[MITgcm-support] 回复: 转发: The obvious difference between ERA5 and NCEP-R1 forcing
Stanislav Martyanov
martyanov.sd at gmail.com
Mon Mar 16 04:48:30 EDT 2020
Hello, Mike!
I have recently downloaded the ERA5 reanalysis data (daily fields,
GLOBAL_REANALYSIS_PHY_001_030 as labeled in Copernicus network) in order to
construct the meteorological forcing for a regional ocean model (Kara Sea)
based on the MITgcm. I chose the following fields:
% 10m u-component of wind
% 10m v-component of wind
% 2m dewpoint temperature
% 2m temperature
% Mean total precipitation rate
% Mean sea level pressure
% Mean surface downward long-wave radiation flux
% Mean surface downward short-wave radiation flux
In order to compute the specific humidity, as advised in the ERA5
documentation, I used formulas given in IFS Documentation CY46R1 -
part-iv-physical-processes (2m dewpoint temperature and Mean sea level
pressure are used there).
Regards,
Dr. Stanislav Martyanov,
Shirshov Institute of Oceanology,
Russia
пн, 16 мар. 2020 г. в 09:27, Leming Van <ifanliming at outlook.com>:
> Hi, Matt
>
> Thank you for your advice. I'm sorry that I didn't provide enough
> information.
>
> I downloaded the ERA5 dataset at
> https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab=form
> Copernicus Climate Data Store | Copernicus Climate Data Store
> <https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab=form>
> CDS Menu. Home; Search; Datasets; Applications; Toolbox; FAQ; Live;
> Copernicus Climate Data Store
> cds.climate.copernicus.eu
>
> And I selected precip[mean_total_precipitation_rate. kg m-2 s-1], atemp[2m_temperature.
> K], swdown[mean_surface_downward_short_wave_radiation_flux. W m-2
> ], lwdown[mean_surface_downward_long_wave_radiation_flux. W m-2], uwind[
> 10m_u_component_of_wind. m s-1], vwind[10m_v_component_of_wind. m s-1],
> because ERA5 does not provide aqh directly, I used air pressure[
> surface_pressure Pa] and dewpoint temperature[2m_dewpoint_temperature K]
> to calculate aqh.
>
> Since the data is hourly, I only downloaded the area of interest(bigger
> than South China Sea), and besides, the data is zonally aligned from 35N to
> 5S, I flipped it to 5S-35N.
>
> I compared the ERA5 with NCEP, and I don't think there is much difference
> except for the short-wave radiation. Please check the attachment.
>
> I only have one question, do you choose the same ERA5 variables like me?
> If not, could you tell me which variables you choose?
>
> Please let me know if any other files are needed for diagnosis. Thanks in
> advance.
>
>
> -Mike
>
>
> Here is the setting of my data.exf
>
> # $Header:
> /u/gcmpack/MITgcm_contrib/eh3/llc/ecco-godae/input_50lev/data.exf,v 1.1
> 2007/03/06 19:13:51 heimbach Exp $
> #
> # *********************
> # External Forcing Data
> # *********************
> &EXF_NML_01
> useAtmWind = .TRUE.,
> # rotateStressOnAgrid = .TRUE.,
> exf_iprec = 32,
> exf_yftype = 'RL',
> useExfYearlyFields = .false.,
> twoDigitYear = .false.,
> useExfCheckRange =.false.,
> &
>
> &EXF_NML_02
> climsstfile = 'woa13_sst_monthly_globe_relax.box',
> climsssfile = 'woa13_sss_monthly_globe_relax.box',
> precipfile = 'era5_prate_2002-2005_hourly.box',
> atempfile = 'era5_air_2002-2005_hourly.box',
> aqhfile = 'era5_shum_2002-2005_hourly.box',
> swdownfile = '',
> swfluxfile = 'era5_nswrs_2002-2005_hourly.box',
> lwfluxfile = '',
> lwdownfile = 'era5_dlwrf_2002-2005_hourly.box',
> uwindfile = 'era5_uwnd_2002-2005_hourly.box',
> vwindfile = 'era5_vwnd_2002-2005_hourly.box',
> runofffile = 'run-off.bin_1x1',
> #
> climsststartdate1 = 20020101,
> climsststartdate2 = 000000,
> climsstperiod = -12,
> climsssstartdate1 = 20020101,
> climsssstartdate2 = 000000,
> climsssperiod = -12,
> runoffstartdate1 = 20020101,
> runoffstartdate2 = 000000,
> runoffperiod = -12,
> #
> precipstartdate1=20020101,
> precipstartdate2=000000,
> precipperiod=3600.0,
> atempstartdate1=20020101,
> atempstartdate2=000000,
> atempperiod=3600.0,
> aqhstartdate1=20020101,
> aqhstartdate2=000000,
> aqhperiod=3600.0,
> swdownstartdate1=20020101,
> swdownstartdate2=000000,
> swdownperiod=3600.0,
> lwfluxstartdate1=20020101,
> lwfluxstartdate2=000000,
> lwfluxperiod=3600.0,
> swfluxstartdate1=20020101,
> swfluxstartdate2=000000,
> swfluxperiod=3600.0,
> lwdownstartdate1=20020101,
> lwdownstartdate2=000000,
> lwdownperiod=3600.0,
> uwindstartdate1=20020101,
> uwindstartdate2=000000,
> uwindperiod=3600.0,
> vwindstartdate1=20020101,
> vwindstartdate2=000000,
> vwindperiod=3600.0,
> hfluxstartdate1=20020101,
> hfluxstartdate2=000000,
> hfluxperiod=3600.0,
> sfluxstartdate1=20020101,
> sfluxstartdate2=000000,
> sfluxperiod=3600.0,
> ustressstartdate1=20020101,
> ustressstartdate2=000000,
> ustressperiod=3600.0,
> vstressstartdate1=20020101,
> vstressstartdate2=000000,
> vstressperiod=3600.0,
> &
>
> &EXF_NML_03
> exf_inscal_precip=1.,
> exf_offset_atemp=0.0,
> exf_inscal_runoff = 3.1710e-08,
> &
>
> &EXF_NML_04
> precip_lon0 = 95.0D0,
> precip_lon_inc = 0.25D0,
> precip_lat0 = -5.0D0,
> precip_lat_inc = 160*0.25D0,
> precip_nlon = 160,
> precip_nlat = 160,
> #
> atemp_lon0 = 95.0D0,
> atemp_lon_inc = 0.25D0,
> atemp_lat0 = -5.0D0,
> atemp_lat_inc = 160*0.25D0,
> atemp_nlon = 160,
> atemp_nlat = 160,
> #
> aqh_lon0 = 95.0D0,
> aqh_lon_inc = 0.25D0,
> aqh_lat0 = -5.0D0,
> aqh_lat_inc = 160*0.25D0,
> aqh_nlon = 160,
> aqh_nlat = 160,
> #
> swdown_lon0 = 95.0D0,
> swdown_lon_inc = 0.25D0,
> swdown_lat0 = -5.0D0,
> swdown_lat_inc = 160*0.25D0,
> swdown_nlon = 160,
> swdown_nlat = 160,
> #
> lwflux_lon0 = 95.0D0,
> lwflux_lon_inc = 0.25D0,
> lwflux_lat0 = -5.0D0,
> lwflux_lat_inc = 160*0.25D0,
> lwflux_nlon = 160,
> lwflux_nlat = 160,
> #
> swflux_lon0 = 95.0D0,
> swflux_lon_inc = 0.25D0,
> swflux_lat0 = -5.0D0,
> swflux_lat_inc = 160*0.25D0,
> swflux_nlon = 160,
> swflux_nlat = 160,
> #
> lwdown_lon0 = 95.0D0,
> lwdown_lon_inc = 0.25D0,
> lwdown_lat0 = -5.0D0,
> lwdown_lat_inc = 160*0.25D0,
> lwdown_nlon = 160,
> lwdown_nlat = 160,
> #
> uwind_lon0 = 95.0D0,
> uwind_lon_inc = 0.25D0,
> uwind_lat0 = -5.0D0,
> uwind_lat_inc = 160*0.25D0,
> uwind_nlon = 160,
> uwind_nlat = 160,
> #
> vwind_lon0 = 95.0D0,
> vwind_lon_inc = 0.25D0,
> vwind_lat0 = -5.0D0,
> vwind_lat_inc = 160*0.25D0,
> vwind_nlon = 160,
> vwind_nlat = 160,
> #
> ustress_lon0 = 95.0D0,
> ustress_lon_inc = 0.25D0,
> ustress_lat0 = -5.0D0,
> ustress_lat_inc = 160*0.25D0,
> ustress_nlon = 160,
> ustress_nlat = 160,
> #
> vstress_lon0 = 95.0D0,
> vstress_lon_inc = 0.25D0,
> vstress_lat0 = -5.0D0,
> vstress_lat_inc = 160*0.25D0,
> vstress_nlon = 160,
> vstress_nlat = 160,
> #
> hflux_lon0 = 95.0D0,
> hflux_lon_inc = 0.25D0,
> hflux_lat0 = -5.0D0,
> hflux_lat_inc = 160*0.25D0,
> hflux_nlon = 160,
> hflux_nlat = 160,
> #
> sflux_lon0 = 95.0D0,
> sflux_lon_inc = 0.25D0,
> sflux_lat0 = -5.0D0,
> sflux_lat_inc = 160*0.25D0,
> sflux_nlon = 160,
> sflux_nlat = 160,
> #
> runoff_lon0 = 0.50D0,
> runoff_lon_inc = 1.0D0,
> runoff_lat0 = -79.5D0,
> runoff_lat_inc = 159*1.0D0,
> runoff_nlon = 360,
> runoff_nlat = 160,
> #
> climsst_lon0 = -179.875D0,
> climsst_lon_inc = 0.25D0,
> climsst_lat0 = -89.875D0,
> climsst_lat_inc = 719*0.25D0,
> climsst_nlon = 1440,
> climsst_nlat = 720,
> #
> climsss_lon0 = -179.875D0,
> climsss_lon_inc = 0.25D0,
> climsss_lat0 = -89.875D0,
> climsss_lat_inc = 719*0.25D0,
> climsss_nlon = 1440,
> climsss_nlat = 720,
> #
> &
>
> &EXF_NML_OBCS
> obcsNstartdate1 = 20020101,
> obcsNstartdate2 = 000000,
> obcsNperiod = 2628000.0,
> obcsEstartdate1 = 20020101,
> obcsEstartdate2 = 000000,
> obcsEperiod = 2628000.0,
> obcsSstartdate1 = 20020101,
> obcsSstartdate2 = 000000,
> obcsSperiod = 2628000.,
> &
>
> ------------------------------
> *发件人:* MITgcm-support <mitgcm-support-bounces at mitgcm.org> 代表 Matthew
> Mazloff <mmazloff at ucsd.edu>
> *发送时间:* 2020年3月16日 0:44
> *收件人:* mitgcm-support at mitgcm.org <mitgcm-support at mitgcm.org>
> *主题:* Re: [MITgcm-support] 转发: The obvious difference between ERA5 and
> NCEP-R1 forcing
>
> Hi Mike
>
> It is possible it could give worse results, but very unlikely. However its
> too hard for me to diagnose what is going on. There are many variables to
> your problem.
>
> For ERA5 I have this in my data.exf:
> &EXF_NML_03
> exf_offset_atemp = 273.15,
> exf_inscal_swdown = -1.0,
> exf_inscal_lwdown = -1.0,
>
> Not sure how to help you,
> Matt
>
>
>
> On Mar 15, 2020, at 5:41 AM, Leming Van <ifanliming at outlook.com> wrote:
>
> Hi, everyone
>
> Recently I tried to change forcing dataset from NCEP-R1(6-hourly) to
> ERA5(hourly), but the results of them look so different. I compared the
> results of NCEP-R1 with the reanalysis data of HYCOM, and these two
> data look similar.
>
> Did I pick the wrong variables from ERA5? Or does this mean that higher
> temporal and spatial resolution atmospheric forcing ERA5 results in worse
> simulation results than lower resolution NCEP-R1?
>
> I put the results at here,
> https://1drv.ms/u/s!AoS5GLJhmvDtjB5Ovnz63FidKeMo?e=c2hS7z
> Suggestions are welcome.
>
>
> -Mike
>
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