High School Geography Morning and Dusk Line Calculation There must be a problem solving process, if

The second question has been solved upstairs, so I won't say more. The first question is indeed lacking, but I can help you analyze the diagram: the cab line in the figure should be the morning and dusk line, and a is the tangent point between the morning and dusk line and 70n.

What cannot be determined is the diurnal condition at 70N and north of it, or whether AC and AB are morning or dusk, and if the conditions are in the diagram, they must be in the title text. In two cases--- assuming that the north of point A is the polar daytime region, then point A is zero o'clock in local time, and if two points B and C are the intersection points of the morning and dusk lines and the equator, then the local time is 6 o'clock and 18 o'clock respectively. At this time, the direct point of the sun is 20N, 85W.

Assuming that the north of point A is the polar night region, then point A is 12 o'clock local time, and B and C are the intersection points of the morning and dusk lines and the equator, then local time is 18 o'clock and 6 o'clock respectively.

Principle of solution: 1. The equator equinox of the day throughout the year. Then the intersection of the equator and the morning and dusk lines must be 6 o'clock and 18 o'clock; 2. 24-hour daylight at the boundary of the polar day zone, the lowest solar altitude angle at zero is zero, tangent to the morning and dusk line; At the boundary of the polar night zone, the height of the sun is at zero at the highest at 12 o'clock, tangent to the morning and dusk line.

Good luck with your geography studies.

Do you want both? The conditions in the picture above are not sufficient.

The diagram below is 6 o'clock at points A and C, and 8 o'clock at point B.

Key to the problem: The direction of the arrow is clockwise, indicating that it is the Southern Hemisphere; The shaded part represents the night hemisphere, combined with the direction of the earth's rotation is the arrow in the figure, judging that point A is located on the morning line, the intersection of the morning line and the equator is 6 o'clock, and the place where the dusk line and the equator intersect is 18 o'clock, so the place at point A is 6 o'clock; Since the same meridian is the same, and both point A and point C are located on the same meridian, then point C is also 6 points; Since point B is located on the 0° meridian, the diagram is 30 degrees away from the meridian where point A is located (1 hour is equal to 15°), and point B is located on the east side of point A, so the local time of point B is 8 o'clock.

The above is correct, the key to solving the time calculation problem is to understand these meanings: the intersection of the morning and dusk line and the equator is 6 o'clock and 18 o'clock respectively, and the morning and dusk line should be judged according to the direction of rotation of the earth and the distribution of the day and night hemisphere "You can also use your hand to judge the east and west longitude, south, left, north and right", followed by knowing how to convert longitude and time fluently "15 degrees is equal to one hour, one degree is equal to four minutes". I'll answer the first question with additional conditions:

Point A is the tangent point between the circle of morning and dusk and the parallel, so point A is 0 or 12 o'clock, and assuming that the two points are on the equator, "the two points are the midpoint of the meridian where they are located", so there are two answers: 1, a is 0, b is 18 o'clock, c is 6 o'clock, 2, a is 12 o'clock, b is 6 o'clock, and c is 18 o'clock.

It's not too difficult, and the younger brother can't solve it in his first year of high school.

The morning slag line is a dividing line that divides every location in the world into "sunrise zone" and "sunset zone", which is a large ring that connects the earliest and latest sunrise and sunset times of each place. At the equator, the Dawn and Dusk Line is a line located exactly 180 degrees east longitude, also known as the International Date Line (IDL), which divides the world into east and west. So in this question, if a location is at 30 degrees east longitude, this place is 150 degrees wide from 180 degrees east longitude, because the morning and dusk line crosses 180 degrees east longitude and divides the earth into east and west halves.

Therefore, according to the direction of the Earth's rotation, the place on the east side of the morning and dusk line is the "sunrise zone", and the place on the west side of the morning and dusk line is the "sunset zone". Thus, according to the description of option D, the location in question is a location on the east side of the twilight line, and the area east of the twilight line is 30 degrees east longitude.

The above answer is correct, the key to solving the time calculation problem is to understand these meanings: the intersection of the morning and dusk line and the equator are 6 o'clock and 18 o'clock respectively, and the morning and dusk line should be judged according to the direction of rotation of the earth and the distribution of the day and night hemisphere "You can also use your hand to judge the east-west meridian, south, left, north and right", followed by knowing how to convert longitude and time fluently "15 degrees is equal to one hour, one degree is equal to four minutes". Let me add the conditions to solve the first question: point A is the tangent point of the circle of morning and dusk and the parallel, so the time of point A is 0 or 12 o'clock, and assuming that the two points are on the equator, "the two points are the midpoint of the meridian where they are located", so there are two answers: 1, a is 0, and b is 18 points.

6 o'clock in C, 12 o'clock in 2, 12 o'clock in A, 6 o'clock in B.

It is 18 o'clock in place c.

Do you want both? The conditions in the picture above are not sufficient.

The picture below.

Point A and Point C.

It is 6 o'clock in local time and 8 o'clock in local time at point B.

Key to the problem: The direction of the arrow is clockwise.

Southern Hemisphere; The shaded part is indicated.

Night hemisphere, combined.

The rotation of the Earth. The direction is the arrow in the figure, judging the point A.

On the morning line, it is 6 o'clock at the intersection of the morning line and the equator, and at 18 o'clock at the intersection of the dusk line and the equator, so it is 6 o'clock at point A; Due to the same.

If the meridian is the same, and both point A and point C are on the same meridian, then point C is also 6 o'clock; Since point B is located on the 0° meridian, the diagram is 30 degrees away from the meridian where point A is located (1 hour is equal to 15°), and point B is located on the east side of point A, so the local time of point B is 8 o'clock.

The conditions for the first question are insufficient.

However, there are only two situations: 1, the morning and dusk line cab is the day hemisphere, the outside is the night hemisphere (BC should be on the equator, otherwise BC can not be counted when the place), the polar night occurs at 70°N, and the sun shines directly at 20°s

At this time, the meridian where place A is located exactly equinoxes the day hemisphere, so the local time is 12 o'clock, then c is the equatorial sunrise time at 6 o'clock, and b is the equatorial sunset time at 18 o'clock (following the direction of the earth's rotation, crossing the morning and dusk line into the day hemisphere is the morning line, and vice versa).

2. The morning and dusk line cab is the night hemisphere, and the outside is the day hemisphere (BC should still be on the equator, otherwise the BC place cannot be counted), the polar day occurs at 70 °N, and the sun shines directly at 20 °N

At this time, the meridian where place A is located exactly equinoxes the night hemisphere, so the local time is 0 o'clock, then c is the equatorial sunset time at 18 o'clock, and b is the equatorial sunrise time at 6 o'clock.

The second question is easy:

The time of a is 6 o'clock: from the map, we can see that a is on the equator, and from the direction of the earth's rotation, we can find that the morning and dusk line where a is located is the morning line, that is, a is just at sunrise tomorrow. The sun rises at 6 o'clock all year round on the equator, so it is 6 o'clock at the place of a.

BC is 8 o'clock at all times, because BC is on the same meridian and the same meridian is the same. From the diagram, we can see that the meridian where BC is located is 30° different from the meridian of A, and the time difference is 2 hours, and the meridian where BC and BC are located is east of the meridian where A is located, so the time difference should be added, so adding 2 hours on the basis of 6 o'clock is 8 o'clock.

1, A: There are two date lines, namely the zero meridian and the 180 degrees meridian, the North Pole is the center, the earth rotates counterclockwise, and the degree gradually increases to east longitude along the direction of the earth's rotation, so 60 degrees in the figure is east longitude, that is, the meridian where the zero point is located is 60 degrees east longitude. On March 21, the global equinox of day and night, that is, the sunrise at 6 o'clock, the morning line coincides with the meridian; 60 degrees east longitude is the zero point, and the difference from six o'clock is 6 hours, the difference is 90 degrees, that is, 60 degrees east longitude and then 90 degrees east, that is, the morning line is 150 degrees east longitude.

B: Rotate clockwise, the center is the South Pole, and the morning line is from night to day, that is, the arc CA.

C: South of 0 degrees is the southern hemisphere, rotating clockwise, from night to day as the morning line, that is, the arc ao.

D: In the Northern Hemisphere, it rotates counterclockwise, and the morning line is from night to day, that is, the arc AB.

2, A, the day of the vernal equinox, the global equinox. B, Polar day occurs within the Antarctic Circle, and day is less than night in the Northern Hemisphere. C, the polar night of the Antarctic Circle, the winter solstice, the longest day in the Northern Hemisphere. D, there is a polar day in the North Pole, so the day is greater than the night. Therefore, C and D are selected for this question.

3. A: Beijing is at 120 degrees east longitude, and it can be seen from the first question that 60 degrees east longitude is zero, and the difference is 60 degrees, that is, the difference is 4 hours, so the local time in Beijing is 4 hours. 60 degrees is the zero time meridian, and it is a new day when it crosses it, so it is 4 o'clock on March 22 in Beijing in Figure A.

C: It is the winter solstice, that is, December 22. Most of the meridian at 75 degrees east longitude is daylight, and the day is equally divided, so it is the meridian at 12 o'clock.

The difference between 75 degrees east longitude and 120 degrees east longitude is 45 degrees, that is, the difference is 3 hours, so 120 degrees is 15 hours. Therefore, Figure C shows Beijing at 15 o'clock on December 22.

1. A: The morning line is 120 degrees east longitude (792970666 speak very well).

B: arc ac (seen by the arrow, it is the southern hemisphere, because the earth turns from west to east, and the area passing through the arc ac becomes daylight).

C: Arc ao (from 0 degrees and 75 degrees east longitude in the figure, it is the eastern hemisphere, because the earth turns from west to east, and the area passing through the arc ao becomes daylight).

D: Arc ab (because the hint is said to be a certain region of the northern hemisphere, as can be seen from the map, the further north the day, the longer the day, because the earth turns from west to east, so the area that passes through the arc ab becomes daylight).

2. C and D (use the elimination method. Because of the vernal equinox on March 21, the global equinox of day and night, excluded; B is the southern hemisphere, showing that the days are long and the nights are short, so the northern hemisphere has short days and long nights, which is excluded. As for C and D, both show that the days are longer the further north, so it is determined that the days are longer and the nights are shorter in the Northern Hemisphere).

3. Figure A: The 60 degrees is 60 degrees east longitude, so Beijing time is 4 o'clock on March 22.

There are two date lines, 180 degrees meridian and zero meridian, because it is 60 degrees, so it can only be zero meridian, that is, 60 degrees east longitude is 0 hours, Beijing is 110 degrees east longitude, in the east eighth district, 60 degrees east longitude is in the east fourth district, a difference of one hour in the east zone, the east time is early, so Beijing is 4 o'clock, because it passes through the zero point date line, so it is 4 o'clock on March 22).

It seems that it can only be 60 degrees east longitude, and there is no way to calculate west longitude.

C: Beijing time at 15 o'clock on December 22 (because 75 degrees east longitude is equinoxical day, so 75 degrees east longitude is 12 noon, 75 degrees east longitude is the fifth east zone, Beijing's east eight districts are three time zones, that is, three hours, and the east time is early, so Beijing time is 15 o'clock; Figure C is the winter solstice, so it is December 22).

1.A is located in the northern hemisphere, and in the top view, it rotates counterclockwise, then 60 degrees coincides with the zero time meridian, if it is 60 east longitude, the morning line is 150 east longitude, if it is 60 west longitude, the morning line is 30 east longitude B shows the CA segment.

1. The line that goes from the shadow to the white part is the morning line [just like night walking to day].

From the white part to the shadow is the dusk line [like day to night].

2. Judge the length of day and night The spring equinox and autumn equinox are as long as day and night In summer, the days are longer than the night, and there will be polar days in the Arctic Circle.

120 degrees west longitude.

In the picture of Beijing A, it is 4 o'clock on March 22, and I can't see what is in the picture B!

Is it the original question? Feeling that the information is incomplete.

The fastest rotation of the Earth occurs at the beginning of January, when the Earth rotates at a faster rate, indicating that the direct point of the Sun is in the Southern Hemisphere. AB is part of the morning and dusk line, then the southeast part of the AB line (lower right) is daytime, the AB line is the morning line, and it is 6 o'clock at 20°W; A is the highest point of latitude on the morning and dusk line, and the latitude is 70°N (the angle shown in the figure), so the meridian passing through point A is the direct meridian of the sun, and the local time is 12 o'clock.

1. At this time, the geographical coordinates of the direct sun point are (20°S, 70°E), and the Beijing time is (15:20).

Analysis: Because a is the highest point of latitude on the morning and dusk line, there is a polar night north of 70°N, when the sun shines directly for 20°s, and the latitudes of the two places are more than each other. It is 6 o'clock at 20°W and 12 o'clock when the sun shines directly at the meridian.

The difference between the two places is 6 hours and a total of 90°, so the direct meridian of the sun is at 20°W and the difference is 90° east, which is 70°E.

70°E local time is 12 o'clock, Beijing time is 120°E local time, the difference between the two longitude is 50°, local time difference is 3 hours and 20 minutes, so Beijing time is 12:00 + 3h20m = 15:20

2. The length of day at point C on this day is (6) hours, and the range of polar day is (70°S-90°S) at 70°S and the area south of it

a c d is the same longitude at three o'clock, so the longitude difference is 90° 2 = 45°, and the time difference is 3 hours.

The sunrise time at point C is 6:00 + 3 = 9:00, and the day length = (12:00-9:00) 2 = 6 hours.

The sun shines directly at 20°s, so the area south of 70°S is a polar daylight phenomenon.

3. The length of day and night in Beijing is (short days and long nights), and the shadow of the object faces (northwest) at sunrise

The direct point of the sun is in the southern hemisphere, and the northern hemisphere is the winter half year, so the length of days and nights in Beijing is short days and long nights; The sun rises in the southeast, so the shadow of the object faces northwest.