Weather and Climate Climate is the long-term trend of temperature and precipitation (rain, snow). Weather is the day-to-day variation in temperature and precipitation .
TEKS Obj. 4a - Explain the distribution of different types of climate in terms of patterns of temperature, wind, and precipitation. <ul><li>L atitude </li></ul><ul><li>A ir Pressure </li></ul><ul><li>M ountain Barriers/topography </li></ul><ul><li>E levation </li></ul><ul><li>C ontinental Location </li></ul><ul><li>O cean currents </li></ul><ul><li>prevailing W ind direction </li></ul><ul><li>S torms </li></ul>The climate where you live is called regional climate . It is the average weather in a place over more than thirty years. The acronym LAMECOWS helps you to remember the factors influencing climate including:
solar radiation One unit of solar energy strikes the Earth most directly at the equator and is spread over a given area. The same unit of energy that strikes the pole is spread over a larger area. Consequently, the equator heats up more than the poles.
The chief factor that determines climate is the distance a place is from the equator in terms of Latitude. The closer a place is to the equator, the warmer it will be.
heat transfer Heat in the atmosphere is transferred via greater heating of the atmosphere over the equator which causes air to expand, become less dense and rise; as it rises it releases its water vapor -- this is a permanent low pressure belt
the tropics Because of the earth’s 23 ½ ° tilt, four more imaginary lines delineate the polar and tropical regions: the Arctic and Antarctic Circles, and the Tropics of Cancer and Capricorn, each at 23 ½° from their respective poles and the Equator. The Antarctic Circle (not shown) is at 23 ½° from the South Pole or 66 ½° South latitude.
In a cyclone (low-pressure cell) air converges and rises. In an anticyclone cell, (high pressure cell) air descends and diverges. “ Highs” descend “ Lows” ascend
low, middle, high latitudes This diagram shows one way the Earth's surface can be divided into regions according to latitude. It is helpful to refer to a place as being in the low , middle , or high latitudes. Heated air that rises from the tropics descends at latitudes 30°, 60°, and at the poles.
Coriolis Effect Figure 1: In the inertial frame of reference (upper part of the picture), the black object moves in a straight line. However, the observer (red dot) who is standing in the rotating frame of reference (lower part of the picture) sees the object as following a curved path.
prevailing w inds The Coriolis effect means that winds caused by atmospheric highs and lows do not move straight north-south, but appear to bend relative to the earth’s rotation. Text pg. 54
wind belts The currents in the high, middle, and low latitudes produce predictable wind currents that ancient sailors knew well.
topography – the shape of the earth’s surface If not for landforms and topography, the Coriolis Effect would appear as in the diagram at left. The actual wind directions are shown on the right side globe.
surface o cean currents This illustration shows the circulation of the o cean's surface water. Names of the major o cean currents are noted with warm currents are red and cold currents blue.
The weather in this otherwise cold climate zone, is moderated by the effects of The North Atlantic Drift which originates from the Gulf Stream along North America and from the northern Sargasso Sea. North Atlantic Drift
Gulf Stream Its effect is sufficient to cause certain parts of the west of Britain and Ireland to be an average of several degrees warmer than most other parts of those countries. False-color image of the temperature of the Gulf Stream
Prevailing w inds push air from ocean currents over land
What factors contribute to the patterns of heavy and light rainfall on this map? Consider W ind and O cean currents, M ountain barriers and C ontinental Location
Compare this map with the previous one showing rainfall. What physical feature most obviously affects rainfall patterns?
Comparing marine climates The significant difference between climate characteristics of Vancouver and London, both Marine West Coast climates, arises from location, local topography, and ocean current influence. The dry summer in Vancouver is due in part to subsiding, subtropical high pressure lying to the south. Precipitation is nearly double that of London due to local orographic uplift of air.
Orographic Effect text pg. 50 Mountain ranges force moisture-laden clouds to release precipitation as they rise up the windward side.
mapping precipitation The high precipitation totals are located on the western side of the Cascade mountains, while the extremely low precipitation totals are on the eastern, or lee side of the mountain range . Average annual precipitation for the state of Washington shows that within a distance of 250 miles, annual precipitation totals change from more than 180”/yr. (deep purple) to less than 10”/yr. (bright red). This distribution is a direct result of the topography of the land.
Like directors on a globular stage, the ocean currents determine where heavy rains will fall spreading the equator’s heat to all corners of the earth. ocean currents direct rainfall
W inds W inds begin with differences in a ir pressures. Pressure that's higher at one place than another sets up a force pushing from the high toward the low pressure. The greater the difference in pressures, the stronger the force.