11:15 AM - 11:30 AM
[AAS05-09] Evaluation of the JRA-3Q reanalysis using various observational datasets
Keywords:Global long-term reanalysis, JRA-3Q, Evaluation, Observational dataset
The Japan Meteorological Agency (JMA) is conducting the third Japanese global atmospheric reanalysis named Japanese Reanalysis for Three Quarters of a Century (JRA-3Q) using the JMA operational data assimilation system that has been upgraded and improved since the Japanese 55-year Reanalysis (JRA-55) was conducted. Main points of improvement in the specifications of the data assimilation system are as follows (specifications of the JRA-55 data assimilation system are shown in parentheses for comparison): Vertical levels are increased up to 100 (60) layers; The top level of the system is 0.01 (0.1) hPa; The inner model resolution for 4D-Var is also increased up to TL319 (T106); Various parameterization schemes have been improved and several new schemes have been implemented. In addition, we use observations newly rescued and digitized by the ERA-CLIM and other projects as well as newly reprocessed and improved satellite observations. As for GNSS radio occultation, bending angle is assimilated up to 60 km (refractivity up to 30 km).
We have conducted the evaluation of JRA-3Q quality using various observational datasets: precipitation provided by the Global Precipitation Climatology Project (GPCP, Adler et al. 2003) and the Tropical Rainfall Measuring Mission (TRMM, Huffman et al. 2007), Spectral latent heating from the Global Precipitation Measurement (GPM) mission by Japan Aerospace Exploration Agency (JAXA) and National Aeronautics and Space Administration (NASA) (Hou et al. 2014), Water vapor retrieved from Global Navigation Satellite System Radio Occultation (GNSS-RO), Heat fluxes provided by the Objectively Analyzed Air-sea Fluxes (OAFlux) Project (Yu et al. 2008), Radiation fluxes from the clouds and the Earth’s radiant energy system project (CERES, Wielicki et al. 1996), Water vapor, ozone mixing ratio and temperature retrieved from the Earth Observing System Microwave Limb Sounder (MLS) (MLS/Aura, Waters et al. 2006).
The results show that overestimation of precipitation in the tropics is decreased compared with that in JRA-55, and JRA-3Q shows a higher anomaly correlation with GPCP throughout the period after 1979. In addition, dry bias in the middle troposphere is diminished compared with that in JRA-55, and homogeneity of water vapor in JRA-3Q is improved for the period after 1960’s. Furthermore, the representation of diabatic heating rate is also improved. In addition, biases of surface heat fluxes and radiation fluxes at the top of the atmosphere are also reduced.
We have conducted the evaluation of JRA-3Q quality using various observational datasets: precipitation provided by the Global Precipitation Climatology Project (GPCP, Adler et al. 2003) and the Tropical Rainfall Measuring Mission (TRMM, Huffman et al. 2007), Spectral latent heating from the Global Precipitation Measurement (GPM) mission by Japan Aerospace Exploration Agency (JAXA) and National Aeronautics and Space Administration (NASA) (Hou et al. 2014), Water vapor retrieved from Global Navigation Satellite System Radio Occultation (GNSS-RO), Heat fluxes provided by the Objectively Analyzed Air-sea Fluxes (OAFlux) Project (Yu et al. 2008), Radiation fluxes from the clouds and the Earth’s radiant energy system project (CERES, Wielicki et al. 1996), Water vapor, ozone mixing ratio and temperature retrieved from the Earth Observing System Microwave Limb Sounder (MLS) (MLS/Aura, Waters et al. 2006).
The results show that overestimation of precipitation in the tropics is decreased compared with that in JRA-55, and JRA-3Q shows a higher anomaly correlation with GPCP throughout the period after 1979. In addition, dry bias in the middle troposphere is diminished compared with that in JRA-55, and homogeneity of water vapor in JRA-3Q is improved for the period after 1960’s. Furthermore, the representation of diabatic heating rate is also improved. In addition, biases of surface heat fluxes and radiation fluxes at the top of the atmosphere are also reduced.