GDPS 🅱#

BETA Requires MetPy >=1.6

This demonstrates using data from Canada’s GEM Global or Global Deterministic Prediction System (GDPS).

GDPS Model Description

Data Sources

prioriy=

Data source

Archive Duration

"mcs"

Meteorological Service of Canada

Last 24 hours

Model Initialization

Model cyles every twelve hours.

Forecast Hour

For the most recent version of GDPS…

fxx=

Forecast lead time

0 through 240, step=3

3-hourly forecasts available

Products

product=

Product Description

"15km/grib2/lat_lon"

Global domain

Variable and Level

You will need to specify the variable and level for each request.

NOTE: The organization of these files is different than other NWP products.

  1. There are no index files provided.

  2. Each GRIB2 file only contains one message. The variable name and level is in the file’s name.

Herbie requires you provide a keyword argument for both variable and level. Pay special attention to model description (linked above) to understand how the model data is organized. If you don’t provide input for variable or level, Herbie will give you some ideas. For example, variable=TMP and level=TGL_2 will give you the filename that contains

TMP_TGL_2

Note: This requires MetPy version 1.6 or greater which has the capability to parse the rotated latitude longitude map projection type (see MetPy/#3123).

[1]:

from herbie import Herbie
import xarray as xr
import numpy as np

import matplotlib.pyplot as plt
from toolbox import EasyMap, pc
import cartopy.crs as ccrs
import cartopy.feature as feature
import pandas as pd

recent = pd.Timestamp("now").floor("12h") - pd.Timedelta("12h")

[2]:

recent

[2]:

Timestamp('2024-04-11 00:00:00')

[3]:

# Some examples

H = Herbie(
    recent,  # Datetime
    model="gdps",
    fxx=30,
    variable="TMP",
    level="TGL_2",
)
H.grib

✅ Found ┊ model=gdps ┊ product=15km/grib2/lat_lon ┊ 2024-Apr-11 00:00 UTC F30 ┊ GRIB2 @ msc ┊ IDX @ None

[3]:

'https://dd.weather.gc.ca/model_gem_global/15km/grib2/lat_lon/00/030/CMC_glb_TMP_TGL_2_latlon.15x.15_2024041100_P030.grib2'

[4]:

H = Herbie(
    recent,  # Datetime
    model="gdps",
    fxx=12,
    variable="HGT",
    level="ISBL_500",
)
H.grib

✅ Found ┊ model=gdps ┊ product=15km/grib2/lat_lon ┊ 2024-Apr-11 00:00 UTC F12 ┊ GRIB2 @ msc ┊ IDX @ None

[4]:

'https://dd.weather.gc.ca/model_gem_global/15km/grib2/lat_lon/00/012/CMC_glb_HGT_ISBL_500_latlon.15x.15_2024041100_P012.grib2'

Get the 2-metre temperature#

[5]:

H = Herbie(
    recent,
    model="gdps",
    fxx=0,
    variable="TMP",
    level="TGL_2",
)
ds = H.xarray()
ds

✅ Found ┊ model=gdps ┊ product=15km/grib2/lat_lon ┊ 2024-Apr-11 00:00 UTC F00 ┊ GRIB2 @ local ┊ IDX @ None

/p/home/blaylock/BB_python/Herbie/herbie/core.py:1100: UserWarning: Will not remove GRIB file because it previously existed.
  warnings.warn("Will not remove GRIB file because it previously existed.")

[5]:

<xarray.Dataset> Size: 12MB
Dimensions:              (latitude: 1201, longitude: 2400)
Coordinates:
    time                 datetime64[ns] 8B 2024-04-11
    step                 timedelta64[ns] 8B 00:00:00
    heightAboveGround    float64 8B 2.0
  * latitude             (latitude) float64 10kB -90.0 -89.85 ... 89.85 90.0
  * longitude            (longitude) float64 19kB -180.0 -179.8 ... 179.7 179.8
    valid_time           datetime64[ns] 8B ...
Data variables:
    t2m                  (latitude, longitude) float32 12MB ...
    gribfile_projection  object 8B None
Attributes:
    GRIB_edition:            2
    GRIB_centre:             cwao
    GRIB_centreDescription:  Canadian Meteorological Service - Montreal
    GRIB_subCentre:          0
    Conventions:             CF-1.7
    institution:             Canadian Meteorological Service - Montreal
    model:                   gdps
    product:                 15km/grib2/lat_lon
    description:             Canada's Global Deterministic Prediction System ...
    remote_grib:             /p/cwfs/blaylock/data/gdps/20240411/CMC_glb_TMP_...
    local_grib:              /p/cwfs/blaylock/data/gdps/20240411/CMC_glb_TMP_...
    search:            None
[6]:

ds.valid_time.dt.strftime("%Y-%m-%d %H:%M").item()

[6]:

'2024-04-11 00:00'

[ ]:

Plot data on Plate Carree projection#

[7]:

ax = EasyMap("50m").BORDERS().STATES(alpha=0.5).ax
p = ax.pcolormesh(ds.longitude, ds.latitude, ds.t2m, transform=pc, cmap="Spectral_r")
plt.colorbar(p, ax=ax, orientation="horizontal", pad=0.01, shrink=0.8)
ax.set_title(
    f"2-m Temperature\nValid {ds.valid_time.dt.strftime('%Y-%m-%d %H:%M').item()} UTC",
    loc="right",
    fontsize=10,
)
ax.set_title(f"{ds.model.upper()}: {H.product_description}", loc="left")
ax.gridlines()

[7]:

<cartopy.mpl.gridliner.Gridliner at 0x2b335baf5690>
../../_images/gallery_eccc_models_gdps_10_1.png

Get 10-m U and 10-m V wind#

[8]:

# loading more than one variable requires a loop, because the
# data is stored in multiple files (and a Herbie object only
# represents a single file).

store = []
for var, lev in zip(["UGRD", "VGRD"], ["TGL_10", "TGL_10"]):
    _ds = Herbie(
        recent,
        model="gdps",
        fxx=0,
        product="15km/grib2/lat_lon",
        variable=var,
        level=lev,
    ).xarray()
    store.append(_ds)

ds = xr.merge(store)
ds

✅ Found ┊ model=gdps ┊ product=15km/grib2/lat_lon ┊ 2024-Apr-11 00:00 UTC F00 ┊ GRIB2 @ local ┊ IDX @ None

/p/home/blaylock/BB_python/Herbie/herbie/core.py:1100: UserWarning: Will not remove GRIB file because it previously existed.
  warnings.warn("Will not remove GRIB file because it previously existed.")

✅ Found ┊ model=gdps ┊ product=15km/grib2/lat_lon ┊ 2024-Apr-11 00:00 UTC F00 ┊ GRIB2 @ local ┊ IDX @ None

/p/home/blaylock/BB_python/Herbie/herbie/core.py:1100: UserWarning: Will not remove GRIB file because it previously existed.
  warnings.warn("Will not remove GRIB file because it previously existed.")

[8]:

<xarray.Dataset> Size: 23MB
Dimensions:              (latitude: 1201, longitude: 2400)
Coordinates:
    time                 datetime64[ns] 8B 2024-04-11
    step                 timedelta64[ns] 8B 00:00:00
    heightAboveGround    float64 8B 10.0
  * latitude             (latitude) float64 10kB -90.0 -89.85 ... 89.85 90.0
  * longitude            (longitude) float64 19kB -180.0 -179.8 ... 179.7 179.8
    valid_time           datetime64[ns] 8B 2024-04-11
Data variables:
    u10                  (latitude, longitude) float32 12MB ...
    gribfile_projection  object 8B None
    v10                  (latitude, longitude) float32 12MB ...
Attributes:
    GRIB_edition:            2
    GRIB_centre:             cwao
    GRIB_centreDescription:  Canadian Meteorological Service - Montreal
    GRIB_subCentre:          0
    Conventions:             CF-1.7
    institution:             Canadian Meteorological Service - Montreal
    model:                   gdps
    product:                 15km/grib2/lat_lon
    description:             Canada's Global Deterministic Prediction System ...
    remote_grib:             /p/cwfs/blaylock/data/gdps/20240411/CMC_glb_UGRD...
    local_grib:              /p/cwfs/blaylock/data/gdps/20240411/CMC_glb_UGRD...
    search:            None
[9]:

# MetPy version >= 1.6 is required to parse the map projection
ds.herbie.crs

[9]:
2024-04-11T22:41:25.994384 image/svg+xml Matplotlib v3.8.4, https://matplotlib.org/ 
<cartopy.crs.PlateCarree object at 0x2b334b583d50>
[10]:

ax = (
    EasyMap("50m", crs=ds.herbie.crs, figsize=8, linewidth=1)
    .BORDERS()
    .STATES(alpha=0.5)
    .ax
)
p = ax.pcolormesh(
    ds.longitude,
    ds.latitude,
    np.hypot(ds.u10, ds.v10),  # Wind Speed
    transform=pc,
)
plt.colorbar(
    p, ax=ax, orientation="horizontal", pad=0.01, shrink=0.8, label="Wind speed (m/s)"
)

ax.set_title(
    f"10-m Wind Speed\nValid {ds.valid_time.dt.strftime('%Y-%m-%d %H:%M').item()} UTC",
    loc="center",
    fontsize=10,
)
ax.set_title(f"{ds.model.upper()}", loc="left")

[10]:

Text(0.0, 1.0, 'GDPS')
../../_images/gallery_eccc_models_gdps_14_1.png

500 hPa Humidity and Geopotential Height#

[11]:

# loading more than one variable requires a loop, because the
# data is stored in multiple files (and a Herbie object only
# represents a single file).

store = []
for var, lev in zip(["HGT", "RH"], ["ISBL_500", "ISBL_500"]):
    _ds = Herbie(
        recent,
        model="gdps",
        fxx=0,
        product="15km/grib2/lat_lon",
        variable=var,
        level=lev,
    ).xarray()
    store.append(_ds)

ds = xr.merge(store)
ds

✅ Found ┊ model=gdps ┊ product=15km/grib2/lat_lon ┊ 2024-Apr-11 00:00 UTC F00 ┊ GRIB2 @ local ┊ IDX @ None

/p/home/blaylock/BB_python/Herbie/herbie/core.py:1100: UserWarning: Will not remove GRIB file because it previously existed.
  warnings.warn("Will not remove GRIB file because it previously existed.")

✅ Found ┊ model=gdps ┊ product=15km/grib2/lat_lon ┊ 2024-Apr-11 00:00 UTC F00 ┊ GRIB2 @ local ┊ IDX @ None

/p/home/blaylock/BB_python/Herbie/herbie/core.py:1100: UserWarning: Will not remove GRIB file because it previously existed.
  warnings.warn("Will not remove GRIB file because it previously existed.")

[11]:

<xarray.Dataset> Size: 23MB
Dimensions:              (latitude: 1201, longitude: 2400)
Coordinates:
    time                 datetime64[ns] 8B 2024-04-11
    step                 timedelta64[ns] 8B 00:00:00
    isobaricInhPa        float64 8B 500.0
  * latitude             (latitude) float64 10kB -90.0 -89.85 ... 89.85 90.0
  * longitude            (longitude) float64 19kB -180.0 -179.8 ... 179.7 179.8
    valid_time           datetime64[ns] 8B 2024-04-11
Data variables:
    gh                   (latitude, longitude) float32 12MB ...
    gribfile_projection  object 8B None
    r                    (latitude, longitude) float32 12MB ...
Attributes:
    GRIB_edition:            2
    GRIB_centre:             cwao
    GRIB_centreDescription:  Canadian Meteorological Service - Montreal
    GRIB_subCentre:          0
    Conventions:             CF-1.7
    institution:             Canadian Meteorological Service - Montreal
    model:                   gdps
    product:                 15km/grib2/lat_lon
    description:             Canada's Global Deterministic Prediction System ...
    remote_grib:             /p/cwfs/blaylock/data/gdps/20240411/CMC_glb_HGT_...
    local_grib:              /p/cwfs/blaylock/data/gdps/20240411/CMC_glb_HGT_...
    search:            None
[12]:

ax = (
    EasyMap("50m", crs=ds.herbie.crs, figsize=8, linewidth=1, dark=True)
    .BORDERS()
    .STATES(alpha=0.5)
    .ax
)

# Draw Relative Humidity
p = ax.pcolormesh(
    ds.longitude, ds.latitude, ds.r * 100, transform=pc, cmap="BrBG", vmin=0, vmax=100
)
plt.colorbar(
    p,
    ax=ax,
    orientation="horizontal",
    pad=0.01,
    shrink=0.8,
    label="Relative Humidity (%)",
)

# Draw Geopential Height Contours
ax.contour(
    ds.longitude,
    ds.latitude,
    ds.gh,
    colors="k",
    transform=pc,
    levels=range(0, 6000, 40),
)

ax.set_title(
    f"500 hPa RH and Geopotential height\nValid {ds.valid_time.dt.strftime('%Y-%m-%d %H:%M').item()} UTC",
    loc="center",
    fontsize=10,
)
ax.set_title(f"{ds.model.upper()}", loc="left")

[12]:

Text(0.0, 1.0, 'GDPS')
../../_images/gallery_eccc_models_gdps_17_1.png
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