Editorial Type:
Article
Article Type:
Research Article

Near-Surface Satellite Wind Observations of Hurricanes and Their Impact on ECMWF Model Analyses and Forecasts

M. Tomassini European Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading, Berkshire, United Kingdom

Search for other papers by M. Tomassini in
Current site
Google Scholar
PubMed Close
,
D. LeMeur European Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading, Berkshire, United Kingdom

Search for other papers by D. LeMeur in
Current site
Google Scholar
PubMed Close
, and
R. W. Saunders European Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading, Berkshire, United Kingdom

Search for other papers by R. W. Saunders in
Current site
Google Scholar
PubMed Close
Print Publication:
01 May 1998
DOI:
https://doi.org/10.1175/1520-0493(1998)126<1274:NSSWOO>2.0.CO;2
Page(s):
1274–1286
Restricted access

Abstract

During August–September 1995 new near-surface wind datasets over the tropical Atlantic from both the ERS-1 scatterometer and Meteosat satellites were available at the European Centre for Medium-Range Weather Forecasts. At this time there was an unusually high number of hurricanes present in the tropical Atlantic and so the impact of these data on analyzing and forecasting the main cyclones was investigated. Assimilation experiments using a new variational scheme, with the ERS-1 winds, showed clear improvements both in the analyses and short-range forecasts, compared with the optimal interpolation scheme without these data. For example, the forecast positions for Hurricane Iris were reduced by almost 50% when the scatterometer data was included. For Hurricane Luis the improvement was for a higher percentage of cases when the model identified the cyclone in the 24- and 48-h forecasts. For the 72-h forecasts 80% of the reported cyclones were detected compared with only 33% for the analyses without ERS-1 data.

The impact of the Meteosat lower-tropospheric cloud motion winds was found to be small due to lack of coverage in the vicinity of the center of the hurricanes at this time. The impact of one profile from a ship in the vicinity of Hurricane Luis just before its approach to the Caribbean Islands was clearly demonstrated by large improvements to both analyses with and without the scatterometer winds.

Corresponding author address: Dr. Roger W. Saunders, ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.

Abstract

During August–September 1995 new near-surface wind datasets over the tropical Atlantic from both the ERS-1 scatterometer and Meteosat satellites were available at the European Centre for Medium-Range Weather Forecasts. At this time there was an unusually high number of hurricanes present in the tropical Atlantic and so the impact of these data on analyzing and forecasting the main cyclones was investigated. Assimilation experiments using a new variational scheme, with the ERS-1 winds, showed clear improvements both in the analyses and short-range forecasts, compared with the optimal interpolation scheme without these data. For example, the forecast positions for Hurricane Iris were reduced by almost 50% when the scatterometer data was included. For Hurricane Luis the improvement was for a higher percentage of cases when the model identified the cyclone in the 24- and 48-h forecasts. For the 72-h forecasts 80% of the reported cyclones were detected compared with only 33% for the analyses without ERS-1 data.

The impact of the Meteosat lower-tropospheric cloud motion winds was found to be small due to lack of coverage in the vicinity of the center of the hurricanes at this time. The impact of one profile from a ship in the vicinity of Hurricane Luis just before its approach to the Caribbean Islands was clearly demonstrated by large improvements to both analyses with and without the scatterometer winds.

Corresponding author address: Dr. Roger W. Saunders, ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.

Save
Cover Monthly Weather Review
Monthly Weather Review

  • Andersson E., J. Pailleux, J.-N. Thepaut, J. R. Eyre, A. P. McNally, G. A. Kelly, and P. Courtier, 1994: Use of cloud cleared radiances in three/four-dimensional variational data assimilation. Quart. J. Roy. Meteor. Soc.,120, 627–653.

  • Courtier, P., and Coauthors, 1993: Variational assimilation at ECMWF. ECMWF Research Dept. Tech. Memo. 194, 84 pp. [Available from ECMWF Librarian, Reading, Berkshire RG2 9AX, United Kingdom.].

  • Eyre, J. R. G. Kelly, A. P. McNally, E. Andersson, and A. Persson, 1993: Assimilation of TOVS radiances through one-dimensional variational analysis. Quart. J. Roy. Meteor. Soc.,119, 1427–1463.

  • Gaffard, C., and H. Roquet, 1995: Impact of the ERS-1 scatterometer wind data on the ECMWF 3D-VAR assimilation system. ECMWF Research Department Tech. Memo. 217, 21 pp. [Available from ECMWF Librarian, Reading, Berkshire RG2 9AX, United Kingdom.].

  • Heming, J. T., J. C. L. Chan, and A. M. Radford, 1995: A new scheme for the initialisation of tropical cyclones in the UK Meteorological Office global model. Meteor. Appl.,2, 171–184.

  • Ottenbacher, A., M. Tomassini, K. Holmlund, and J. Schmetz, 1996:Low-level cloud motion winds from Meteosat high-resolution imagery. Wea. Forecasting,12, 175–184.

  • Reed, R. A., A. Hollingsworth, W. A. Heckley, and F. Delsol, 1988:An evaluation of the ECMWF operational system analyzing and forecasting tropical easterly wave disturbances over Africa and the tropical Atlantic. Mon. Wea. Rev.,116, 824–865.

  • Ritchie, H., C. Temperton, A. Simmons, M. Hortal, T. Davies, D. Dent, and M. Hamrud 1995: Implementation of the semi-Lagrangian method in a high-resolution version of the ECMWF forecast model. Mon. Wea. Rev.,123, 489–514.

  • Serrano, E., and P. Unden, 1994: Evaluation of a tropical cyclone bogusing method in data assimilation and forecasting. Mon. Wea. Rev.,122, 1523–1547.

  • Shun, C. M., 1992: Performance of the ECMWF model in tropical cyclone track forecasting over the western North Pacific during 1990–91. ECMWF Research Dept. Tech. Memo. 184, 32 pp. [Available from ECMWF Librarian, Reading, Berkshire RG2 9AX, United Kingdom.].

  • Stoffelen, A. and D. Anderson, 1997: Ambiguity removal and assimilation of scatterometer data. Quart. J. Roy. Meteor. Soc.,123, 491–518.

  • Tiedtke, M. 1989: A comprehensive mass flux scheme for cumulus parameterization in large scale models. Mon. Wea. Rev.,117, 1779–1800.

  • Velden, C., T. Olander, and S. Wanzon, 1998: The impact of multispectral GOES-8 wind information on Atlantic tropical cyclone track forecasts in 1995. Part I: Dataset methodology, description and case analysis. Mon. Wea. Rev.,126, 1202–1218.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 340 233 24
PDF Downloads 107 43 6