下载ERA5数据

从官网上下载ERA5主要分为三步：

1. 官网注册账号，获取CDS API key。
2. 安装python相关的库。
3. 复制粘贴代码，下载数据。

注册账户获取密钥

点击网址： ERA5注册网址 ，右上角点击注册账户，一般使用教育邮箱

注册完成后登录，然后还是在这个网址： 获取key密钥 ，点击下面图中的红色框，

然后，下图红框内就是你的密钥，将其全部复制下来：

如果你是Linux系统，就在你的系统用户目录下创建一个 .cdsapirc 的文件，将刚刚复制的内容粘贴到该文件下：

• 如果你是windows系统，就在c盘/用户/用户名 这个目录下创建一个 创建一个 .cdsapirc 文件。可以先建立一个txt文件，将内容粘贴进去后再改文件名为 .cdsapirc 。

安装python的cdsapi库

我这里是在Linux系统下， 直接在你的python环境下使用命令： conda install cdsapi

即可。window下应该同理。

获取ERA5数据

下载地址 在官网上搜索你要下载的数据类型：

点击进入后勾选你需要的参数、时间、变量等。

然后到最后，选择红框内显示下载代码

将代码复制到你的python脚本中，运行脚本即可下载。

运行 WRF 模式

基于上述方式，我们可以通过下载ERA5数据制作WRF模式的初始场，运行wrf模式。其中，需要下载的ERA5的数据如下所示：

3D数据：

ERA5 monthly averaged data on pressure levels from 1979 to present**：Monthly averaged reanalysis by hour of day**

变量：

• Geopotential
• Relative humidity
• U-component of wind
• V-component of wind
• Temperature

压力层

所有

year

2022

month

02

day

17-18

Pressure level data (download.py)

import cdsapi
c = cdsapi.Client()
c.retrieve(
    'reanalysis-era5-pressure-levels',
        'product_type': 'reanalysis',
        'format': 'grib',
        'variable': [
            'geopotential', 'relative_humidity', 'temperature','specific_humidity',
            'u_component_of_wind', 'v_component_of_wind','vertical_velocity'
        'pressure_level': [
            '1', '2', '3',
            '5', '7', '10',
            '20', '30', '50',
            '70', '100', '125',
            '150', '175', '200',
            '225', '250', '300',
            '350', '400', '450',
            '500', '550', '600',
            '650', '700', '750',
            '775', '800', '825',
            '850', '875', '900',
            '925', '950', '975',
            '1000',
        'year': '2022',
        'month': '02',
        'day': ['17','18',],
        'time': [
            '00:00', '01:00', '02:00',
            '03:00', '04:00', '05:00',
            '06:00', '07:00', '08:00',
            '09:00', '10:00', '11:00',
            '12:00', '13:00', '14:00',
            '15:00', '16:00', '17:00',
            '18:00', '19:00', '20:00',
            '21:00', '22:00', '23:00',
    '/ERA5_data/ERA5-2022-02_17-18_pl.grib')

2D数据：

Product type

Monthly averaged reanalysis by hour of day

Variable

• 10m u-component of wind
  
• 10m v-component of wind
  
• Mean sea level pressure
  
• Sea surface temperature
  
• Surface pressure
  
• 2m temperature
  
• Soil data (temperature and moisture) and soil height
  
  

year

2021

month

02

day

17-18

Single level data (down.py)

import cdsapi
c = cdsapi.Client()
c.retrieve(
    'reanalysis-era5-single-levels',
        'product_type': 'reanalysis',
        'format': 'grib',
        'variable': [
         '10m_u_component_of_wind','10m_v_component_of_wind','2m_dewpoint_temperature',
            '2m_temperature','forecast_albedo',
            'forecast_surface_roughness','high_cloud_cover',
            'land_sea_mask','low_cloud_cover',
            'mean_sea_level_pressure','medium_cloud_cover',
            'sea_ice_cover','sea_surface_temperature',
            'skin_temperature','snow_albedo',
            'snow_depth','surface_pressure',
            'total_cloud_cover',
            'total_column_water','total_column_water_vapour',
            'soil_temperature_level_1','soil_temperature_level_2',
            'soil_temperature_level_3','soil_temperature_level_4','volumetric_soil_water_layer_1','volumetric_soil_water_layer_2',
            'volumetric_soil_water_layer_3','volumetric_soil_water_layer_4'
        'year': '2022',
        'month': '02',
        'day': ['17','18',],
        'time': [
            '00:00', '01:00', '02:00',
            '03:00', '04:00', '05:00',
            '06:00', '07:00', '08:00',
            '09:00', '10:00', '11:00',
            '12:00', '13:00', '14:00',
            '15:00', '16:00', '17:00',
            '18:00', '19:00', '20:00',
            '21:00', '22:00', '23:00',
    '/ERA5_data/ERA5-2022-02_17-18-sl.grib')

具体细节的运行可以看这篇博客：

https://blog.csdn.net/weixin_44237337/article/details/123152177?spm=1001.2014.3001.5501

下面只介绍不同的地方

WPS前处理

链接Vtable这里需要进行修改，如下：

cd  /Users/WRF/ERA_practice/
ln -sf ungrib/Variable_Tables/Vtable.ECMWF  Vtable

然后同样是链接你下载的ERA5数据：

./link_grib.csh  ../ERA5_data/ERA5-2022-02_17-18*

ungrid

因为我这个里是三层嵌套，需要修改namelist.wps后，再运行ungrid程序

&share
 wrf_core = 'ARW',
 start_date = '2022-02_17_00:00:00','2022-02_17_00:00:00','2022-02_17_00:00:00',
 end_date = '2022-02_17_06:00:00','2022-02_17_06:00:00','2022-02_17_06:00:00',
 interval_seconds = 10800,
 max_dom = 3,
 io_form_geogrid = 2, 
 opt_output_from_geogrid_path = '/WRF/ERA5_pactice/',
&geogrid
 parent_id         =   1,      1,      2,
 parent_grid_ratio =   1,      3,      3,
 i_parent_start    =   1,     21,    27,
 j_parent_start    =   1,     21,    26,
 e_we                     = 247,      574,    1471,
 e_sn                     = 158,      370,      889,
 geog_data_res     = 'default','default','default',
 dx = 36000,
 dy = 36000,
 map_proj  = 'mercator',
 ref_lat   =  15.00,
 ref_lon   = 0.00,
 truelat1  =  10.0,
 truelat2  =  20.0,
 stand_lon =0.00,
  geog_data_path = '/Software/Models/WRF/WPS_GEOG',
 !!!!!!!!!!!!!!!!!!!!!!!!!!!! IMPORTANT NOTE !!!!!!!!!!!!!!!!!!!!!!!!!!!!
 ! The default datasets used to produce the MAXSNOALB and ALBEDO12M
 ! fields have changed in WPS v4.0. These fields are now interpolated
 ! from MODIS-based datasets.
 ! To match the output given by the default namelist.wps in WPS v3.9.1,
 ! the following setting for geog_data_res may be used:
 ! geog_data_res = 'maxsnowalb_ncep+albedo_ncep+default', 'maxsnowalb_ncep+albedo_ncep+default', 
 !!!!!!!!!!!!!!!!!!!!!!!!!!!! IMPORTANT NOTE !!!!!!!!!!!!!!!!!!!!!!!!!!!!
&ungrib
 out_format = 'WPS',
 prefix = '/WRF/ERA5_pactice/FILE',
&metgrid
 fg_name = 'FILE',
 io_form_metgrid = 2, 
 opt_output_from_metgrid_path = '/WRF/ERA5_pactice/',
/

下面正常运行 ./geogrid.exe 、 ./metgrid.exe

WRF后处理

修改一下 namelist.input ，与 wps 中的一致：

 &time_control
 run_days                            = 0,
 run_hours                           = 06,
 run_minutes                         = 0,
 run_seconds                         = 0,
 start_year                          = 2022, 2022, 2022,
 start_month                         = 02,   02,   02,
 start_day                           = 17,   17,   17,
 start_hour                          = 00,   00,   00,
 end_year                            = 2022, 2022, 2022,
 end_month                           = 02,   02,   02,
 end_day                             = 17,   17,   17,
 end_hour                            = 06,   06,   06,
 interval_seconds                    = 10800,
 input_from_file                     = .true.,.true.,.true.,
 history_interval                    = 60,  60,   60,
 frames_per_outfile                  = 1000, 1000, 1000,
 restart                             = .false.,
 restart_interval                    = 1440,
 io_form_history                     = 2
 io_form_restart                     = 2
 io_form_input                       = 2
 io_form_boundary                    = 2
 &domains
 time_step                           = 60,
 time_step_fract_num                 = 0,
 time_step_fract_den                 = 1,
 max_dom                             = 3,
 i_parent_start    =   1,     21,    27,
 j_parent_start    =   1,     21,    26,
 e_we                     = 247,      574,    1471,
 e_sn                     = 158,      370,      889,
 e_vert                              = 50,    50,   50,
 p_top_requested                     = 5000,
 num_metgrid_levels                  = 38,
 num_metgrid_soil_levels             = 4,
 dx                                  =  36000,  12000,4000,
 dy                                  =  36000,  12000,4000,
 grid_id                             = 1,     2,     3,
 parent_id         =   1,      1,      2,
 parent_grid_ratio =   1,      3,      3,
 parent_time_step_ratio              = 1,     3,     3,
 feedback                            = 1,
 smooth_option                       = 0,
 &physics
 physics_suite                       = 'CONUS'
 mp_physics                          = -1,    -1,    -1,
 cu_physics                          = -1,    -1,     0,
 ra_lw_physics                       = -1,    -1,    -1,
 ra_sw_physics                       = -1,    -1,    -1,
 bl_pbl_physics                      = -1,    -1,    -1,
 sf_sfclay_physics                   = -1,    -1,    -1,
 sf_surface_physics                  = -1,    -1,    -1,
 radt                                = 30,    30,    30,
 bldt                                = 0,     0,     0,
 cudt                                = 5,     5,     5,
 icloud                              = 1,
 num_land_cat                        = 21,
 sf_urban_physics                    = 0,     0,     0,
 &dynamics
 hybrid_opt                          = 2, 
 w_damping                           = 0,
 diff_opt                            = 1,      1,      1,
 km_opt                              = 4,      4,      4,
 diff_6th_opt                        = 0,      0,      0,
 diff_6th_factor                     = 0.12,   0.12,   0.12,
 base_temp                           = 290.
 damp_opt                            = 3,
 zdamp                               = 5000.,  5000.,  5000.,
 dampcoef                            = 0.2,    0.2,    0.2
 khdif                               = 0,      0,      0,
 kvdif                               = 0,      0,      0,
 non_hydrostatic                     = .true., .true., .true.,
 moist_adv_opt                       = 1,      1,      1,     
 scalar_adv_opt                      = 1,      1,      1,     
 gwd_opt                             = 1,
 &bdy_control
 spec_bdy_width                      = 5,
 specified                           = .true.
 &grib2
 &namelist_quilt
 nio_tasks_per_group = 0,
 nio_groups = 1,
 /

之后正常运行./real.exe、./wrf.exe即可、、、

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