surface pressure

Recent Strengthening of the Pacific Walker circulation

Created by michelle.lheureux on - Updated on 08/09/2016 11:28

Citation: L'Heureux, M.L., S. Lee, and B. Lyon, 2013: Recent multidecadal strengthening of the Walker circulation across the tropical Pacific. Nature Clim Change, doi: 10.1038/nclimate1840.

Ten different datasets from reanalyses, reconstructions, and in situ measurements are examined for sea level pressure (SLP) trends over the tropical Pacific.  Instead of fitting a single least squares linear trend through the entire 1900-2011 record, running linear trends are calculated every six months over varying length windows (10-, 20-, 30-, and 40-year).  For the 20-40 year windows over Indonesia (110-160E, 10S-10N), a gradual increase from negative to positive SLP trends is evident beginning in 1910-1920 (see top figure below).  Then, starting in 1955-1965, the the positive trends cease growing and eventually trends become significantly negative over the last several decades. In contrast, over the Eastern Pacific (130-80W, 10S-10N), trends are less significant but there is evidence for a tendency towards positive SLP trends starting in the late 1950s or 1960s (see bottom figure below).  The tendency towards lower SLP over Indonesia and higher SLP over the eastern Pacific suggests a strengthening Walker circulation over the last half of the 20th century.  This increase in the Walker circulation becomes even more apparent when ENSO variability (using the Nino-3.4 index) is linearly removed from the datasets.  Moreover, the tendency for a strengthening Walker circulation appears to be nearly concurrent with the shift toward positive trends in global average temperatures.

While not shown below (see supplementary info), we note that a significant lack of in situ SLP data (ICOADS.v2.5) over the tropical Pacific is linked to larger disagreement in the datasets during the first half of the 20th century. Therefore, caution is recommended when interpreting the observed linear SLP trends prior to the 1950s.   

SLP linear trends for 10-, 20-, 30-, 40-year moving windows from January 1900 to December 2011.  (TOP FIGURE) Trends for the region over Indonesia (110◦–160◦ E, 10◦ S–10◦ N) and (BOTTOM FIGURE) for the region over the eastern Pacific Ocean (130◦–80◦ W, 10◦ S–10◦ N) . SLP is expressed as the change (hPa) over the window length. Grey shading represents the 95% confidence level based on a two-tailed Student’s t-test. The dashed, horizontal lines represent the 95% range of trends based on 1,000 synthetic AR(1) time series. The x axis shows the initial year of the trend (for 10-year windows, 1950 denotes the 1950–1959 trend). 

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ISPD Acknowledgments

Created by gilbert.p.comp… on - Updated on 07/18/2016 10:13

Work in progress

Digitization of Indian Monsoon data 1893-1899 are funded by the University of Giessen, Germany.

Feedback information in the ISPD comes from the 20th Century Reanalysis Project. The 20th Century Reanalysis Project used resources of the National Energy Research Scientific Computing Center and of the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory, which are supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and Contract No. DE-AC05-00OR22725, respectively. Support for the 20th Century Reanalysis Project dataset is provided by the U.S. Department of Energy, Office of Science Innovative and Novel Computational Impact on Theory and Experiment (DOE INCITE) program, and Office of Biological and Environmental Research (BER), and by the National Oceanic and Atmospheric Administration Climate Program Office. Support for the compilation of the ISPD is provided by the National Oceanic and Atmospheric Administration Climate Program Office and SwissRe.

 

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Submitting station data for the ISPD

Created by gilbert.p.comp… on - Updated on 07/18/2016 10:13

Guidelines for station data submission to the International Surface Pressure Databank

To submit station observations, please contact Dr. Gil Compo of the University of Colorado Cooperative Institute for Research in Environmental Sciences  and NOAA Earth System Research Laboratory Physical Sciences Division using <compo@colorado.edu>.

Observations of pressure, either surface or sea level pressure from the time that they were taken, are welcome.

Please include essential metadata such as the time that the observation was taken and station latitude, longitude, and elevation.

Depending on the size of the files, observation data files can be emailed to NOAA's National Climatic Data Center to the dataset assembler Dr. Xungang Yin Xungang.Yin@noaa.gov.

Please submit the data to NOAA's National Climatic Data Center Xungang.Yin@noaa.gov using the ASCII exchange format v1.0. Other data formats can also be accepted. Please coordinate your format with Dr. Yin and Dr. Compo

Depending on the instrument, the pressure data should be corrected for gravity and temperature. The data do not need to be reduced to sea level. 

If you have temperature data of subdaily, daily-averaged, or monthly-averaged resolution, please consider submitting that to surfacetemperatures.org.

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International Surface Pressure Databank Contributing Organizations

Created by gilbert.p.comp… on - Updated on 10/07/2019 19:45

Back to ISPD homepage

  1. All-Russian Research Institute of Hydrometeorological Information World Data Center
  2. Atmospheric Circulation Reconstructions over the Earth (ACRE)
  3. Australian Bureau of Meteorology
  4. Australian Meteorological Association, Citizen Science team
  5. British Antarctic Survey
  6. China University of Geosciences
  7. China Meteorological Administration
  8. Cook Islands Meteorological Service
  9. Danish Meteorological Institute
  10. Deutscher Wetterdienst (DWD; German Weather Service)
  11. Environment Canada, Climate Research Division
  12. ETH Zurich, Switzerland
  13. European and North Atlantic Daily to Multidecadal Climate Variability (EMULATE)
  14. European Reanalysis and Observations for Monitoring (EURO4M)/The WMO MEditerranean DAta REscue Initiative (MEDARE)
  15. European Reanalysis of Global Climate Observations (ERA-CLIM)
  16. GCOS Atmospheric Observation and Ocean Observation Panels for Climate WG on Surface Pressure
  17. GCOS/WCRP Working Group on Observational Data Sets for Reanalysis
  18. Hong Kong Observatory
  19. Icelandic Meteorological Office (IMO)
  20. International Best Track Archive for Climate Stewardship (IBTrACS)
  21. International Comprehensive Ocean–Atmosphere Data Set (ICOADS)
  22. International Environmental Data Rescue Organization (IEDRO)
  23. Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  24. Japan Meteorological Agency
  25. Jersey Met Department
  26. Koninklijk Nederlands Meteorologisch Instituut (KNMI; Royal Netherlands Meteorological Institute)
  27. Lamont-Doherty Earth Observatory of Columbia University
  28. McGill University, Canada
  29. Met Office Hadley Centre, UK
  30. MetéoFrance
  31. MeteoFrance—Division of Climate
  32. Meteorological and Hydrological Service, Croatia
  33. National Center for Atmospheric Research (NCAR), USA
  34. National Climate Center, Beijing, China
  35. National Institute for Water and Atmospheric Research (NIWA), New Zealand
  36. Nicolaus Copernicus University—Department of Meteorology and Climatology, Poland
  37. Niue Meteorological Service
  38. NOAA Climate Database Modernization Program (CDMP), USA
  39. NOAA Earth System Research Laboratory (ESRL) Physical Sciences Division, USA
  40. NOAA Midwest Regional Climate Center at UIUC, USA
  41. NOAA National Centers for Environmental Prediction (NCEP), USA
  42. NOAA National Centers for Environmental Information (NCEI), USA
  43. NOAA Northeast Regional Climate Center at Cornell Univ., USA
  44. NOAA Pacific Marine Environmental Laboratory, USA
  45. Norwegian Meteorological Institute
  46. Ohio State Univ.—Byrd Polar Research Center, USA
  47. Oldweather.org
  48. Portguese Institute of Sea and Atmosphere (IPMA), Portugal
  49. Proudman Oceanographic Laboratory, UK
  50. Signatures of environmental change in the observations of the Geophysical Institutes (SIGN)
  51. South African Weather Service
  52. South Eastern Australian Recent Climate History (SEARCH) project, The University of Melbourne
  53. Tanzania Meteorological Agency
  54. Univ. of Aberdeen, Scotland, UK
  55. Univ. of Bern, Switzerland
  56. Univ. of Colorado—Cooperative Institute for Research in Environmental Sciences (CIRES)
  57. Univ. of East Anglia—Climatic Research Unit, UK
  58. Univ. of Giessen—Department of Geography, Germany
  59. Univ. of Lisbon—Instituto Dom Luiz, Portugal
  60. Univ. of Milan—Department of Physics, Italy
  61. Univ. of Porto-Instituto Geofisico, Portugal
  62. Univ. Rovira i Virgili—Center for Climate Change (C3), Spain
  63. Univ. of South Carolina, USA
  64. Univ. of Toronto-Department of Physics, Canada
  65. Univ. of Washington, USA
  66. Weather Detective citizen science project
  67. WeatherRescue.org
  68. World Meteorological Organization-Mediterranean Climate Data Rescue (MEDARE)
  69. ZentralAnstalt für Meteorologie und Geodynamik (ZAMG; Austrian Weather Service)

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The International Surface Pressure Databank

Created by tcram on - Updated on 06/25/2024 14:24

The International Surface Pressure Databank

 
Created by tcram on Thu, 05/19/2011 - 16:31 - Updated on 07/24/2020 11:16

The International Surface Pressure Databank (ISPD, Cram et al. 2015) is the world's largest collection of pressure observations. It spans 1722-2015. It has been developed by extracting observations from established international archives of meteorological variables and by combining these with observations made available through additional international cooperation with data recovery facilitated by the Atmospheric Circulation Reconstructions over the Earth (ACRE) Initiative and the other contributing organizations. The ISPD is assembled under the auspices of the GCOS Working Group on Surface Pressure and the GCOS/WCRP Working Group on Observational Data Sets for Reanalysis by NOAA Earth System Research Laboratory (ESRL), NOAA's National Centers for Environmental Information (NCEI), and the University of Colorado's Cooperative Institute for Research in Environmental Sciences (CIRES).  

The ISPD consists of three components: station observations, marine observations, and tropical cyclone best track pressure reports.

The station component is a blend of many national and international collections, with the largest contributor being surface and sea level pressure observations from the International Surface Database (ISD, Lott et al., 2008). Procedures for blending the station component are described at Yin et al. (2008).

The marine component consists of the available version of the International Comprehensive Ocean Atmosphere Data Set (ICOADS, Worley et al., 2005). In some ISPD versions, ICOADS Auxiliary data, ACRE recovered expeditions, and Oldweather.org data are also used.

The tropical cyclone component comes mainly from the available version of the International Best Track Archive for Climate Stewardship (IBTrACS, Knapp et al., 2010). In the absence of a central pressure estimate, IBTrACS wind estimates are converted to pressure using an empirical gradient wind equation (Compo et al. 2011).

 

To submit station observations, please submit your observations to NOAA's National Center for Environmental Information via Xungang.Yin@noaa.gov using the ASCII exchange format v1.0.

Version 5 (1755-2012)

Version 5 of the International Surface Pressure Databank is currently being assembled. 
 

Additional guidelines for station data submission are under development.

Version 4 (1836-2015)

Version 4 of the ISPD is available courtesy of the Research Data Archive of the Computational and Information Systems Laboratory (CISL) at the National Center for Atmospheric Research (NCAR) from http://rda.ucar.edu/datasets/ds132.2/. Subsetting tools are available to retrieve the data in ASCII format. Documentation for the HDF5 format is provided at https://rda.ucar.edu/datasets/ds132.2/index.html#!docs.  Users can also browse an interactive map displaying observation locations by type, date, and region using the NCAR Interactive Station Viewer at https://rda.ucar.edu/datasets/ds132.2/index.html#wstationViewer.

NOAA's National Centers for Environmental Information has merged the station component using the ASCII exchange format v1.1.  The marine component comes from ICOADS version 3+, with enhancements to ICOADS version 3 from ACRE, Oldweather.org and Weather Detective courtesy of P. Brohan of the UK Met Office. The tropical cyclone component comes mainly from IBTrACS V03r10. See Slivinski et al. 2019 for details.

Maps showing the location of stations in a selected year can be browsed at https://psl.noaa.gov/data/ISPD/.

Maps showing the location of observations used in 20CRV3 in a selected year can be browsed at https://psl.noaa.gov/data/20CRv3_ISPD_obscounts/

Maps showing the location of all available, rejected, and assimilated observations used in 20CRV3 in a selected month can be browsed at https://psl.noaa.gov/data/20CRv3_ISPD_obscounts_bymonth/

The V4 list of stations, including location and period of coverage, and their history is a text file that can be imported into Excel or read into other programs using this format.

DOI: 10.5065/9EYR-TY90

Citation: Compo, G. P., et al. 2019. The International Surface Pressure Databank version 4. Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory. https://doi.org/10.5065/9eyr-ty90. Accessed § dd mmm yyyy.
  §Please fill in the "Accessed" date with the day, month, and year (e.g. - 5 Aug 2011) you last accessed the data from the NCAR Research Data Archive.

 

Version 3 (1755-2011)

Version 3 of the ISPD is available courtesy of the Research Data Archive of the Computational and Information Systems Laboratory (CISL) at the National Center for Atmospheric Research (NCAR) from http://rda.ucar.edu/datasets/ds132.1/. NCAR also has documentation on the HDF5 Format for International Surface Pressure Data Bank v10.11.

NOAA's National Climatic Data Center has merged the station component using the ASCII exchange format v1.1.  The marine component comes from ICOADS version 2.5. The tropical cyclone component comes from IBTrACS V03r03. ISPDv3 is being used in the century long reanalysis ERA-20C generated by ERA-CLIM,  by the century long reanalysis being generated by JMA/MRI, and by NOAA/CIRES in 20CR version 2c.

Maps showing the location of stations in a selected year can be browsed at http://www.esrl.noaa.gov/psd/data/ISPD/v3.0/
The V3 list of stations, including location and period of coverage, and their history is a text file that can be imported into Excel or read into other programs using this format.

DOI: 10.5065/D6D50K29

Citation: Compo, G. P., et al. 2015. The International Surface Pressure Databank version 3. Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory. http://dx.doi.org/10.5065/D6D50K29. Accessed § dd mmm yyyy.
  §Please fill in the "Accessed" date with the day, month, and year (e.g. - 5 Aug 2011) you last accessed the data from the NCAR Research Data Archive.

 

Version 2 (1768-2012)

Version 2 of the ISPD can be obtained courtesy of Data Engineering and Curation Section of the Computational and Information Systems Laboratory at the National Center for Atmospheric Research from http://rda.ucar.edu/datasets/ds132.0/. NCAR also has documentation on the HDF5 Format for International Surface Pressure Data Bank v10.11.

For the period 1871-2011, Version 2 includes metadata information from the quality control system of the 20th Century Reanalysis Project. These so-called "feedback" records include the difference between the final analysis and each observation, the estimated uncertainty in the observation, and other quality information.

See Compo et al. (2011) and Cram et al. (2015) for a more detailed description. 

Maps showing the location of stations in a selected year can be browsed at http://www.esrl.noaa.gov/psd/data/ISPD/v2.0/.
The V2 list of stations, including location and period of coverage, and their history is a text file that can be imported into Excel or read into other programs using this format.

DOI:10.5065/D6SQ8XDW

Citation: Compo, G. P., et al. 2010. International Surface Pressure Databank (ISPDv2). Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory. http://dx.doi.org/10.5065/D6SQ8XDW. Accessed§ dd mmm yyyy.
  §Please fill in the "Accessed" date with the day, month, and year (e.g. - 5 Aug 2011) you last accessed the data from the NCAR Research Data Archive.

      Future Additions

         At http://badc.nerc.ac.uk/browse/badc/corral/images/metobs there any many useful links to information about known observations and their recovery status. The site has links to scanned images of hard copy meteorological observations held by the National Meteorological Archive of the UK Met Office that have been imaged to date. It also has an EXCEL file containing the status of all of the historical weather data (whether hard copy, scanned or digitised) being recovered, imaged, and digitised by the international ACRE community and international organisations projects and researchers linked to the Initiative for the ISPD. Additionally, the site has annual global maps showing terrestrial weather data distribution and their status.

Guidelines for station data submission

Data Access

The International Surface Pressure Databank would like to thank the contributing organizations and make many grateful acknowledgments. Support for the compilation of the ISPD is provided by the National Oceanic and Atmospheric Administration Climate Program Office and SwissRe.

The 20th Century Reanalysis Project used resources of the National Energy Research Scientific Computing Center and of the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory, which are supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and Contract No. DE-AC05-00OR22725, respectively. Support for the 20th Century Reanalysis Project dataset is provided by the U.S. Department of Energy, Office of Science Innovative and Novel Computational Impact on Theory and Experiment (DOE INCITE) program, and Office of Biological and Environmental Research (BER), by the National Oceanic and Atmospheric Administration Climate Program Office, and by NOAA Earth System Research Laboratory Physical Sciences Division.

References:

Compo, G.P., J.S. Whitaker, P.D. Sardeshmukh, N. Matsui, R.J. Allan, X. Yin, B.E. Gleason, R.S. Vose, G. Rutledge, P. Bessemoulin, S. Brönnimann, M. Brunet, R.I. Crouthamel, A.N. Grant, P.Y. Groisman, P.D. Jones, M. Kruk, A.C. Kruger, G.J. Marshall, M. Maugeri, H.Y. Mok, Ø. Nordli, T.F. Ross, R.M. Trigo, X.L. Wang, S.D. Woodruff, and S.J. Worley, 2011: The Twentieth Century Reanalysis Project. Quarterly J. Roy. Meteorol. Soc., 137, 1-28. DOI: 10.1002/qj.776.

Cram, T.A., G. P. Compo, X. Yin, R. J. Allan, C. McColl, R. S. Vose, J.S. Whitaker, N. Matsui, L. Ashcroft, R. Auchmann, P. Bessemoulin, T. Brandsma, P. Brohan, M. Brunet, J. Comeaux, R. Crouthamel, B. E. Gleason, Jr., P. Y. Groisman, H. Hersbach, P. D. Jones, T. Jonsson, S. Jourdain, G. Kelly, K. R. Knapp, A. Kruger, H. Kubota, G. Lentini, A. Lorrey, N. Lott, S. J. Lubker, J. Luterbacher, G. J. Marshall, M. Maugeri, C. J. Mock, H. Y. Mok, O. Nordli, M. J. Rodwell, T. F. Ross, D. Schuster, L. Srnec, M. A. Valente, Z. Vizi, X. L. Wang, N. Westcott, J. S. Woollen, S. J. Worley, 2015: The International Surface Pressure Databank version 2. Geoscience Data Journal, 2, 31-46. DOI: 10.1002/gdj3.25.

Knapp KR, Kruk MC, Levinson DH, Diamond HJ, Neumann CJ, 2010: The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data. Bull. Amer. Meteorol. Soc.91: 363–376. DOI: 10.1175/2009BAMS2755.1.

Lott N, Vose R, Del Greco SA, Ross TF, Worley S, Comeaux J. 2008. ‘The Integrated Surface Database: Partnerships and progress.’ In Proceedings of 88th AMS Annual Meeting, 20–25 January 2008, New Orleans, Louisiana, combined preprints (CD-ROM), Amer. Meteorol. Soc: Boston, MA. Available from http://www1.ncdc.noaa.gov/pub/data/ish/ams-isd-jan08.pdf.

McColl, C., X. Yin, G. Compo, R. Allan, R. Vose, S. Woodruff, K. Knapp, and T. Cram, 2011: Assembling the International Surface Pressure Databank. World Climate Resarch Programme Open Science Conference, Denver, USA, 24 October. Poster link.

Slivinski, L. C., Compo, G. P., Whitaker, J. S., Sardeshmukh, P. D., Giese, B. S., McColl, C., Allan, R., Yin, X., Vose, R., Titchner, H., Kennedy, J., Spencer, L. J., Ashcroft, L., Brönnimann, S., Brunet, M., Camuffo, D., Cornes, R., Cram, T. A., Crouthamel, R., Domínguez‐Castro, F., Freeman, J. E., Gergis, J., Hawkins, E., Jones, P. D., Jourdain, S., Kaplan, A., Kubota, H., Le Blancq, F., Lee, T., Lorrey, A., Luterbacher, J., Maugeri, M., Mock, C. J., Moore, G. K., Przybylak, R., Pudmenzky, C., Reason, C., Slonosky, V. C., Smith, C., Tinz, B., Trewin, B., Valente, M. A., Wang, X. L., Wilkinson, C., Wood, K. and Wyszyński, P. (2019), Towards a more reliable historical reanalysis: Improvements for version 3 of the Twentieth Century Reanalysis system. Q J R Meteorol Soc. (accepted) doi:10.1002/qj.3598.

Worley SJ, Woodruff SD, Reynolds RW, Lubker SJ, Lott N. 2005. ICOADS release 2.1 data and products. Int. J. Climatol.25: 823–842. DOI: 10.1002/joc.1166.

Yin X, Gleason BE, Compo GP, Matsui N, Vose RS, 2008: The International Surface Pressure Databank (ISPD) land component version 2.2.  National Climatic Data Center, Asheville, NC. Available from ftp://ftp.ncdc.noaa.gov/pub/data/ispd/doc/ISPD2_2.pdf or from this site.

Yvan Dutil (not verified)

Sat, 08/30/2014 - 10:15

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Checking the map of the V4, the deepest in time we could expect to do a decent continuous North Atlantic Climate reanalysis using ISPD alone would be 1828. At this moment 1800, seams to be a hard limit to do any reanalysis at all for Europe. Unfortunately, they appears to be very little weather data available before 1850 not yet uncovered that could significantly improve this situation. I assume the 20CR version 2C is using a database close to the version 4. In consequence, the 1871 spatial coverage will be significantly extended compared to version 2. For 1850, the reanalysis will be comparable to the reanalysis for 1871 of the version 2.

Dear Yvan, As presented at the recent ACRE workshop in Toronto (proceedings will be online soon), the 20CRv2c currently being generated is using ISPDv3 not version 4, which is still being merged. You can access annual maps of the version 3 station component at http://www.esrl.noaa.gov/psd/data/ISPD/ . Note that these are not quite the version 3.2.9 that 20CRv2c is using, which has additional coverage over New Zealand, for example. Even so, the 1871 coverage is a substantial improvement over ISPDv2 used in 20CRv2. As to coverage before 1828, our ACRE colleagues continue to uncover new sources, so I would not rule out additional stations being digitized for that period.

Thank's for the prompt answer. Actually, I did notice that ISPDv4 map did not match with Phil Brohan visualisation of 20CR version 2C, after posting my comment. I did also notice that many potential sites on the ISPD 2.2.4 map are not yet included in the version 4. I assume the 20CR version 3 will be able to use version 4 or better.

Yvan, Correct. We expect 20CRv3 to use ISPDv4 or later. Similarly, ISPDv4 will be available to ECMWF's CERA-20C, a coupled centential reanalysis, as well as to the JMA SOUSEI project, which is also undertaking a coupled centennial reanalysis. Both of these were also presented at the ACRE 7th workshop. best wishes,

Yvan Dutil (not verified)

Thu, 01/23/2014 - 12:58

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Hi, When browsing the ISPD station map (http://www1.ncdc.noaa.gov/pub/data/ispd/add-station/v3.0/), I found a large gap in data between 1755 and 1767. I am under the impression that this is artifact and that data exist, but are not presented on these maps. Does I am right?

Xiaoxiao (not verified)

Fri, 11/22/2013 - 02:13

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Dear Dr. Compo, Thank you for your time of explaining for me. I'd like to consult you on some terminology.In your paper"The Twentieth Century Reanalysis Project", a minimum-error estimate of the 'true state' can be represented by the analysis ensemble mean(x¬a), page 6,in the bottom left corner,the paper also mentioned "the ensemble-mean analysis"(Hx¬a), page 8,in the bottom right corner. In the file Description of column data in ASCII format there is a variable ——"Ensemble mean analysis pressure". What are the differences between the analysis ensemble mean(x¬a),the ensemble-mean analysis(Hx¬a) and "Ensemble mean analysis pressure"? Thank you again for your time on this matter. Xiaoxiao

Dear Xiaoxiao, "H" is the operator which interpolates the analysis vector to the observation time and location. In this case, it is interpolating pressure from the model grid to the observation location and time. The xa you are referring to is the mean of 56 fields or vectors. Hxa is the mean of 56 scalars. Please let me know if I can clarify further. best wishes, gil

Dear Xiaoxiao, If you are interested, the individual members of the analysis fields from 20CR can be obtained at portal.nersc.gov The individual ensemble mean values of Hxa can be obtained from NCAR in the ISPD v2 http://rda.ucar.edu/datasets/ds132.0/ either in text files (see documentation http://rda.ucar.edu/datasets/ds132.0/docs/h5ftotxt.pdf ) or in HDF5 files (see documentation http://rda.ucar.edu/datasets/ds132.0/docs/International_Surface_Pressure_Data_Bank_format_v10.11.pdf) Please reply if you need any further assistance. best wishes, gil

Anonymous (not verified)

Sat, 11/16/2013 - 01:06

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TYPE 183 and TYPE 180 ： relative to mean sea level TYPE 181："Observed Sea Level Press" is corrected and “Observed Surface Pressure” is not corrected . So, the 3 types are all relative to mean sea level except “Observed Surface Pressure” in type 181 . Am I right ? Many thanks.

Dear Anonymous, Yes, you are correct. TYPE 183 and TYPE 180 ： relative to mean sea level TYPE 181："Observed Sea Level Press" is corrected and “Observed Surface Pressure” is not corrected . So, the 3 types are all relative to mean sea level except “Observed Surface Pressure” in type 181 . May I suggest obtaining a login at this site? You can post comments with usually faster responses this way. Please let us know if we can be more help. best wishes, gil compo

Chesley.McColl

Fri, 11/15/2013 - 15:41

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Dear Xiaoxiao,

The H5ftotxt is outputting the Observed Pressure, you are correct that the NCEP Type will tell you if this is Sea Level Pressure (ship observations) or Surface Pressure (station observations).

The pressure reported is not corrected to mean sea level, so it truly is surface pressure, at its reported elevation. Great questions. Respectfully yours, Chesley McColl
~

Anonymous (not verified)

Fri, 11/15/2013 - 11:16

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Dear professor, May I ask two questions ? On this page:http://rda.ucar.edu/datasets/ds132.0/index.html?hash=!access#!docs I found two documentations ("h5ftotxt.doc "and" International_Surface_Pressure_Data_Bank_format_v10.11.doc") contained the following information: h5ftotxt.doc(for ASCII format )： Observed Pressure Float 8 8.2F International_Surface_Pressure_Data_Bank_format_v10.11.doc(for HDF-5 format)： 1. Observed Sea Level Pressure The atmospheric sea level pressure observation (hectopascals) 4. Observed Surface Pressure The atmospheric surface pressure observation at the indicated elevation (hectopascals) Elevation The elevation of a geophysical point observation relative to Mean Sea Level (meters) My first question is : Are "Observed Sea Level Pressure" and "Observed Surface Pressure" mentioned in the second file for HDF-5 format both included in the “Observed Pressure” mentioned in the first file for ASCII format, which can be distinguished according to the NCEP Type ? The second question is : The "Observed Surface Pressure" mentioned in the second file for HDF-5 format means "the atmospheric surface pressure observation at the indicated elevation",dose this suggests that the observed surface pressure data have been normalised to sea level (these data have been reduced to sea level) since the Elevation is relative to Mean Sea Level ? Thank you for your kind consideration of the questions. It would be much appreciated if you can reply me about this. Best wishes! Sincerely yours, Xiaoxiao Zhang

Dear Xiaoxiao, Note that if you are seeing an NCEP type code of 183, this is a _station_ for which the ISPD only has a sea level pressure report. In no case is the column for Observed Surface Pressure reduced to sea level. It will be missing for stations that are of type 183. For stations of type 181, you may get both the Observed Surface Pressure and the Observed Sea Level Pressure. In the ASCII file you are referring to, when a station has reported both surface and sea level pressure, it will coded as type 181 and both reports will be included. Please let us know of any additional question. best wishes, gil compo

gilbert.p.comp…

Mon, 05/20/2013 - 10:14

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Dear Asia, There are many such sites. It depends on what you mean by "latest surface and upper air chart". Numerical Weather Prediction combines the available observations ("actual data") with a short term forecast to form the so-called "analysis". One site with such products is the NOAA Earth System Research Laboratory Physical Sciences Division Map Room http://www.esrl.noaa.gov/psd/map/ . See, e.g., the Current Weather page at http://www.esrl.noaa.gov/psd/map/wx/current.shtml Many products target a particular region. What is your region of interest? The Unisys Weather Page has many useful maps for the United States http://www.weather.unisys.com/index.php ECMWF has many useful maps. See http://www.ecmwf.int/products/forecasts/d/charts. In general, this is a site for constructing analyses in retrospect, or "reanalysis". Please let me know if I can be of more help. best wishes, gil compo

gilbert.p.comp…

Mon, 03/18/2013 - 10:02

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Dear Michel,

What you are seeing is the result of having used a T62 resolution spectral model to represent the orography of the earth in the 20th Century Reanalysis.

The pressure observations were adjusted to be consistent with the surface elevation of the assimilating NCEP model. Because of the long time period and many ensemble members, the resolution of the model was lower than one would prefer. This resolution is about 2degrees latitude by 2degree longitude. The spectral transformation will produce elevations in some reasons that have the sort of difference you are seeing from the true elevation.

Please see Compo et al. 2011 http://dx.doi.org/10.1002/qj.776 Section 3 equations 5-7. Also, you may be interested in Appendix B on the quality control system.

Note that the ISPD record preserves the original elevation and value (or values if both station and sea level pressure were reported), as well as providing the value as modified to be consistent with the assimilating model's orography.

Please let me know if I can be of more assistance.

best wishes,
gil compo

Michel Aïdonidis (not verified)

Mon, 03/18/2013 - 03:59

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Bonjour, Using data from your ISPD, I saw that, for some observed Pressures, the gap between the observation and the modified value can sometimes be huge. For example, one can read that an observation for the station of Biarritz, along the Atlantic sea shore, Souwestern France, for which elevation = 0m, Pobs = 1009.0hPa and the modified one = 947.0hPa with an error of 1.6hPa. But, at the end of the line, the modified elevation is then 531m. How could one explain these different values and such important discrepancies? Many thanks, Michel

gilbert.p.comp…

Thu, 08/09/2012 - 10:43

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Dear Xavier,

I'm glad you are finding the 20th Century Reanalysis project (20CR) data useful. Thank you for the kind words.

I apologize for the confusion on what was assimilated. No wind data were ever assimilated from any platform. Only pressure data were assimilated.

The web page you mention
http://www.esrl.noaa.gov/psd/data/ISPD/v2.0/
is showing only locations of the station component of the ISPDv2: these station pressure or sea level pressure from stations were available for assimilation. It does not refer to the ships used (the marine component of ISPD) in any way. I apologize for the confusion.

ISPD version 2 described above was used in 20CR.

You can access all of observations used in 20CR, including the specific ICOADS ship pressure observations and their associated feedback information, from
http://rda.ucar.edu/datasets/ds132.0/

From the Compo et al (2011) http://dx.doi.org/10.1002/qj.776 paper Section 4 page 7 describes the precise data that were used, including the specific ICOADS version numbers as a function of year.

Please let me know if I can be of more help.

best wishes,

gil

Xavier Bertin (not verified)

Thu, 08/09/2012 - 05:58

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Dear Dr. Compo, I'm a French researcher working at CNRS in La Rochelle University in the field of coastal oceanography. I'm presently using the 20CR reanalysis to investigate long-term variability of wind-waves and storm surges. My preliminary results are are very promising and by the way, I would like to congratulate you and thank you for the outstanding work that you did with your team. In order to evaluate the time evolution of the acuracy of SLP and winds, I've planned to make a comparison between 20CR and data derived from Vonluntary Observing Ships taken from the ICOADS. Nevertheless, I was not able to understand from your 2011 paper if this data was assimilated in the 20CR reanalysis. Based on this webpage: http://www.esrl.noaa.gov/psd/data/ISPD/v2.0/ I would conclude that it is not the case but I would be very grateful if you could confirm me. Thank you by advance and best regards, Xavier Bertin

As mentioned above,

Version 2 of the ISPD can be obtained courtesy of Data Support Section of the Computational and Information Systems Laboratory at the National Center for Atmospheric Research from http://rda.ucar.edu/datasets/ds132.0/

To make a clearer, a link has been added for
Data Access

Thanks for the question.

Anonymous (not verified)

Mon, 02/06/2012 - 13:42

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Dear David, This is curious, I would like to look into it further. But, first, from the HURDAT site http://www.aoml.noaa.gov/hrd/hurdat/easyread-2012.html , I only see 2 storms during the 10-14 September period, not three: Storm NOT NAMED is number 4 of the year 1928 Storm NOT NAMED is number 5 of the year 1928 Would you indicate what is the third system you are thinking of? Perhaps the third did not make it into HURDAT? Thanks in advance, Gil Compo

David Roth (not verified)

Sat, 02/04/2012 - 21:19

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I have a question. I just ran across this link, which explains why some storms (particularly the historic ones landfall-wise) within Atlantic HURDAT seem to be depicted with the correct strength within the 20th century reanalysis pressure maps. The question is, if IBTrACS is used, which contains the Atlantic HURDAT, then why do some tropical storms and hurricanes appear to be missing? In particular, during the September 10-14, 1928 time frame, there are 3 tropical cyclones in existence between Florida, Bermuda, and the West Indes. However, the only tropical cyclone which appears on the pressure maps is the Great Miami Hurricane, which hit Florida on September 18. Why would two of the TCs not show up, when they showed up well in conventional data in real-time as well as HURDAT? See the October 1926 Monthly Weather Review article around page 411 for the conventional maps of the pressure pattern. Curious.

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Atmospheric Pressure

Created by Cathy.Smith@noaa.gov on - Updated on 01/09/2019 09:57

The International Surface Pressure Databank (ISPD) 1755-2010: contains surface and sea level pressure observations from three components: land (largely from ISD and also 43 other national and international collections of pressure observations), marine (largely from ICOADS), and tropical cyclone pressure reports from IBTrACS.

Gridded fields for Surface and Sea Level Pressure can be obtained from Atmospheric Reanalysis Datasets.

Compositing map tools for several global and near-global gridded Sea Level Pressure data sets are available at the GCOS Working Group on Surface Pressure website.

 

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