> iTacs (Interactive Tool for Analysis of the Climate System)
iTacs (Interactive Tool for Analysis of the Climate System)
- 4 October 2021 - iTacs will be under maintenance from 15:00 to 18:00 (UTC) on 9th October and it is not available for about 40 minutes during the maintenance.
- 26 August 2021 - The “forecast time” of Data2 had not been specified by the chosen value from a pull-down list of Data2, but had been derived from that of Data1 instead. We have fixed this functional error. We apologize for any inconvenience it might have caused.
- 25 May 2021 - From 0430 UTC on 19th May to 0040 UTC on 25th May, the climatological normals for all elements in isentropic levels of JRA-55 dataset remained the old one based on the previous normal period of 1981 –2010.
- 25 May 2021 - From 0430 UTC on 19th May to 0400 UTC on 24th May, the climatological normals for COBE-SST dataset (daily) were unavailable.
- 31 March 2021 - The JMA's Global Ensemble Prediction System (GEPS) for one-month prediction was updated on 30 March 2021.
Along with this update, the hind-cast data were replaced by those of the new GEPS.
The operational forecast data of the new GEPS are available from 31 March 2021 initial.
- 28 January 2021 - Indian Ocean Dipole monitoring indices are available on iTacs.
- 30 September 2016 - Isentropic potential vorticity of JRA-55 is available on iTacs.
iTacs version 5.0
Datasets and Elements
What is iTacs?
iTacs stands for Interactive Tool for Analysis of the Climate System.
It is a web-based application developed by the Japan Meteorological Agency (JMA)
to assist National Meteorological and Hydrological Services (NMHSs)
in their production of analysis information on extreme climate events and their climate status monitoring.
It can be accessed via a web browsers without the need for additional software or plug-ins.
Various types of charts are available.
Time-longitude cross section
Time series graph
The application features various types of statistical evaluation, including EOF analysis and correlation analysis.
- Japanese 55-year reanalysis (JRA-55) data
- Outgoing Longwave Radiation (OLR) data (original data from NOAA polar-orbiting satellite observation)
- Sea surface temperature analysis (COBE-SST) data
- Ocean data assimilation system developed by the Meteorological Research Institute/JMA
- World climate data from surface stations (CLIMAT reports)
Note: The latest daily mean datasets are for two days prior. For example, the daily data sets for 1 November 2011 were produced on 3 November 2011. Pentad (five-day)/monthly mean datasets for a certain pentad/month are produced two days after the last day of the relevant time period. For example, the monthly datasets for October 2011 were made on 2 November 2011.
- JMA's one-month prediction model products (ensemble mean ('1MONTH_ENS_MEAN') and hind-cast dataset ('1MONTH_HIND'))
Major web browsers (e.g., Microsoft Internet Explorer, Mozilla Firefox, Apple Safari, Google Chrome) are recommended for iTacs usage. Plug-ins such as Adobe Flash Player or Microsoft Silverlight are not required.
Requests for iTacs access
Please read the Conditions of Use outlined below before submitting a request for iTacs access to JMA. All requests will be screened, and an ID and password will be issued for those that are approved. Staff at National Meteorological and Hydrological Services are eligible to use iTacs.
Please email the information below with "Request for iTacs access" as the subject. A reply with further information mail will be sent to the e-mail address provided within a few days.
- 1.Name (first/last):
- 2.Affiliation (e.g., Climate Prediction Division, Japan Meteorological Agency):
- 3.Address of organization of affiliation:
- 4.E-mail address:
- 5.Purpose of use (Requests simply stating "study" or "research" will not be approved.):
Conditions of Use
- 1.Users must provide the information requested, including their name, affiliation, e-mail address and purpose of data use.
- 2.The use of iTacs figures and/or data for commercial purposes is prohibited.
- 3.Users must not let any third party use the ID/password issued, and must keep this information private at all times.
- 4.The use of iTacs should be duly acknowledged in scientific or technical papers, publications, press releases and other communications.
Sample of citation: The figures and statistical analysis in this study were based on iTacs data provided by the Japan Meteorological Agency.
- 5.The data source used for iTacs must be referenced and acknowledged if necessary in scientific or technical papers, publications, press releases and other communications.
- 6.Users must provide JMA with a copy of any scientific or technical papers, publications, press releases and other communications whose production involved the use of iTacs.
- 7.Users must agree to the following operation policy:
JMA will send a warning message in the event of inappropriate use (e.g., if a user causes excessive server load). In the event of failure to comply with the content of this message, the Japan Meteorological Agency will disable the offending account.
Accounts that remain unused for more than a year will be deactivated. Users wishing to reactivate an ID should contact JMA.
Although JMA has taken the utmost care in developing the functions of iTacs, it assumes no responsibility regarding the system's reliability or for any damage that may result from its use. JMA reserves the right to change or delete information on this site without prior notice, and accepts no responsibility for any inconvenience that may result from such changes or deletion.
Tokyo Climate Center, Climate Prediction Division.
Copyright(C) 2002. Japan Meteorological Agency.
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