Modified NCEP surface pressure data, key-dates for superposed epoch analyses, and videos of surface pressure responses

The data interval is 1995 to 2017, excluding end-points imposed by averaging.NCEP/NCAR reanalysis surface pressure data was obtained from https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surface.html. Surface pressure residuals are produced consisting of 1-day, 3-day and 5-day averages from which long-term variations are removed by subtracting a pressure average of the remaining, centred, 27-days. These data are in NCEP format (2.5°lat. x 2.5°long.) ASCII csv files.Selected daily-averaged solar wind and auroral activity indices, and solar sector boundary crossing dates are derived from data obtained at GSFC/NASA OMNIWeb data at https://omniweb.gsfc.nasa.gov. These data are listed in an EXCEL xlsx file.Videos of +/-13 day lags of four superposed epoch analyses of surface pressure responses to selected solar sector boundary crossings. The video are designated NH_MAMJJA_3dpc, SH_JJASON_3dpc_ave-of-3,NH_DJFMAM_6dpc and Equ_Year_8dpc, indicating the region (Northern Hemisphere, Southern Hemisphere, and Equatorial), the interval (acronym of first letter of each month or the entire Year) and the days of IMF By phase consistency (dpc) used to select the solar sector boundary crossing key-dates. The 'ave-of-3' designation indicates the averaging of initial superposed epoch responses across the original lags at -27 days, the key-date and +27 days.We use surface pressure data from the NCEP/NCAR reanalysis (Kalnay et al., 1996) obtained from https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surface.html. This product is derived from a numerical weather prediction model which uses a data assimilation scheme to provide boundary conditions. Observational data for surface pressure in the polar regions comes primarily from fixed surface stations, ship and buoys collected under the International Comprehensive Ocean-Atmosphere Data Set (ICOADS; Woodruff et al., 2011). The reanalysis performs generally adequately, capturing intraseasonal variability in surface pressure (Yu et al., 2010; Bromwich and Fogt, 2004) although some discontinuities have been identified in particular epochs in the 1990s (Hines et al., 2000). The NCEP re-analysis does not assimilate cloud or aerosol data, and models clouds and radiation fields based on parameterisations informed mainly by temperature and water vapour data. As shown by Trenberth and Fasullo (2010), large biases exist in the SH surface radiation fields because of inadequacies in the correct representation of clouds, particularly because of underestimation of the presence of supercooled liquid water layers (Hyder et al. 2018).Daily-averaged values are obtained from the six-hourly analysis values for each grid point (2.5°lat. x 2.5°long.) across each UT-day as [0.5*00UT + 06UT + 12UT + 18UT + 0.5*24UT]/4. Long-term variability in the pressure data is removed by calculating 27-day running-mean residuals, matching the solar rotation. From each daily-averaged pressure at each grid point, the average of all other pressures for that grid point across +/-13 days is subtracted. To test if a pressure response accumulates over a number of days, similar running mean residuals are calculated for 3-day and 5-day averages from which are subtracted the pressure averages of the remaining 27-days. The 1-day, 3-day and 5-day residual pressure surfaces are designated as XdPSurf. Surface pressure residuals are produced consisting of 1-day, 3-day and 5-day averages from which long-term variations are removed by subtracting a pressure average of the remaining, centred, 27-days.These data are in NCEP global format (2.5°lat. x 2.5°long.) ASCII csv files. The individual daily files are in yearly folders and the yearly folders are in 1dPSurf, 3dPSurf and 5dPSurf folders depending on the averaging and residual determinations described above.The residual surface-level pressures are listed in hecta-Pascals (hPa) with a resolution of 2 decimal points.Individual daily csv ASCII data files are designated NCEP-DOE_PSurf_1d_1995-01-14.csv or similar.Data coverage is from 14 Jan 1995 to 17 Dec 2017. The endpoints are different from the start and end of these years associated with the determination of the 27-day residuals of the complete years.References:Bromwich, D. H., and R. L. Fogt, 2004: Strong trends in the skill of the ERA-40 and NCEP-NCAR reanalysis in the high and midlatitudes of the Southern Hemisphere, 1958–2001. J. Climate, 17, 4603–4619, doi:10.1176/3241.1.Hines, K.M., D. H. Bromwich, and G. J. Marshall, 2000: Artificial Surface Pressure Trends in the NCEP–NCAR Reanalysis over the Southern Ocean and Antarctica. J. Climate, 13, 3940–3952, doi:10.1175/1520-0442(2000)0132.0.CO;2.Hyder, P., J.M. Edwards, R.P. Allan, H.T. Hewitt, T.J. Bracegirdle, J.M. Gregory, R.A. Wood, A.J.S. Meijers, J. Mulcahy, P. Field, K. Furtado, A. Bodas-Salcedo, K.D. Williams, D. Copsey, S.A. Josey, C. Liu, C.D. Roberts, C. Sanchez, J. Ridley, L. Thorpe, S.C. Hardiman, M. Mayer, D.I. Berry, and S.E. Belcher, 2018: Critical Southern Ocean climate model biases traced to atmospheric model cloud errors. Nature Communications, 9:3625, doi: 10.1038/s41467-018-05634-2.Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin, M. Iredell, S. Saha, G. White, J. Woollen, Y. Zhu, M. Chelliah, W. Ebisuzaki, W. Higgins, J. Janowiak, K. C. Mo, C. Ropelewski, J. Wang, A. Leetmaa, R. Reynolds, R. Jenne, and D. Joseph, 1996: The NCEP/NCAR 40-year reanalysis project, Bull. Amer. Meteor. Soc., 77, 437-470, doi: 10.1175/1520-0477(1996)0772.0.CO;2.Trenberth, K.E., and J.T. Fasullo, 2010: Simulation of present-day and twenty-first-century energy budgets in the southern oceans. J. Climate, 23, 440-454, doi: 10.1175/2009JCLI3152.1.Woodruff, S.D., S.J. Worley, S.J. Lubker, Z. Ji, J.E. Freeman, D.I. Berry, P. Brohan, E.C. Kent, R.W. Reynolds, S.R. Smith, and C. Wilkinson, 2011: ICOADS Release 2.5: extensions and enhancements to the surface marine meteorological archive. Int. J. Climatol. (CLIMAR-III Special Issue), 31, 951-967, doi:10.1002/joc.2103.Yu, L., Z. Zhang, M. Zhou, S. Zhong, D. Lenschow, H. Hsu, H. Wu, and B. Sun, 2010: Validation of ECMWF and NCEP-NCAR reanalysis data in Antarctica, Adv. Atmos. Sci. 27: 1151, doi:10.1007/s00376-010-9140-1.