JRA-55: Notes, Questions, and Discussion

Created by mapr8844 on - Updated on 01/29/2020 12:54

JRA-55: Notes, Questions, and Discussion

Quick Overview and useful links

 

General Reanalysis Notes, Questions, and Discussion

01/29/2020: Some tropical cyclones occurring over the Northeast Pacific and the North Atlantic from 1959 to 1987 were erroneously represented as anti-cyclonic vortices in the Japanese 55-year Reanalysis (JRA-55) dataset. A detailed report is available at the JRA-55 website:



# Issue with tropical cyclone analysis in JRA-55

https://jra.kishou.go.jp/JRA-55/index_en.html#quality


Note: the following comments have been added to the body of this page due to them not migrating during our recent site upgrade:

 

JRA-55: 2016 Data

Submitted by Johanna Yepes (not verified) on Fri, 05/27/2016 - 08:30. 

Hi, Does the 2016 hourly data available? Thank you

Re: JRA-55: 2016 Data

Submitted by Kazutoshi Onogi (not verified) on Wed, 06/01/2016 - 01:53. 

Unfortunately hourly data is not available in JRA-55. Please visit http://jra.kishou.go.jp/JRA-55/index_en.html and read the documents "JRA-55 Product Users' Handbook" at the bottom of the page.

Re: JRA-55: 2016 Data

Submitted by Chiaki Kobayashi (not verified) on Mon, 05/30/2016 - 04:00. 

JRA data are available a couple of days behind the real time from JMA's web site (http://jra.kishou.go.jp/JRA-55/index_en.html) except for 3-dimensional average diagnostic fields and model level forecast fields. Thanks, Chiaki KOBAYASHI Climate Research Department Meteorological Research Institute Tsukuba, Ibaraki, 305-0052, Japan.

Re: JRA-55: 2016 Data

Submitted by gilbert.p.compo on Fri, 05/27/2016 - 13:32. 

It appears that the data are not yet at NCAR in http://rda.ucar.edu/datasets/ds628.0/ . I recommend contacting the Data Specialist mentioned on the page directly.

Gilbert P. Compo

University of Colorado/CIRES

NOAA/ESRL/Physical Sciences Division

http://www.esrl.noaa.gov/psd/people/gilbert.p.compo

JRA-55 assmilation of horizontal wind from land stations

Submitted by gilbert.p.compo on Thu, 05/19/2016 - 13:25. 

Does JRA-55C or JRA-55 assimilate horizontal winds from land surface stations? Thanks.

Gilbert P. Compo

University of Colorado/CIRES

NOAA/ESRL/Physical Sciences Division

http://www.esrl.noaa.gov/psd/people/gilbert.p.compo

Re: JRA-55 assmilation of horizontal wind from land stations

Submitted by Chiaki Kobayashi (not verified) on Fri, 05/20/2016 - 07:47. 

Dear Gil Horizontal winds from land surface stations are assimilated only in the screen-level analysis component, not in the atmospheric analysis component. Screen-level analysis fields are not used as the initial conditions for forecasts, therefore have no impact on subsequent assimilation cycles. Best regards, Chiaki -- Chiaki KOBAYASHI Climate Research Department Meteorological Research Institute Tsukuba, Ibaraki, 305-0052, Japan.

JRA-55C assimilation of horizontal wind from aircraft

Submitted by gilbert.p.compo on Thu, 05/19/2016 - 13:24. 

Does JRA-55C assimilate horizontal wind observations from aircraft? I do not think so based on Kobayashi et al. 2014 but wanted to double check. Thanks.

Gilbert P. Compo

University of Colorado/CIRES

NOAA/ESRL/Physical Sciences Division

http://www.esrl.noaa.gov/psd/people/gilbert.p.compo

Re: JRA-55C assimilation of horizontal wind from aircraft

Submitted by Chiaki Kobayashi (not verified) on Fri, 05/20/2016 - 07:50. 

Dear Gil, No, The observation from air crafts are not assimilated in JRA-55C. I think you are understanding correctly. Best regards, Chiaki -- Chiaki KOBAYASHI Climate Research Department Meteorological Research Institute Tsukuba, Ibaraki, 305-0052, Japan.

nenghan wan (not verified)

Mon, 06/06/2022 - 22:40

Hi, Sir,

From previous comments, I konw Brightness temperature is the SST, but I'd like to know if the SST over Arctic and Antarctica are the water temperature or sea ice temperature, the trend is so different when I compare the monthly time series of SST for ERA5 and JRA55 over Arctic and Antarctica, as I understand the SST in EAR5 is for water temperature. Would you mind provide some references? Thank you for your help, I really appreciate.

best,

nenghan

Do you mean references for JRA55?

https://climate.mri-jma.go.jp/pub/ocean/JRA55-do/docs/v1_5-manual/User_…

As I understand it, the COBE2-SST is the model SST. COBE2 references are

  • Hirahara, S., Ishii, M., and Y. Fukuda, 2014: Centennial-scale sea surface temperature analysis and its uncertainty. J of Climate27, 57-75.
  • Folland, C. K. and D. E. Parker, 1995: Correction of instrumental biases in historical sea surface temperature data. Q. J. R. Meteorol. Soc., 121, 319-367.
  • Ishii, M., A. Shouji, S. Sugimoto, and T. Matsumoto, 2005: Objective Analyses of Sea-Surface Temperature and Marine Meteorological Variables for the 20th Century using ICOADS and the Kobe Collection. Int. J. Climatol., 25, 865-879.
  • Japan Meteorological Agency, 2006: Characteristics of Global Sea Surface Temperature Analysis Data (COBE-SST) for Climate Use. Monthly Report on Climate System Separated Volume, 12, 116pp.

 

Cathy Smith

Dear Aaron,

Here are some papers that intercompare upper tropospheric winds field from different reanalyses, though the latest reanalyses such as ERA5 are not covered.

 

Long et al., 2017: Climatology and interannual variability of dynamic variables in multiple reanalyses evaluated by the SPARC Reanalysis Intercomparison Project (S-RIP). Atmos. Chem. Phys., 17, 14593–14629, https://doi.org/10.5194/acp-17-14593-2017.

Manney et al., 2017: Reanalysis comparisons of upper tropospheric–lower stratospheric jets and multiple tropopauses. Atmos. Chem. Phys., 17, 11541–11566, https://doi.org/10.5194/acp-17-11541-2017.

Manney, and Hegglin, 2018: Seasonal and regional variations of long-term changes in upper-tropospheric jets from reanalyses. J. Climate, 31, 423-448, https://doi.org/10.1175/JCLI-D-17-0303.1.

 

I hope this helps.

 

Regards,

Shinya

 

Dear Aaron,

To my knowedge, no detailed reanalysis intercomparison of upper-tropospheric/lower-stratospheric winds similar to what Long et al. and manney et al. have done has been published yet that includes ERA5, unfortunately. The report from the SPARC Reanalysis Intercomparison Project (S-RIP), which should be published this fall and whose Chap 3 provided the basis for the Long et al. paper, may include some evaluation of ERA5 winds (but this is still to be confirmed). In addition, some insight into the skill of ERA5 upper-level winds can be found in Hersbach et al. (2020) and - with focus on the QBO - in Simmons et al. (2020).

Hersbach, H., et al., 2020: The ERA5 global reanalysis. Q.J.R. Meteorol Soc., 146, 1999-2049, https://doi.org/10.1002/qj.3803.

Simmons, A., et al., 2020: Global stratospheric temperature bias and other stratospheric aspects of ERA5 and ERA5.1. ECMWF Technical Memorandum number 859, https://doi.org/10.21957/rcxqfmg0.

I hope this helps.

Kind regards,
Julien
(ERA5 Team)

Jih-Wang Aaron Wang (not verified)

Thu, 05/02/2019 - 11:03

Dear All:

Sorry, I made a mistake in the previous post.

I don't understand why JRA55's resolution is ~55km. If it uses T319 spectral model, isn't the horizontal resolution=[earth circumference]/[320*2]=40000km/640=62.5km.

Thanks,

Aaron

Dear Aaron,

I'm sorry for the delay in replying to you.

Your calculation is basically correct for the grid intervals in the tropics and for those in the north-south direction. The value of ~55km represents the grid intervals in the west-east direction in the mid-latitudes since they are narrower in higher latitudes.

Regards,

Shinya 

Cathy.Smith@noaa.gov

Mon, 02/25/2019 - 11:00

Brightness temperature is actually SST. This SST comes from the COBE daily data, but is not exactly the same because it includes a parameterized diurnal cycle. So it differs from the COBE data in terms of the temporal variability as well as the resolution.

This brightness temperature is computed from surface upward longwave radiation assuming that the surface is a black body. As long as this assumption is valid, the brightness temperature can be used as skin temperature as well.

David Carvalho (not verified)

Tue, 03/27/2018 - 15:33

Hi, I need to know what variables (T, UV winds, surface pressure, etc.) JRA55 assimilates from land met stations and moored buoy arrays such as TAO, TRITON and RAMA. I saw on this forum that it doesn't assimilate winds from land met stations, if I understood correctly.

Also, does JRA55 assimilates any variables measured by moored buoys offshore the Spanish Atlantic coast, operated by the Spanish Agency Puertos del Estado?

Any help would be much appreciated, thanks!

Cathy.Smith@noaa.gov

Mon, 10/24/2016 - 10:09

Users should be aware that for 2mT, 2mq, 10m u and v and some others, that they should use the "forecast" variable and not the "analysis" variable. The WRIT pages now have both.

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Table 5 and section 3.2a "screen level analysis" of

Kobayashi, S., Y. Ota, Y. Harada, A. Ebita, M. Moriya, H. Onoda, K. Onogi, H. Kamahori, C. Kobayashi, H. Endo, K. Miyaoka, and K. Takahashi , 2015: The JRA-55 Reanalysis: General Specifications and Basic Characteristics. J. Meteorol. Soc. Japan, 93, 5-48, doi: 10.2151/jmsj.2015-001

describes the details of this "separate" analysis:

The analysis of screen-level variables (2-m temperatures, 2-m relative humidities and 10-m winds) is performed separately from the atmospheric analysis component. These variables are analyzed with a univariate 2-dimensional optimal interpolation (2D-OI). In JRA-25, departures were estimated by comparing observations with the first guess at the analysis time. In JRA-55, observations are compared with the first guess at the actual observation time and the departures are applied at the analysis time (the so-called first guess at the appropriate time (FGAT) approach). Temperature and wind observations from islands are not used because they are not necessarily representative at the grid scale of JRA-55. Determining whether an observation is from an island is based on the 0.25-degree resolution land cover data; consequently, observations from the coast are also excluded. Screen-level analysis fields are not used as initial conditions for forecasts.

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