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WAFSOPSG/5-IP/6
/ WAFSOPSG/5-IP/6
28/7/09

WORLD AREA FORECAST SYSTEM OPERATIONS GROUP (WAFSOPSG)

FIFTH MEETING

Paris, France, 16 to 18 September 2009

Agenda Item / 6: / Development of the WAFS
6.1: / Improved GRIB 2 forecasts for convective clouds, icing and turbulence

SUMMARY OF DISCUSSIONS FROM THIRD WORLD AREA FORECAST CENTRE SCIENCE MEETING

(Presented by the WAFS Provider States)

SUMMARY
The World Areas Forecast Centre (WAFC) Provider States convened a science meeting in WashingtonDC, 20-21 April 2009. The purpose of the science meeting was to report out on the progress in the development of the new icing, turbulence, and cumulonimbus (CB) Cloud forecasts for the World Area Forecast System.

1.INTRODUCTION

1.1The WAFC Provider States convened their third WAFC Science Co-ordination Meeting in Washington, DC on 20-21 April 2009. The meeting was an opportunity for the WAFC Provider States to present the progress that has been made towards the generation and verification of gridded forecasts for icing, turbulence and CB cloud. Participants at the science meeting included representatives from the London and Washington WAFCs, International Civil Aviation Organization (ICAO), World Meteorological Organization (WMO), International Air Transport Association (IATA), and International Federation of Airline Pilots Association (IFALPA). The appendix of this report includes the list of attendees.

1.2The information paper summarizes the discussions from the meeting. Presentations were made by the WAFCProviderStates, IATA and ICAO stating the requirements for these products, background on the scientific algorithms, and the results of the verification. The PowerPoint presentations from the two day session are available at URL:

2.BACKGROUND TO THE FLIGHT PLANNING REQUIREMENT

2.1The Chair of the IATA MET Task Force (TF), opened the meeting and informed the audience that the requirement for gridded icing turbulence and CB cloud forecasts had resulted from the ICAO/WMO Met Divisional Meeting in 2002. IATA has continued to be engaged in the development of the WAFS gridded forecasts for icing, turbulence and CB through the ICAO WAFSOPSG and IATA MET TF. IATA has provided input about the look and feel of the automated SIGWX products, and stated that the accuracy of the products should be at least as good as the human generated forecasts produced today.

3.icing forecast

3.1Icing verification was conducted by the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory and led by Jennifer Mahoney. The two WAFCs’ gridded icing forecasts were compared to each other as well as compared to the manually produced SIGWX forecasts.

3.2An initial phase of the verification looked at understanding how the icing product performed in the data rich CONUS (Contiguous US) region from November 2007 through January 2008. A second phase extended the verification to the global domain for the period November 2008 through January 2009. Cloud profiling radar from CloudSat onboard instrumentation was used to generate geometrical profiles and cloud classification, amongst others. The prevalence of icing (with which to verify the gridded data against) was then derived from the CloudSat data.

3.3Results indicated that the UK gridded icing product appeared to outperform the US icing for both mean and maximum attributes. When comparing the mean and maximum icing product of the UK with the US, they appeared to show distinct differences with respect icing potential, however spatially they were consistent. The UK product appeared to have greater values of icing potential compared to the US. There was also an indication that the UK and the US icing products have some geographical differences.

3.4In verifying the gridded icing products against the human generated SIGWX at medium-levels, both the UK and the US gridded icing forecasts outperformed the traditional human generated forecasts.

3.5Overall the results were very favourable and appear to meet the needs of IATA for global icing forecasts which will help reduce (or eliminate) the fuel carried on board for icing contingencies, in particular for twin-engine oceanic operations (e.g. ETOPS).

4.turbulence (CAT) forecast

4.1Senior Applied Scientists from the UK Met Office presented an objective verification of the gridded CAT forecasts and the human generated SIGWX forecasts. A global verification was conducted using data from both WAFCs. The period Nov 2008 to Jan 2009 was studied, with verification against aircraft observations from the Global Aircraft Data Set (GADS). Both WAFCs currently use the Ellrod TI1 algorithm to predict CAT in their gridded products.

4.2The results of the verification showed that both the UK and the US gridded products showed equivalent or greater skill than the manually produced SIGWX products. Global UK and US gridded CAT forecasts scored about the same. There were slight differences in scores as the forecast range increased. There was also latitudinal variations, with 50N to 90N showing the most skill, 20N to 50N showing some skill, 20S to 20N showing little or no skill, and 50S to 20S indeterminable due to lack of GADS data to validate against.

4.3ICAO noted that the new turbulence forecast products appear to be more accurate than the human generated products, and more consistent – both of which addresses the needs of the WAFSOPSG.

5.CB clouds FORECAST

5.1At the previous WAFC Science Co-ordination Meeting (2007), significant differences between the two WAFCs CB Cloud products had been noted. As a consequence, the WAFCs aligned, using a non-linear function of convective rainfall rate to predict the presence of CB. This has resulted in greater consistency between the two WAFCs.

5.2Verification was generated for the automated CB forecasts, and the human generated CB forecasts, from both WAFCs, during November 2008 and January 2009.

5.3Overall, the US manual product appeared to perform the best – ranking 1st for combined latitudes during both verification periods. However, conclusions were inconclusive.

5.4Further verification effort will be required to focus on the northern hemisphere summer period in particular, where there is a maximum of convective activity and a maximum of flight traffic. The UK Met Office will conduct a further verification of CB clouds in May-July 2009, in order to quantify how reliable the automated and manually generated CB forecasts are during a northern hemisphere summer.

5.5Overall, there was agreement that the CB products need to be aligned more and fine tuned. The UK and the US automated products appear to be over-forecasting CB cloud top height in certain areas. Also, the UK CB tops appear to be too low in the tropics compared to the US forecasts.

6.SUMMARY

6.1ICAO expressed that there had been two important outputs from the results. Firstly to demonstrate that the gridded products are equivalent to, or superior to, the current human generated SIGWX forecasts. And secondly, that they are compatible. Positive progress had clearly been shown on a number of fronts, not least icing and turbulence, but additional effort was required to improve the CB cloud algorithm.

7.ACTION BY THE WAFSOPSG

7.1The group is invited to note the information contained in this paper.

A-1 / WAFSOPSG/5-IP/6
Appendix A
WAFSOPSG/5-IP/6
Appendix

APPENDIX

List of attendees

Surname / First name / Title / Affiliation / Telephone number / Email address
Abelman / Cyndie / Chief, NWS Aviation Weather Branch / NOAA/NWS / +1-301-713-1726 x140 /
Albersheim / Steven / Meteorologist / FAA / +1-202-385-7185 /
Brock / Greg / SADIS Manager / UK Met Office / +44-1392-884892 /
Burch / Larry / Deputy Director, NWS/AWC / NWS/AWC WAFC Washington / +1-816-582-1904 /
Chuang / Hui-Ya / Research Meteorologist / NOAA/NCEP/EMC / +1-301-763-8000 x7219 /
DiMego / Geoff / Mesoscale Modeling NCEP/EMC / NOAA/NWS/NCEP / +1-301-763-8000 x7221 /
Gait / Nigel / Regulatory Group Manager / UK Met Office / +44-1392-886268 /
Gill / Philip / Senior Scientist / UK Met Office / +44-1392-886133 /
Graf / Michael / Meteorologist / NOAA/NWS / +1-301-713-1726 /
Hart / Dennis / Aviation MET expert / EuroControl / +32-2729-3050 /
Helgeson / Robert / Lead Safety Engineer / FAA ATO AJP / +1-202-385-7117 /
Heuwinkel / Rick / Manager, Plans & Requirements / FAA / +1-202-365-6253 /
Hord / Colin / Meteorologist / UKCAA / +44-207-453-6527 /
Lunnon / Bob / Aviation Outcomes Manager / UK Met Office / +44-1392-886423 /
Madine / Sean / Project Lead, Forecast Verification Section / NOAA/ESRL (and CSU/CIRA) / +1-303-497-6769 /
Mahoney / Jennifer / Chief, Forecast Verification Section / NOAA/ESRL / +1-303-497-6514 /
Maxson / Robert / Director, NOAA Aviation Weather Centre / NWS/AWC / +1-816-584-7200 /
Morone / Lauren / Operations Officer/NCEP / NOAA/NWS/NCEP / +1-301-763-8000 x7010 /
Murphy / M. Pat / Warning Co-ordination Meteorologist, NWS/AWC / NOAA/NWS/AWC / +1-816-584-7239 /
Puempel / Herbert / Chief, AEM Division / WMO / +41-22-730-8283 /
Qualley / Warren / Senior Weather Engineer / Harris Corporation / +1-202-729-3725 /
Ruiz Chaves / Luis / External Relations Director Flight Operations / Iberia Airlines / +34-915874018 /
Sakamoto / Kei / Assistant Manager, Operations Control Centre / All Nippon Airlines / +81-3-5757-5597 /
Sonnabend / Hans-Rudi / Head of MET Services / Lufthansa / +49-69-696-90362 /
Trojan / George / NOAA/NWS/AR / +1-907-271-6642 /
Turpeinen / Olli / Chief, MET/AIM Section / ICAO / +1-514-954-8194 /
Wachina / Ndiwa / Assistant Manager, Operations & Infrastructure / IATA / +1-514-874-0202 x3244 /
Walden / Steve / Contract Support / AMTI/FAA AFS430 / +1-703-922-2089 /
Ward / John / NOAA/NWS/NCEP/EMC / +1-301-763-8000 x7185 /
White / John / Staff Engineer / ALPA / +1-703-689-4325 /
Yoshino / Katsumi / Director, Operations Control Centre / All Nippon Airlines / +81-3-5757-5597 /
Zhou / Binbin / Research Meteorologist / NOAA/NWS/NCEP / +1-301-763-8000 x7577 /

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