FY2 Product Format Introduction

FY2 PRODUCT FORMAT INTRODUCTION

1 FY2C Normalized Geostationary Projection Dataset File Format

The FY2C Normalized Geostationary Projection Dataset is stored in HDF5 data

format in Normalized Geostationary Projection.

1.1 Introduction of Normalized Geostationary Projection

The normalized geostationary projection describes the view from a virtual

satellite of an idealized earth. Herein, the virtual satellite is in a geostationary orbit,

perfectly located in the equator plane exactly at subsatellite longitude. The distance

between spacecraft and centre of earth is 42164 km. The idealized earth is a perfect

ellipsoid with an equator radius of 6378.137 km and flattening of 1/298.257223563.

The subsatellite longitude of FY2C Normalized Geostationary Projection is

104.5°E.

1.2 About HDF5 file format

HDF5 is a completely new Hierarchical Data Format product consisting of a data

format specification and a supporting library implementation. HDF5 is designed to

address some of the limitations of the older HDF product and to address current and

anticipated requirements of modern systems and applications.

HDF5 files are organized in a hierarchical structure, with two primary structures:

groups and datasets.

HDF5 group: a grouping structure containing instances of zero or more groups or

datasets, together with supporting metadata.

HDF5 dataset: a multidimensional array of data elements, together with

supporting metadata.

Details on HDF5 are at http://www.hdfgroup.org/.

1.3 FY2C dataset struct in HDF5

1.3.1 File information struct

The file information dataset name of HDF5 datase is “/NomFileInfo”.

struct structNOMFileInfo{

char strSatellite[12]; // satellite name : “FY-2C”, “FY-2D” etc.

char strProductID[3]； // product ID: “NOM”

char strProductName[64]； // procut name: “Nomalized Projection Full Disc Image”

float fNOMCenterLat; // idealized subsatellite lantitude: 0.0

float fNOMCenterLon; // idealized subsatellite longitude: 104.5(FY2C)

float fNOMSatHeight; // idealized satellite height: 35785.863km

char strNOMType[12]; // processing mode: “draft” or “fit”

unsigned short iCalTabCreateYear; // year of calibration time (UTC)

unsigned short iCalTabCreateMonth; // month

unsigned short iCalTabCreateDay; // day

unsigned short iCalTabCreateHour; // hour

unsigned short iCalTabCreateMinute; // minute

unsigned short iCalTabCreateSecond; // second

unsigned short iStartYear; // year of time of the first valid scan line (UTC)

unsigned short iStartMonth; // month

unsigned short iStartDay; // day

unsigned short iStartHour; // hour

unsigned short iStartMinute; // minute

unsigned short iStartSecond; // second

unsigned short iEndYear; // year of time of the last valid scan line (UTC)

unsigned short iEndMonth; // month

unsigned short iEndDay; // day

unsigned short iEndHour; // hour

unsigned short iEndMinute; // minute

unsigned short iEndSecond; // second

unsigned short iProcessYear; // year of processing time (UTC)

unsigned short iProcessMonth; // month

unsigned short iProcessDay; // day

unsigned short iProcessHour; // hour

unsigned short iProcessMinute; // minute

unsigned short iProcessSecond; // second

double dEA; // equator radius: 6378137.0 (m)

double dSamplingAngle; // sample angle: 0.00014 (rad)

double dSteppingAngle; // step angle: 0.00014 (rad)

double dObRecFlat; // the reciprocal of earth flattening: 298.257223563

char strComment[128]； // comment

}NOMFileInfo；

1.3.2 Other dataset

The dataset of channel data and angle data has a nadir resolution of 5 km in each

direction.

content dataset name

Calibration table of IR1（1024 float） /CALIR1




Calibration table of VIS（64 float） /CALVIS

IR1 channel data (2288x2288 uint16) /NOMChannelIR1



R4 channel data (2288x2288 uint16) /NOMChannelIR4

VIS channel data (2288x2288 uint8) /NOMChannelVIS

Satellite zenith distance (2288x2288 float) /NOMSatelliteZenith

Sun zenith distance (2288x2288 float) /NOMSunZenith

Sun/satellite azimuth angle (2288x2288 float) /NOMAzimuth

Sun glint angle (2288x2288 float) /NOMSunGlintAngle

Cloud classification result (2288x2288 uint8） /NOMCloudClassification

The defininition of cloud classification result is in the product of Cloud

Classification.

2 Precipitation Estimation Product

2.1 Format

The files are binary, file head and data are included.

The length of the file head is 1001×2×2 characters, consisting of the record of the

first and the second file head, and the idle segment. Table 1 and Table 2 describe the

record format of the first and the second file head individually.

The length of the data is 1001 columns×501 lines×2byte. The value recorded is

rain rate(mm)×10.

Table 1. Record of the first file head

number byte Byte type description

1 1~12 12 A*12 File name

2 13~14 2 I*2 Byte order of integer

3 15~16 2 I*2 The length of the first file head

4 17~18 2 I*2 The length of the second file head

5 19~20 2 I*2 The length of the filled data

6 21~22 2 I*2 The length of the record

7 23~24 2 I*2 Record number of file head

8 25~26 2 I*2 Record number of data

9 27~28 2 I*2 Type of product

10 29~30 2 I*2 Compress method

11 31~38 8 A*2 Strings of format description

12 39~40 2 I*2 Quality flag of the data

Table 2. Record of the second file head

number byte Byte type description

1 41~48 8 A*8 Satellite name

2 49~50 2 I*2 Element of grid field

3 51~52 2 I*2 Bytes of grid data

4 53~54 2 I*2 Standard value of grid data

5 55~56 2 I*2 Scaling factor of grid data

6 57~58 2 I*2 Code of time limit

7 59~60 2 I*2 Starting year

8 61~62 2 I*2 Starting month

9 63~64 2 I*2 Starting day

10 65~66 2 I*2 Starting hour

11 67~68 8 I*2 Starting minute

12 69~70 2 I*2 Ending year

13 71~72 2 I*2 Ending month

14 73~74 2 I*2 Ending day

15 75~76 2 I*2 Ending hour

16 77~78 2 I*2 Ending minute

17 79~80 2 I*2 Latitude of the top left grid corner

18 81~82 2 I*2 Longitude of the top left grid corner

19 83~84 2 I*2 Latitude of the bottom right grid corner

20 85~86 2 I*2 Longitude of the bottom right grid corner

21 87~88 2 I*2 unit of grid resolution

22 89~90 2 I*2 Horizontal grid resolution

23 91~92 2 I*2 vertical grid resolution

24 93~94 2 I*2 Number of Horizontal grid

25 95~96 2 I*2 Number of vertical grid

26 97~98 2 I*2 Land mask

27 99~100 2 I*2 Value of land mask

28 101~102 2 I*2 Cloud mask

29 103~104 2 I*2 Value of cloud mask

30 105~106 2 I*2 Water mask

31 107~108 2 I*2 Value of water mask

32 109~110 2 I*2 Ice mask

33 111~112 2 I*2 Value of ice mask

34 113~114 2 I*2 Quality flag

35 115~116 2 I*2 Maximum of quality flag

36 117~118 2 I*2 Minimum of quality flag

37 119~4004 482 I*2 spare

2.2 Reference C routines

//open file

if( (fp=fopen(filename,”rb”))==NULL) return; //read the file head:

//read the record of the first file head（40 characters）

char filename[12]; fread(filename,1,12,fp); //filename short a[9]; fread(a,2,9,fp);

//parameters char string1[8];fread(string1,1,8,fp); //strings of format description

short b; fread(&b,2,1,fp); //quality flag of the data

// read the record of the second file head（80 characters）

char string2[8];fread(string2,1,8,fp); //name of the satellite

short c[36]; fread(c,2,36,fp); // time, scope etc.

//read idle segment (3884 characters）

char d[3884]; fread(d,1,3884,fp);

//read data (1001 columns×501 lines×2byte)

char data[501][1001];

for(int j=0;j<501;j++) fread(data[j],1,1001,fp);

//real rainrate＝data[j][i]/10.

//close file

fclose(fp);

3 FY-2C Temperature of Brightness Blackbody (TBB) Product

3.1 Format

Data is made of two parts, head record and data record. Head record has two

levels and the first has two parts.

The first level head record (Part one + Part two) The second level head record

Data record … …

Data record

3.1.1 Head Record

Table 1 Part one of the first level head record’s structure sequence byte bytes type Content Value example remark

1 1~12 12 A*12 File name TMGMDDHN.AWX

Fixed Value except

GMDDHN

2 13~14 2 I*2 Order of integer

0 Fixed Value

3 15~16 2 I*2 Length of

head record part one

40 Fixed Value

4 17~18 2 I*2 Length of

head record part two

80 Fixed Value

5 19~20 2 I*2 Length of filling data

1081 Fixed Value

6 21~22 2 I*2 Length of a

record 1201 Fixed Value

7 23~24 2 I*2 Number of head record

2 Fixed Value

8 25~26 2 I*2 Number of data record

1201 Fixed Value

9 27~28 2 I*2 Product type 3 Fixed Value

10 29~30 2 I*2 Zip model 0 Fixed Value

11 31~38 8 A *8

Character String

Illumination of Format

SAT2004 Fixed Value

12 39~40 2 I*2 Quality Mark for Product

2 Fixed Value

Table 2 Part two of the first level head record’s structure

sequence byte bytes type Content Value

example remark

1 41~48 8 A*8 Satellite Name FY2C Fixed Value

2 49~50 2 I*2 Factor of Grid Field 19 Fixed Value

3 51~52 2 I*2 Byte of Grid Data 1 Fixed Value

4 53~54 2 I*2 Reference Mark for

Grid Data 100 Fixed Value

5 55~56 2 I*2 Scale for Grid Data 1 Fixed Value

6 57~58 2 I*2 Code of time frame 1 Fixed Value

7 59~60 2 I*2 Start for Satellite observation: year

2006 Varying Value

8 61~62 2 I*2 month 8 Varying Value

9 63~64 2 I*2 day 15 Varying Value

10 65~66 2 I*2 hour 8 Varying Value

11 67~68 2 I*2 minute 0 Varying Value

12 69~70 2 I*2 End for Satellite observation: year

2006 Varying Value

13 71~72 2 I*2 month 8 Varying Value

14 73~74 2 I*2 day 15 Varying Value

15 75~76 2 I*2 hour 8 Varying Value

16 77~78 2 I*2 minute 25 Varying Value

17 79~80 2 I*2 Upper Left Latitude 6000 Fixed Value 18 81~82 2 I*2 Upper Left 4500 Fixed Value

Longitude

19 83~84 2 I*2 Lower Right

Latitude -6000 Fixed Value

20 85~86 2 I*2 Lower Right Longitude

16500 Fixed Value

21 87~88 2 I*2 Unit of Grid 0 Fixed Value

22 89~90 2 I*2 Space of Lateral

Grid 10 Fixed Value

23 91~92 2 I*2 Space of longitudinal

Grid 10 Fixed Value

24 93~94 2 I*2 Number of Lateral

Grid 1201 Fixed Value

25 95~96 2 I*2 Number of

longitudinal Grid 1201 Fixed Value

26 97~98 2 I*2 If Land Mask exists 0 Fixed Value 27 99~100 2 I*2 Value of Land Mask 0 Fixed Value 28 101~102 2 I*2 If Cloud Mask exists 0 Fixed Value 29 103~104 2 I*2 Value of Cloud Mask 0 Fixed Value

30 105~106 2 I*2 If Water Body Mask

exists 0 Fixed Value

31 107~108 2 I*2 Value of Water Body

Mask 0 Fixed Value

32 109~110 2 I*2 If Ice Mask exists 0 Fixed Value 33 111~112 2 I*2 Value of Ice Mask 0 Fixed Value

34 113~114 2 I*2 If Quality Control is

done 3 Fixed Value

35 115~116 2 I*2 Upper limit of

Quality Control 330 Fixed Value

36 117~118 2 I*2 Lower of Quality

Control 170 Fixed Value

37 119~120 2 I*2 Standby 0 Temporal

Value

38 121~362 242 I*2 Fill Flags 0 Temporal

Value

Table 3 the second level head record’s structure sequence byte bytes type Content Value example remark

FY2C_TBB_I Fixed Value

1 1~64 64 A*64 File Identification By

SAT2004 R1_OTG_200

except observation time

60815_0800. (20060815_0800

AWX )

2 65~72 8 A*8 Format Version AWX2.0 Temporal Value

3 73~80 8 A*8 Producer NSMC CMA Fixed Value

4 81~88 8 A*8 Satellite Flat FY2C Fixed Value

5 89~96 8 A*8 Instrument VISSR Fixed Value

6 97~104 8 A*8 Procedural Version V1.0 Temporal Value

7 105~112 8 A*8 Reserved Temporal Value

8 113~120 8 A*8 Copyright NSMC Fixed Value

9 121~128 8 A*8 Length of extended

filling data 1073 Fixed Value

10 129~120

1 1073 Fill flags 0 Temporal Value

3.1.2 Data Record

Data is saved as two dimensions. The dimension size is 1201*1201. It means that

data has 1201 records, and every record contains 1201 pixels. The first point locates at

the left-up corner, 60ºN & 45ºE. The last pixel locates at the right- down corner, 60ºN

& 165ºE. The data is written from left to right, then from up to down. Each pixel is

one byte.

4 FY2C Total Cloud Amount Product

4.1 Format

Data is made of two parts: head record and data record. Head record has two

records.

The first level head record

The second level head record

Data record

…

…

Data record

4.1.1 The first level head record

Table 1 the first level head record’s structure

Series

Number

Series

number of

byte

Byte

number

type description content

1 1－12 12 Char×12 Sat96 文件名 TCZS0300.AWX

2 13－14 2 Int16 Series number of

integer data

0

3 15－16 2 Int16 Record length of the

first record

40


first record

80

5 19－20 2 Int16 填充段数据长度 881

6 21－22 2 Int16 Record length 1001

7 23－24 2 Int16 Head record number 2

8 25－26 2 Int16 Data record number 1001

9 27－28 2 Int16 Data ID 3

10 29－30 2 Int16 Compress ID 0

11 31－38 8 Char×8 Format describe SAT2004

12 39－40 2 Int16 Quality ID 0

4.1.2 The second level of head record

Table 2 the second level head record’s structure

Series

number

Series number

of byte

Byte

number

Data

type

Description Content

1 41—48 8 Char×8 Satellite name FY2C

2 49—50 2 Int16 Element ID 20

3 51—52 2 Int16 Byte number 1

4 53—54 2 Int16 Basic value 0

5 55—56 2 Int16 Scale factor 100

6 57—58 2 Int16 Time scope ID 0

7 59—60 2 Int16 Start time -year

8 61—62 2 Int16 Start time-month

9 63—64 2 Int16 Start time-day

10 65—66 2 Int16 Start time-hour

11 67—68 2 Int16 Start time-minute

12 69—70 2 Int16 End time-year

13 71—72 2 Int16 End time- month

14 73—74 2 Int16 End time-day

15 75—76 2 Int16 End time-hour

16 77—78 2 Int16 End time- minute

17 79—80 2 Int16 Latitude at the left-up

corner

50

18 81—82 2 Int16 Longitude at the left-up

corner

55

19 83—84 2 Int16 Latitude at the

right-down corner

-50

20 85—86 2 Int16 Longitude at the

right-down corner

155

21 87—88 2 Int16 Grid unit 0

22 89—90 2 Int16 landscape grid 10

23 91—92 2 Int16 Portrait grid 10

24 93—94 2 Int16 landscape grid number 1001

25 95—96 2 Int16 Portrait grid number 1001

26 97—98 2 Int16 Land ID

27 99—100 2 Int16 Land ID value

28 101—102 2 Int16 Cloud ID

29 103—104 2 Int16 Cloud ID value

30 105—106 2 Int16 Water body ID

31 107—108 2 Int16 Water ID value

32 109—110 2 Int16 Ice ID

33 111—112 2 Int16 Ice ID value

34 113—114 2 Int16 Quality ID

35 115—116 2 Int16 The Max. limit of

quality control

1

36 117—118 2 Int16 The Min. limit of

quality control

100

37 119—120 2 Int16 backup

4.1.3 Extended head record

Table3 Extend head record structure

Series

number

Series byte

number

Byte

number


1 1-64 64 Char×8 File name File name

2 65-72 8 Char×8 Version number AWX2.0

3 73-80 8 Char×8 production NSMC.IBM

4 81-88 8 Char×8 Satellite name FY2C

5 89-96 8 Char×8 Instrument name VISSR

6 97-104 8 Char×8 Processing version V1.0

7 105-112 8 Char×8 reserve

8 113-120 8 Char×8 Version right NSMC

9 121-128 8 Char×8

4.1.4 Data record

Data is saved as two dimensions. The dimension size is 1001*1001. It means data

has 1001 records, every record contains 1001 pixels. The first point locates at the

left-up corner. The last pixel locates at the right- down corner. The data is written

from left to right, then from up to down. Each pixel is one byte.

5 FY2C Total Precipitable Water Product

5.1 Format


records.



Data record

…

…

Data record



Series

Number

Series

number of

byte

Byte

number

type describe content

1 1－12 12 Char×12 Sat96 文件名 TZPS0300.AWX


integer data

0


first record

40


first record

80

5 19－20 2 Int16 填充段数据长度 881




9 27－28 2 Int16 Data ID 3






Series

number

Series byte

number

Byte

number

type describe content


2 65-72 8 Char×8 Version mumber AWX2.0







9 121-128 8 Char×8

5.1.3 Data record





1 2 ---------------------------------Æ1001

2

⏐

⏐

⏐

⏐

⏐.

⏐.

⏐.

⏐

⏐.

↓.

1001--------------------------------Æ1001

6 FY2C Surface Solar Irradiance Product

6.1 Format


records.



Data record

…

…

Data record

The files are binary, file head and data are included.

The length of the file head is 1001×2×2 characters, consisting of the record of

the first and the second file head, and the idle segment. Table 1 and Table 2 describe

the record format of the first and the second file head individually.

The length of the data is 1001 columns×501 lines×2byte. The value recorded is

rain rate (mm)×10.

Table 1. Record of the first file head number byte Byte number type description

1 1~12 12 A*12 File name

2 13~14 2 I*2 Byte order of integer

3 15~16 2 I*2 The length of the first file head

4 17~18 2 I*2 The length of the second file head

5 19~20 2 I*2 The length of the filled data

6 21~22 2 I*2 The length of the record

7 23~24 2 I*2 Record number of file head

8 25~26 2 I*2 Record number of data

9 27~28 2 I*2 Type of product

10 29~30 2 I*2 Compress method

11 31~38 8 A*2 Strings of format description

12 39~40 2 I*2 Quality flag of the data

Table 2. Record of the second file head

number byte Byte number type description

1 41~48 8 A*8 Satellite name

2 49~50 2 I*2 Element of grid field

5

10

15

20

25

3 51~52 2 I*2 Bytes of grid data

4 53~54 2 I*2 Standard value of grid data

55~56 2 I*2 Scaling factor of grid data

6 57~58 2 I*2 Code of time limit

7 59~60 2 I*2 Starting year

8 61~62 2 I*2 Starting month

9 63~64 2 I*2 Starting day

65~66 2 I*2 Starting hour

11 67~68 8 I*2 Starting minute

12 69~70 2 I*2 Ending year

13 71~72 2 I*2 Ending month

14 73~74 2 I*2 Ending day

75~76 2 I*2 Ending hour

16 77~78 2 I*2 Ending minute

17 79~80 2 I*2 Latitude of the top left grid corner

18 81~82 2 I*2 Longitude of the top left grid corner

19 83~84 2 I*2 Latitude of the bottom right grid corner

85~86 2 I*2 Longitude of the bottom right grid corner

21 87~88 2 I*2 unit of grid resolution

22 89~90 2 I*2 Horizontal grid resolution

23 91~92 2 I*2 vertical grid resolution

24 93~94 2 I*2 Number of Horizontal grid

95~96 2 I*2 Number of vertical grid

26 97~98 2 I*2 Land mask

27 99~100 2 I*2 Value of land mask

28 101~102 2 I*2 Cloud mask

29 103~104 2 I*2 Value of cloud mask

30 105~106 2 I*2 Water mask

31 107~108 2 I*2 Value of water mask

32 109~110 2 I*2 Ice mask

33 111~112 2 I*2 Value of ice mask

34 113~114 2 I*2 Quality flag

35 115~116 2 I*2 Maximum of quality flag

36 117~118 2 I*2 Minimum of quality flag

37 119~4004 482 I*2 spare

6.2 Reference C Routines

//open file

if( (fp=fopen(filename,”rb”))==NULL) return;

//read the file head:

//read the record of the first file head（40 characters）

char filename[12]; fread(filename,1,12,fp);

//filename

short a[9]; fread(a,2,9,fp);

//parameters

char string1[8];fread(string1,1,8,fp); //strings of format description

short b; fread(&b,2,1,fp);

//quality flag of the data

// read the record of the second file head（80 characters）

char string2[8];fread(string2,1,8,fp);

//name of the satellite

short c[36]; fread(c,2,36,fp);

// time, scope etc.

//read idle segment (3884 characters）

char d[3884]; fread(d,1,3884,fp);

//read data (1001 columns×501 lines×2byte)

char data[501][1001];

for(int j=0;j<501;j++) fread(data[j],1,1001,fp);

//real rainrate＝data[j][i]/10.

//close file

fclose(fp);

7 FY2C Humidity product analysed by cloud information Product

7.1 Format


records.



Data record

…

…

Data record



Series

Number

Series

number of

byte

Byte

number


1 1－12 12 Char×12 Sat96 文件名 TZCS0300.AWX


integer data

0


first record

40


first record

80

5 19－20 2 Int16 填充段数据长度 881




9 27－28 2 Int16 Data ID 3






Series

number

Series byte

number

Byte

number



2 65-72 8 Char×8 Version number AWX2.0







9 121-128 8 Char×8

7.1.3 Data record





1 2 ---------------------------------Æ1001

2

⏐

⏐

⏐

⏐

⏐.

⏐.

⏐.

⏐

⏐.

↓.

1001--------------------------------Æ1001

8 FY2C Cloud Classification Product

8.1 Format


records.



Data record

…

…

Data record


NO. Byte

Sequence

Byte

Number

Type description Remarks

1 1－12 12 Char×12 File Name

2 13－14 2 Int16 Byte Order

=0: Intel ≠ 0: Motorola

3 15－16 2 Int16 First File Header Length

4 17－18 2 Int16 Second File Header Length

5 19－20 2 Int16 Fill Field Length(Bytes)

6 21－22 2 Int16 Record Length（Bytes）

7 23－24 2 Int16 Record Number of File Header

8 25－26 2 Int16 Record Number of Data

9 27－28 2 Int16 Product Type

(=3: Grid Product)

10 29－30 2 Int16 Compress Method

(=0: No Compress)

11 31－38 8 Char×8 Format Description

12 39－40 2 Int16 reservation


NO. Byte

Sequence

Byte

Number

Type Description Remarks

1 41—48 8 Char×8 Satellite Name

5

10

15

20

25

2 49—50 2 Int16 Grid Type

(=21: Cloud Classification)

3 51—52 2 Int16 Byte number

(=1: unsigned char)

4 53—54 2 Int16 No Use

55—56 2 Int16 No Use

6 57—58 2 Int16 Time Scope

(=0: real time)

7 59—60 2 Int16 Year

8 61—62 2 Int16 Month

9 63—64 2 Int16 Day

65—66 2 Int16 Hour

11 67—68 2 Int16 Minute

12 69—70 2 Int16 Reservation



75—76 2 Int16 Reservation


17 79—80 2 Int16 Max Latitude ×100

18 81—82 2 Int16 Min Longitude ×100

19 83—84 2 Int16 Min Latitude ×100

85—86 2 Int16 Max Longitude ×100

21 87—88 2 Int16 Unit

(=0: 0.01 Degree)

22 89—90 2 Int16 Horizontal Grid Size

23 91—92 2 Int16 Vertical Grid Size

24 93—94 2 Int16 Horizontal Grid Number

95—96 2 Int16 Vertical Grid Number













8.1.3 Cloud Type Definition

Value Chinese English

0 晴空海面 Clear Oceans

1 晴空陆地 Clear Lands

11 混合像元 Mixed Pixels

12 高层云或雨层云 Altostratus or nimbostratus

13 卷层云 Cirrostratus

14 密卷云 Cirrus dens

15 积雨云 Cumulonimbus

21 层积云或高积云 Stratocumulus or altocumulus

9 FY2C Snow Fraction Product

9.1 Format

Data is made of two parts, head record and data record. Head record has two levels and the first has two parts.

The first level head record Part one Part two

The second level head record Data record

… …

Data record

9.1.1 Head record

Table 1 Part one of the first level head record’s structure sequence byte bytes type Content Value example remark

1 1~12 12 A*12 File name TSGMYYFR.AWX

Fixed Value except MYY

2 13~14 2 I*2 Order of integer 0 Fixed Value

3 15~16 2 I*2 Length of head record part one

40 Fixed Value

4 17~18 2 I*2 Length of head record part two

80 Fixed Value

5 19~20 2 I*2 Length of filling

data 242

Fixed Value

6 21~22 2 I*2 Length of a

record 362

Fixed Value

7 23~24 2 I*2 Number of head

record 2

Fixed Value

8 25~26 2 I*2 Number of data

record 91

Fixed Value

9 27~28 2 I*2 Product type 3 Fixed Value

10 29~30 2 I*2 Zip model 0 Fixed

Value

11 31~38 8 A *8 Character String Illumination of

Format SAT2004#

Fixed Value

12 39~40 2 I*2 Quality Mark for

Produact Data 0

Fixed Value

Note：Each symbol ‘#’ represent a blank（the same as follows）.

Table 2 Part two of the first level head record’s structure


example remark

1 41~48 8 A*8 Satellite Name FY2C#### Fixed Value 2 49~50 2 I*2 Factor of Grid Field 7 Fixed Value 3 51~52 2 I*2 Byte of Grid Data 2 Fixed Value

4 53~54 2 I*2 Fiducial Value of

Grid Data 0 Fixed Value

5 55~56 2 I*2 factor of

proportionality for Grid Data

1 Fixed Value

6 57~58 2 I*2 Code of time frame 6 Fixed Value

7 59~60 2 I*2 Oldest time, year YYYY Varying Value

8 61~62 2 I*2 Oldest time, month MM Varying Value

9 63~64 2 I*2 Oldest time, day DD Varying Value

10 65~66 2 I*2 Oldest time, hour 3 Temporal

Value

11 67~68 2 I*2 Oldest time, minute 0 Temporal

Value

12 69~70 2 I*2 Youngest time, year YYYY Varying Value

13 71~72 2 I*2 Youngest time,

month MM

Varying Value

14 73~74 2 I*2 Youngest time, day DD Varying Value

15 75~76 2 I*2 Youngest time, hour 8 Temporal

Value

16 77~78 2 I*2 Youngest time,

minute 0

Temporal Value

17 79~80 2 I*2 Upper Left Latitude 6000 Fixed Value 18 81~82 2 I*2 Upper Left 6000 Fixed Value

Longitude

19 83~84 2 I*2 Lower Right

Latitude 1500 Fixed Value

20 85~86 2 I*2 Lower Right Longitude

15000 Fixed Value

21 87~88 2 I*2 Unit of Grid 0 Fixed Value

22 89~90 2 I*2 Space of Lateral

Grid 50 Fixed Value

23 91~92 2 I*2 Space of longitudinal

Grid 50 Fixed Value

24 93~94 2 I*2 Number of Lateral

Grid 181 Fixed Value

25 95~96 2 I*2 Number of

longitudinal Grid 91 Fixed Value

26 97~98 2 I*2 If Land Mask exists 0 Fixed Value 27 99~100 2 I*2 Value of Land Mask 0 Fixed Value 28 101~102 2 I*2 If Cloud Mask exists 0 Fixed Value 29 103~104 2 I*2 Value of Cloud Mask 0 Fixed Value

30 105~106 2 I*2 If Water Body Mask

exists 1 Fixed Value

31 107~108 2 I*2 Value of Water Body

Mask -1 Fixed Value

32 109~110 2 I*2 If Ice Mask exists 0 Fixed Value 33 111~112 2 I*2 Value of Ice Mask 0 Fixed Value

34 113~114 2 I*2 If Quality Control is

done 3 Fixed Value

35 115~116 2 I*2 upper limit of

Quality Control 100 Fixed Value

36 117~118 2 I*2 Lower of Quality

Control -1 Fixed Value

37 119~120 2 I*2 Standby 0 Temporal

Value

38 121~362 242 I*2 Fill Flags 0 Temporal

Value



example remark

1 1~64 64 A*64 File Identification By

SAT2004

FY2C_TSG_ MLT_OTG_ YYYYMMD D_TOAD.A

Fixed Value except

YYYYM

WX##……## MDD (30‘#’ in

total)

2 65~72 8 A*8 Format Version AWX2.0## Temporal

Value

3 73~80 8 A*8 Producer NSMC#CMA Fixed Value

4 81~88 8 A*8 Satellite Flat FY2C#### Fixed Value

5 89~96 8 A*8 Instrument VISSR### Fixed Value

6 97~104 8 A*8 Procedural Version V1.0#### Temporal

Value

7 105~112 8 A*8 Reserved ######## Temporal

Value

8 113~120 8 A*8 Copyright NSMC#### Fixed Value

9 121~128 8 A*8 Length of extended

filling data 234#####

Fixed Value

10 129~362 234 A*234 Fill flags ##……## (234 ‘#’ in

total)

Temporal Value

9.1.2 Data record

Data is saved as two dimensions. The dimension size is 181*91. It means data has

91 records, every record contains 181 pixels. The first point locates at the left-up

corner, 60ºN & 60ºE. The last pixel locates at the right- down corner, 15ºN & 150ºE.

The data is written from left to right, then from up to down. Each pixel is two-byte.

Each grid value ranges from -1 to 100, 0 for water body and 0 to 100 for snow

fraction that is percentage of ratio of snow-cover area to land-cover area.

1 2 ---------------------------------Æ181 2 ⏐

⏐

⏐

⏐

⏐. ⏐. ⏐. ⏐

⏐. ↓. 91----------------------------------Æ181

10 FY2C Outgoing Long wave Radiation Product

10.1 Format

The AWX file of FY-2C OLR is a 1003*1001*2 Byte array. The first record is head record which includes the first-level record and the second-level record. The record length is 2002 Byte. The second record is the head record in character which gives detailed information on the OLR data. The record length is 2002 Byte. From 3rd to 1003rd record there is OLR grid data. Each record has a length of 2002 Byte and every 2 Bytes is an OLR value. The unit of OLR value is W/M**2. The coverage of the grid data is 50N-50S, 55E-155E, and the resolution is 0.1*0.1 latitude/longitude. The size of the grid is 1001*1001. For example, the first row of the grid array (also the 3rd record) stores the 1001 values of OLR at 55.0E, 55.1E, 55.2E……154.9E, 155.0E in the latitude of 50.0N, the second row of the grid array (also the 4th record) stores the 1001 values of OLR at 55.0E, 55.1E, 55.2E……154.9E, 155.0E in the latitude of 49.9N,……from north to south, the 1001st row of the grid array (also the 1003rd record) stores the 1001 values of OLR at 55.0E, 55.1E, 55.2E……154.9E, 155.0E in the latitude of 50.0S.

10.2 A FORTRAN program for reading out the OLR from AWX file

C C THIS PROGRAM READOLR.FOR IS USED TO READ OUT THE FY-2C OLR DATA FROM *.AWX FILES

C 程序 READOLR.FOR 是用于从*.AWX 文件读取 FY-2C OLR 格点场资料

C THE AREA IS:50N-50S,55E-155E,AND THE RESOLUTION IS 0.1*0.1 LATITUDE/LONGITUDE

C 资料地理范围： 50N-50S，55E-155E，数据分辨率： 0.1*0.1 经纬度。

C 2007.9.10 C

LOGICAL*1 N(2002),NN(2002),N1(2002),NNN(2002),L(70),LL(70) CHARACTER*1 AHD(12),HH(10),HHH(8),HEAD(126) INTEGER*2 L1,L2,L3,L4,L5,L6,L7,L8,L9,L10

INTEGER*2 LLL(35) INTEGER*2 YEAR1,MONTH1,DATE1,HOUR1,MIN1 INTEGER*2 YEAR2,MONTH2,DATE2,HOUR2,MIN2 REAL*4 LAT1,LAT2,LONG1,LONG2 INTEGER*2 OUT(1001),OLR(1001,1001),PUT(1001) EQUIVALENCE(NNN(1),AHD(1)) EQUIVALENCE(NNN(13),L1) EQUIVALENCE(NNN(15),L2) EQUIVALENCE(NNN(17),L3) EQUIVALENCE(NNN(19),L4) EQUIVALENCE(NNN(21),L5) EQUIVALENCE(NNN(23),L6) EQUIVALENCE(NNN(25),L7) EQUIVALENCE(NNN(27),L8) EQUIVALENCE(NNN(29),L9) EQUIVALENCE(NNN(31),HH(1)) EQUIVALENCE(NNN(41),HHH(1)) EQUIVALENCE(NNN(49),L(1)) EQUIVALENCE(L(1),LLL(1)) EQUIVALENCE(NNN(1),HEAD(1))

EQUIVALENCE(N1(1),OUT(1)) EQUIVALENCE(NN(1),PUT(1))

C OPEN(1,FILE='FY2C_OLR_MLT_OTG_20070909_2100.AWX',ACCESS='DIRECT',

$ RECL=2002) C OPEN(2,FILE='tt.dat',ACCESS='DIRECT',RECL=2002) C C

C READ THE FIRST HEAD RECORD AND GET THE TIME AND AREA OF OLR DATA

C 读取第 1 条头记录，获取 OLR 资料的时间和地理范围。

C C

READ(1,REC=1) NNN WRITE(6,70) AHD

70 FORMAT(/1X,12A1) C

YEAR1=LLL(6) MONTH1=LLL(7) DATE1=LLL(8) HOUR1=LLL(9) MIN1=LLL(10) YEAR2=LLL(11) MONTH2=LLL(12) DATE2=LLL(13) HOUR2=LLL(14) MIN2=LLL(15) LAT1=LLL(16)/100.0 LONG1=LLL(17)/100.0 LAT2=LLL(18)/100.0 LONG2=LLL(19)/100.0 WRITE(6,81) YEAR1,MONTH1,DATE1,HOUR1,MIN1,YEAR2,MONTH2,DATE2, $ HOUR2,MIN2

81 FORMAT(/1X,'TIME INFORMATION--',5I6,'-',5I6) WRITE(6,82) LAT1,LAT2,LONG1,LONG2

82 FORMAT(/1X,'LATITUDE:',F7.2,'-',F7.2,' LONGITUDE:',F7.2,'-',F7.2) C C READ THE SECOND HEAD RECORD AND GET THE DETAILED INFORMATION ON OLR DATA

C 读取第 2 条头记录

C READ(1,REC=2) NNN WRITE(6,74) HEAD

74 FORMAT(/1X,63A1) C C READ OUT THE OLR GRID DATA

C 读出 OLR 格点场

C DO 1000 I=3,1003

READ(1,REC=I) N1 DO 1001 J=1,1001 OLR(I-2,J)=OUT(J)

1001 CONTINUE 1000 CONTINUE C C

WRITE(6,77) (OLR(1,J),J=1,50) 77 FORMAT(/1X,10I4)

C C

STOP

END

Documents

FY2 Product Format Introduction