The Upgrade History of the Global Spectral Model 05 MAR 2024 : Assimilation of the ATMS and CrIS data from NOAA-21 was started. 09 MAY 2023 : Assimilation of AMV and CSR from GOES-18 was started. Assimilation of AMV and CSR from Meteosat-10 switching from Meteosat-11 was started. 14 MAR 2023 : Major upgrade was made to the Global Spectral Model (GSM). Major changes were, - Increase of the horizontal resolution -- Incorporation of quadratic grid: from TL959(linear grid, approx. 20km grid spacing) to TQ959 (quadratic grid, approx. 13km grid spacing) with refinement of numerical diffusion in the model and filters for mean orography - Replacement of the source data set for orographic ancillary files: GTOPO30 to MERIT DEM + RAMP2 - Revision of several physical processes such as non-orographic gravity wave, boundary layer, orographic drag and radiation. - Improvement of lake surface process - Revision of the global snow depth analysis - Assimilation of Suomi-NPP, NOAA-20/VIIRS AMV was started 13 DEC 2022 : Assimilation of AMV and CSR from Himawari-9 was started. 30 JUN 2022 : Assimilation of EUMETSAT Dual-Metop AMV was started. 24 NOV 2021 : Assimilation of Metop-C/IASI was started. 29 JUN 2021 : All-sky assimilation of microwave water-vapor sounder from GMI/GPM, ATMS/NOAA-20, Suomi-NPP, SSMIS/DMSP-F17, F18, SAPHIR/Megha-Tropiques, MWHS-2/FY-3C was started. - Assimilation of AMV and CSR from GOES-17 was started. - Bias correction method for aircraft-based observations was revised. 30 MAR 2021 : Major upgrade was made to the Global Spectral Model (GSM). Major changes were, - increase of the number of vertical layers from 100 to 128, - revision of the global snow analysis, - introduction of the global soil moisture analysis. Improvements were made to the 4DVAR-LETKF hybrid data assimilation. - increase of ensemble members from 50 to 100. - increase of weight for ensemble-based background error covariance. 15 SEP 2020 : Assimilation of AMSU-A and MHS from Metop-C was started. 29 JUL 2020 : Assimilation of ScatSat-1/OSCAT and GOES-16 AMV data was started. 24 MAR 2020 : Major upgrade was made to the Global Spectral Model (GSM). Major changes were, - revision of parameterization schemes such as gravity wave and boundary layer, - improvement of land surface process, - adjustment of sea ice albedo and cloud processes in polar regions, - the forecast period was extended to 264 hours at 00UTC. 11 DEC 2019 : All-sky assimilation of microwave imager (AMSR2/GCOM-W, GMI/GPM, SSMIS/DMSP F-17, F-18, WindSat/Coriolis, MWRI/FY-3C) and microwave water-vapor sounder (GMI/GPM, MHS/NOAA-19, Metop-A, -B) was started. Assimilation of ASCAT from Metop-C was started. Hybrid background error covariances estimated with LETKF and outer-loop iteration were introduced in 4D-Var system. 18 JUN 2019 : Assimilation of GOES-16 CSR data was started. 05 MAR 2019 : Assimilation of the ATMS and CrIS data from NOAA-20 was started. 18 OCT 2018 : Usage of Clear-Sky Radiance (CSR) data was enhanced. Major changes were, - the assimilation of surface-sensitive CSR data from Himawari-8 Band 9 and 10 and Meteosat-8, 11 Channel 6, and - the assimilation of hourly CSR data from Meteosat-8, 11 and GOES-15 with cessation of data thinning every two hours. (Note: Hourly CSR data from Himawari-8 have been already used since March 2016.) 05 JUN 2018 : The forecast period was extended to 132 hours at 00, 06 and 18UTC. 25 JUL 2017 : Usage of GNSS radio occultation data was revised. 25 MAY 2017 : Major upgrade was made to the Global Spectral Model (GSM). Major changes were, - revision of various parameterization schemes such as deep convection, cloud, radiation, land surface and sea surface, - implementation of a stratospheric methane oxidation parameterization scheme, - improvement of discretization in calculation of pressure gradient force terms, Background error statistics in the data assimilation system were revised. 29 MAR 2017 : Assimilation of Suomi-NPP/ATMS, Suomi-NPP/CrIS and DMSP-F17,18/SSMIS(183GHz) started. Transition of AMV and CSR from Meteosat-7 to Meteosat-8 completed. 15 DEC 2016 : Quality Control for Himawari-8 AMV was revised. Assimilation of GRACE-B/BlackJack radio occultation data was enabled. 28 SEP 2016 : The typhoon bogus scheme was revised. 24 MAR 2016 : Major upgrade was made to the model. Major changes were, - The parameterization schemes of the Global Spectral Model (GSM) such as land surface processes, deep convection, cloud, radiation, sea ice and so on were revised. - Assimilation of the GPM Microwave Imager (GMI) data started. 17 MAR 2016 : Assimilation of Himawari-8 AMV and CSR data started. 08 OCT 2015 : Assimilation of METAR surface pressure data started. Usage of ASCAT ocean surface wind vector data was improved. 25 JUN 2015 : Assimilation of Megha-Tropiques/SAPHIR started. 04 SEP 2014 : Assimilation of Metop-A/IASI, Metop-B/IASI, and Aqua/AIRS started. 18 MAR 2014 : Major upgrade was made especially to the model. Major changes were, - increase in the resolution from TL959L60 to TL959L100 with a topmost level raised from 0.1hPa to 0.01hPa, - revision of several physical processes such as boundary layer, radiation, non-orographic gravity wave and deep convection. - The assimilation of AMSU-A channel 14 and ground-based GNSS-ZTD (Zenith Total Delay) data were started, and the GNSS RO assimilation was revised from refractivity assimilation up to 30 km AMSL to bending angle assimilation up to 60 km AMSL. 28 NOV 2013 : Assimilation of GRAS, AMSU-A, MHS, ASCAT and AVHRR-AMV data from Metop-B started. 16 OCT 2013 : Assimilation of SYNOP BUFR started. 12 SEP 2013 : Assimilation of JAXA's GCOM-W1/AMSR2 radiance data started. 28 MAR 2013 : The forecast period was extended to 264 hours at 12UTC. 18 DEC 2012 : Improved stratocumulus cloud scheme and revised the usage of GNSS RO data. 25 OCT 2011 : Horizontal resolution of the inner loop was increased from T159 (~80km) to TL319 (~60km). 01 NOV 2010 : Assimilation of COSMIC radio occultation data started. 30 NOV 2009 : Assimilation of GRACE-A/BlackJack and Metop-A/GRAS radio occultation data started. Assimilation of aircraft temperature data started with a bias correction scheme for the data. 28 JUL 2009 : Assimilation of DMSP F16 SSMIS radiance data (UK Met Office pre-processed temperature sounding channels) started. Assimilation of Metop-A/ASCAT data started. 26 MAR 2009 : The radiative transfer model was upgraded from RTTOV-8 to RTTOV-9, which improved analysis quality in the stratosphere significantly. 23 MAR 2009 : Number and position of pseud-data for typhoon analysis were revised, which improved typhoon track forecasts. 10 NOV 2008 : Quality control thresholds for the conventional observing system were revised. 15 OCT 2008 : Improved quality control for microwave radiance was implemented and the radiative transfer model was upgraded from RTTOV-7 to RTTOV-8. The microwave ocean emissivity model of RTTOV was also upgraded. A bias correction scheme for radiosonde observation was improved. 27 AUG 2008 : Direct assimilation of clear-sky radiances of water vapour channels from geostationary satellites (MTSAT-1R/IMAGER, GOES11/IMAGER, GOES12/IMAGER, METEOSAT7/MVIRI, METEOSAT9/SEVIRI) started. Background errors of variational bias correcttion for radiance data were revised. 05 AUG 2008 : Reduced Gaussian Grids was implemented in GSM and number of grid points in calculation of nonlinear terms was reduced. 10 JAN 2008 : Calculation procedure of the convective triggering scheme was revised. Excessive limitation on cumulus mass flux from redundant vertical CFL condition was corrected. 11 DEC 2007 : The initialization procedures were removed from a 9-hour forecast in the data assimilation. 21 NOV 2007 : Major upgrade was made to the model. Major changes were, - increase in the resolution from TL319L40 to TL959L60 with a topmost level raised from 0.4hPa to 0.1hPa, - use of a new high-resolution analysis of sea surface temperature and sea ice concentration as ocean surface boundary conditions, - use of surface snow depth data from the domestic dense observational network in the global snow depth analysis, - introduction of a convective triggering scheme into the deep convection parameterization, - introduction of a new 2-dimensional aerosol climatology derived from satellite observations for the radiation calculation, - increase in the resolution of inner loop model of the four-dimensional variational (4D-Var) data assimilation system from T106L40 to T159L60, - change of forecast time to 84 hours for operations at 00, 06 and 18UTC. Assimilation of Metop-A/AMSU-A and MHS started. 02 AUG 2007 : Assimilation of EARS (EUMETSAT Advanced Retransmission Service) ATOVS data started. 07 JUN 2007 : Direct assimilation of clear-sky radiances of water vapour channel from MTSAT-1R/IMAGER started. 18 APR 2007 : Assimilation of NOAA18/AMSU-A, MHS started. 22 MAR 2007 : Assimilation of GPS-RO(Radio Occultation) data from CHAMP started. 22 FEB 2007 : Assimilation of AP-RARS (Asia-Pacific Regional ATOVS Retransmission Service) data started. 18 OCT 2006 : BUFR winds of GOES-11/12 and MTSAT-1R started to be used instead of SATOB winds. A thinning scheme and QI thresholds for QC were revised for all geostationary satellite BUFR winds. 21 AUG 2006 : QC and bias correction procedures and observation error assignment were revised in ATOVS radiance assimilation. 15 MAY 2006 : Direct assimilation of SSM/I, TMI, and AMSR-E radiance data started. Bias correction method for ATOVS radiance data was revised. 01 MAR 2006 : Major upgrade was introduced on an occasion of the operation of the new mainframe computer, Hitachi SR11000K1 (80 nodes*2), with a peak performance of 21.5 Tflops and main memory of 10.0 Tbytes. Major changes were, - new operation at 06, 18UTC with forecast time of 36 hours in addition to 00UTC with 90 hours and 12UTC with 216 hours, - increase in the resolution of inner loop of the four-dimensional variational (4D-Var) from T63L40 to T106L40. 02 AUG 2005 : A thinning scheme for one-hour time slots in 4D-Var was introduced for ATOVS assimilation. 07 JUL 2005 : The radiation scheme was updated for the better treatment of cloud effects. A new ozone climatology was introduced for the radiation calculations. 10 MAR 2005 : Assimilation of Aqua/AMSU-A started. 17 FEB 2005 : Major upgrade was made to the data assimilation system. Major changes were, - introduction of a four-dimensional variational (4D-VAR) data assimilation method with the horizontal resolution of TL319L40 for outer loop and T63L40 for inner loop, - revision of background error statistics. GSM was upgraded. Major changes were, - introduction of a semi-Lagrangian advection scheme, - increase in the spectral resolution from T213 (quadratic grid) to TL319 (linear grid), - minor modifications of the cumulus convection and the prognostic cloud water schemes to accommodate them to the semi-Lagrangian advection scheme, - introduction of an incremental non-linear normal mode initialization and a vertical mode initialization. 02 DEC 2004 : Direct assimilation of ATOVS level1C data replaced that of level1D data. The radiative transfer model for the radiance assimilation was upgraded from RTTOV-6 to RTTOV-7. The new long-wave radiation scheme was introduced. Major changes were, - use of a lookup-table method and a k-distribution method instead of a traditional band model, - increase in number of spectral bands from 4 to 9, - improvement of a parameterization of water vapor continuum absorption, - introduction of an effect of minor gases such as methane, nitrous oxide and CFCs. A parameterization of absorption in the short-wave radiation scheme was improved for ozone, carbon dioxide and oxygen. 16 SEP 2004 : Assimilation of Terra/MODIS and Aqua/MODIS in the south polar region started. 29 JUL 2004 : A new parameterization scheme for marine stratocumulus was introduced. Cloud water/ice scheme was improved. Land surface model was improved in ice sheet treatment. 27 MAY 2004 : Assimilation of Terra/MODIS and Aqua/MODIS in the north polar region started. 15 APR 2004 : Assimilation of radio sonde temperature instead of the geopotential height started. Quality check on radio sonde relative humidity was intensified. 15 DEC 2003 : Assimilation of German, Dutch, Swiss wind profilers started. 12 AUG 2003 : Assimilation of British wind profilers started. 28 MAY 2003 : Direct assimilation of ATOVS radiance data from the NOAA satellites started. Physical process for cumulus convection was improved. 06 MAY 2003 : Assimilation of QuikSCAT/SeaWinds data started. 19 APR 2002 : A regression coefficient for the 3D-VAR was revised again. 05 DEC 2001 : A regression coefficient for the 3D-VAR was revised. 26 SEP 2001 : A 3-dimentional variational (3D-VAR) data assimilation method was introduced. Improvements were seen in wind forecasts in the upper troposphere as well as in temperature in the middle and upper troposphere. 12 JUN 2001 : Assimilation of the nation-wide wind profiler network data started. 01 MAR 2001 : Major upgrade was introduced on an occasion of the operation of the new mainframe computer, Hitachi SR8000E1 (80 nodes), with a peak performance of 768 Gflops and main memory of 640 Gbytes. Major changes were, - increase of the number of vertical levels from 30 to 40 and raising the model top from 10hPa to 0.4hPa, - extension of the forecast time up to 216 hours (12UTC) and 90 hours (00UTC), respectively, - introduction of a high resolution global elevation data set (GTOPO30) into both the model topography and the gravity wave drag parameters, - introduction of a high resolution global land cover characterization data set of USGS into the land-sea mask, - refinement of both the cumulus convection scheme and the radiation scheme. The upper stratosphere analysis using a function fitting method was discontinued, since 3D-OI analysis up to 0.4 hPa started. Improvements were seen in wind forecasts in the upper troposphere. 23 MAR 2000 : A 1D-VAR assimilation system for RTOVS radiance data from the NOAA-14 satellite was introduced. 07 MAR 2000 : A global snow depth analysis using SYNOP data started. 27 JAN 2000 : Assimilation of ATOVS/BUFR data from the NOAA-15 satellite started. 07 DEC 1999 : An extensive change was introduced to the physical package. Major changes were, - making cloud water a prognostic variable, - improvement of the cumulus parameterization, - introduction of a direct aerosol effect for the radiation processes. Improvements were seen in several aspects, such as - geopotential height forecasts in the Northern Hemisphere in winter, - wind forecasts in the upper troposphere, - precipitation forecasts associated with Asian summer monsoon, - velocity potential field analysis in the upper troposphere, - typhoon track and intensity forecasts. 06 JUL 1999 : Assimilation of SATEM data from the NOAA15 satellite started. 06 JUL 1999 : The observational error of PAOB data was revised. 04 AUG 1998 : The quality control for both sea level pressure and surface pressure data was revised. 14 JUL 1998 : Assimilation of scatterometer data from the ERS-2 satellite started. 05 NOV 1997 : The bias correction system for radiosonde data was revised. 17 MAR 1997 : A dynamic quality control system was introduced for all observational data. 10 DEC 1996 : The initialization scheme was revised. 25 APR 1996 : The vertical correlation function in the data assimilation system was revised. 01 MAR 1996 : Major upgrade was introduced on an occasion of the operation of the new mainframe computer, Hitachi S3800/480 (4 CPU), with a peak performance of 32 Gflops and main memory of 2+12 Gbytes. Major changes were, - increase of the horizontal resolution from T106 to T213, - increase of the number of vertical levels from 21 to 30, - replacement of the cumulus convection scheme from a Kuo scheme to a prognostic Arakawa-Schubert scheme, - refinement of the radiation scheme, - change of the data assimilation method from a 2D-OI on mandatory pressure levels to a 3D-OI on the model vertical levels. Significant improvements were seen in typhoon track forecasts and wind forecasts in the lower troposphere in the tropics. 16 DEC 1993 : A consistency check of sailing route for SHIP data was introduced. 01 JUL 1993 : A optimum interpolation (OI) method for a global stratospheric analysis was implemented. 09 MAR 1993 : Assimilation of TOVS retrieved data from the NOAA satellites started. 05 NOV 1992 : Physical process for a cumulus convection (Kuo scheme) and a horizontal diffusion were improved. 03 OCT 1991 : Considering the atmospheric tide in a nonlinear normal mode initialization was introduced. 14 NOV 1989 : GSM was upgraded. Major changes were, - increase of the horizontal resolution from T63 to T106, - increase of the number of vertical levels from 16 to 21, - introduction of a hybrid eta-coordinate system, - introduction of the Simple Biosphere model in a land surface process, - improvement of a physical process for radiation and gravity wave drag. 01 MAR 1988 : The global spectral model (T63L16, 6 hourly data assimilation cycle) was put into operation.