AMT Atmospheric Measurement Techniques AMT Atmos. Meas. Tech. 1867-8548 Copernicus Publications Göttingen, Germany 10.5194/amt-6-765-2013 The CM SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite Schröder M. https://orcid.org/0000-0002-9693-7812 1 Jonas M. 1 4 Lindau R. 2 Schulz J. 3 Fennig K. 1 Satellite-based Climate Monitoring, Deutscher Wetterdienst/Frankfurter Straße 135, 63067 Offenbach, Germany Meteorologisches Institut, Universität Bonn, Auf dem Hügel 20, 53121 Bonn, Germany European Organisation for the Exploitation of Meteorological Satellites, Eumetsat-Allee 1, 64295 Darmstadt, Germany now at: Centre de Recherche Public – Gabriel Lippmann, Systèmes d'Information et Organisation, Service HPC/41, rue du Brill, 4422 Belvaux, Luxemburg 19 03 2013 6 3 765 775 Copyright: © 2013 M. Schröder et al. 2013 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://amt.copernicus.org/articles/6/765/2013/amt-6-765-2013.html The full text article is available as a PDF file from https://amt.copernicus.org/articles/6/765/2013/amt-6-765-2013.pdf

The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring (CM SAF) aims at the provision and sound validation of well documented Climate Data Records (CDRs) in sustained and operational environments. In this study, a total column water vapour path (WVPA) climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I), a climatology of WVPA has been generated within the Hamburg Ocean–Atmosphere Fluxes and Parameters from Satellite (HOAPS) framework. Within a research and operation transition activity the HOAPS data and operation capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, namely kriging, has been applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses) and from the Japan Meteorological Agency (JMA–JRA). This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m<sup>−2</sup>. The absolute value of the bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m<sup>−2</sup>. For the period 1991–2006, the root mean square error (RMSE) for both reanalyses is approximately 2 kg m<sup>−2</sup>. As SSM/I WVPA and radiances are assimilated into JMA and all ECMWF analyses and to assess consistency with existing WVPA climatologies, the SSM/I-based climatology is also compared to the time series of SSM/I and TMI (Tropical Rainfall Measuring Mission Microwave Imager) WVPA from Remote Sensing Systems (RSS), leading to results consistent with the reanalyses results. This evaluation study gives confidence in consistency, accurateness and stability of the total water vapour climatology produced.

 References Allan, R. P. and Soden, B. J.: Large discrepancy between observed and simulated precipitation trends in the ascending and descending branches of the tropical circulation, Geophys. Res. Lett., 34, L18705, <a href="http://dx.doi.org/10.1029/2007GL031460">https://doi.org/10.1029/2007GL031460</a>, 2007. Allan, R. P., Soden, B. J., John, V. O., Ingram, W., and Good, P.: Current changes in tropical precipitation, Environ. Res. Lett., 5, 025205, <a href="http://dx.doi.org/10.1088/1748-9326/5/2/025205">https://doi.org/10.1088/1748-9326/5/2/025205</a>, 2010. Andersson, A., Fennig, K., Klepp, C., Bakan, S., Gra{ß}l, H., and Schulz, J.: The Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data – HOAPS-3, Earth Syst. Sci. Data, 2, 215–234, <a href="http://dx.doi.org/10.5194/essd-2-215-2010">https://doi.org/10.5194/essd-2-215-2010</a>, 2010. Chou, C. and Neelin, J. D.: Mechanisms of global warming impacts on regional tropical precipitation, J. Climate, 17, 2688–2701, 2004. Chou, S.-H., Nelkin, E., Ardizzone, J., and Atlas, R. M.: A comparison of latent heat fluxes over global oceans for four flux products, J. Climate, 17, 3973–3989, 2004. Curry, J. A., Bentamy, A., Bourassa, M. A., Bourras, D., Bradley, E. F., Brunke, M., Castro, S., Chou, S. H., Clayson, C. A., Emery, W. J., Eymard, L., Fairall, C. W., Kubota, M., Lin, B., Perrie, W., Reeder, R. A., Renfrew, I. A., Rossow, W. B., Schulz, J., Smith, S. R., Webster, P. J., Wick, G. A., and Zeng, X.: Seaflux, B. Am. Meteorol. Soc., 85, 409–424, 2004. Dee, D. P., Uppala, S. M., Simmons, A. J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Balmaseda, M. A., Balsamoa, G., Bauer, P., Bechtold, P., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S. B., Hersbach, H., Holm, E. V., Isaksen, L., Kallberg, P., Köhler, M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J.-J., Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thepaut, J.-N., and Vitart, F.: The ERA-Interim reanalysis: configuration and performance of the data assimilation system, Q. J. Roy. Meteorol. Soc., 137, 553–597, 2011. Fennig, K.: Interkalibration verschiedener SSM/I Mikrowellenradiometer im Hinblick auf eine gemeinsame Nutzung für eine fernerkundete Klimatologie (Homogenization of different SSM/I microwave radiometers for a combined satellite-derived climatology), Diploma Thesis, Met. Institute of the University of Hamburg, Hamburg, 2001. Gershunov, A. and Roca, R.: Coupling of latent heat flux and the greenhouse effect by large-scale tropical/subtropical dynamics diagnosed in a set of observations and model simulations, Clim. Dynam., 22, 205–222, 2004. Hagemann, S., Arpe, K., and Bengtsson, L.: Validation of the hydrological cycle of ERA40, in: ECMWF ERA-40 Project Report Series, No.&nbsp;24, European Centre for Medium-Range Weather Forecasts, Shinfield, Reading, UK, available at: <a href="www.ecmwf.int/publications">www.ecmwf.int/publications</a> (last access: October&nbsp;2011), 2005. Held, I. M. and Soden, B. J.: Water vapour feedback and global warming, Annu. Rev. Energ. Env., 25, 441–475, 2000. Hollinger, J. P., Lo, R., Poe, G., Savage, R., and Peirce, J.: Special Sensor Microwave/Imager User's Guide (Washington DC, Naval Research Laboratory), 1987. IPCC: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2007. Jonas, M., Schröder, M., Schulz, J., Andersson, A., Bakan, S., Fennig, K., Grassl, H., and Klepp, C. P.: Vertically Integrated Water Vapour from SSM/I – Daily/Monthly Means, Satellite Application Facility on Climate Monitoring, <a href="http://dx.doi.org/10.5676/EUM_SAF_CM/HTW_SSMI/V001">https://doi.org/10.5676/EUM_SAF_CM/HTW_SSMI/V001</a>, 2009. Jost, V., Bakan, S., and Fennig, K.: HOAPS – A new satellite-derived freshwater flux climatology, Meteorol. Z., 11, 61–70, 2002. Kiehl, J. T. and Trenberth, K. E.: Earth's annual global mean energy budget, B. Am. Meteorol. Soc., 78, 197–208, 1997. Kumar, R. M. R. and Schulz, J.: Analysis of freshwater flux climatology over the Indian Ocean using the HOAPS data, Remote Sens. Environ., 80, 363–372, 2002. Lindau, R. and Schröder, M.: Algorithm Theoretical Basis Document: Objective analysis (Kriging) for water vapour products, Ref Nr.&nbsp;SAF/CM/DWD/ATBD/KRIGING, Issue&nbsp;1.1, 25&nbsp;June&nbsp;2010. Mears, C. A., Santer, B. D., Wentz, F. J., Taylor, K. E., and Wehner, M. F.: Relationship between temperature and precipitable water changes over tropical oceans, Geophys. Res. Lett., 34, L24709, <a href="http://dx.doi.org/10.1029/2007GL031936">https://doi.org/10.1029/2007GL031936</a>, 2007. Ohring, G., Wielicki, B., Spencer, R., Emery, B., and Datla, R.: Satellite instrument calibration for measuring global climate change, B. Am. Meteorol. Soc., 86, 1303–1313, <a href="http://dx.doi.org/10.1175/BAMS-86-9-1303">https://doi.org/10.1175/BAMS-86-9-1303</a>, 2005. Onogi, K., Tsutsui, J., Koide, H., Sakamoto, M., Kobayashi, S., Hatsushika, H., Matsumoto, T., Yamazaki, N., Kamahori, H., Takahashi, K., Kadokura, S., Wada, K., Kato, K., Oyama, R., Ose, T., Mannoji, N., and Taira, R.: The JRA-25 re-analysis, J. Meteorol. Soc. Jpn., 85, 369–432, 2007. Randel, D. L., Vonder Haar, T. H., Ringerud, M. A., Stephens, G. L., Greenwald, T. J., and Combs, C. L.: A new global water vapor dataset, B. Am. Meteorol. Soc., 77, 1233–1246, 1996. Röske, F.: A global heat and freshwater forcing dataset for ocean models, Ocean Model., 11, 235–297, 2006. Schlüssel, P. and Emery, W. J.: Atmospheric water vapour over oceans from SSM/I measurements, Int. J. Remote Sens., 11, 753–766, 1990. Schulz, J., Jost, V., and Bakan, S.: A new satellite-derived freshwater flux climatology (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite), International WOCE Newsletter, 32, 20–26, 1998. Sherwood, S. C., Roca, R., Weckwerth, T. M., and Andronova, N. G.: Tropospheric water vapor, convection and climate, Rev. Geophys., 48, RG2001, <a href="http://dx.doi.org/10.1029/2009RG000301">https://doi.org/10.1029/2009RG000301</a>, 2010. Sohn, B. J. and Smith, E. A.: Explaining sources of discrepancy in SSM/I water vapour algorithms, J. Climate, 16, 3229–3255, 2003. Sohn, B. J., Smith, E. A., Robertson, F. R., and Park, S. C.: Derived Over-Ocean Water Vapor Transports from Satellite-Retrived <i>E</i> − <i>P</i> Datasets, J. Climate, 17, 1352–1365, 2004. Trenberth, K. E.: Changes in precipitation with climate change, Clim. Res., 47, 123–138, <a href="http://dx.doi.org/10.3354/cr00953">https://doi.org/10.3354/cr00953</a>, 2011. Trenberth, K. E., Fasullo, J., and Smith, L.: Trends and variability in column-integrated water vapor, Clim. Dynam., 24, 741–758, 2005. Uppala, S. M., Kallberg, P. W., Simmons, A. J., Andrae, U., Da Costa Bechtold, V., Fiorino, M., Gibson, J. K., Haseler, J., Hernandez, A., Kelly, G. A., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R. P., Andersson, E., Arpe, K., Balmaseda, M. A., Beljaars, A. C. M., Vande Berg, L., Bidlot, J., Bormann, N., Caires, S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Holm, E., Hoskins, B. J., Isaksen, L., Janssen, P. A. E. M., Jenne, R., McNally, A. P., Mahfouf, J.-F., Morcrette, J.-J., Rayner, N. A., Saunders, R. W., Simon, P., Sterl, A., Trenberth, K. E., Untch, A., Vasiljevic, D., Viterbo, P., and Woollen, J.: The ERA-40 re-analysis, Q. J. Roy. Meteorol. Soc., 131 Part B, 2961–3012, 2005. Vonder Haar, T. H., Bytheway, J. L., and Forsythe, J. M.: Weather and climate analyses using improved global water vapor observations, Geophys. Res. Lett., 39, L15802, <a href="http://dx.doi.org/10.1029/2012GL052094">https://doi.org/10.1029/2012GL052094</a>, 2012. Wentz, F. J.: Recommendations from Utah meeting, Salt Lake City, UT, USA, available at Remote Sensing Systems, Santa Rosa, CA, USA, 1995. Wentz, F. J.: A well-calibrated ocean algorithm for SSM/I, J. Geophys. Res., 102, 8703–8718, 1997.