How to issue SIGMET SIGMET Seminar for Asia/Pacific Region Bangkok, Thailand, 11-13 July 2007 Shikembaru, Toru 志堅原透 Japan Meteorological Agency (JMA) 日本気象庁 Japan Meteorological Agency 1
Contents of lecture I. Outline of SIGMET II. How to issue SIGMET Japan Meteorological Agency 2
I. Outline of SIGMET Japan Meteorological Agency 3
Definition of SIGMET information Information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of aircraft operations. Excerpt from WMO Technical Regulations [C.3.1.] 1.1 Japan Meteorological Agency 4
Importance of SIGMET information SIGMET information is the highest priority among other types of meteorological information provided to the aviation users. SIGMET information is used for flight planning of the airlines globally. Japan Meteorological Agency 5
Principal operation as a Meteorological watch office (MWO) for issuing SIGMET information To prepare SIGMET and other information relating to its area of responsibility. To supply SIGMET information and, as required, other meteorological information to associated air traffic services units. To disseminate SIGMET information. Japan Meteorological Agency 6
Dissemination of SIGMET SIGMET messages shall be disseminated to MWOs, WAFCs other meteorological offices SIGMET messages for volcanic ash shall be disseminated to VAACs. Japan Meteorological Agency 7
Note to issue SIGMET Although SIGMET information is required to be issued for cruising level, there is no stated lower limit regarding the height. MWOs should not issue SIGMET for weather phenomena of lower intensity, transient nature, or smaller scale, which do not affect significantly the flight safety. Japan Meteorological Agency 8
Type of SIGMET at subsonic cruising levels Thunderstorm OBSC TS EMBD TS FRQ TS SQL TS OBSC TSGR EMBD TSGR FRQ TSGR SQL TSGR Turbulence SEV TURB SEV ICE SEV ICE(FZRA) SEV MTW HVY DS HVY SS Icing Mountain wave Duststorm Sandstorm Tropical cyclone TC (+ cyclone name) where the criterion of 10-minute mean surface wind speed is 63km/h(34kt) or more. Volcanic ash VA (+ volcano name, if known) Japan Meteorological Agency 9
Type of SIGMET at transonic and supersonic cruising levels Cumulonimbus ISOL CB OCNL CB FRQ CB Turbulence MOD TURB SEV TURB GR Hail Volcanic ash VA (+ volcano name, if known) Note : Only one of the weather phenomena should be selected and included in each SIGMET. Japan Meteorological Agency 10
Period of validity of SIGMET Phenomena TURB, TS, ICE, MTW, DS, SS, CB, GR TC, VA Hours Up to 4 Up to 6 Japan Meteorological Agency 11
Update and cancellation of SIGMET When the Sig-WX phenomena (which is on SIGMET) is growing, MWO should issue a new updated SIGMET. When the phenomena is no longer occurring nor expected to occur, MWO should cancel the SIGMET speedily. Japan Meteorological Agency 12
Principal components of SIGMET message of ICAO Amendment 74 to Annex 3 Direction of the requirement of SIGMET for transonic and supersonic cruising level. Elimination of OTLK from SIGMET messages related to VA and TC. See the ICAO Working Paper APPROVAL OF DRAFT REPORT TO COUNCIL ON AMENDMENT 74 TO ANNEX 3 - METEOROLOGICAL SERVICE FOR INTERNATIONAL AIR NAVIGATION. Japan Meteorological Agency 13
II. How to issue SIGMET Japan Meteorological Agency 14
Example of SIGMET for phenomena excluded TC and VA Message indicator Validity period Location indicator of MWO and hyphen ICAO Location indicator of FIR or CTA Daily sequence number Validity indicator RJJJ SIGMET 4 VALID 260725/261125 RJTD- RJJJ FUKUOKA FIR SEV TURB OBS AT 0715Z S OF N3450 E13950 FL280/320 MOV NE 20KT INTSF (This SIGMET is fictitious) ICAO Location indicator and name of the FIR(/UIR) or CTA Expected changes in intensity Location Vertical extent or level Phenomenon Movement or expected movement Indication of observed and expected to continue, or forecast Japan Meteorological Agency 15
Types of satellite image Visible image Infrared image Water-vapour image The Visible image or infrared image is useful for judging occurrences or expected occurrences phenomena to SIGMET information. But the watervapour image is more useful for expected occurrences TURB. (To know occurrences of air turbulences, we need to get pilot reports.) It is because that occurring TURB, especially CAT, is connected with pattern of Jet Streams. If estimated position of Jet Streams can be understood with a water-vapour image, it will be possible to issue SIGMET information for turbulence. Japan Meteorological Agency 16
NWP data over the satellite image The left image is that the NWP data of 300hPa winds and 300hPa parallel of altitude lap over the infrared image. (at 26 Feb. 2007 00UTC) Relationship between position of Jet Streams, trough and ridge, value of wind shears and cloud can be understood with NWP data over the satellite image. Japan Meteorological Agency 17
Aerologic observation and NWP data over the satellite image The left image is that the aerologic observation wind data at 300hPa, light blue pennants, the NWP data of 300hPa winds and 300hPa parallel of altitude lap over the infrared image. (at 26 Feb. 2007 00UTC) T Td Additionally, three dimensional meso-scale phenomena can be understood using aerologic observation and NWP data over the satellite image. Japan Meteorological Agency 18
How to make SIGMET information for TS moving direction The moving direction and moving velocity will be estimated with the animated satellite images. This blue area is estimated the area of frequent TS on this image. This red area is described in SIGMET information. Area except at a stationary area may be widened in consideration of validity period and moving direction and velocity. The following SIGMET main body is determined in this situation. Where the name of the FIR is Fukuoka FIR, the moving direction is northeastward, the moving velocity is 15kt and the phenomenon s intensity is intensifying. RJJJ FUKUOKA FIR FRQ TS FCST WI N40E148 - N40E158 - N45E156 - N45E150 - N43E148 MOV NE 15KT INTSF Japan Meteorological Agency 19