How to analyze the dynamic changes of weather system

How to analyze the dynamic changes of weather system should first understand that weather system refers to the form of atmospheric movement accompanied by a certain weather, and is not limited to several common forms listed in textbooks. Students usually think that weather systems only refer to fronts, cyclones and anticyclones. When they encounter problems about weather changes, they apply these weather systems mechanically. Once it doesn't match, it is very helpless. Secondly, the weather system is dynamic, with the process of generation and extinction, and the static weather system does not exist. Students are often confused about the discrimination of various weather phenomena caused by the movement of weather system, especially when they encounter unfamiliar situations. In fact, the so-called cultivation of students' geographical literacy in the new curriculum standard refers to many aspects, not through mastering relevant geographical knowledge and skills, or transferring and applying according to textbook cases, so as to have geographical literacy. Geographical literacy refers to having an innovative thinking ability and being able to flexibly apply unfamiliar information to demonstrate and explore new problems. The following questions:

Example 1. Generally speaking, the density of air is negatively correlated with air temperature and water vapor content in the air. The figure below shows the topography of the mid-latitude area in the northern hemisphere and the temperature profile at 8 o'clock. The air velocity from west to east at high altitude is about 20 km/h ... correspondingly completed 1 ~ 2 questions.

9℃

12℃

15℃

18℃

0℃

3℃

Altitude/meter

6℃

2500

2000

1500

1000

500

40

80

120

160

Distance/km

east

western

lake

first

second

The third/third in ten days' work

1. Compare the vertical atmospheric conditions of A, B and C at this time ()

Is A.A more stable than B? B. convection is strongest at B.

Is C.B more stable than c? Washington is the most stable place.

2. About noon

The temperature rises fastest in a.a.? There may be strong convective weather at B.B.

C. the northeast wind has a strong south wind at C.D.A.

The biggest misunderstanding in solving this problem is trying to infer what kind of weather system and front it is according to the temperature profile at 8 o'clock in the picture. A whirlwind? Anti-cyclone thermodynamic cycle? Paradoxically, I am very confused, because I can't judge what kind of weather system it is and I can't start. This is a manifestation of rigid thinking. In fact, although we need to use the accumulated knowledge and skills when analyzing specific problems, it is more important to learn to be faithful to the situation set by specific problems, extract relevant information contained in the situation, give up ourselves and follow others, instead of applying fixed knowledge in a preconceived way. The information provided in the question can fully satisfy the answer to each question. This question does not need to determine what kind of weather system it is, and it is also inconsistent with several common weather systems mentioned in the textbook.

In 1, air density is negatively correlated with air temperature and water vapor content. As can be seen from the temperature profile at 8 o'clock in the figure, the temperature difference between the near ground and the upper air is the largest, the air density difference between the upper and lower floors of the ground is the largest, the vertical atmospheric conditions are the most unstable, and the vertical convection is the most intense. Compared with B and C, the near-surface isotherm of B bends upward, so the temperature is higher than C. Because of the negative correlation between air density and water vapor content, the near-surface air density of B is lower because of more water vapor, and the upper air temperature of B and C is not much different. Therefore, the density difference between the upper and lower air of B is greater than that of C, the vertical convection of air is stronger than that of C, and the atmospheric vertical condition of C is the most stable. Item d is correct.

Question 2: According to the topic "The velocity of air flow from west to east at high altitude is about 20km/h", at 8:00- 12 (noon), the weather system will move eastward by about 80km, and the "air flow at high altitude" will just move to the second place (east of the lake) around noon, which shows that the area of the second lake is large and there is more water vapor near the lake, resulting in the low air density near the surface at the second place. As can be seen from the temperature profile at 8 o'clock, the isotherm of upper air flow is dense, cold and dense. When it moves to the second place, the density difference between the upper and lower layers of the air mass will increase, and the greater the density difference between the upper and lower layers of the air mass, the more likely it will lead to convection, so there may be strong convective weather in the second place, and item B is correct. As far as item A is concerned, the high-altitude airflow (dense isotherm-cold high density) originally located in the west of ground A has completely covered the ground A around noon. At this time, the temperature difference between ground A and ground B is not as big as that of ground B, but there should also be obvious convection movement. The weather changes, and it may be cloudy or even rainy, so the temperature rise must be slower than that of ground C (ground C has not been covered by high-altitude cold airflow around noon). The evidence of C and D is insufficient, and some students subjectively speculate on how the low-level airflow should move around noon, and what is unnecessary. If the topic does not explain the moving trend of the low-level airflow, it can be considered that the state of the low-level atmosphere has not changed. Then the wind direction of a and c is uncertain. Even for the application of cyclone system, place C in the eastern part of the cyclone in the northern hemisphere should be south around noon, while place A is located in the western part of the cyclone and should be north. So only item B is the most consistent statement.

Example 2. The following four weather charts reflect the weather process of a cold wave. Illustrated answers to questions 1~2. Civil band

b

Tianjin

1060

a

1062.5

Wuhan

c

Beijing

1060

d

1072.5

Hangzhou

Figure 6 (Pascal)

1. According to the process of cold wave weather, the order of the four weather maps from the first to the last should be

a

c

b

d

A.

b

c

d

a

B.

d

a

c

b

D.

c

b

d

a

C.

2. Judging from the four weather maps in Figure 6, the weather conditions in the following cities are close to reality.

Wuhan is sunny and warm. Tianjin is windy and cool.

C.C.-Thunderstorm in Beijing D.D.-Continuous rain in Hangzhou.

This topic provides four isobars near the ground in China, reflecting the weather process of a cold wave, which mostly occurs in late autumn, early winter or early spring. From the "cold wave", we know that it is cold front weather, and the moving direction is from north to south, so the position of cold front also moves from north to south. 1 The answer is C. Combined with the performance of cold front weather behind the front, we can see that Wuhan in Figure A and Tianjin in Figure B are both behind the front and close to the front, with strong winds, cooling and precipitation; Beijing and Hangzhou are located in front of the cold front, and the weather is fine. Moreover, the cold front precipitation is short, and thunderstorms mostly occur in the summer afternoon in northern China. So both items C and D are wrong, and the correct answer is item B.

Example 3. Look at the picture below, because of the change of air pressure, the four seasons in Hangzhou show changeable weather phenomena. The following weather map is correct in the order of spring, summer, autumn and winter.

①? ②? ③? ④

Figure 7

A.①②③④? B.③④①②？ C.①②④③？ D.③②①④

Different from the above question, this question gives four weather system diagrams to investigate the time of front rain belt, the season of strong Mongolian high pressure and the season of typhoon. Figure 1 Quasi-static front appears in South China, and it rains in the Qingming period, which is spring. In Figure 2, the ocean high pressure is relatively strong, the ruling area is expanded, and Hangzhou is shrouded by it, resulting in summer drought weather. Figure ③ The cold high pressure is strong in the middle of the land, while it is cold and rainy in Hangzhou at this time, and it is winter. Figure 4 Hangzhou is affected by typhoon activities, mostly in autumn. The correct answer is item C.