Articles | Volume 5, issue 2
https://doi.org/10.5194/wcd-5-491-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-5-491-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
05 Apr 2024
Research article |
| 05 Apr 2024
| 05 Apr 2024
Influence of radiosonde observations on the sharpness and altitude of the midlatitude tropopause in the ECMWF IFS
Konstantin Krüger
CORRESPONDING AUTHOR
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Andreas Schäfler
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Martin Weissmann
Institut für Meteorologie und Geophysik, Universität Wien, Vienna, Austria
George C. Craig
Meteorologisches Institut München, Ludwig-Maximilians-Universität, Munich, Germany
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Cited articles
Birner, T.: Fine-scale structure of the extratropical tropopause region, J. Geophys. Res., 111, D04104, https://doi.org/10.1029/2005JD006301, 2006.
Birner, T., Dörnbrack, A., and Schumann, U.: How sharp is the tropopause at midlatitudes?, Geophys. Res. Lett., 29, 45-1–45-4, https://doi.org/10.1029/2002GL015142, 2002.
Birner, T., Sankey, D., and Shepherd, T. G.: The tropopause inversion layer in models and analyses, Geophys. Res. Lett., 33, L14804, https://doi.org/10.1029/2006GL026549, 2006.
Bland, J., Gray, S., Methven, J., and Forbes, R.: Characterizing extratropical near-tropopause analysis humidity biases and their radiative effects on temperature forecasts, Q. J. Roy. Meteor. Soc., 140, 3878–3898, https://doi.org/10.1002/qj.4150, 2021.
Boljka, L. and Birner, T.: Potential impact of tropopause sharpness on the structure and strength of the general circulation, npj Clim. Atmos. Sci., 5, 98, https://doi.org/10.1038/s41612-022-00319-6, 2022.
Bonavita, M.: On some aspects of the impact of GPSRO observations in global numerical weather prediction, Q. J. Roy. Meteor. Soc., 140, 2546–2562, https://doi.org/10.1002/qj.2320, 2014.
Borne, M., Knippertz, P., Weissmann, M., Martin, A., Rennie, M., and Cress, A.: Impact of Aeolus wind lidar observations on the representation of the West African monsoon circulation in the ECMWF and DWD forecasting systems, Q. J. Roy. Meteor. Soc., 149, 933–98, https://doi.org/10.1002/qj.4442, 2023.
Bukenberger, M., Rüdisühli, S., and Schemm, S.: Jet stream dynamics from a PV gradient perspective: The method and its application to a km-scale simulation, Q. J. Roy. Meteor. Soc., 149, 2409–2432, https://doi.org/10.1002/qj.4513, 2023.
Cucurull, L. and Anthes, R. A.: Impact of infrared, microwave and radio occultation satellite observations in operational numerical weather prediction, Mon. Weather Rev., 142, 4164–4186, https://doi.org/10.1175/MWR-D-14-00101.1, 2014.
ECMWF: IFS Documentation – Cy43r1: Part III: Dynamics and Numerical Procedures, IFS Documentation, ECMWF, https://doi.org/10.21957/m1u2yxwrl, 2016.
ECMWF: Meteorological Archival and Retrieval System (MARS), ECMWF, https://www.ecmwf.int/en/forecasts/access-forecasts/access-archive-datasets, last access: 1 June 2023.
Gettelman, A., Hoor, P., Pan, L. L., Randel, W. J., Hegglin, M. I., and Birner, T.: The extratropical upper troposphere and lower stratosphere, Rev. Geophys., 49, RG3003, https://doi.org/10.1029/2011RG000355, 2011.
Gray, S., Dunning, C., Methven, J., Masato, G., and Chagnon, J.: Systematic model forecast error in Rossby wave structure, Geophys. Res. Lett., 41, 2979–2987, https://doi.org/10.1002/2014GL059282, 2014.
Grise, K. M., Thompson, D. W. J., and Birner, T.: A global survey of static stability in the stratosphere and upper troposphere, J. Climate, 23, 2275–2292, https://doi.org/10.1175/2009JCLI3369.1, 2010.
Haualand, K. F. and Spengler, T.: Relative importance of tropopause structure and diabatic heating for baroclinic instability, Weather Clim. Dynam., 2, 695–712, https://doi.org/10.5194/wcd-2-695-2021, 2021.
Harvey, B., Methven, J., and Ambaum, M. H. P.: An Adiabatic Mechanism for the Reduction of Jet Meander Amplitude by Potential Vorticity Filamentation, J. Atmos. Sci., 75, 4091–4106, https://doi.org/10.1175/JAS-D-18-0136.1, 2018.
Hodyss, D. and Nichols, N.: The error of representation: Basic understanding, Tellus A, 67, 1–17, https://doi.org/10.3402/tellusa.v67.24822, 2015.
Hoerling, M. P., Schaack, T. K., and Lenzen, A. J.: Global Objective Tropopause Analysis, Mon. Weather Rev., 119, 1816–1831, https://doi.org/10.1175/1520-0493(1991)119<1816:GOTA>2.0.CO;2, 1991.
Hoffmann, L. and Spang, R.: An assessment of tropopause characteristics of the ERA5 and ERA-Interim meteorological reanalyses, Atmos. Chem. Phys., 22, 4019–4046, https://doi.org/10.5194/acp-22-4019-2022, 2022.
Houchi, K., Stoffelen, A., Marseille, G. J., and De Kloe, J.: Comparison of wind and wind shear climatologies derived from high-resolution radiosondes and the ECMWF model, J. Geophys. Res.-Atmos., 115, D22123, https://doi.org/10.1029/2009JD013196, 2010.
Ingleby, B.: An assessment of different radiosonde types 2015/2016, ECMWF Technical Memorandum 69, https://doi.org/10.21957/0nje0wpsa, 2017.
Ingleby, B., Pauley, P., Kats, A., Ator, J., Keyser, D., Doerenbecher, A., Fucile, E., Hasegawa, J., Toyoda, E., Kleinert, T., Qu, W., St. James, J., Tennant, W., and Weedon, R.: Progress toward high-resolution, real-time radiosonde reports, B. Am. Meteorol. Soc., 97, 2149–2161, https://doi.org/10.1175/BAMS-D-15-00169.1, 2016.
Janjic, T., Bormann, N., Bocquet, M., Carton, J. A., Cohn, S. E., Dance, S. L., Losa, S. N., Nichols, N. K., Potthast, R., Waller, J. A., and Weston, P.: On the representation error in data assimilation, Q. J. Roy. Meteor. Soc., 144, 1257–1278, https://doi.org/10.1002/qj.3130, 2018.
Kaluza, T., Kunkel, D., and Hoor, P.: On the occurrence of strong vertical wind shear in the tropopause region: a 10-year ERA5 northern hemispheric study, Weather Clim. Dynam., 2, 631–651, https://doi.org/10.5194/wcd-2-631-2021, 2021.
König, N., Braesicke, P., and von Clarmann, T.: Tropopause altitude determination from temperature profile measurements of reduced vertical resolution, Atmos. Meas. Tech., 12, 4113–4129, https://doi.org/10.5194/amt-12-4113-2019, 2019.
Krüger, K., Schäfler, A., Wirth, M., Weissmann, M., and Craig, G. C.: Vertical structure of the lower-stratospheric moist bias in the ERA5 reanalysis and its connection to mixing processes, Atmos. Chem. Phys., 22, 15559–15577, https://doi.org/10.5194/acp-22-15559-2022, 2022.
Lavers, D. A., Torn, R. D., Davis, C., Richardson, D. S., Ralph, F. M., and Pappenberger, F.: Forecast evaluation of the North Pacific jet stream using AR Recon Dropwindsondes, Q. J. Roy. Meteor. Soc., 149, 3044–3063, https://doi.org/10.1002/qj.4545, 2023.
Martin, A., Weissmann, M., and Cress, A.: Investigation of links between dynamical scenarios and particularly high impact of Aeolus on numerical weather prediction (NWP) forecasts, Weather Clim. Dynam., 4, 249–264, https://doi.org/10.5194/wcd-4-249-2023, 2023.
Martius, O., Schwierz, C., and Davies, H. C.: Tropopause-Level Waveguides, J. Atmos. Sci., 67, 866–879, https://doi.org/10.1175/2009JAS2995.1, 2010.
Pan, L. L., Randel, W. J., Gary, B. L., Mahoney, M. J., and Hintsa, E. J.: Definitions and sharpness of the extratropical tropopause: A trace gas perspective, J. Geophys. Res.-Atmos., 109, D23103, https://doi.org/10.1029/2004JD004982, 2004.
Pauley, P., and Ingleby, B.: Assimilation of in-situ observations, in: Data Assimilation for Atmospheric, Oceanic and Hydrologic Applications (Vol. IV), edited by: Park, S. K. and Xu, L., Springer, ISBN 978-3-030-77722-7, https://link.springer.com/book/10.1007/978-3-030-77722-7 (last access: 1 June 2023), 2022.
Pilch Kedzierski, R., Matthes, K., and Bumke, K.: Synoptic-scale behavior of the extratropical tropopause inversion layer, Geophys. Res. Lett., 42, 10018–10026, https://doi.org/10.1002/2015GL066409, 2015.
Pilch Kedzierski, R., Neef, L., and Matthes, K.: Tropopause sharpening by data assimilation, Geophys. Res. Lett., 43, 8298–8305, https://doi.org/10.1002/2016GL069936, 2016.
Polichtchouk, I., Bechtold, P., Bonavita, M., Forbes, R., Healy, S., Hogan, R., Laloyaux, P., Rennie, M., Stockdale, T., Wedi, N., Diamantakis, M., Flemming, J., English, S., Isaksen, L., Vána, F., Gisinger, S., and Byrne, N.: Stratospheric Modelling and Assimilation, ECMWF Technical Memorandum 877, https://doi.org/10.21957/25hegfoq, 2021.
Rabier, F., Järvinen, H., Klinker, E., Mahfouf, J.-F., and Simmons, A.: The ECMWF operational implementation of fourdimensional variational assimilation. I: Experimental results with simplified physics, Q. J. Roy. Meteor. Soc., 126, 1148–1170, https://doi.org/10.1002/qj.49712656415, 2000.
Radnóti, G., Bauer, P., McNally, A., Cardinali, C., Healy, S., and de Rosnay, P.: ECMWF study on the impact of future developments of the space-based observing system on numerical weather prediction, ECMWF Technical Memorandum 638, https://doi.org/10.21957/skfhvask, 2010.
Saffin, L., Gray, S. L., Methven, J., and Williams, K. D.: Processes Maintaining Tropopause Sharpness in Numerical Models, J. Geophys. Res.-Atmos., 122, 9611–9627, https://doi.org/10.1002/2017JD026879, 2017.
Schäfler, A., Craig, G., Wernli, H., Arbogast, P., Doyle, J. D., McTaggart–Cowan, R., Methven, J., Rivière, G., Ament, F., Boettcher, M., Bramberger, M., Cazenave, Q., Cotton, R., Crewell, S., Delanoë, J., Dörnbrack, A., Ehrlich, A., Ewald, F., Fix, A., Grams, C. M., Gray, S. L., Grob, H., Groß, S., Hagen, M., Harvey, B., Hirsch, L., Jacob, M., Kölling, T., Konow, H., Lemmerz, C., Lux, O., Magnusson, L., Mayer, B., Mech, M., Moore, R., Pelon, J., Quinting, J., Rahm, S., Rapp, M., Rautenhaus, M., Reitebuch, O., Reynolds, C. A., Sodemann, H., Spengler, T., Vaughan, G., Wendisch, M., Wirth, M., Witschas, B., Wolf, K., and Zinner, T.: The North Atlantic Waveguide and Downstream Impact Experiment, B. Am. Meteorol. Soc., 99, 1607–1637, https://doi.org/10.1175/BAMS-D-17-0003.1, 2018.
Schäfler, A., Harvey, B., Methven, J., Doyle, J. D., Rahm, S., Reitebuch, O., Weiler, F., and Witschas B.: Observation of jet stream winds during NAWDEX and characterization of systematic meteorological analysis error, Mon. Weather Rev., 148, 2889–2907, https://doi.org/10.1175/MWR-D-19-0229.1, 2020.
Schindler, M., Weissmann, M., Schäfler, A., and Radnóti, G.: The impact of dropsonde and extra radiosonde observations during NAWDEX in autumn 2016, Mon. Weather Rev., 148, 809–824, https://doi.org/10.1175/MWR-D-19-0126.1, 2020.
Schmidt, T., Wickert, J., and Haser, A.: Variability of the upper troposphere and lower stratosphere observed with GPS radio occultation bending angles and temperatures, Adv. Space Res., 46, 150–161, https://doi.org/10.1016/j.asr.2010.01.021, 2010.
Schwierz, C., Dirren, S., and Davies, H. C.: Forced Waves on a Zonally Aligned Jet Stream, J. Atmos. Sci., 61, 73–87, https://doi.org/10.1175/1520-0469(2004)061<0073:FWOAZA>2.0.CO;2, 2004.
Shepherd, T. G., Polichtchouk, I., Hogan, R. J., and Simmons, A. J.: Report on Stratosphere Task Force, ECMWF Technical Memorandum 824, https://doi.org/10.21957/0vkp0t1xx, 2018.
Tinney, E. N., Homeyer, C. R., Elizalde, L., Hurst, D. F., Thompson, A. M., Stauffer, R. M., Vömel, H., and Selkirk, H. B.: A modern approach to stability-based definition of the tropopause, Mon. Weather Rev., 150, 3151–3174, https://doi.org/10.1175/MWR-D-22-0174.1, 2022.
Vaisala: Comparison of Vaisala Radiosondes RS41 and RS92, Vaisala, https://www.vaisala.com/sites/default/files/documents/RS-Comparison-White-Paper-B211317EN.pdf (last access: 1 December 2023), 2017.
Weissmann, M. and Cardinali, C.: Impact of airborne Doppler lidar observations on ECMWF forecasts, Q. J. Roy. Meteor. Soc., 133, 107–116, https://doi.org/10.1002/qj.16, 2007.
Weissmann, M., Busen, R., Dörnbrack, A., Rahm, S., and Reitebuch, O.: Targeted observations with an air-borne wind lidar, J. Atmos. Ocean. Tech., 22, 1706–1719, https://doi.org/10.1175/JTECH1801.1, 2005.
Weissmann, M., Langland, R. H., Cardinali, C., Pauley, P. M., and Rahm, S.: Influence of airborne Doppler wind lidar profiles near Typhoon Sinlaku on ECMWF and NOGAPS forecasts, Q. J. Roy. Meteor. Soc., 138, 118–130, https://doi.org/10.1002/qj.896, 2012.
World Meteorological Organization (WMO): Meteorology – A three-dimensional science, WMO Bull., 6, 134–138, 1957.
Short summary
Initial conditions of current numerical weather prediction models insufficiently represent the sharp vertical gradients across the midlatitude tropopause. Observation-space data assimilation output is used to study the influence of assimilated radiosondes on the tropopause. The radiosondes reduce systematic biases of the model background and sharpen temperature and wind gradients in the analysis. Tropopause sharpness is still underestimated in the analysis, which may impact weather forecasts.
Initial conditions of current numerical weather prediction models insufficiently represent the...
