[MITgcm-support] 回复: 转发: The obvious difference between ERA5 and NCEP-R1 forcing
Raphael Dussin
raphael.dussin at gmail.com
Mon Mar 16 08:24:58 EDT 2020
Have you checked the heights for the atmospheric variables are correctly
set?
you should have something like this in data.blk
zref = 10.0
zwd = 10.0
zth = 2.0
I've seen a lot of runs going off the rails because of this kind of problem:
If the height is not set right, the fluxes are not either and you end up
with large biases.
hope it helps,
Raf
Raf
Le lun. 16 mars 2020 à 04:49, Stanislav Martyanov <martyanov.sd at gmail.com>
a écrit :
> 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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