Geog_102_Week_5_online

Geog_102_Week_5_online - WeatherSystems AirMasses...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Weather Systems Air Masses • Fronts: warm, cold, occluded • Cyclonic storms • Anticyclonic weather • Tropical Weather Systems • Weather system: a recurring pattern of atmospheric circulation (e.g., high pressure system , low pressure system ) associated with characteristic weather events. • Occur at a wide range of scales, from a few kilometers (e.g. a tornado) to more than a thousand kilometers (e.g. cyclones and anticyclones) • Weather patterns are typically a response to the movement of large bodies of air called air masses , comprising 10 5 ­ 10 7 km 3 of air. Weather Systems
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Air Masses An air mass is a large body of air with fairly uniform temperature and moisture characteristics. Air masses acquire their characteristics in source regions and are classified on the basis of: 1. Latitudinal position (Polar, Tropical) 2. Nature of source region surface (maritime, continental) Air Mass Types Lat. of origin: ­ Arctic (A) ­ Polar (P) ­ Tropical (T) Surface type: ­ maritime (m) ­ continental (c) Fig. 8.2a
Image of page 2
3 Airmasses Affecting Vancouver Area: Winter Over the Vancouver region in winter , we typically see the following air masses and weather conditions: Maritime Polar (mP): cool, moist, 5° to 8° C (rain) This is the dominant air mass over Vancouver. Maritime Arctic (mA): cold, moist, ­ 5° to 5° C (rain/snow) Continental Arctic (cA): very cold, very dry, ­ 5° to ­15° C (snow or clear, very cold weather) Airmasses Affecting Vancouver Area: Summer • Over the Vancouver region in summer , we typically see the following air masses and weather conditions: Maritime Tropical (mT): warm, moist 15° to 25° C (dry weather if anticyclonic flow, otherwise showery if cyclonic). This is the typical mid­summer airmass. Maritime Polar (mP): cool, moist 10° to 15° C (showery). This is the cooler airmass which causes cooler, wetter interludes in summer.
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4 • A given air mass usually has a well­defined boundary between itself and a neighbouring air mass. This boundary is termed a front . • Fronts are drawn on a weather map when there are notable temperature differences between air masses. • Three types of fronts: cold, warm, occluded • Frontal precipitation: precipitation occurring where air is lifted and cooled adiabatically at the frontal boundary between air masses; extensive clouds occur. Fronts How and Why Fronts Form Fronts form because a cold airmass (blue) and a warm airmass (red) converge towards each other towards a low­pressure centre . The front is the interface between the air masses drawn at the surface . Low cool mP warm sector mT cool mP High High High Warm Front Cold front Typical mid­latitude cyclone with warm and cold fronts
Image of page 4
5 Development of a Mid­Latitude Wave Cyclone These diagrams show a 3­D view of a frontal surface separating two air masses. Convergence of warm and cold air masses causes the frontal surface to buckle, so that the warm sector is surrounded by colder air.
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern