eesti teaduste
akadeemia kirjastus
SINCE 1952
Proceeding cover
of the estonian academy of sciences
ISSN 1736-7530 (Electronic)
ISSN 1736-6046 (Print)
Impact Factor (2021): 1.024
Impact of the ASCAT scatterometer winds on the quality of HIRLAM analysis in case of severe storms; pp. 177–194
PDF | doi: 10.3176/proc.2016.3.03

Jekaterina Služenikina, Aarne Männik

The impact of the Advanced Scatterometer (ASCAT) data assimilation on the quality of HIRLAM analysis is assessed in cases of rapidly developing severe storms of 2013. The HIRLAM quality is analysed for two observing system experiments: with and without the ASCAT data assimilation. Mainly impact on the model analysis output is evaluated. Marine observations of 10-m wind speed and mean sea level pressure are used as measures of quality. The results show that depending on ASCAT data coverage in the HIRLAM domain and temporal availability of the data at the assimilation time moment, the impact may be either more or less accurate. It is also detected that some narrow places of the Baltic Sea (Bothnian Bay, Gulf of Finland) are not affected by the ASCAT data assimilation. According to the ASCAT Wind Product specification, ASCAT measurements near the shoreline are usually flagged as land contaminated. The ASCAT winds in these areas are not admitted to the analysis after the procedure of the HIRLAM quality control, most likely due to the proximity to the land. The use of the ASCAT Coastal Wind Product in the future may enlarge the ASCAT data coverage in these areas. In addition, some weaknesses of the ASCAT data assimilation were detected in the study raising the question of the optimal ASCAT data usage. Further attempts to improve the quality of the HIRLAM analyses are expected in the ASCAT data thinning before assimilation or by reducing time differences between the HIRLAM analyses.


Bi, L., Jung, J., Morgan, M., Le Marshall, J., Baker, N., and Santek, D. 2010. Impact of METOP ASCAT Ocean Surface Winds on Global Weather Forecasts. In 10th International Winds Workshop, Tokyo, Japan, 22–26 February 2010. 267700761_Impact_of_METOP_ASCAT_Ocean_Surface_Winds_on_Global_Weather_Forecasts (accessed 2016-04-04).

Cotton, J. 2013. The impact of ASCAT winds from Metop-B and a new scatterometer thinning scheme. Forecasting Research Technical Report No. 580, Met Office. (accessed 2015-10-20).

De Chiara, G., Janssen, P., English, S., Bidlot, J.-R., and Laloyaux, P. 2014. Scatterometer impact studies at ECMWF. In Proceedings of the EUMETSAT Meteoro­logical Satellite Conference, Geneva, Switzerland, 22–26 September 2014. (accessed 2015-10-20).

De Haan, S., Marseille, G.-J., De Valk, P., and De Vries, J. 2013. Impact of ASCAT Scatterometer wind observations on the High-Resolution Limited-Area Model (HIRLAM) within an operational context. Weather Forecast., 28, 489–503.

De Valk, P. 2013. ASCAT assimilation in the HIRLAM report. De Bilt, international report, IR-2013-02. (accessed 2015-10-20).

Deutschländer, T., Friedrich, K., Haeseler, S., and Lefebvre, C. 2013. Severe storm XAVER across northern Europe from 5 to 7 December 2013. Deutscher Wetterdienst. 20131230_XAVER_europe_en.pdf?__blob=publication File&v=4 (accessed 2016-04-04).

Figa-Saldaña, J., Wilson, J. W., Attema, E., Gelsthorpe, R., Drinkwater, M. R., and Stoffelen, A. 2002. The advanced scatterometer (ASCAT) on the meteorological operational (MetOp) platform: a follow on for the European wind scatterometers. Can. J. Remote Sens., 28(3), 404–412.

Haeseler, S. and Lefebvre, C. 2013. Heavy storm CHRISTIAN on 28 October 2013. Deutscher Wetterdienst. Orkantief_Christian_PDF.pdf?__blob=publicationFile&v=3 (accessed 2015-10-18).

Hersbach, H. and Janssen, P. 2007. Operational assimilation of surface wind data from the MetOp ASCAT scattero­meter at ECMWF. ECMWF Newsletter, 113, 6–8.

Hersbach, H., Stoffelen, A., and de Haan, S. 2007. An improved C-band ocean geophysical model function: CMOD-5. J. Geophys. Res., 112, C03006.

Hsu, S. A., Meindl, E. A., and Gilhousen, D. B. 1994. Determining the power-law wind-profile exponent under near-neutral stability conditions at sea. Appl. Meteorol., 33(6), 757–765.<0757:DTPLWP>2.0.CO;2

Huang, X.-Y., Morgensen, K. S., and Yang, X. 2002. First-guess at the appropriate time: the HIRLAM implementation and experiments. In Proceedings for HIRLAM workshop on variational data assimilation and remote sensing, Helsinki, 22–23 January 2002, pp. 28–43.

Ingleby, B. 2009. Factors affecting ship and buoy data quality. Technical Report No. 529, Met Office, Meteorology Research and Development. http:// papers/technical_reports/reports/529.pdf (accessed 2015-10-20).

Männik, A., Luhamaa, A., Loorits, V., and Toll, V. 2014. Numerical weather prediction environment in Estonian Environmental Agency. In Joint 24th ALADIN Workshop & HIRLAM All Staff Meeting 2014, 7–11 April 2014, Romania. aladin/IMG/pdf/nationalposterkaur_asm2014.pdf (accessed 2015-10-16).

Ollinaho, P. 2010. Feasibility of Assimilating ASCAT Surface Winds into a Limited Area Model. M.S. thesis, Department of Physics, University of Helsinki. (accessed 2015-10-20).

OSI-SAF Project Team. 2013. ASCAT Wind Product User Manual version 1.13 May. KNMI, De Bilt, The Netherlands. Technical Report Reference: SAF/OSI/ CDOP/KNMI/TEC/MA/126. scatterometer/publications/pdf/ASCAT_Product_Manual.pdf (accessed 2015-10-20).

Payan, C. 2010. Improvements in the use of scatterometer winds in the operational NWP system at Méteó-France. 10th International Winds Workshop, Tokyo, Japan, 22–26 February 2010. /.../ConferencesandEvents/DAT_2042632... (accessed 2016-04-04).

Portabella, M., Stoffelen, A., Verhoef, A., and Verspeek, J. 2012. A new method for improving ASCAT wind quality control. IEEE Geoscience and Remote Sensing Letters, 9(4), 579–583.

Služenikina, J. and Männik, A. 2011. A comparison of ASCAT wind measurements and the HIRLAM model over the Baltic Sea. Oceanologia, 53(1, SI), 229–244.

Stoffelen, A. 1998. Scatterometry. Thesis, Universiteit Utrecht. full.pdf?sequence=1 (accessed 2015-10-20).

Stoffelen, A., Portabella, M., Verhoef, A., Verspeek, J., and Vogelzang, J. 2006. Mesoscale winds from the new ASCAT scatterometer. KNMI Res. Biennial Rep. 2005–2006, 30–35.

Stoffelen, A., Verhoef, A., Verspeek, J., Vogelzang, J., Driesenaar, T., Risheng, Y., et al. 2013. Research and Development in Europe on Global Application of the OceanSat-2 Scatterometer Winds. Final Report of OceanSat-2 Cal/Val A0 project.

Storch, H., Feser, F., Haeseler, S., Lefebvre, C., and Stendel, M. 2014. A violent mid-latitude storm in northern Germany and Denmark, 28 October 2013. BAMS, 95(9). (accessed 2015-10-20).

Takahashi, M. 2010. Operational use of Scatterometer Winds at JMA. In Proceedings of 10th International Winds Workshop, Tokyo, Japan, 22–26 February 2010.

Tveter, F. 2006. Assimilating ambiguous QuikScat scatterometer observations in HIRLAM 3-D-Var at the Norwegian Meteorological Institute. Tellus, 58A, 59–68.

Undén, P., Rontu, L., Järvinen, H., Lynch, P., Calvo, J., Cats, G., et al. 2002. HIRLAM-5 scientific documentation. (accessed 2015-10-20).

Valkonen, T. and Schyberg, H. 2015. The impact of ASCAT winds in storm cases using the HARMONIE model system. EUMETSAT Fellowship Programme: First year report. MET report 2/2015, ISSN 2387-4201, Norwegian Meteorological Institute, Norway. (accessed 2015-10-20).

Verhoef, A. and Stoffelen, A. 2014. Algorithm Theoretical Basis Document for the OSI SAF wind products version 1.1. Document external project: SAF/OSI/CDOP2/KNMI/SCI/MA/197.

Verhoef, A., Portabella, M., and Stoffelen, A. 2012. High-Resolution ASCAT scatterometer winds near the coast. Geoscience and Remote Sensing, 50(7), 2481–2487.

Verspeek, J., Verhoef, A., and Stoffelen, A. 2013a. ASCAT-B NWP Ocean Calibration and Validation. Technical Report Reference: SAF/OSI/CDOP2/KNMI/TEC/RP/199.

Verspeek, J., Stoffelen, A., Verhoef, A., Portabella, M., and Vogelzang, J. 2013b. ASCAT-B ocean calibration and wind product results. In 2013 EUMETSAT Meteoro­logical Satellite Conference, Vienna, Austria, 16–20 September 2013.

Vogelzang, J., Stoffelen, A., Verhoef, A., De Vries, J., and Bonekamp, H. 2009. Validation of two-dimensional variational ambiguity removal on SeaWinds scatterometer data. J. Atm. Oceanic Technol., 7(26), 1229–1245.

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