The geothermal capacity is small, the temperature rises and falls quickly, the ocean heat capacity is large, and the temperature rises and falls slowly, so the isotherm at the same latitude is not straight. In the study of geography in senior high school, it is divided into land and sea.
It is always difficult for students to understand the isotherm bending caused by cloth, and it is also one of the key contents of college entrance examination to judge the season or land distribution according to the isotherm bending. In teaching, the author
It is easy to break through this difficulty through several techniques and methods. The summary is as follows: "One place goes south", that is, the land isotherm bends south in January (regardless of the northern and southern hemispheres, the land DOC format paper is convenient for you to copy, modify and delete.
Isotherms all bend to the south). "One Sea North", that is, 1 month ocean isotherm bends northward (regardless of the northern and southern hemispheres, ocean isotherm bends northward).
"Seven continents move northward", that is, the land isotherm bends northward in July (regardless of the northern and southern hemispheres, the land isotherm bends northward).
"Seven Hainan", that is, the ocean isotherm bends southward in July (regardless of the northern and southern hemispheres, the ocean isotherm bends southward).
Due to the difference of thermal properties between land and sea, the land temperature is high in summer and low in winter, and then according to the law of "high and low", that is, when the temperature is high, the isotherm protrudes to the high latitude; The temperature is very low,
Isotherms protrude to low latitudes. On the contrary, the isotherm protrudes to high latitudes and the temperature is high; Isotherms protrude to low latitudes and the temperature is low. Applying this law requires students to master the thermodynamic properties of land and sea skillfully.
Principle of difference. According to this law, we can judge the seasonal season and land-sea distribution of a place through the bending law of isotherm.
For example, it is known that the land isotherm (northern hemisphere) in the figure bends to low latitude, so the land temperature is lower than the ocean, so it is winter at this time. If it represents the summer isotherm (northern hemisphere)
According to the distribution map, it can be judged that the place that bends to low latitude is the ocean, and the place that bends to high latitude is the land. Using this rule, we can also verify the correctness of the homophonic memory method of "one place in the south": 1 serving, the temperature in the northern hemisphere continent is low, so it bulges to the low latitude, that is, it bulges to the south; The continental temperature in the southern hemisphere is high, so the isotherm is convex to the high latitude and also to the south. Therefore, regardless of the northern and southern hemispheres, the "one place in the south" harmony method is applicable. Docformat papers are convenient for you to copy, modify and delete.
I-migratory bird migration law. As we all know, geese will fly to the south before winter comes in northern China. At this time, the land isotherm can be imagined as a land with herringbone bending and geese flying south.
The temperature line bends to the south. On the contrary, before summer comes, migratory birds come back and the isotherm bends to the north. Suppose that the isotherm of A in the figure bends (slightly) to the south, which is 1 month; Set b again.
If the isotherm bends to the north, it will be July. Law summary: In winter (northern hemisphere), the land isotherm bends to the south and the ocean isotherm bends to the north.
The second is skipping rope. Students are familiar with the wind direction in winter and summer, and can think of the land isotherm as skipping rope. When the north wind blows in winter, skipping rope is blown by the wind.
Bend to the south; When the south wind blows in summer, the skipping rope is bent to the north by the wind. According to this method, students are very easy to understand and accept, and they are also handy when doing problems, which is not easy to be confused.
Point-the direct point of the sun, that is, if the direct point of the sun is in the northern (southern) hemisphere, the continental isotherms of the two hemispheres protrude to the north (south) and the ocean protrudes to the south (north). According to this law, the following reasoning can be made: the direct point of July is in the northern hemisphere, which is the summer half year of the northern hemisphere, and the land isotherm protrudes northward. From this, we can get the distribution law of global isotherm: 1 month by month.
The direct point of the moon and the sun is in the southern hemisphere, and the continental isotherm protrudes southward. In July, the direct point of the sun is in the northern hemisphere, and the continental isotherm protrudes northward.
On the ocean, the situation is just the opposite; According to the season, the continental isotherm protrudes to the low latitude in winter and to the high latitude in summer, but the ocean is just the opposite. To sum up, as long as we understand the difference between land and sea and the south.
The seasons in the northern hemisphere are opposite, so we can judge the distribution of land and sea according to the isotherm characteristics. DOC format paper is convenient for you to copy, modify and delete.
The season (month) can also be judged according to the characteristics of land and sea temperatures.
Draw an arbitrary straight line (representing a latitude) on the isotherm distribution map and intersect with any isotherm to meet the condition of "same latitude". Compare the bending area with
The numerical difference between the two sides, so as to determine whether it is a high value area or a low value area, and then use relevant knowledge to further analyze the reasons. You can also use the judgment methods of "convex height is low" and "convex low is high", that is
Where the isoline bends to the side with large value, its value is smaller than that of the adjacent two sides (i.e. low value area). 65438+ 10 month: the land temperature in the northern hemisphere is low, so the isotherm bends to the south (high value), while the temperature in the ocean is high, and the isotherm bends to the north (low value); In the southern hemisphere, the land temperature is high, and the isotherm bends to the south (low value), while the ocean temperature is low, and the isotherm bends to the north (high value). July: The land temperature in the northern hemisphere is high, so the land isotherm bends northward (low value).
The temperature in the ocean is low, so the isotherm of the ocean bends to the south (high value); In the southern hemisphere, the isotherms on land bend to the north, while those on the ocean bend to the south.
If the isotherm is sparse, there is little difference in temperature between different places; The dense isotherms indicate that the temperature varies greatly from place to place; The isotherm is straight, indicating that the underlying surface that affects the temperature is relatively simple.
One; The isotherm curve shows that there are many factors affecting the temperature distribution. The isotherm shows an east-west trend, indicating that the temperature changes with latitude, and the latitude factor (solar radiation) is the main factor; Isotherm and sea
The parallel coastline means that the temperature changes with the distance from the sea, and the main influencing factor is the distribution of land and sea; Isotherms are closed or semi-closed, and are often mainly influenced by topography. Isotherm in the ocean
The bending direction is consistent with the current direction.