Taiga
is a type of habitat. Taiga is a
coniferous forest that is swampy, found generally in high Northern
latitudes. The taiga habitat is
especially common between the tundra and the steppes of Siberia and North America.
Boreal
Relating to or characteristic of the climatic zone south of the Arctic, esp. the cold temperate region dominated by taiga and forests of birch, poplar, and conifers