Review of weather and climate in the first volume of seventh grade geography

The first section changeable weather

1. Two concepts describing atmospheric conditions: weather and climate.

Weather and climate

Concept refers to the atmospheric conditions of a place in a short time, such as rain, rain, heat and cold. The weather in different places at the same time may vary greatly, which refers to the average weather situation in a place for many years. Climate is a combination of long-term weather.

The characteristic time is short; It often changes for a long time, but not much.

Words judge the rain and wind at night, and I don't know how many flowers have been folded.

Sunrise in the east and rain in the west, the road is sunny but sunny. In April, the peach blossoms in the temple began to bloom.

Wuyuan spring returns late, and weeping willows come to hang silk in February.

Description: Sunny rain, precipitation probability, wind direction, wind force, temperature, precipitation, air pressure and wind force. The probability of precipitation indicates the probability of precipitation. The probability of precipitation is 100%, which means it must be "rainy"; The probability of precipitation is 0, which means it is definitely not raining. Temperature is how hot or cold the atmosphere is. The wind direction is the direction of the wind, which has four basic directions: north, south, west and east. The wind direction is "north", which means the wind comes from the north. Wind force is the intensity of wind, and the scale is 13 (0- 12). The larger the scale, the stronger the wind.

Second, the weather forecast chart

1. Weather forecast map (satellite cloud image): blue indicates ocean, green indicates land, and white indicates cloudy and rainy areas. The thicker the clouds, the heavier the rain.

2. Weather symbol map: (identify common weather symbols)

3. Weather forecast chart: Under normal circumstances, the weather forecast should explain the weather, rain, temperature, precipitation, etc. in a day. Know: (1) Precipitation probability means precipitation probability. (2) Temperature is the degree of heat and cold of the atmosphere, and the unit of temperature is generally expressed in℃, which is pronounced as℃. (3) Representation of wind force and direction. Wind direction refers to the direction in which the wind blows, and wind force refers to the size of the wind. (4) Pollution index and air quality grade: small index with good quality and large grade with poor quality.

Temperature and its distribution in the second quarter

1. The temperature is measured by a thermometer placed in the shutter. The thermometer should be placed at a height of 1.5m above the ground. Unit:℃ (Celsius). Generally, the average daily temperature is eight o'clock, 14 o'clock, 20 o'clock and 2 o'clock.

Second, the change of temperature: (see P5 1 Figure 3. 12, 3. 13, which can be used as an activity question 1.2).

1, daily change: refers to the temperature change in a day. Daily temperature range = maximum temperature-minimum temperature. The highest temperature in a day appears at 2 pm, and the lowest temperature appears around sunrise (the same in the northern and southern hemispheres).

2. Annual change: temperature change within one year. Temperature annual range = highest monthly average temperature-lowest monthly average temperature. In a year, the temperature in the northern hemisphere is the highest in July and the lowest in 65438+ 10. In the ocean, it is the highest in August and the lowest in February (contrary to the northern and southern hemispheres: 65438+ 10, the temperature in the central and southern hemisphere is the highest in October and the lowest in July; The ocean is the highest in February and the lowest in August)

Three. Regularity of temperature distribution: (see figure 3 of P53.17)

1, isotherm: a line composed of points with the same temperature at the same time.

2. Influencing factors A. Latitude factors: the world temperature gradually decreases from low latitude to polar regions; B. land and sea factors: the temperature at the same latitude varies with land and sea. Summer: Hot Land Leng Hai; Winter: the sea is warm and the land is cool. C. topographic factors: the temperature at the same latitude changes with altitude. The higher the altitude, the lower the temperature. (The temperature drops by about 0.6℃ for every increase of 100 m). Temperature difference between the two places = relative height between the two places/100×0.6℃

The third quarter precipitation and precipitation distribution

1. Rain, hail and snow falling from the atmosphere are collectively called precipitation. Rainfall is the most important form of precipitation.

2. Measurement of rainfall: The basic instrument for measurement is the rain gauge, which is calculated in mm (millimeter). Generally, it is measured at 8: 00 and 20: 00 every day, and the sum of the measurement results is the daily precipitation. Usually, the monthly precipitation histogram is used to represent the seasonal variation of precipitation in a place within one year, and the isoprecipitation line chart is used to represent the distribution of precipitation around the world.

Third, the global precipitation distribution law: the equatorial region has more rain and less rain; Near the Tropic of Cancer, there is little rain on the west coast and much rain on the east coast of the mainland. The mid-latitude zone is rainy along the coast and less rainy inland; It is rainy on windward slopes and rainy on leeward slopes in mountainous areas.

4. The world's "rain pole" is Kilapanchi in Asia and India, and the world's "dry pole" is Atacama Desert in Chile, South America. It didn't rain in 9 1 year.

Section 4 World Climate

I. Main climate types and distribution in the world (read the map on page 58)

1, main tropical climate types:

① Tropical rain forest climate: mainly distributed near the equator, with high temperature and rainy all year round.

② Tropical grassland climate: mainly distributed in the north and south sides of equatorial rainforest climate in Africa and South America. It is hot all year round, with obvious dry season and rainy season.

③ Tropical monsoon climate: The Indian Peninsula and Indo-China Peninsula in the south and southeast of Asia are the most significant. This climate is hot all year round, and a year can also be divided into dry season and rainy season, and the wind direction changes with the seasons. In dry season, the wind blows from land to sea, and there is little rain; In the rainy season, the wind blows from the ocean to the land, and the precipitation is concentrated.

④ Tropical desert climate: mainly distributed in the west coast near the Tropic of Cancer and mainland inland areas. This climate has little precipitation, is hot and dry all year round, and has a large desert on the ground.

2, the main climate types of temperate zone:

① temperate subtropical monsoon climate: distributed in eastern Asia. Summer is hot and rainy, and winter is cold and dry. It is roughly bounded by the 0℃ isotherm of the monthly average temperature of 65438+ 10, with temperate monsoon climate in the north and subtropical monsoon climate in the south.

② Mediterranean climate: It is mainly located in the middle and low latitudes on the west coast of the mainland, with the most distribution along the Mediterranean coast. It is hot and dry in summer and mild and rainy in winter.

③ Temperate continental climate: mainly distributed in mid-latitude inland areas, with intense heat in winter, great temperature change, less precipitation and concentrated in summer.

④ Temperate maritime climate: Located on the west coast of the mainland in the mid-latitude area, it is the most widely distributed in Western Europe, with mild and rainy weather and relatively small annual changes in temperature and precipitation.

3. The severe cold climate is distributed along the coast of Antarctica and the Arctic Ocean; It's cold all year round.

4. Alpine climate is distributed in alpine and plateau areas; The climate is complex and varies greatly vertically.

Second, the factors that affect the climate.

1, latitude: high latitude, low temperature, low latitude, high temperature; There is more precipitation in low latitudes and less precipitation in high latitudes.

2. Land and sea: it is rainy near the sea, and it is less rainy away from the sea; The temperature difference near the sea is small, and the temperature difference far from the sea is large.

3. Terrain: high altitude, low temperature, low altitude, high temperature (the temperature drops by 0.6 degrees Celsius for every elevation increase of 100 meters); The windward slope is rainy and the leeward slope is rainy.

4. Ocean current: Warm current increases temperature and humidity, while cold current decreases temperature and humidity.

5. Human activities: planting trees and repairing reservoirs will reduce drought and flood disasters; The increase of carbon dioxide emission forms the greenhouse effect, the ice and snow melt, the water temperature rises, and floods are caused.