What is the definition of temperature curve?
Wu Jianguo, Xu Yanyan, New Century Middle School, Langfang Development Zone, Hebei Province
The temperature range is also called the temperature amplitude, which refers to the difference between the highest temperature and the lowest temperature in a day or a year. The difference between the highest temperature and the lowest temperature in a year is called annual range or annual amplitude. The temperature difference is one of the important signs to distinguish the climate type of each region. For example, the regions with large daily range and annual range belong to continental climate; On the contrary, it belongs to a maritime climate. The temperature in annual range is higher than that in low latitudes. The daily temperature range is higher than that in high latitudes. Of course, this is a big law (the daily temperature range and annual range change with latitude as shown in the following figure: ① annual range in continental latitude; ② annual range of ocean latitude; ③ The diurnal range of latitude on the mainland; ④ is the daily range of ocean latitude.), which is briefly explained as follows.
The daily range of temperature and the graph of annual range's variation with latitude
(1) The annual variation of temperature
Like the daily variation of temperature, the monthly average temperature has a maximum value and a minimum value in a year. As far as the northern hemisphere is concerned, the monthly average maximum temperature in the middle and high latitudes inland areas appears in July. The lowest monthly average temperature appears in January. The temperature in the ocean is the highest in August and the lowest in February. The difference between the highest and lowest monthly average temperature in a year is called the temperature annual range.
There are several factors that affect the temperature annual range.
(a) Latitude temperature annual range increases with the increase of latitude. This is because the annual change of solar radiation energy increases with the increase of latitude. The temperature annual range in low latitudes is very small. The temperature in annual range at high latitudes can reach 4 ~ 5℃.
(b) Due to the different thermal characteristics of land and sea, the difference of heat income in winter and summer in mainland China is larger than that in ocean, so the temperature in annual range on mainland China is much larger than that in ocean. Generally, the difference in temperate ocean last year is 11℃, and that in mainland China last year can reach 2 ~ 6℃. ② annual range at the latitude of the ocean.
(c) Distance from the sea. Due to the thermal characteristics of water, the temperature of the ocean is moderate. The closer to the ocean, the greater the influence of the ocean, the smaller the temperature annual range, the farther away from the ocean, the less the influence of the ocean, and the greater the temperature annual range.
In addition, Terrain and weather have the same influence on the temperature annual range as on the daily range of temperature.
(2) Daily variation of temperature
The continuous variation of temperature with time in a day is called daily variation of temperature. In a day, the air temperature has a maximum value and a minimum value, and the difference between them is the daily range of temperature. Usually, the maximum temperature appears at 14-15 o'clock and the minimum temperature appears around sunrise. Due to the influence of seasons and weather, In winter, it is between 13: and 14: . Because the sunrise time is different at different latitudes, the time of the lowest temperature will vary with different latitudes. The daily temperature range is smaller than that of the soil temperature on the ground surface, and the farther away from the ground, the smaller the daily temperature range is, and the time of the highest and lowest temperatures is also lagging behind. In agricultural production, sometimes a large daily temperature range is needed, which is beneficial to the high yield of crops. Because a large daily temperature range means that the daytime temperature is higher. However, the temperature is low at night, so that the photosynthesis of leaves is strong during the day, and more carbohydrates are produced, while the respiration consumption at night is less, and the accumulation is more, and the crop yield is high and the quality is good. < P > The factors that affect the daily temperature range are as follows.
(a) The daily temperature range at latitude decreases with the increase of latitude. This is because the variation of solar height in a day decreases with the increase of latitude. The daily temperature range in tropical areas on the mainland is 12. The daily temperature range in temperate zone is 8. ~ 9.℃; The daily range of temperature in the polar circle is 3. ~ 4.℃, so ③ in the figure is the daily range of continental latitude.
(b) Generally, the daily range of temperature in summer is greater than that in winter, but in the middle and high latitudes, the maximum daily range of temperature in a year appears in spring. Because although the sun has a large altitude angle in summer, the sunshine time is long and the temperature is high in the daytime, the temperature at night is also short in the middle and high latitudes. Therefore, the daily temperature range in summer is not as large as that in spring.
(c) The daily temperature range in low-lying terrain (such as basins and valleys) is larger than that in convex terrain (such as hills). In low-lying terrain, the contact area between air and the ground is large, the ventilation is poor, and it is often where cold air sinks and meets at night, so the daily temperature range is large. In convex terrain, the wind speed is high, the turbulence is strong, the heat exchange is rapid, and the temperature is high. The flat land is in between.
(d) The nature of the underlying surface is different due to the different thermal characteristics and solar radiation absorption capacity of the underlying surface. The daily temperature range on land is greater than that of the ocean, and the farther away from the sea, The greater the diurnal range, the greater the diurnal range of temperature in sandy soil, dark soil and dry loose soil is than that in clay, light soil and moist compact soil respectively, so ④ in the figure is the diurnal range of ocean latitude.
(e) The diurnal range of temperature in sunny days is greater than that in cloudy (rainy) days, because in sunny days, the solar radiation is strong, the ground temperature is strong, and the effective radiation on the ground is strong at night, and the diurnal range of temperature in windy days is small.