AERODROME METEOROLOGICAL OBSERVATION AND FORECAST STUDY GROUP (AMOFSG)

Transcription

1 MOFSG/8-SN No /12/09 EROROME METEOROLOGIL OSERVTION N FOREST STUY GROUP (MOFSG) EIGHTH MEETING Melbourne, ustralia, 15 to 18 February 2010 genda Item 5: Observing and forecasting at the aerodrome and in the terminal area 5.1: erodrome observations REVIEW OF SRPS FOR THE REPORTING OF PRESENT WETHER WHEN REPORTE UTOMTILLY (Presented by olin Hord) SUMMRY This study note reviews the SRPs associated with the reporting of present weather from sensors. 1. INTROUTION 1.1 This paper relates to Task: MOFSG-02 'Revision of the requirements for weather parameters in MET reports'. 1.2 It is noted that considerable progress is being made in the automation of meteorological observing, which is now reflected in nnex 3 Meteorological Service for International ir Navigation since it enables UTO METR to be used by States in a position to do so during operational hours of the aerodrome as determined by the meteorological authority. 1.3 Many of the required parameters can be effectively provided automatically, e.g. wind, temperature dew-point temperature and atmospheric pressure. Sensors that provide visibility and cloud height measurements are required for aerodromes operating at TIII (nnex 3 hapter ) and these provide representative information on most occasions. (7 pages) MOFSG.8.SN en.doc

2 MOFSG/8-SN No It is for the reporting of present weather information where automated sensors exhibit the most limitations and it is for this reason that where automated sensors are used the identifier UP (Unidentified Precipitation) can be used in addition to the precipitation types listed in nnex 3 ppendix a) when the type of precipitation cannot be identified by the automatic observing system. 2. ISUSSION 2.1 It is reasonable to assume that in time the ability of automated weather sensors will mean that the full requirements for present weather can be replicated in automated weather reports for METR, SPEI and local reports. In this respect, this is a reasonable aim for States to aspire to, however at present, automated observations cannot fully replicate all these present weather parameters, whether that is a result of technology or prohibitive costs of implementation. 2.2 In this respect, there is merit in evaluating each present weather (and their combinations with qualifiers) to assess whether these can currently either be satisfied (either relatively straightforwardly or with some difficulty) with present weather sensors. 2.3 dditionally the present weather parameters are reviewed in terms of their requirement i.e. as a Standard or RP. This review is carried out against nnex 3, h 4, para The present weather occurring at the aerodrome and/or its vicinity shall be observed and reported as necessary. The following present weather phenomena shall be identified, as a minimum: precipitation and freezing precipitation. Precipitation (including intensity) Freezing precipitation (including intensity) Fog Freezing fog Thunderstorms (including in the vicinity) 2.4 In addition, it is noted that mendment 75 to nnex 3 will upgrade the current RP at ppendix 3 Para to a Standard for the reporting of Thunderstorm and Freezing qualifiers, i.e.: In local routine and special reports and in METR and SPEI, the following characteristics of present weather phenomena, as necessary, shall be reported, using their respective abbreviations and relevant criteria, as appropriate: Thunderstorm TS Used to report a thunderstorm with precipitation in accordance with the templates shown in Tables 3-1 and 3-2. When thunder is heard or lightning is detected at the aerodrome during the 10-minute period preceding the time of observation but no precipitation is observed at the aerodrome, the abbreviation TS should be used without qualification. Freezing FZ

3 - 3 - MOFSG/8-SN No. 31 Supercooled water droplets or precipitation, used with types of present weather phenomena in accordance with the templates shown in Tables 3-1 and In making an assessment against the weather parameters, the results have been classified into one of the following groups: Group. Present weather groups that can reasonably be met with automated sensors and are noted as a requirement in hapter 4 para Group. Present weather groups that can reasonably be met with automated sensors, but are not noted as a requirement in hapter 4 para Group. Present weather groups that are noted as a requirement in hapter 4 para , but where automated sensors can resolve these with some limitations (ie inferred results or where sensors are considered difficult, expensive, unproven or unreliable to utilise). Group. Present weather groups that are not noted as a requirement in hapter 4 para and where sensors are considered difficult, expensive, unproven or unreliable to utilise. GROUP Elements required in para Resolved by instrumentation: FG FZFG Z R SN RZ RSN FZR FZZ GROUP Elements required in para Resolved by instrumentation with some limitations: SHR SHSN SHGR SHGS SHRSN SHRGR SHRGS TS TSR TSSN TSGR TSGS TSRSN TSRGR TSRGS VTS PL SG GROUP Elements not required in para Resolved by instrumentation: R HZ FU LSN SQ GROUP Elements not required in para Unresolved by instrumentation: F PO FG MIFG PRFG RSN V VLSN VF VFG VSH S U SS S

4 MOFSG/8-SN No It is assumed that automated systems can adequately differentiate between slight (-), moderate and heavy (+) precipitation) 2.6 Group could be regarded as essential for aviation purposes and their resolution and detection is satisfactory. Therefore the reporting of these elements when using automated sensors could be introduced as a Standard. 2.7 Group are also regarded as essential for aviation purposes and consequently these are weather elements that are required to be reported. Present weather sensors may generate some limitations to the results offered. For example, present weather sensors can easily infer showers, by noting the intermittent nature of precipitation. Whilst the rationale for this may not be meteorologically sound it appears currently to meet the needs of aviation. lternatively, with more expensive remote sensing techniques, more meteorologically correct results may be able to be provided. The question to consider therefore is whether inferred showery precipitation meets the existing needs of Industry, or whether convective cloud must be demonstrated to be present in order to report SHxx. In this regard it would be valuable to the meteorological community if industry could review these requirements and ascertain the continued requirement to differentiate between showery and non-showery precipitation. 2.8 In the case of TS, it is more difficult to resolve this without remote sensing capabilities, although a lightning detector will assist and enable TS to be inferred if lightning is present. 2.9 It is noted that to automate the provision of in the vicinity i.e. for the reporting of VTS, VFG, VF and VLSN are difficult and expensive to provide automatically, the group may seek industry clarification as to whether the reporting of these phenomena are required when automated reports are being provided Group are weather parameters that are able to be resolved although are not presently required in a Standard. These could be RPs Group details weather parameters that are not able to be resolved nor required in any nnex 3 Standard. It would once again be useful to ascertain if these elements are still required to be reported for aviation purposes Whilst these may be considered a rather subjective UK view, it is hoped that this will provoke some discussion on the relative merits of separating the SRPs in this way. y doing so, one could argue that the needs of Industry should be recognised, whilst taking account of existing and developing capabilities. Further, the SRPs could be reviewed for each IO mendment ycle as technology and user needs change Many MET observations are now made from the Visual ontrol Rooms (VR) which in many locations are elevated sometimes by a few hundred feet, in these cases it is often difficult especially at night to ascertain the presence of present weather. In the UK it has proved of benefit and enabled greater consistency in the reporting of present weather to require all T III aerodromes have in addition to the sensors listed at hap , a present weather sensor. This sensor is integrated in to the MET system and enables acquisition, processing, dissemination and display of real time MET information. For this reason it is proposed to include the requirement for a present weather sensor in this paragraph as detailed below.

5 - 5 - MOFSG/8-SN No t aerodromes with runways intended for ategory II and III instrument approach and landing operations, automated equipment for measuring or assessing, as appropriate, and for monitoring and remote indicating of surface wind, visibility, present weather, runway visual range, height of cloud base, air and dew-point temperatures and atmospheric pressure shall be installed to support approach and landing and take-off operations. These devices shall be integrated automatic systems for acquisition, processing, dissemination and display in real time of the meteorological parameters affecting landing and take-off operations. The design of integrated automatic systems shall observe Human Factors principles and include back-up procedures. For consistency the RP at para should be similarly updated ased on the subjective assessment above, the following new SRPs, could be added: 1. In automated local routine and special reports and in METR and SPEI, the following types of present weather phenomena shall be reported as a minimum, using their respective abbreviations and relevant criteria, as appropriate: Fog (including freezing fog) Rain rizzle Snow Freezing precipitation 2. Recommendation. In automated local routine and special reports and in METR and SPEI, the following types of present weather phenomena should be reported as a minimum, using their respective abbreviations and relevant criteria, as appropriate: Thunderstorms (with precipitation as appropriate) Showers Ice Pellets Snow grains lowing Snow Mist Haze Smoke Squall 3. TION Y MOFSG 3.1 The MOFSG is invited to: a) note the contents of this paper; b) consider updating nnex 3 with the revised requirements for the automated reporting of present weather, as detailed in this SN; and c) seek clarification from industry on the requirement to report in the vicinity when automated reports are being generated.

6 MOFSG/8-SN No. 31 ppendix PPENIX OMPLETE LIST OF PRESENT WETHER PRMETERS List of commonly used weather codes with their decodes F Funnel cloud PO ust devil ssessed Group omments F, PO & SQ are secondary priorities for Industry, and are also difficult to automate. SQ Squall Secondary requirement, but can be resolved by sensors. FG FZFG Fog Freezing fog primary requirement of Industry (IO Standard), with sensors having the ability to provide good estimations of FG and FZFG (with temperature sensors) FG MIFG PRFG Fog patches Shallow fog Fog bank secondary requirement of Industry, and multiple sensors required to present the spatial variation of FG adequately, making this expensive. R HZ FU S U SS S V Mist Haze Smoke Sand ust Sandstorm uststorm Volcanic ash secondary requirement for Industry, but one which sensors can reasonably easily and accurately detect. Little evidence of sensor reconciling these phenomena, and secondary requirement. LSN lowing snow secondary requirement for Industry, but one that could be readily resolved by sensors through a combination of snow detection and visiometer. RSN Low drifting snow secondary requirement for Industry, and one that cannot easily be resolved by sensor owing to the wind blown deposit extending to less than the height of the visiometer. Z R SN RZ RSN FZR FZZ rizzle Rain Snow Rain & drizzle Rain & snow Freezing rain Freezing drizzle Primary requirement (precipitation) (IO Standard), and readily resolved by present weather sensors Primary requirement (precipitation) (IO Standard), with the ability to be readily resolved by ground temperature sensors.

7 MOFSG/8-SN No. 31 ppendix -2 PL SG Ice pellets Snow grains Little sensor reliability at present SHGR Shower of hail SHGS Shower of small hail SHR Shower of rain SHRSN Shower of rain & snow SHRGR Shower of rain & hail SHRGS Shower of rain & small hail SHSN Shower of snow TS Thunderstorm (w/o ppn) TSGR Thunderstorm with hail TSGS Thunderstorm with small hail TSR Thunderstorm with rain TSRSN Thunderstorm with rain & snow TSRGR Thunderstorm with rain & hail TSRGS Thunderstorm with rain & small hail TSSN Thunderstorm with snow VLSN lowing snow in the vicinity VF Funnel cloud in the vicinity VFG Fog in the vicinity VSH Showers in the vicinity VTS Thunderstorm in the vicinity Primary requirement (precipitation) (IO Standard), but not readily resolved by present weather sensors, owing to a difficulty in reconciling convective cloud types. Primary requirement (thunderstorm) (IO Standard), but requires remote sensing to provide this in automated reports, requiring substantial work from many States to comply. secondary requirement for Industry, with these weather groups not easy to resolve unless there are multiple automated sensors. Primary requirement (thunderstorm) (IO Standard), but requires remote sensing to provide this in automated reports, requiring substantial work from many States to comply. EN