This notebook continues the previous post by showing the actual code for distributed data processing.

In [1]:

%matplotlib inline
import xarray as xr
import matplotlib.pyplot as plt
import cartopy.crs as ccrs

from dask.diagnostics import ProgressBar
from dask_jobqueue import SLURMCluster
from distributed import Client, progress

In [2]:

import dask
import distributed
dask.__version__, distributed.__version__

Out[2]:

('1.1.3', '1.26.0')

In [3]:

%env HDF5_USE_FILE_LOCKING=FALSE

env: HDF5_USE_FILE_LOCKING=FALSE

Data exploration¶

Data are organized by year/month:

In [4]:

ls /fsx

2008/  2010/  2012/  2014/  2016/  2018/
2009/  2011/  2013/  2015/  2017/  QA/

In [5]:

ls /fsx/2008/

01/  02/  03/  04/  05/  06/  07/  08/  09/  10/  11/  12/

In [6]:

ls /fsx/2008/01/data  # one variable per file

air_pressure_at_mean_sea_level.nc*
air_temperature_at_2_metres_1hour_Maximum.nc*
air_temperature_at_2_metres_1hour_Minimum.nc*
air_temperature_at_2_metres.nc*
dew_point_temperature_at_2_metres.nc*
eastward_wind_at_100_metres.nc*
eastward_wind_at_10_metres.nc*
integral_wrt_time_of_surface_direct_downwelling_shortwave_flux_in_air_1hour_Accumulation.nc*
lwe_thickness_of_surface_snow_amount.nc*
northward_wind_at_100_metres.nc*
northward_wind_at_10_metres.nc*
precipitation_amount_1hour_Accumulation.nc*
sea_surface_temperature.nc*
snow_density.nc*
surface_air_pressure.nc*

In [7]:

# hourly data over a month
dr = xr.open_dataarray('/fsx/2008/01/data/sea_surface_temperature.nc')
dr

Out[7]:

<xarray.DataArray 'sea_surface_temperature' (time0: 744, lat: 640, lon: 1280)>
[609484800 values with dtype=float32]
Coordinates:
  * lon      (lon) float32 0.0 0.2812494 0.5624988 ... 359.43674 359.718
  * lat      (lat) float32 89.784874 89.5062 89.22588 ... -89.5062 -89.784874
  * time0    (time0) datetime64[ns] 2008-01-01T07:00:00 ... 2008-02-01T06:00:00
Attributes:
    standard_name:  sea_surface_temperature
    units:          K
    long_name:      Sea surface temperature
    nameECMWF:      Sea surface temperature
    nameCDM:        Sea_surface_temperature_surface

In [8]:

# Static plot of the first time slice
fig, ax = plt.subplots(1, 1, figsize=[12, 8], subplot_kw={'projection': ccrs.PlateCarree()})
dr[0].plot(ax=ax, transform=ccrs.PlateCarree(), cbar_kwargs={'shrink': 0.6})
ax.coastlines();

What happens to the values over the land? Easier to check by an interactive plot.

In [9]:

import geoviews as gv
import hvplot.xarray

fig_hv = dr[0].hvplot.quadmesh(
    x='lon', y='lat', rasterize=True, cmap='viridis', geo=True,
    crs=ccrs.PlateCarree(), projection=ccrs.PlateCarree(), project=True,
    width=800, height=400, 
) * gv.feature.coastline

# fig_hv