Modul 4 - Dinamika Bumi [PDF]

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BUMI DALAM TATASURYA • Matahari dan planet-planetnya • Anatomi bumi • Dinamika bumi



Orbital change



Axial tilt change



Wobble



Distributian of day and night; and climate along year



Energy budget



Heat Flow



0



40



60



85 120 mW m-2



180



240



350



The hottest and the coldest places



Winds circulation



Winds circulation



Siklon dan antisiklon rendahan dan tinggian



TINGGIAN



RENDAHAN (dekat permukaan)



Isobar dan arah angin



Pembentukan siklon dan antisiklon



Spiral awan



How does water move among reservoirs?



Ocean Currents • Redistribute heat across planet



Sirkulasi air di samudera



Weather and Climate What is weather? What is climate? How do they differ? • Weather is the short-term state of the atmosphere at a particular place at any given time • Climate is a long-term composite of weather conditions at a particular place • Short term versus long term---that is how they differ



Iklim dunia



5. Landforms and Surface Processes H.C. Berann (1915-1999) Yosemite National Park, 1987



• Glaciers • Mass Wasting • Streams • Shorelines • Deserts • Groundwater http://www.berann.com



What drives plate motions • Forces that drive plate motion – Slab-pull • Cold, dense slabs of subducted oceanic lithosphere pull the plate towards the subduction zone – Ridge-push • The higher elevation of spreading centers result in oceanic lithosphere wanting to move “downhill”, away from the ridge • Far less important than slab-pull – Mantle drag and plate resistance • Can act to increase or decrease plate motion



Mantle convection provides the primary drive for plate tectonics



What drives plate motions • •



• •



Models of plate-mantle convection Any model must be consistent with observed physical and chemical properties of the mantle Horizontal movement of plates causes mantle upwelling Models – Layering at 660 km – Explains why basalts erupted at mid-ocean ridges are different (more evolved, relatively shallow source) compared to those erupted at hot-spots (more primitive, deeper source). – We know that subducting slabs descend beneath 660 km



What drives plate motions •



Whole-mantle convection – Would mix the entire mantle in the space of a few hundred million years, removing heterogeneities



What drives plate motions •



Deep-layer model – “Lava lamp model” – Two layers swell and shrink in a complex fashion in response to heat from the Earth’s interior



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