JRA‐25: Japanese 25‐year re‐analysis project—progress and status

Onogi, Kazutoshi; Koide, Hiroshi; Sakamoto, Masami; Kobayashi, Shinya; Tsutsui, Junichi; Hatsushika, Hiroaki; Matsumoto, Takanori; Yamazaki, Nobuo; Kamahori, Hirotaka; Takahashi, K.; Kato, Koji; Oyama, Ryo; Ose, Tomoaki; Kadokura, Shinji; Wada, Koji

doi:10.1256/qj.05.88

Cited by 99 publications

(77 citation statements)

References 7 publications

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“…Onogi et al (2005Onogi et al ( , 2007 provide details. Briefly, while JRA-25 draws from the same basic satellite and conventional data streams as NCEP and ERA-40, the system assimilates satellite radiances rather than retrieved profiles, an approach which avoids trends and variability due to changes introduced in satellite data processing over the years.…”

Section: The Ncep/ncar and Jra-25 Reanalysesmentioning

confidence: 99%

“…Graversen et al (2008) examined temperature trends as a function of latitude and height over the period 1979-2001, based on fields from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 reanalysis (Uppala et al, 2005), JRA-25, a recent effort of the Japanese Meteorological Agency (Onogi et al, 2005(Onogi et al, , 2007, and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR, hereafter NCEP) reanalysis (Kalnay et al, 1996). While ERA-40 documents larger positive trends in surface temperatures in the Arctic by comparison with lower latitudes in all seasons except summer, the largest Arctic trends in winter and summer lie above the surface.…”

Section: Introductionmentioning

confidence: 99%

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The emergence of surface-based Arctic amplification

et al. 2009

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Abstract. Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from both the NCEP/NCAR and JRA-25 reanalyses point to emergence of surface-based Arctic amplification in the last decade.

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Section: The Ncep/ncar and Jra-25 Reanalysesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The emergence of surface-based Arctic amplification

et al. 2009

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“…It covers 26 years from 1979 to 2004. Onogi et al (2005) reported briefly the JRA-25 progress in an interim report in the first half of 2005.…”

Section: Introductionmentioning

confidence: 99%

The JRA-25 Reanalysis

Onogi

Tsutsui

Koide

et al. 2007

Journal of the Meteorological Society of Japan

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A long-term global atmospheric reanalysis, named ''Japanese 25-year Reanalysis (JRA-25)'' was completed using the Japan Meteorological Agency (JMA) numerical assimilation and forecast system. The analysis covers the period from 1979 to 2004. This is the first long-term reanalysis undertaken in Asia. JMA's latest numerical assimilation system, and specially collected observational data, were used to generate a consistent and high-quality reanalysis dataset designed for climate research and operational monitoring and forecasts. One of the many purposes of JRA-25 is to enhance the analysis to a high quality in the Asian region.Six-hourly data assimilation cycles were performed, producing 6-hourly atmospheric analysis and forecast fields of various physical variables. The global model used in JRA-25 has a spectral resolution of T106 (equivalent to a horizontal grid size of around 120 km) and 40 vertical layers with the top level at 0.4 hPa. In addition to conventional surface and upper air observations, atmospheric motion vector (AMV) wind retrieved from geostationary satellites, brightness temperature from TIROS Operational Vertical Sounder (TOVS), precipitable water retrieved from orbital satellite microwave radiometer radiance and other satellite data are assimilated with three-dimensional variational method (3D-Var). JMA produced daily sea surface temperature (SST), sea ice and three-dimensional ozone profiles for JRA-25. A new quality control method for TOVS data was developed and applied in advance.Many advantages have been found in the JRA-25 reanalysis. Predicted 6-hour global total precipitation distribution and amount are well reproduced both in space and time. The performance of the long time series of the global precipitation is the best among the other reanalyses, with few unrealistic variations from degraded satellite data contaminated by volcanic eruptions. Secondly, JRA-25 is the first reanalysis to assimilate wind profiles around tropical cyclones reconstructed from historical best track information; tropical cyclones were analyzed properly in all the global regions. Additionally, low-level cloud along the subtropical western coast of continents is well simulated and snow depth analysis is also of a good quality. The article also covers material which requires attention when using JRA-25.

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“…Some of the advantages and deficiencies of JRA-25 were reported in connection with the impact of some newlyproduced observational data, which was summarized by Onogi et al (2005). In this study, we examine the characteristics of global circulation represented by the JRA-25 data, from the viewpoint of global energetics.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of the JRA-25 Dataset from the Viewpoint of Global Energetics

Watarai

Tanaka

2007

SOLA

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In this study, the global circulation represented by JRA-25 is examined from the viewpoint of global energetics, compared with ERA-40 and NCEP/NCAR reanalysis. Although the peak and slope of the spectrum for JRA-25 are consistent with those of the other datasets, the magnitude of energy or energy conversion is generally ERA-40 > JRA-25 > NCEP. For short waves, a rapid decrease of amplitude with increasing wave number is shown for NCEP/NCAR reanalysis and ERA-40. The energy conversion from zonal available potential energy to zonal kinetic energy, caused by zonalmean meridional circulation, is the largest for JRA-25, which is the result of a large amount of cancellation of the local conversion term in the Hadley cell. IntroductionThe Japanese 25-year reanalysis (JRA-25) is an up-todate dataset produced by the Japan Meteorological Agency (JMA) and the Central Research Institute of Electric Power Industry (CRIEPI). The dataset contains global data, with multiple layers from the surface to the middle stratosphere; it is very useful for the study of various meteorological and climatological phenomena.In order to diagnose the new reanalysis dataset and improve a future reanalysis, it is essential to examine features of the dataset from a variety of perspectives. Some of the advantages and deficiencies of JRA-25 were reported in connection with the impact of some newlyproduced observational data, which was summarized by Onogi et al. (2005). In this study, we examine the characteristics of global circulation represented by the JRA-25 data, from the viewpoint of global energetics. Data usedThe JRA-25 dataset used in this study was downloaded from the JRA-25 homepage (http://jra.kishou.go. jp/). Resolution of given data is 2.5°× 2.5°intervals in longitude/latitude and 23 vertical levels (1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 20, 10, 7, 5, 3, 2, 1 and 0.4 hPa). Field variables used for computing the energy cycle are the horizontal wind (u, v), temperature (T), and dew-point depression (T Td), which is available in 8 levels up to 300 hPa.Two other reanalysis datasets were compared with the JRA-25. Both have the same horizontal resolution as JRA-25 (2.5°× 2.5°). One is the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis (hereafter NCEP1) dataset (Kalnay et al. 1996), which is available from the Climate Diagnostics Center (CDC) of the National Oceanic and Atmospheric Administration (NOAA)-Cooperative Institute for Research in Environmental Sciences (CIRES) (http://www.cdc.noaa.gov/ cdc/reanalysis/), which has a vertical resolution of 17 levels (1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 20 and 10 hPa). The other dataset used in this study is the European Centre for MediumRange Weather Forecasts (ECMWF) 40-year reanalysis (ERA-40) dataset (Uppala et al. 2005), obtained from the ECMWF Data Server (http://data.ecmwf.int/data/), which has a vertical resolution of 23 levels (1000, 925, 850, 775,...

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JRA‐25: Japanese 25‐year re‐analysis project—progress and status

Cited by 99 publications

References 7 publications

The emergence of surface-based Arctic amplification

The emergence of surface-based Arctic amplification

The JRA-25 Reanalysis

Characteristics of the JRA-25 Dataset from the Viewpoint of Global Energetics

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