The technical method of tropical cyclone intensity analysis using geostationary meteorological satellite data
Some standard content:
ICS07.060
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Meteorological Industry Standard of the People's Republic of China
QX/T519—2019
The technical method of tropical cyclone intensity analysis using geostationarymeteorological satellitedata2019-12-26Release
China Meteorological Administration
2020-04-01Implementation
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Terms and definitions
Data source requirements
Tropical cyclone cloud type classification
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Technical method for determining the intensity of tropical cyclones using visible light imagesEnhanced infrared imageryTechnical method for determining the intensity of tropical cyclones 6
Current intensity index and tropical cyclone grade Appendix A (Informative Appendix)
Appendix B (Informative Appendix)
Appendix C (Informative Appendix)
Appendix D (Informative Appendix)||t t||Appendix E (Normative Appendix)
Appendix F (Normative Appendix)
References
FY-2D/E/F/G/H geostationary meteorological satellite VISSR channel parametersFY-4A geostationary meteorological satellite AGRI channel parametersMTSAT-2 geostationary meteorological satellite JAMI channel parametersHimawari geostationary meteorological satellite AHI channel parameters10° logarithmic spiral plate
Infrared band grayscale enhancement display range and terminologyQX/T519—2019
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This standard is drafted in accordance with the rules given in GB/T1.1—2009. QX/T519—2019
This standard is proposed and managed by the National Technical Committee for Satellite Meteorology and Space Weather Standardization (SAC/TC347). Drafting units of this standard: National Satellite Meteorological Center, National Meteorological Center. The main drafters of this standard are: Wang Xin, Fang Xiang, Xu Yinglong, Xiang Chunyi, Liao Mi, Cao Zhiqiang. m
QX/T519—2019
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Tropical cyclones are one of the important disastrous weather systems that affect my country. Meteorological satellites are the main means of monitoring tropical cyclones on tropical oceans where conventional observation data are scarce. The Dvorak satellite intensity determination technology currently used by major tropical cyclone business centers around the world is to link the visible light or infrared cloud characteristics and specific parameters of meteorological satellites with the intensity of tropical cyclones. Through a series of empirical rules and constraints, the tropical cyclone intensity index is estimated as the basis for determining the intensity of tropical cyclones at sea in operations. This standard is formulated based on the internationally used Dvorak satellite intensity determination technology, aiming to standardize the methods and processes for estimating the intensity of tropical cyclones by geostationary meteorological satellites, and to improve the scientificity, objectivity and operability of tropical cyclone intensity determination analysis in my country. IV
1 Scope
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Technical methods for tropical cyclone intensity determination by geostationary meteorological satellites This standard specifies the methods and processes for tropical cyclone intensity determination using geostationary meteorological satellites. This standard is applicable to tropical cyclone intensity determination operations and scientific research. 2 Terms and definitions
The following terms and definitions apply to this document. 2.1
Tropical cyclone cloud system center tropicalcyclonecloud systemcenter;CsC describes the circulation center of a tropical cyclone cloud system or vortex 2.2
Tropical cyclone dataT indexdataTnumber;DTQX/T519—2019
An index that describes the intensity of a tropical cyclone based on the estimated values obtained by measuring cloud characteristics according to the cloud type classification in Chapter 4. Note: Its value is between 1.0 and 8.0.
eye index eyenumber; E-no
An index describing the intensity of an eye-type tropical cyclone (see Chapter 4 c)) by measuring the distance at which the eye of the typhoon is embedded in the tropical cyclone cloud system and the estimated value of the surrounding temperature.
Note: Its value is between 3.0 and 7.5
eyeadjustment number; E-adj
eye adjustment index
An index describing the clarity, size, structure and other characteristics of the eye of an eye-type tropical cyclone, which is calculated by adding or subtracting on the basis of E-no. Note: Its value is between -1.0 and 1.0. 2.5
Central feature index
centralfeaturenumber;CF
The result obtained by adding E-no and E-adj is used to describe the strength of the eye structure of the eye-type tropical cyclone, or the index of the intensity of the central dense cloud area type tropical cyclone according to the clarity and size of the dense cloud area near the CSC. Note: Its value is between 2.0 and 7.5,
banding feature number;BF
Cloud band feature index
The index of the intensity of the tropical cyclone's peripheral cloud system is described by the characteristics of the width and helicity of the cloud band surrounding the center of the tropical cyclone cloud system. Note: Its value is between 0 and 2.0
Tropical cyclone model expected T index
modelexpectedTnumber;MET
The development trend of the tropical cyclone is determined by comparing the changes in the characteristics of the tropical cyclone center and the changing characteristics of the dense cloud area or cloud band surrounding the center on the satellite cloud map at that time and 24 hours ago. The final T index 24 hours ago is added with the 24-hour change trend, and is divided into rapid strengthening or weakening (D+/W+), normal development or weakening (D/W) and slow development or weakening (D-/W-) to estimate the current tropical cyclone intensity index.
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Note: Its value is between 1.0 and 8.0.
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patternTnumber;PT
Cloud type T index
An index describing the intensity of tropical cyclones. According to the cloud type classification in Chapter 4 and the lookup table (see Table 9 and Table 16), select the image with the highest degree of consistency with the tropical cyclone cloud type at that time in the adjacent left (right) column of the current MET corresponding index. The corresponding index in the lookup table is the estimated result.
Note: Its value is between 1.0 and 7.0
Final T indexfinalTnumber;FT
An index describing the intensity of tropical cyclones that is finally determined by selecting between DT, MET and PT according to the clarity of cloud system features and following certain constraints.
Note: Its value is between 1.0 and 8.0.
Current intensity index current intensity number; CI is an index that describes the intensity of tropical cyclones based on the determination of FT, using the increase or decrease calculation according to the life history stage of the tropical cyclone or the estimated value obtained by taking the same value as FT. It is the final product of the Dvorak technique for tropical cyclone intensity determination. Note: Its value is between 1.0 and 8.0.
Grade of tropical cyclone The grade of tropical cyclone intensity in my country's forecast responsibility area Note: It is divided into six grades: tropical depression, tropical storm, severe tropical storm, typhoon, severe typhoon, super typhoon, 3 Data source requirements
Should come from geostationary meteorological satellites equipped with visible-infrared scanning radiometers, such as my country's first-generation Fengyun-2 meteorological satellite (FY2), the second-generation Fengyun-4 meteorological satellite (FY-4), Japan's first-generation multi-functional meteorological observation and flight control satellite (MTSAT-2) and the second-generation Himawari satellite. The instruments carried by these satellites are the FY-2 satellite visible light and infrared spin scanning radiometer (FY-2/VISSR), the FY-4A satellite multi-channel scanning imaging radiometer (FY-4A/AGRI), the Japanese MTSAT-2 satellite satellite imager (MTSAT-2/JAMI), and the Japanese Himawari satellite imager (Himawari/AHI) (see Appendix A to Appendix D for channel parameters). The data of each satellite should be accurately positioned, calibrated, projected, and other pre-processed to form visible light reflectance and infrared brightness temperature data. Usually, the central wavelength of 0.The tropical cyclone intensity is analyzed by using the reflectance data of the visible light channel at 6μm, the brightness temperature data of the infrared window channel at a central wavelength of 11μm, and the enhancement method of the infrared band grayscale enhancement curve (BD). 4 Classification of tropical cyclone cloud types
The classification of tropical cyclone cloud types is based on three considerations: first, according to the different geometric and radiation characteristics of tropical cyclone cloud systems on satellite cloud images; second, according to the different development stages of tropical cyclones; third, according to the applicable scope of cloud types on each channel cloud image. Tropical cyclone cloud types are divided into the following six categories:
a) Curved band pattern (CBpattern). It is an organized curved band cloud type formed by broken clouds or convective clouds. It usually appears when the tropical cyclone is in the tropical depression to typhoon level stage. b) Shear pattern (Spattern). It is characterized by the partial exposure of the low-level cloud line and the separation from the high-level convective clouds. There is a steep boundary on one side of the low brightness temperature zone surrounding the center of the tropical cyclone, and a cirrus anvil on the other side. Usually appears when a tropical cyclone is at the stage of tropical depression to severe tropical storm.
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QX/T519-2019
Eye pattern (Epattern). It is manifested as a closed ring of white convective clouds surrounding the CSC, with a clear sky or c
eye area inside the ring. The brightness temperature of the closed ring cloud area is lower than that of the eye area inside the ring. Usually appears when a tropical cyclone is at the stage of typhoon to super typhoon.
Central dense overcast pattern (CDOpattern). Only used for visible light cloud image analysis, it is manifested as a large range of dense white bright cloud system, with no obvious steep boundaries around, and the CSC is completely covered by dense cloud system. Usually appears when a tropical cyclone is at the stage of tropical storm to typhoon. e)
Embedded center pattern (ECpattern). Only used for enhanced infrared cloud image analysis, it is manifested as CSC completely falling into the central dense cloud area (CDO), surrounded by relatively low brightness temperature cloud areas on the periphery of the center. It usually appears when the intensity of the tropical cyclone is at the level of strong tropical storm or above. f
Central cold cover pattern (CCC pattern). It is manifested as isolated white bright strong convective cloud clusters with clear edges, and the area with brightness temperature less than 203K is greater than 60% and unevenly distributed, without obvious outer spiral cloud bands. It usually appears in the transition stage of tropical cyclone cloud type to CDO pattern or EC pattern, and the tropical cyclone is at the level of tropical storm to strong tropical storm.
5 Technical method for determining the intensity of tropical cyclones using visible light images 5.1 Technical flow chart for determining the intensity of tropical cyclones using visible light images. The technical process is shown in Figure 1. This standard only specifies steps 2 to 9 in this technical process.
QX/T519—2019
Use the following
cloud type for analysis as much as possible. bzxZ.net
Then go to step 3
Bending cloud band type
Use 10° logarithmic frequency
plate, and analyze the winding reduction degree with 0, 1 ring as the unit
Shear type
Measure the distance between CSC and CDO boundary
(unit is
nmile)
Central dense cloud area type
Diameter (latitude and longitude) )
Central cold cloud cover type
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Set the cloud center at the convergence point of the reference cloud line or cloud band. For the initial development of disturbances, set FT to 1.0. When the line type does not match the type of 2A to 2D, proceed to steps 3, 4, 5, and 6. If necessary, return to step 2 based on the hot prompt
[0.2,0.35][0.4, 0.55][0.6,0.75][0.8,.1.0][1.05,1.3][1.35.1.70]
For very wide or long test curves, 2C eye pattern should be used for analysis.
DT1. 5±0. 5
In the past 24 hours, was NET larger than 12.0?
Walk 2A or 4
Is the diameter
greater than 0.75*
Walk 2A or 4
Closest distance
Average width
Limited shape characteristics
Eye adjustment index (E-ad)):
Bend E-no≤4.5, E-adj-0.5
Unclear and broken
(Eye diameter is greater than
30nmile or 56|| tt||In the smooth and dense CDO
clear eyes
when E-no25,0;E-adj--1.0
same clear eyes: adjust E so that the estimated eyes: adjust E-no so that all are less than or equal to 6.0, E-adj is determined by the adjustment range of E
the value is all less than or equal to 15.0E-ad
determined according to the adjustment range of Eo
After DT is determined: if OT1 Flow chart of tropical cyclone intensity determination technology using visible light images. The technical process is shown in Figure 1. This standard only specifies steps 2 to 9 in the technical process.
QX/T519—2019
Use the following
cloud types for analysis as much as possible.
Then go to step 3
Bending cloud band type
Use a 10° logarithmic frequency plate and analyze the winding reduction degree with 0 and 1 rings as units
Shear type
Measure the distance between CSC and CDO boundary
(in
nmile)
Central dense cloud area type
Diameter (latitude and longitude) )
Central cold cloud cover type
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Set the cloud center at the convergence point of the reference cloud line or cloud band. For the initial development of disturbances, set FT to 1.0. When the line type does not match the type of 2A to 2D, proceed to steps 3, 4, 5, and 6. If necessary, return to step 2 based on the thermal prompt
[0.2,0.35][0.4, 0.55][0.6,0.75][0.8,.1.0][1.05,1.3][1.35.1.70]
For very wide or long test curves, 2C eye pattern should be used for analysis.
DT1. 5±0. 5
In the past 24 hours, has the NET been large?
equal to 12.0?
Walk 2A or 4
Is the diameter
greater than 0.75*
Walk 2A or 4
Closest distance
Average width
Limited shape characteristics
Eye adjustment index (E-ad)):
Bend E-no≤4.5, E-adj-0.5
Unclear and broken
(Eye diameter is greater than
30nmile or 56|| tt||In the smooth and dense CDO
clear eyes
when E-no25,0;E-adj--1.0
same clear eyes: adjust E so that the estimated eyes: adjust E-no so that all are less than or equal to 6.0, E-adj is determined by the adjustment range of E
the value is all less than or equal to 15.0E-ad
determined according to the adjustment range of Eo
After DT is determined: if OT1 Flow chart of tropical cyclone intensity determination technology using visible light images. The technical process is shown in Figure 1. This standard only specifies steps 2 to 9 in the technical process.
QX/T519—2019
Use the following
cloud types for analysis as much as possible.
Then go to step 3
Bending cloud band type
Use a 10° logarithmic frequency plate and analyze the winding reduction degree with 0 and 1 rings as units
Shear type
Measure the distance between CSC and CDO boundary
(in
nmile)
Central dense cloud area type
Diameter (latitude and longitude) )
Central cold cloud cover type
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Set the cloud center at the convergence point of the reference cloud line or cloud band. For the initial development of disturbances, set FT to 1.0. When the line type does not match the type of 2A to 2D, proceed to steps 3, 4, 5, and 6. If necessary, return to step 2 based on the thermal prompt
[0.2,0.35][0.4, 0.55][0.6,0.75][0.8,.1.0][1.05,1.3][1.35.1.70]
For very wide or long test curves, 2C eye pattern should be used for analysis.
DT1. 5±0. 5
In the past 24 hours, has the NET been large?
equal to 12.0?
Walk 2A or 4
Is the diameter
greater than 0.75*
Walk 2A or 4
Closest distance
Average width
Limited shape characteristics
Eye adjustment index (E-ad)):
Bend E-no≤4.5, E-adj-0.5
Unclear and broken
(Eye diameter is greater than
30nmile or 56|| tt||In the smooth and dense CDO
clear eyes
when E-no25,0;E-adj--1.0
same clear eyes: adjust E so that the estimated eyes: adjust E-no so that all are less than or equal to 6.0, E-adj is determined by the adjustment range of E
the value is all less than or equal to 15.0E-ad
determined according to the adjustment range of Eo
After DT is determined: if OT2.25(1.75.2.25)1.75
(1.25.1.75)
Determination rules:
(1) When the past T≤3.0, follow the pattern trend for 12 hours and remain unchanged after heat: (2) When the past T≥3.5, keep T unchanged: (3) Use it as the lowest T index, and then transfer it to step 9. Follow the changes in the central closed public area of CS when the dense acid and sugar condition is type 2 to determine the development of the system and measure the results! 5
Determine the model expectation index (MET)
Determine the cloud type index (PT)
or the two adjacent columns on the left and right match the cloud of the current tropical cyclone (2)
(1) If the cloud type continues
pattern:
and the (left) column adjacent to the corresponding column of the energy T matches: then add (minus) 0.5 to the energy T as the current PT with cyclone
Final T index (FT) selection principle
The DT analyzed in step 2 is used as FT,
(2) When the cloud type characteristics are not necessary,
7 is adjusted in the list period,
PT
( 3) In other cases, use
final T index (FT) constraint original
MtEu on e
1.0 or 1.5
(2) Within the first 48 hours of the system development, the night cannot reduce FT: (3) Within 24 hours after the first analysis FT is 1.0, FT must be ≤2.50.75
plus 5 coupons 1
original m is E7.0
irregular
>1.5[1.1.5]
1.25(0.75,1.25)0.75
CF2.0CF3.a
Does the eye index need to be adjusted?
E-no+Eadj=CF
After CF is determined
CF+BF=DT
Medical belt characteristic index (BF)
Cloud type index (PT) corresponding to different tropical cyclone cloud types on the visible light cloud map 1.5±0.5
Curved cloud band type
Central dense cloud area type
Shear type
When the cloud system at the center is very small (≤2:5"), subtract 1.0 from PT to determine the current intensity index (CI)
(1) When there is no sign of deterioration or redevelopment of the tropical atmosphere, CI-FT: (2) Within 12 hours after the beginning of the deterioration, CI remains unchanged. When continuing (4) When FT<4.0, the 6-hour change cannot exceed 0.5: When FT ≥4.06 hour change does not exceed 1.0, 12 hour change cannot exceed 1.518 hour change cannot exceed 2.0, 24 hour change cannot exceed 2.5: (5) FT must be equal to MT±1.0
, the weakening is small, CI=FT+1.0, the weakening is large CI=FT+0.5
(3) When the FT is re-strengthened and the FT is less than or equal to the CI of the last certain strong time, CI remains unchanged
Figure 1 Flow chart of tropical cyclone intensity determination technology based on visible light images of geostationary meteorological satellites 24-hour forecast
Non-systematic cloud period structure
and environmental conditions show obvious signs of being favorable or unfavorable for its intensity development.
All use C1 index for the past 24 hours
The extrapolated forecast of the intensity
can be made based on the changing trend of the tropical cyclone data
5.2 Tropical cyclone data T index (DT)
5.2.1 Curved cloud band type DT
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Estimate the arc range of the curved cloud band around the CSC and determine the DT in radians. It is divided into two steps: Step 1: Draw the axis of the curved cloud band, and the axis is parallel to the inner boundary of the cloud band. QX/T519—2019
Step 2: Put the 10° logarithmic spiral plate (see Figure E.1 in Appendix E) on the axis of the curved cloud band, and convert the spiral winding radians in units of 0.1 rings into DT by referring to Table 1. Table 1 Curved cloud band type tropical cyclone DT lookup table based on visible light images of geostationary meteorological satellites Number of radians
[0.2.0.35]
5.2.2 Shear-type DT
[0.4.0.55]
[0.6.0.75]
Measure the shortest distance between the boundary of CSC and CDO, and convert it into DT by referring to Table 2. [0.8.1.0]
[1.05.1.3]
Table 2 Shear-type tropical cyclone DT lookup table based on visible light images of geostationary meteorological satellites Shortest distance between CSC and CDO boundary
5.2.3 Eye-type DT
[45.60)
[1.35.1.70]
It should be confirmed that the MET in the 24 hours before the current intensity determination time is greater than or equal to 2.0 (see 5.3 for MET calculation method). DT is obtained in the following five steps:
Step 1: If it is an approximately circular eye area, measure the closest distance from the center of the eye area through CDO to the nearest curved cloud band, shadow or fracture; if it is a strip eye, measure the average width of the eye area cloud band, and convert it to E-no by referring to Table 3. Step 2: Calculate E-adj by referring to Table 4.
Step 3: Calculate the sum of E-no and E-adj. The result is CF. Step 4: Compare the characteristics of the cloud band surrounding CSC in the cloud map with Table 5, and select the one with the greatest similarity as BF. Step 5: Calculate the sum of CF and BF, and the result is DT. 5
QX/T519—2019
Most recent distance
(latitude and longitude)
Average width
(latitude and longitude)
Eye shape characteristics
Unclear or broken eyes
Large eyes (eye diameter greater than
30nmile or 56km)
Located in smooth CDO Clear
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Table 3 E-no lookup table based on visible light images of geostationary meteorological satellites (0.5,
Table 4: E-adi lookup table based on visible light images of geostationary meteorological satellites E-adj
When E-no≤4.5.E-adj=-0.5
Round and clear eyes: adjust E-no so that the value is less than or equal to 6.0, and E-adj is determined according to the adjustment range of E-no
Strip eyes
When E-no≥5.0.Eadj=-1.0
Large and fragmented eyes: adjust E-no so that the value is less than or equal to 5.0, and E-adj is determined according to the adjustment range of E-no When DT is determined, if DT
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