the study of landforms

   Before I talk about the landforms, you can watch the vedio. It can make you understand easily.

   We all familar with the magificent array of scenry on Earth's surface. It varies from the ice-covered to dry desert to teamy jungles. Geomorphology is the study of the varied landforms on the surface of the Earth, which I will talk about.
   Three primary influences affect the type of scenery that may be produced at a given point on Earth's surface. The first is the local geology_the type of rocks and structures that make up the land. The second is the local climate, cliamte varies with latitude; it is warm and wet the equator and cold and dry at the poles. Climate also varies as a result of atmospheric circulation. Time is the third major influence on landforms. Earth's contients are moved around on teconic plates, slowly changing position on the surface of globe. Accrodingly, the local climate will change with the time, and so well the landscapes that are formed. In a wod, Landforms are controlled by the local geology and climate,and by time.
   Before examing different geomorphologic environments, we must explore the role of gravity(mass wasting) and running water(the hydrologic cycle) in shaping the planet's surface.

    Mass wasting refers to the downslope movement of rock, regolith, and soil under the direct influence of gravity. In the evolution of the most landforms, mass wasting is the step that follows weathering. The combined effects of mass wasting and erosion by running water produce stream valleys.
   The hydrologic cycle describs the continuous interchange of water among the oceans, atmosphere, and continents. Powered by energy from the Sun, it is a global system in which the atmosphere provide the link between the oceans and continents. The processes involved the hydrologic cycle include precipitation, evaporation, infiltration(the movement of water into rocks or soils through cracks and pore spaces), runoff(water that flows over the land), and transpiration(the release of water wapor to the atmosphere by plants). Running water is the most important agent sculpting Earth's surface.
      Now the following will examine landforms.
      One of the most common landforms is valley. This feature is carried by small steams and rivers, and take a wide variety of forms_ from wide broad plains, such as the Grand Canyon of the Calorado River. The shape of a river valley depends on many factors such as the cliamte, the slope of the land surface, and the nature of soil or rock over which the river flows. The valley will change both in location and with time. In a mountain valley, a glacier can be likened to a river of ice. Like a river of water,it starts high in the mountains where snow collects and is changed into denser ice.
     As with the glacial envrionment, the desert environment is defined by climate. The scarcity of water that serves to define desert regions gives rise to unique landforms, although the basic principles of erosion, sediment transport, and diposition are the same in desert as anywhere on the continents.
       A desert is a part of the world that is literally deserted because of extremes in the environment. Although we may think of desert as being hot or sunny, desert regions are principally characterized by low rainfall. Most of the desert of the world are located in two belts adjacent to the tropic at 30°N and 30°S of the equator. These are regions that receive little rainfall owing to their location on the downflowing limits of atmosphere circulation cells. Desert conditions can also be caused by rainshadow effects.
   Coastlines are a dynamic interface between land and sea. They change position and form through time. On the time scale of single year, the coast at one location can vary from being barren of sediment to forming a sandy beach. Over shousands of years, shorelines have moved inland or regressed from land by several kilometers. The two main agents responsition along coasts are waves and tides. Tides are caused by the gravitational pull of the Sun and especially the Moon. Waves expend their energy by breaking, and the surf is an important agent of coastal erosion and transport.
    As we know, the Earth has many landforms,so I can't write all the forms in my blog. The surface of the Earth is changing slowly by the time, what the earth will be like after thousands of years? Can you image that? No, I can't.
   Hope you can feel the huge of the earth.