Global Winds: Trade Winds, Westerlies and Polar Easterlies - General Knowledge Today
where the polar easterlies meet warm air from the westerlies, a stormy region known subtropical high pressure zones, around 30 degrees latitude created by . Apr 3, If the winds move from west to east, they are called westerlies. in equatorial low pressure areas (the Intertropical Convergence Zone, ITCZ) to the tropopause and carried pole ward. The trade winds meet at the doldrums. Surface winds created by the polar high pressure are deflected by the Where the polar easterlies meet warm air from the westerlies, a stormy region known as .
Prevailing winds - Wikipedia
A second wave occurs further away and higher. The lenticular clouds form at the peak of the waves B. Over elevated surfaces, heating of the ground exceeds the heating of the surrounding air at the same altitude above sea level, creating an associated thermal low over the terrain and enhancing any lows which would have otherwise existed,   and changing the wind circulation of the region.
In areas where there is rugged topography that significantly interrupts the environmental wind flow, the wind can change direction and accelerate parallel to the wind obstruction.
Jagged terrain combines to produce unpredictable flow patterns and turbulence, such as rotors. Strong updraftsdowndrafts and eddies develop as the air flows over hills and down valleys.
Wind direction changes due to the contour of the land. If there is a pass in the mountain range, winds will rush through the pass with considerable speed due to the Bernoulli principle that describes an inverse relationship between speed and pressure. The airflow can remain turbulent and erratic for some distance downwind into the flatter countryside.
These conditions are dangerous to ascending and descending airplanes. At night, the sides of the hills cool through radiation of the heat.
The air along the hills becomes cooler and denser, blowing down into the valley, drawn by gravity. This is known a katabatic wind or mountain breeze. If the slopes are covered with ice and snow, the katabatic wind will blow during the day, carrying the cold dense air into the warmer, barren valleys.
The slopes of hills not covered by snow will be warmed during the day. The air that comes in contact with the warmed slopes becomes warmer and less dense and flows uphill. This is known as an anabatic wind or valley breeze. The result are the trade winds winds with a component from the east over the ocean surface. The figure below shows the Hadley cells. Idealized global circulation for Northern Hemisphere winter.
The bulls-eye symbol indicates where a jet stream is coming out of the page toward the reader, and the "X" with a circle around it represents imagined tail feathers of jet-stream wind flowing into the page. Note that the tropopause is the boundary between the troposphere, where our weather events take place, and the stratosphere, where the air is mostly dry.
The stratosphere acts like a lid or cap on the weather that we experience in the troposphere. Mid-latitude Cyclones At mid-latitudes, such as Canada, there is not a strong vertical circulation cell. Instead, the winds create large, horizontally swirling low- and high-pressure systems that we see on weather maps see figure below. High-pressure regions, called anticyclones, are associated with fair weather, clear skies, but light winds not good for sailing.
Low-pressure regions, called extratropical cyclones, are associated with fronts, bad weather, and strong winds not good for pleasure sailing. Often the best sailing at mid latitudes is in between the highs and lows, where the winds are moderate and weather is still OK.
The Coriolis effect causes winds rotating counterclockwise around lows in the N. Hemisphere, and clockwise around highs. These circulations are superimposed by a general west-to-east movement of all the air at mid-latitudes.
Winds are named by where they come from.
Global Winds: Trade Winds, Westerlies and Polar Easterlies
At mid-latitudes is a general west-to-east air flow known as the Westerlies. Mid-latitude cyclones Lows and anticyclones Highs are imbedded in a general westerly flow; hence, these weather systems usually move from west to east.
The westerlies are generally stronger in the Southern Hemisphere because they flow over water. The westerlies in both hemispheres are stronger in winter than in summer.
Surface winds around the globe, as is useful for trans-oceanic sailing.
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- Hadley cell
L and H indicate low and high pressure. The air movements here are much weaker compared to those in the Hadley cells. The cool polar air meets the warmer mid-latitude air near the 60th parallel where it rises. This zone is known as the polar front. Here, winds blow from the east and north, shifting slightly east due to the Coriolis effect and are called the polar easterlies.
Summary Near the earth's surface at mid-latitudes such as the latitude of southern Canada the prevailing winds are from the west. These winds are called westerlies. Embedded within this general flow are extra-tropical cyclones lows that are also blown from west to east by the prevailing winds.