How to read high altitude analysis

In order to fully understand and master the changing law of weather,

In addition to analyzing the ground weather map,

Also analyze the high-altitude weather map.

at present

The high-altitude weather map widely used in practical work is an isobar map filled with meteorological records on the same isobar surface. ?

First, the concept of isobaric surface diagram?

A plane composed of points with equal air pressure in space is called.

This is an isobaric surface. Because the surrounding air is at the same height

The pressures cannot all be equal, so the isobaric surfaces are different.

A horizontal plane, but undulating like a terrain.

An uneven surface. Used to represent the fluctuation of space isobaric surface.

The situation map is called isobaric surface situation map, or "isobaric surface situation map" for short.

Pressure surface map.

Contour lines can be drawn when the isobaric surface fluctuates.

Is represented by the method of. Specifically, all localities will

Fill in the figure with the height value of the isobaric surface above.

Then connect the points with the same height to draw contour lines, and we can see the fluctuation of isobaric surface from the distribution of contour lines.

draw

2. 10

As shown in the figure,

P

Is an isobaric surface,

H

1

H

2

,? ,

H

five

It is several horizontal planes with equal thickness interval, which are equal to each other and equal to each other.

The press surface is sectioned (the sectioning line is indicated by a dotted line),

Because each section line is on the isobaric surface.

P

Go ahead,

Therefore, the air pressure at all points on all sections is equal.

what

P

By projecting these sections onto the horizontal plane, you can get

P

The distances from the sea level on the isobaric surface are respectively

H

1

H

2

,? ,

H

five

Dexu

Multi-contour lines, the distribution of which is shown in the figure.

2. 10

Is shown in the lower part of.

As can be seen from the figure, it is similar to the convex part of the isobaric surface.

A high value corresponding to a set of closed contours.

Area, corresponding to the concave parts of the isobaric surface is a group.

Low-value area formed by closed contour line and isobar surface slope.

In steep places, the corresponding contour lines are dense.

The purpose of analyzing isobaric surface diagram is to understand the spatial distribution of pressure field.

Actually,

The fluctuation of isobaric surface reflects isobaric.

Distribution of pressure field near surface water (contour plane). For example, in the figure

2. 1 1

Yes,

P

Perpendicular to the isobaric surface.

Introduction,

H

for

P

Contours near the isobaric surface,

A

、

B

、

C

at all points

P

On the isobaric surface,

C' yes

A

、

C

At two o'clock.

isosurface

H

The projection point is open. Because the air pressure decreases with height,

therefore

P

one

& gtP

A

P

' c '

& ltP

C

And because

P

A

=P

B

=P

C

, because

this

P

one

& gtP

B

& gtP

' c '

(

P

A

、

P

B

、

P

C

、

P

one

、

P

' c '

Respectively, the air pressure values of each point). So the air pressure ratio at the same height is four.

Where the circumference is high, the height of the isobaric surface is also higher than its surroundings, which shows upward bulge; The air pressure at the same height is lower than the surrounding air pressure,

The height of the isobaric surface is also lower than its surroundings, showing a downward depression.

Therefore,

Through the distribution of contour lines on the isobaric surface,

Just do it.

Know the spatial pressure field distribution near the isobaric surface.

The high value center of the contour line on the isobar corresponds to the nearby isobar.

High pressure center of pipeline,

The low-value center corresponds to the low-pressure center of the isobar on the nearby isobar plane,

Contour lines on isobaric surface

The strike is basically the same as that of the isobar on the nearby isobath plane.

Therefore,

Usually people will draw contour lines on isobaric surface maps.

The high value area is called high pressure, and the low value area of contour line is called low pressure.

Since the pressure distribution on the isobar plane is equivalent to the height distribution on the isobar surface,

Why not be like a map,

Use each

How does the pressure distribution map of contour plane reflect the spatial pressure field? This is because,

In weather analysis,

Use isobaric surface ratio

The contour map is better.

The following is the isobar diagram of our daily analysis:

850 hectopascals

Isobaric surface diagram, its potential height is usually

1500

Potential meters or so;

700 hectopascals

Isobaric surface diagram, its potential height is usually

3000

Potential meters or so;

500 hectopascals

Isobaric surface diagram, its potential height is usually

5500

Potential meters or so;

300 hectopascals

Isobaric surface diagram, its potential height is usually

9000

Potential meters or so;

200 hectopascals

Isobaric surface diagram, its potential height is usually

12000

Potential meters or so;

100 hectopascals

Isobaric surface diagram, its potential height is usually

16000

The potential is about meters.

Second, the drawing format of isobaric surface map?

The drawing format of isobaric surface diagram is shown in the following figure.

2. 12

As shown in the figure. The symbols in the figure have the following meanings:

telegraphic transfer

—— Temperature on isobaric surface, in℃. ?

Direct injury

—— The difference between the temperature and dew point on the isobaric surface, in℃. DD≥0 .？

Deadline Date (abbreviation for deadline date)

fire fighting

—Wind direction and wind speed, which have the same meaning as the ground weather map. ?

HHH

—Height of isobaric surface.

This height is not a geometric height,

But the height of potential,

Its unit is potentiometer or potentiometer.

Potential height (

H

) and geometric height (

Z

The relationship between) is as follows:

formula

g

It's the acceleration of gravity.

take for example

,

draw

2. 13

Said the station measured isobaric surface height is

5640

Gravity potential meter

,

The temperature of isobaric surface is below zero.

5℃,

Temperature dew point difference is

7℃, south wind, wind speed

26 m/s

Third, the analysis project of isobaric surface diagram?

1.

Profile analysis?

1)

The outline is drawn with a black pencil and a smooth solid line?

According to the regulations of our country, the contour lines on each isobar surface are spaced from each other.

40

Potentiometer analysis, each line should be marked with potential.

Thousands, hundreds, tens of meters, and stipulates:

exist

850 hectopascals

What is the analytical value on the graph? 144,

148

, 152? The outline of; ?

exist

700 hectopascals

What is the analytical value on the graph? 296,

300

,304? The outline of; ?

exist

500 hectopascals

What is the analytical value on the graph? 496,

500

,504? The outline of. ?

2)

The centers of high-value area (high-pressure area) and low-value area (low-pressure area) of contour lines on each isobaric surface are marked with blue "G".

Mark the word "d" in red. In the isobaric maps analyzed by Japan, the United States, Britain and other countries, the contour interval is every other interval.

60

There is a potentiometer analysis, and the centers of high and low values are marked with "H" and "L" respectively. ?

3)

The relationship between the wind and the contour on the isobaric surface is as follows.

(1) The contour line is parallel to the wind direction. In the northern hemisphere, it stands in the leeward, with a high-value area on the right and a low-value area on the left; In the southern hemisphere,

On the leeward side, the high value area is on the left and the low value area is on the right. ?

② The density of contour lines (that is, the slope of isobaric surface) is directly proportional to the wind speed, that is, the wind speed is high where contour lines are dense; On the contrary,

The wind speed is small. ?

2.

Isothermal analysis

1

) Isotherms are drawn with red pencils and solid lines on color weather maps, and with thin black lines on monochrome weather maps. I

Yi Guo

0℃ as a benchmark, every 4℃ analysis of an isotherm, such as

-

4℃, 0℃, 4℃, 8℃, etc. Both ends of the isotherm should be marked.

Pay attention to the temperature value. The warm center of the temperature field is marked with red "N" and the cold center with blue "L".

2

) The isotherm interval on foreign high-altitude maps is 6℃ or.

At 3℃,

Warm center mark

" W "

Cold center label

" C "

three

) drawing isotherm, in addition to the main basis of isobaric surface temperature.

In addition to the degree record, we should also refer to the contour line for analysis.

ordinary

700 hectopascals

or

500 hectopascals

Above the isobaric surface, the high temperature zone is often

The area with higher isobaric surface height;

On the contrary, the low temperature zone is often equal.

The area with lower pressure surface height.

Therefore,

Usually near the ridge of high pressure

There is a warm ridge with a temperature field,

And there is often temperature near the low pressure trough.

There is a cold slot in the degree field, figure.

2. 14

Represents common temperature and pressure.

Configuration of the field. ?

3.

Slot line and shear line analysis?

The groove line is the contour line with the largest curvature in the low pressure groove.

The connection of this place,

Is the characteristic line in the pressure field.

(as shown in the figure.

2. 15

(

a

))。 The shear line is the wind

Discontinuous lines,

The wind on both sides of the wind direction or shear line.

The velocity has strong cyclonic shear,

This is a wind field.

On the characteristic line (as shown in figure)

2. 15(b)

)。 two

What everyone has in common is the strong wind.

Rotational shear

It is customary to cut a whirlwind along the wind direction.

The narrowing between the two high voltages becomes particularly obvious.

The shear line is analyzed in long and low pressure areas and very sharp and narrow grooves.

The tank is analyzed in a low-pressure tank with obvious pressure gradient.

Line.

On the color weather map,

Groove lines and shear lines are drawn with a brown pencil and solid lines.

On a monochrome weather map,

Slot line and shear line

Draw with a thick black solid line. ?

four

Temperature advection analysis

The cold and warm phenomena in some areas caused by the horizontal movement of cold and warm air,

Called advection change of temperature,

Called temperature level

Flow. ?

Master the method of judging temperature advection,

Not only can it be used to directly judge the temperature change,

But may also be further dependent on temperature.

To infer the change of pressure field.

Because the distribution of contour lines on the isobaric surface determines the flow direction and speed of air,

Therefore,

According to the matching of contour lines and isotherms

The nature and intensity of temperature advection can be judged by setting the situation. ?

1

) the judgment of temperature advection property?

draw

2. 16

As shown in (a), the contour line intersects with the isotherm, and the airflow blows from the low temperature area (cold area) to the high temperature area.

(warm zone) Obviously, in this case, the temperature will drop where the air passes, that is, there will be cold advection. draw

2. 16

(2)

On the contrary, the airflow blows from the high temperature area (warm area) to the low temperature area (cold area), so there is warm advection. draw

2. 16

(3)

Yes,

On the left is cold advection,

On the right is a warm advection,

A dividing line can be drawn between cold advection and warm advection.

(indicated by double dashed lines)

The contour line near this line is parallel to the isotherm.

,

Without cold advection,

Without warm advection,

That is, the temperature advection is zero.

,

So this line is called ping.

Flow the zero line.

2

) the judgment of temperature advection intensity?

Temperature advection intensity means that in unit time,

Temperature variation caused by temperature advection.

Can be obtained from the following three

Qualitative judgment in three aspects:?

(1) Density of contour lines. Other things being equal, the denser the contour lines, that is, the greater the wind speed, the greater the advection intensity.

② Density of isotherm. Other things being equal,

The denser the isotherm,

It shows that the greater the temperature gradient, the stronger the advection intensity.

The bigger it is. ?

(3) The size of the included angle between the contour line and the isotherm. Other things being equal, the closer the intersection angle between contour line and isotherm is.

Then 90.

The greater the advection intensity. ?

Ps (transferred from Baidu Library)