Japanese 25-year Reanalysis Project, Monthly Means

• Main Authors: Japan Meteorological Agency/Japan, Central Research Institute Of Electric Power Industry/Japan
• Format: Dataset
• Language: English
• Published: UCAR/NCAR - Research Data Archive 2008
• Subjects: EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SURFACE WATER > SURFACE WATER PROCESSES/MEASUREMENTS > RUNOFF; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW WATER EQUIVALENT; EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW DEPTH; EARTH SCIENCE > OCEANS > SEA ICE > ICE EXTENT; EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > SEA SURFACE TEMPERATURE; EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > SURFACE ROUGHNESS; EARTH SCIENCE > LAND SURFACE > SURFACE THERMAL PROPERTIES > LAND SURFACE TEMPERATURE; EARTH SCIENCE > LAND SURFACE > SOILS > SOIL TEMPERATURE; EARTH SCIENCE > LAND SURFACE > SOILS > SOIL MOISTURE/WATER CONTENT; EARTH SCIENCE > CRYOSPHERE > SEA ICE > SNOW MELT; EARTH SCIENCE > CRYOSPHERE > SEA ICE > SNOW DEPTH; EARTH SCIENCE > BIOSPHERE > VEGETATION > CANOPY CHARACTERISTICS; EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > SOLID PRECIPITATION > SNOW; EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > PRECIPITATION RATE; EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > PRECIPITATION AMOUNT; EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD FREQUENCY; EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD MICROPHYSICS > CLOUD LIQUID WATER/ICE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > VORTICITY; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > VERTICAL WIND VELOCITY/SPEED; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > STREAMFUNCTIONS; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > CONVERGENCE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > UPPER LEVEL WINDS; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > SURFACE WINDS; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR PROCESSES > EVAPOTRANSPIRATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > WATER VAPOR; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > TOTAL PRECIPITABLE WATER; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > HUMIDITY; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > DEW POINT TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > UPPER AIR TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > POTENTIAL TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > MAXIMUM/MINIMUM TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > AIR TEMPERATURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > SHORTWAVE RADIATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > LONGWAVE RADIATION; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > HEAT FLUX; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > ATMOSPHERIC HEATING; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > SURFACE PRESSURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > SEA LEVEL PRESSURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > HYDROSTATIC PRESSURE; EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > GRAVITY WAVE; EARTH SCIENCE > ATMOSPHERE > ALTITUDE > GEOPOTENTIAL HEIGHT; EARTH SCIENCE > ATMOSPHERE > AIR QUALITY > TROPOSPHERIC OZONE; Sea ice
• Online Access: https://dx.doi.org/10.5065/g3ar-1091; https://rda.ucar.edu/datasets/ds625.1/

The Japanese 25-year Reanalysis (JRA-25) represents the first long-term global atmospheric reanalysis undertaken in Asia. Covering the period 1979-2004, it was completed using the Japan Meteorological Agency (JMA) numerical assimilation and forecast system and specially collected and prepared observational and satellite data from many sources including the European Center for Medium-Range Weather Forecasts (ECMWF), the National Climatic Data Center (NCDC), and the Meteorological Research Institute (MRI) of JMA. A primary goal of JRA-25 is to provide a consistent and high-quality reanalysis dataset for climate research, monitoring, and operational forecasts, especially by improving the coverage and quality of analysis in the Asian region.In JRA-25, three-dimensional variational (3D-Var) data assimilation and a global spectral model were employed to produce 6-hourly atmospheric analysis and forecast cycles. The global spectral model was based on a 320 by 160 (~1.125 degree) Gaussian grid with T106 truncation. Vertical discretization employed a hybrid sigma-pressure coordinate utilizing 40 levels where 0.4 hPa represents the model top level. A predictive mass-flux Arakawa-Schubert scheme was utilized for cumulus parameterization, and Simple Biosphere (SiB) parameterizations for land-surface processes. Assimilated variables include temperature, relative humidity, and surface pressure from conventional observations, and also winds retrieved from geostationary satellites, radiative brightness temperature from TIROS Operational Vertical Sounder (TOVS), and precipitable water from Special Sensor Microwave/Imager (SSM/I). Variables not directly assimilated include daily sea surface temperature (SST) and sea ice based on Centennial in-situ Observation-Based Estimates (COBE), and ozone profiles based on chemical transport models constrained by observations from Total Ozone Mapping Spectrometer (TOMS).The JRA-25 shows marked improvement over previous reanalyses in several notable areas, especially predicted (both 6-hourly and long term) precipitation, with more realistic variability and fewer spurious trends due to contamination of satellite data by volcanic eruptions. JRA-25 is also the first reanalysis to assimilate wind profiles around tropical cyclones deduced from best-track data, resulting in improved tropical cyclone analysis in a global context. In addition, low-level (stratus) cloud decks along the western subtropical coasts of continents are also better simulated, improving radiation budgets in these regions.In 2006, JMA started real-time operation of the JMA Climate Data Assimilation System (JCDAS). JCDAS employs the same system as JRA-25 and the data assimilation cycle is extended to the present time. JRA-25 and JCDAS products will enable users to conduct climate diagnostics with a long-term, and current, homogeneous reanalysis dataset. The JMA has also engaged in ongoing cooperation with ECMWF (European Center for Medium-Range Weather Forecasts) on reanalysis, including the ECMWF CDAS (ECDAS), more commonly known as ERA-Interim.