Application of Satellite analysis in tropical cyclone of CMA

Transcription

1 2 nd International Workshop On Satellite Analysis of Tropical Cyclones (IWSATC-2) Satellite TC Analysis in Operations: Changes since IWSATC-1 17 February 2016 Honolulu, Hawaii, USA Application of Satellite analysis in tropical cyclone of CMA Chunyi XIANG National Meteorological Center China Meteorological Administration (CMA)

2 Contents: 1. Application of Devorak technique 2. Development of objective estimation system 3. Application in best track dataset analysis

3 1 Application of Devorak technique The classical Dvorak technique (1984 version) began to be conducted in operational TC intensity analysis since Since 18 th Apr. 2014, the 24h warning areas entirely includes the South China Sea and 48h warning areas is also enlarged correspondingly. The real time satellite analysis is performed 4 (out of 48h areas) or 8 times (within 48h areas) daily 24h warning areas (8times) 48h warning areas (8times) Warning zone

4 1 Application of Devorak technique Based on classical Dvorak technique, both FY-2 and MTSAT ( replaced by Himawari-8 since 5 th Dec, 2015) can be served as reliable reference for the official TC positioning and intensity determination, which is also officially issued by NMC/CMA. CMA Dvorak analysis working sheet

5 1 Application of Devorak technique For most cases, the following three types can be used to provide a pre-estimated location from a given satellite image. More subsequent data like AMSU, ASCAT/Quick SCAT and surface observations can be correspondingly used to confirm or revise the pre-estimation. The deviations of different Satellites are reasonably considered when determine the final official position.

6 1 Application of Devorak technique The secondary step is to select one of the patterns including Curved Band, Shear, Eye, CDO(Central Dense Overcast for VIS) and Embedded Center (for IR), as well as Central Cold Cover. Each singe pattern has its own categories and corresponding Data T numbers. The T numbers and TC intensity ranges can be typically assigned from the following relationship to cloud patterns.

7 1 Application of Devorak technique Since wind-pressure relationship(wpr) are experimental and different between agencies, NMC starts to use a recommended CI-pressurewind relationship 25% 分位数 50% 分位数 75% 分位数 CI 气压风速气压风速气压风速 TD TS STS TY STY Super TY *Based on CMA operational data in 2013 CI Index MWS(m/s) Rang of Pressure(hPa) ~998~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~880 * Red one is recommended num.

8 1 Application of Devorak technique Reanalysis of CI index and CMA-BT shows the Dvorak technique can be reasonably used in operational work and lead to reliable intensity. Variances in TCs final intensity are still exist on condition that different wind-pressure relationship(wpr) and subjective CI determinant. Intensity (m /s) Intensity - CI (BABJ) CI (BABJ) Pressure - CI (BABJ) Pressure (hpa) *Based on operational data of CMA & JMA CI (BABJ)

9 1 Application of Devorak technique CI=7.5 CI=8.0 Comparison of the Result of Intensity Estimated Based on WPR using the maximum intensity of Rammasun(1409) Different WPR used by each official center ( dash line is calculated from Best-track CMA using the cases of 2013)

10 1 Application of Devorak technique Special Training : ---TC positioning schedule --- TC Dvorak schedule and instructions Advisor: ---S.T Chen, HKO Location---- Training Center of CMA, Beijing Time----22th FEB to 29 th FEB, 2012 Participants: --- National Meteorological Center --- National Meteorological Center --- Shanghai Typhoon Institute of CMA

11 1 Application of Devorak technique Operational guidance : --- operational use of Dvorak technique --- Historical and real-time analysis Advisor ---Dr. Mark. A. Lander, U. of Guam Location----NMC, Beijing Time th AUG to 16 th AUG, 2013 Participants: --- National Meteorological Center

12 1 Application of Devorak technique Operational discussing: ---Specify the use in the South China Sea --- Historical and real-time analysis Advisor: --- Chief forecasters of CMA Location----NMC, Beijing Time th JUL to 20 th JUL, 2015(twice a week) Participants: --- National Meteorological Center

13 Contents: 1. Application of Devorak technique 2. Development of objective estimation system 3. Application in best track dataset analysis

14 2 Development of objective estimation system Based on Dvorak technique, an advanced tropical cyclone intensity objective estimation system was co-developed with CIMSS using both FY2 data and MTSAT data.

15 2 Development of objective estimation system The system is now working with input information from FY2E/2G and also MTSAT. The example of super typhoon Haiyan at 12UTC on 7 th Nov The center temperature is +7.1 C, the cloud region temperature is -84.6C, CI is 8.0, MSLP is 862.3hPa, and Vmax is 170kt. ADT analysis: 891.7hPa,75m/s (14BJT 18 th JUL, 2014 ) Surface Observation: 899.2hPa,anemoscope damaged (13:50BJT 18 th JUL, 2014 )

16 Contents: 1. Application of Devorak technique 2. Development of objective estimation system 3. Application in best track dataset analysis

17 3 Application in best track dataset analysis Post season best track analysis scheme in CMA Satellite application in post season best track analysis I. Reference from other agencies II. A mathematical morphology-based algorithm for TC center location III. An objective TC intensity estimation method

18 3 Application in best track dataset analysis

19 3 Application in best track dataset analysis Satellite application in post season best track analysis 1. Dvorak analysis is not performed specifically during the post season re-analysis process. Instead, the real time satellite analysis issued by NMC/CMA is served as an important reference. 2. The typhoon intensity estimation based on Dvorak technique from CIMSS and NOAA Satellite and Information Service are also used as reference. 3. Microwave images are used more and more frequently in post season satellite analysis. However, no canonical procedure has been set up for the application of these images. 4. A STI-in-house objective intensity estimation method and a TC center location algorithm based on mathematical morphology are also applied to provide extra reference.

20 1 Satellite image analysis morphologic By the process of erosion and dilation the point which is near the biggest grads of the high gray values area will be located as TC center. LIU Zhengguang, QIU Haiming, WU Bing et al. 2003: An algorithm for Tropical Cyclone center location based on satellite images. Journal of Tianjin University, 2003(6),

21 3 Application in best track dataset analysis 2 Satellite image analysis inner-core convection The technique (Lu et al., 2013, 2014) is based on the statistical relationship between TC intensity and its inner-core convection, plus the persistence of TC intensity (Formula 1). In the model, the inner core convection is described by several parameters retrieved from digital infrared (IR) satellite images, including the number of convective cores (Num), their distance to the TC center (DIS), and their blackbody temperature(tbb), among others. The persistence of TC intensity is embodied by the TC intensity six hours previous(v6h). Vmax= V6h Num Lon Lat DISmin TBBdif (1)

22 Thank you!