Editorial Type:
Article
Article Type:
Research Article

Use and Impact of Automated Aircraft Data in a Global 4DVAR Data Assimilation System

Carla Cardinali ECMWF, Reading, United Kingdom

Search for other papers by Carla Cardinali in
Current site
Google Scholar
PubMed Close
,
Lars Isaksen ECMWF, Reading, United Kingdom

Search for other papers by Lars Isaksen in
Current site
Google Scholar
PubMed Close
, and
Erik Andersson ECMWF, Reading, United Kingdom

Search for other papers by Erik Andersson in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Aug 2003
DOI:
https://doi.org/10.1175//2569.1
Page(s):
1865–1877
Restricted access

Abstract

The use of automated aircraft data [Aircraft Meteorological Data Relay (AMDAR) and Aircraft Communication Addressing and Reporting System (ACARS)] has recently been extended in ECMWF's operational 4DVAR data assimilation system. Herein, a modified data selection procedure is reported on that allows the use of more aircraft profiling data during the aircraft's ascending and descending phase, and more of the most frequent reports at cruise level. It is shown that the accuracy of analyzed jet streams is improved through these changes, as verified against independent (non–real time) aircraft data that had not been used in the experiments. The modifications are shown to have a clear positive impact on the short- and medium-range forecast performance. The revised aircraft usage was implemented operationally in January 2002.

The impact in 4DVAR of profiles from American and European automated aircraft in ascending and descending phase has been tested in a data denial impact study, for January and July 2001. This particular impact study was run partly on the request of the WMO/Commission for Basic Systems (CBS) Expert Team on data requirements and the redesign of the global observing system. Their interest is in testing whether a modern data assimilation system (such as 4DVAR) obtains substantial benefit from the aircraft profiles, which sample very irregularly in space and time, given that America and Europe are relatively well covered by radiosondes and wind profilers. The results show a substantial positive impact of the profiling aircraft data on analysis and forecast accuracy. The short-range forecast performance is improved over North America, the North Atlantic, and Europe. In the medium range a clear positive impact is found in the North Atlantic, the European, and Arctic areas in the winter period, and beyond day 6 in the summer period. These results are statistically significant and support the ongoing WMO initiative for further expansion of the AMDAR/ACARS coverage. The results also illustrate the effectiveness of 4DVAR with respect to observations that are irregularly distributed in space and time.

Corresponding author address: Dr. Carla Cardinali, ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom. Email: carla.cardinali@ecmwf.int

Abstract

The use of automated aircraft data [Aircraft Meteorological Data Relay (AMDAR) and Aircraft Communication Addressing and Reporting System (ACARS)] has recently been extended in ECMWF's operational 4DVAR data assimilation system. Herein, a modified data selection procedure is reported on that allows the use of more aircraft profiling data during the aircraft's ascending and descending phase, and more of the most frequent reports at cruise level. It is shown that the accuracy of analyzed jet streams is improved through these changes, as verified against independent (non–real time) aircraft data that had not been used in the experiments. The modifications are shown to have a clear positive impact on the short- and medium-range forecast performance. The revised aircraft usage was implemented operationally in January 2002.

The impact in 4DVAR of profiles from American and European automated aircraft in ascending and descending phase has been tested in a data denial impact study, for January and July 2001. This particular impact study was run partly on the request of the WMO/Commission for Basic Systems (CBS) Expert Team on data requirements and the redesign of the global observing system. Their interest is in testing whether a modern data assimilation system (such as 4DVAR) obtains substantial benefit from the aircraft profiles, which sample very irregularly in space and time, given that America and Europe are relatively well covered by radiosondes and wind profilers. The results show a substantial positive impact of the profiling aircraft data on analysis and forecast accuracy. The short-range forecast performance is improved over North America, the North Atlantic, and Europe. In the medium range a clear positive impact is found in the North Atlantic, the European, and Arctic areas in the winter period, and beyond day 6 in the summer period. These results are statistically significant and support the ongoing WMO initiative for further expansion of the AMDAR/ACARS coverage. The results also illustrate the effectiveness of 4DVAR with respect to observations that are irregularly distributed in space and time.

Corresponding author address: Dr. Carla Cardinali, ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom. Email: carla.cardinali@ecmwf.int

Save
Cover Monthly Weather Review
Monthly Weather Review

  • Andersson, E., and H. Järvinen, 1999: Variational quality control. Quart. J. Roy. Meteor. Soc., 125 , 697–722.

  • Andersson, E., and A. Garcia-Mendez, 2002: Assessment of European wind profiler data, in an NWP context. ECMWF Tech. Memo. 372, 14 pp.

  • Andersson, E., M. Fisher, R. Munro, and A. McNally, 2000: Diagnosis of background errors for radiances and other observable quantities in a variational data assimilation scheme, and the explanation of a case of poor convergence. Quart. J. Roy. Meteor. Soc., 126 , 1455–1472.

    • Search Google Scholar
    • Export Citation

  • Benjamin, S. G., B. E. Schwartz, and R. E. Cole, 1999: Accuracy of ACARS wind and temperature observations determined by collocation. Wea. Forecasting, 14 , 1032–1038.

    • Search Google Scholar
    • Export Citation

  • Bormann, N., S. Saarinen, G. Kelly, and J-N. Thépaut, 2003: The spatial structure of observation errors in atmospheric motion vectors from geostationary satellite data. Mon. Wea. Rev., 131 , 706–718.

    • Search Google Scholar
    • Export Citation

  • Bouttier, F., 2001a: The development of 12-hourly 4D-Var. ECMWF Tech. Memo. 348, 21 pp.

  • Bouttier, F., 2001b: The use of profiler data at ECMWF. Meteor. Z., 10 , 497–510.

  • Courtier, P., J. N. Thépaut, and A. Hollingsworth, 1994: A strategy for operational implementation of 4D-Var, using an incremental approach. Quart. J. Roy. Meteor. Soc., 120 , 1367–1388.

    • Search Google Scholar
    • Export Citation

  • Courtier, P., and Coauthors. 1998: The ECMWF implementation of three-dimensional variational assimilation (3D-Var). Part I: Formulation. Quart. J. Roy. Meteor. Soc., 124 , 1783–1807.

    • Search Google Scholar
    • Export Citation

  • Dalby, T. D., and A. Berney, 1999: Modification to aircraft thinning and observation errors. NWP Forecasting Research, UKMO Tech. Memo. 276, 5 pp.

    • Search Google Scholar
    • Export Citation

  • Järvinen, H., and P. Undén, 1997: Observation screening and first guess quality control in the ECMWF 3D-Var data assimilation system. ECMWF Tech. Memo. 236, 33 pp.

    • Search Google Scholar
    • Export Citation

  • Järvinen, H., E. Andersson, and F. Bouttier, 1999: Variational assimilation of time sequences of surface observations with serially correlated errors. Tellus, 51A , 469–488.

    • Search Google Scholar
    • Export Citation

  • Köpken, C., 2001: Monitoring of METEOSAT WV radiances and solar stray light effects. EUMETSAT/ECMWF Fellowship Programme, Res. Rep. 10, 46 pp.

    • Search Google Scholar
    • Export Citation

  • Liu, Z-Q., and F. Rabier, 2002: The interaction between model resolution, observation resolution and observation density in data assimilation: A one-dimensional study. Quart. J. Roy. Meteor. Soc., 128 , 1367–1386.

    • Search Google Scholar
    • Export Citation

  • Lorenc, A. C., and P. Hammon, 1988: Objective quality control of observations using Bayesian methods: Theory and practical implementation. Quart. J. Roy. Meteor. Soc., 114 , 515–543.

    • Search Google Scholar
    • Export Citation

  • Miller, M., 1999: Resolution studies. ECMWF Tech. Memo. 299, 49 pp.

  • Rabier, F., H. Järvinen, E. Klinker, J. F. Mahfouf, and A. Simmons, 2000: The ECMWF operational implementation of four-dimensional variational assimilation. Part I: Experimental results with simplified physics. Quart. J. Roy. Meteor. Soc., 126 , 1143–1170.

    • Search Google Scholar
    • Export Citation

  • Rukhovets, L., J. Tenenbaum, and M. Geller, 1998: The impact of additional aircraft data on the Goddard Earth Observing System analyses. Mon. Wea. Rev., 126 , 2927–2941.

    • Search Google Scholar
    • Export Citation

  • Teixeira, J., 1999: The impact of increased boundary layer vertical resolution on the ECMWF forecast system. ECMWF Tech. Memo. 268, 55 pp.

    • Search Google Scholar
    • Export Citation

  • Tenenbaum, J., 1996: Jet stream winds: Comparisons of aircraft observations with analyses. Wea. Forecasting, 11 , 188–197.

  • Untch, A., J-J. Morcrette, and M. Hortal, 1996: The ECMWF model with increased resolution in the stratosphere. Research Activities in Atmosphere and Ocean Modelling, A. Staniforth, Ed., Rep. 23, 3.40–3.41.

    • Search Google Scholar
    • Export Citation

  • Untch, A., A. Simmons, M. Hortal, and C. Jakob, 1998: Increased stratospheric resolution in the ECMWF forecasting system. Proc. KNMI Workshop on Chemical Data Assimilation, de Bilt, Netherlands, KNMI, 8 pp.

    • Search Google Scholar
    • Export Citation

  • WMO, 1996: Guide to Meteorological Instruments and Methods of Observation. 6th ed. WMO, II-3-1–II-3-6.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 678 363 25
PDF Downloads 257 58 8