Analysis and Construction of Guangxi Meteorological Data Sharing System

Abstract： With the development of meteorology science， the sources of meteorological data materials are numerous， and the data scale is becoming larger and larger. How to rapidly analyze these data to obtain accurate weather forecast is a problem in meteorological science development. This paper， according to meteorological data features， selects reasonable development scheme， adopts database storage technology to conduct regulatory storage of data materials， uses JAVA to establish query platform and adopts the commonly used MICAPS and GrADS technology in meteorological service department in China for data material Web drawing， thus developing and completing a set of meteorological data sharing system suitable for meteorological service department. This system makes weather forecasters more intuitive to search for various types of historical data materials， which is also very necessary for the science research and business development of Guangxi Meteorological Department， thus enhancing and improving the public meteorological service ability in this region.

Keywords： meteorological data； MICAPS； GrADS； systematic construction；

The weather forecast has a very important role in disaster prevention and reduction， economic construction， social development and national defense construction. The meteorology is a science of extremely depending on reference data for operation and fabricating a weather forecast product needs to compare and analyze a lot of data in various countries and historical periods. So， the accuracy of weather forecast and effective and timely analysis of data are closely related.

The meteorological data refers to that China uses various methods to collect， store various carrier forms and meteorological data and sort out the analysis achievement according to various data observed and accumulated by various meteorological stations according to the meteorological business requirements.

Development meteorological data sharing system can make the vast meteorological data observed and calculated by numerical forecast for regulatory storage. Using MICAPS and GrADS technology and effective format conversion processing to display on web can make weather forecasters more intuitive and convenient to take query and analysis of atmospheric evolution information， in order to make effective weather forecast.

1 Systematic goal

This system will be used for regulating the storage of meteorological data in a large scale， which can provide a “window” for forecasters to check meteorological data materials， making people more directly see the various information in the atmosphere， so as to make accurate weather forecast.

2. Operation environment and systematic environment requirement

2.1 Development system operation environment

The operation system is Red Hat Linux 9.0， and the website adopts Apache Tomcat 5.0.28， and the main development environment includes： BASH 2.05b.o， Perl 5.8.0， Java2SDK 1.4.2_13， C/C++ complier gcc 3.2.2， Fortran complier pgf9 5.1-6.

2.2 Client system operation environment

The system operation system requirement： WindowsXP above

The computer hardware requirement： ①CPU： Pentium 4， 3.0GHZ above； ② memory： 256M above； ③hardware： 50G above

The browser version requirement： IE6.0 above

2.3 Compiling language

This system will construct a website form to users， in order to facilitate forecasters to login in any computer terminal for browsing， so it chooses JAVA language for program compiling.

3. System design and realization

3.1Overall function demand of system

①The database query system access doesn’t need specially installing client.

②The computer in the LAN can visit database query system.

③The material image， element display are complete and rapid.

④It can conduct query and display according to various elements.

⑤The storage time limits are different according to different materials.

3.2 System processing

The meteorological data sharing processing data flow is as shown in Figure 1， and the meteorological database storage data is for query platform use， and the data query platform can form drawing according to different types of meteorological data. The users can operate and make query of data materials.

3.3 Overall structure design

Figure 2 is the overall structure design diagram of meteorological data sharing system. The overall structure of meteorological data sharing system is divided into database system and query platform of the two parts， and query platform is composed of many sub query modules.

3.4 System data management and analysis

3.4.1 Database platform

Through the collection and management of meteorological data， it decides to adopt SQL server 2005 as the database. SQL server 2005 is the third generation of database software launched by Microsoft Company， which provides comprehensive data management component， supporting XML technology and data warehouse and adding .NET language execution environment.

3.4.2 System data analysis

The meteorological data material is mainly divided into： original meteorological observation data and numerical forecast products. The raw observation materials include ground， high altitude conventional observation data， satellite detection data（satellite cloud image）， automatic meteorological observation data. The numerical forecast product materials include T106， T213， MM5， ECMWF， Japan and Germany.

3.5 System function module design

This system can be divided into T213/T106 numerical forecast products， Ecmwf numerical forecast products， 9210 satellite cloud image， 9210 detection observation material and surface observation material， central meteorological station weather analysis chart， Doppler radar product， digital radar image， NCEP/NCAR reanalysis data and other dozen sub modules to form. The function module is as shown in Figure 3， and the meteorological data sharing system in the image includes database and query platform of the two parts.

3.6 System sub module design and realization

3.6.1 T213/T106 numerical forecast product sub module

T213/T106 numerical forecast product sub module set conducts query module according to date， time， numerical region， and element， level and time efficiency.

T213/T106 numerical forecast product sub module realization， as shown in Figure 4.

3.6.2 Ecmwf numerical forecast product sub module

Ecmwf numerical forecast product sub module set conducts query module according to date， time， numerical region， and element， level and time efficiency.

Ecmwf numerical forecast product sub module realization， as shown in Figure 5.

3.6.3 9210 satellite cloud diagram sub module

9210 satellite cloud diagram includes GMS5/GOES9 and FY series， and channel is visible with light， moisture， IR， IR projection containing （Lambert）， （Mercator）. Data is processed into Micaps system by micapscc.exe， which can identifie Diamond 13 type data format， and the format is image data， and the information includes file header， time， image size， longitude coordinate and projection mode and other elements.

Processing and displaying Micaps GMS5/GOES9， FY-2B/FY-2C satellite cloud image data， according to control file， it can obtain pixel corresponding cloud top temperature. If the projection mode of cloud image is Lambert， it can still obtain pixel’s corresponding latitude and longitude. The course module realization process is as shown in Figure 6， in particular as：

1.According to cloud image pixel point， obtaining color index.

2.Reading cloud image data.

3.Drawing cloud image.

4.Loading cloud top temperature control table.

5.Obtaining cloud top temperature of fabricating pixel point.

6.Drawings.

3.6.4 9210 detection data sub module

Sounding observation material is the second type of data format in MICAPS， and the data information includes file header， level， terminal number， district station number， latitude， temperature， temperature dew point difference factor.

Sounding observation material sub module realization process is specifically as：

1.It is defined as the second type of data.

2.Reading file header and data.

3.Outputting file and storage.

4.Conducting aerial map filling and drawing.

Realization method is as shown in Figure 7.

3.6.5 9210 ground observation material sub module

The ground observation material is the first type of data format in MICAPS， and its data information includes file header， terminal number， level， total cloud cover， temperature， low cloud height， medium cloud form and high cloud form factor.

The module realization method is similar to sounding data realization method， and it is not discussed again.

3.6.6 Central meteorological station weather analysis diagram sub module

The central meteorological station weather analysis chart material is the 14th type of data format in MICAPS， and the data information includes file header， time， line width， station number， attribute and other factors.

The module realization method is similar to ground observation material realization method， and it is not discussed again.

3.6.7 Doppler radar map sub module

The realization process of Doppler radar map sub module is specifically as：

1.Defining external input data and needed reading data.

2.Reading Doppler radar product data， not including file header information， before adjusting， it should first position the offset， which is mainly read from. tar.gz.

3.Drawing rador background digram（figure area is 640*480， and radar graphic area is 480*480， and radar site information region is 160*480）

4.Drawing radar information region.

5.Drawing radar product image， according to different types， respectively adjusting corresponding image function.

6.Drawing scanning image.

7.Reading data from random file and conducting BigEndian conversion.

8.Reading data from input flow file and conducting BigEndian conversion.

9.Reading data from buffer， analyzing data and obtaining data.

3.6.8 Digital radar image sub module

Guangxi digital radar image began to store image products since May 1st 2007， including basic reflectivity， combination reflectivity， Doppler velocity， liquid water content， one hour precipitation. All the data is compressed by gzip as 5M， and the file name is as Radar_yyyymmdd.tar.gz， providing radar image GIF animation display， which is convenient for users to track echoevolution. The module realization is similar to Doppler radar product sub module， so it is not discussed any more.

3.6.9 NCEP/NCAR reanalysis material sub module

NCEP/NCAR[33] 6 hour reanalysis material is the monthly and daily average reanalysis materials launched by American environment forecast center（NCEP） and national atmospheric research center （NCAR）. The material takes netCDF（netware Common Data Form） for storage， which can use GrADS technology for processing. The reanalysis material collection includes air， hgt， rhum， shum， omega， uwnd， vwnd， pres or slp of nine elements， according to variable name to generate a separate file. The module and Ecmwf numerical forecast product sub module realization method are similar.

4. Conclusion

This paper analyzes and studies various types of features of meteorological data， introducing the detailed realization methods of various modules in meteorological data sharing system， developing and completing the meteorological data sharing system suitable for forecasters， filling the blank of data sharing business in this region， enhancing and improving the meteorological public service ability in this region， which can make forecasters use the current database query platform.

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