Contents

NEWA Wind Data for Irish Continental Shelf region

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NEWA Wind Data for Irish Continental Shelf region

Introduction

The New European Wind Atlas (NEWA) provides wind statistics covering onshore Europe, 100km offshore over European seas, and the complete North and Baltic Seas, based on 30 years of mesoscale simulations. Further details may be found in the following publications:

This notebook provides details of:

  1. NEWA wind data products retrieval.

  2. The creation of the NEWA Zarr wind stores that are included in the EOOffshore catalog.

  3. A brief look at these Zarr stores, including a demonstration of wind speed calculation.

These NEWA Zarr stores have been uploaded to Zenodo.

How to cite:

  1. O’Callaghan, D. and McBreen, S.: Scalable Offshore Wind Analysis With Pangeo, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2746, https://doi.org/10.5194/egusphere-egu22-2746, 2022.

  2. O’Callaghan, D. and McBreen, S.: EOOffshore: New European Wind Atlas (NEWA) Data for the Irish Continental Shelf Region, (1.0.0) [Data set], Zenodo, 2022. https://doi.org/10.5281/zenodo.6977029

Note: more extensive usage of the EOOffshore NEWA Zarr stores may be found in the following notebooks:

NEWA Wind Data Products

The EOOffshore project uses the mesoscale data products available for selection on the NEWA Map Layers and Datasets website. These contain variables at multiple heights (metres above surface level), which means they are particularly useful for the EOOffshore project due to these heights being similar to typical wind turbine hub heights. Unlike other data sets used by EOOffshore, they also provide a power density variable in addition to variables related to wind speed and direction. The following data variables are relevant:

Variable

Unit

Height (metres above sea level)

Description

WS10

\(m s^{-1}\)

10

Wind Speed at 10m

WD10

degree

10

Wind Direction at 10m

WS

\(m s^{-1}\)

50, 75, 100, 150

Wind Speed

WD

degree

50, 75, 100, 150

Wind Direction

PD

\(W m^{-2}\)

50, 75, 100, 150

Wind Power Density

RHO

\(kg\) \(m^{-3}\)

Surface

Air Density

$$$$

$$$$

$$$$

$$$$

Although both mesoscale and microscale data are available as map layers, plots and data download is only possible for mesoscale outputs. The Meso Download tab enables the selection of a time period (day), height, and variables. The Get script link will generate a wget request for a selected Area Of Interest (AOI), for example;

wget -O 2015-12-30_Area_1.nc http://opendap.neweuropeanwindatlas.eu:80/opendap/newa/NEWA_MESOSCALE_ATLAS/2015/NEWA-2015-12-30.nc.nc?WS[0:1:47][2:2][646:1:685][244:1:293],time[0:1:47],height[2:2],west_east[244:1:293],south_north[646:1:685],XLON[646:1:685][244:1:293],XLAT[646:1:685][244:1:293],Times[0:1:47],crs

This example script will retrieve the selected variables from the corresponding daily NEWA OPeNDAP data set. Four AOIs were selected (see below), corresponding daily wget commands were constructed for 2009 to 2018, and executed for product retrieval:

Observation / Models

Models

Product type

Wind Atlas

Processing level

Level-3

Data type

Gridded (latitude/longitude)

Horizontal coverage

Bounding boxes:
[52.15, -7.05, 54.16, -4.75],
[51.05, -9.03, 52.50, -6.26],
[50.95, -11.14, 51.59, -10.09],
[54.75, -10.55, 55.41, -9.40]

Horizontal resolution

3 km

Vertical coverage

[10, 50, 75, 100, 150] metres above surface level

Temporal coverage

2009-01-01T00:00:00 to 2018-12-31T23:00:00

Temporal resolution

Hourly

Update frequency

n/a

File format

NetCDF-4

Total retrieved products

14,611

Total products size

27G

NEWA Wind Zarr Stores

For each AOI data set:

  • the retrieved NetCDF products were loaded using xarray.open_mfdataset(), combined by their grid coordinates and concatenated along the time dimension.

  • the data set was chunked in time and persisted to a single, chunked, compressed Zarr store (16G), which is a cloud-optimised format suitable for multi-dimensional arrays. A time chunk size was specified that resulted in a low number of time chunks, as this approach is more suitable for subsequent processing of variables over time for AOIs.

Zarr stores were created for four AOIs:

As requested by the NEWA Terms of use, the following attribution is declared:

  • Data [2009 - 2018] obtained from the New European Wind Atlas (NEWA), a free, web-based application developed, owned and operated by the NEWA Consortium. For additional information see www.neweuropeanwindatlas.eu.

NEWA in EOOffshore Catalog

Imports required for subsequent processing

from dataclasses import dataclass, field
from intake import Catalog, open_catalog
import json
import xarray as xr

Open the catalog and view the NEWA metadata

All EOOffshore data sets, including the NEWA Zarr stores described above, are accessible using the EOOffshore Intake catalog. Each catalog entry provides a description and metadata associated with the corresponding data set, defined in a YAML configuration file. The EOOffshore catalog configuration was originally influenced by the Pangeo Cloud Data Store atmosphere.yaml catalog configuration.

catalog = open_catalog('data/intake-catalogs/eooffshore_ics.yaml')

View the Irish Sea NEWA Zarr store metadata

catalog.eooffshore_ics_newa_irishsea

eooffshore_ics_newa_irishsea:
  args:
    storage_options: null
    urlpath: /data/eo/zarr/newa/eooffshore_ics_newa_irishsea.zarr
  description: EOOffshore Project 2009 - 2018 Concatenated NEWA wind variable products
    for Irish Sea area within the Irish Continental Shelf. Data [2009 - 2018] obtained
    from the New European Wind Atlas (NEWA), a free, web-based application developed,
    owned and operated by the NEWA Consortium. For additional information see www.neweuropeanwindatlas.eu.'
  driver: intake_xarray.xzarr.ZarrSource
  metadata:
    catalog_dir: /opt/eooffshore/notebooks/datasets/data/intake-catalogs/
    tags:
    - atmosphere
    - wind
    - newa
    - iwb
    - ocean
    title: NEWA products for the Irish Sea area of interest (2009 - 2018)
    url: https://map.neweuropeanwindatlas.eu/

View the Celtic Sea NEWA Zarr store metadata

catalog.eooffshore_ics_newa_celticsea

eooffshore_ics_newa_celticsea:
  args:
    storage_options: null
    urlpath: /data/eo/zarr/newa/eooffshore_ics_newa_celticsea.zarr
  description: EOOffshore Project 2009 - 2018 Concatenated NEWA wind variable products
    for North Celtic Sea area within the Irish Continental Shelf. Data [2009 - 2018]
    obtained from the New European Wind Atlas (NEWA), a free, web-based application
    developed, owned and operated by the NEWA Consortium. For additional information
    see www.neweuropeanwindatlas.eu.'
  driver: intake_xarray.xzarr.ZarrSource
  metadata:
    catalog_dir: /opt/eooffshore/notebooks/datasets/data/intake-catalogs/
    tags:
    - atmosphere
    - wind
    - newa
    - iwb
    - ocean
    title: NEWA products for the Celtic Sea area of interest (2009 - 2018)
    url: https://map.neweuropeanwindatlas.eu/

View the Irish Weather Buoy Network - M3 buoy NEWA Zarr store metadata

catalog.eooffshore_ics_newa_m3

eooffshore_ics_newa_m3:
  args:
    storage_options: null
    urlpath: /data/eo/zarr/newa/eooffshore_ics_newa_m3.zarr
  description: EOOffshore Project 2009 - 2018 Concatenated NEWA wind variable products
    for surrounding the area surrounding the Irish Weather Buoy Network (IWB) M3 buoy
    within the Irish Continental Shelf. Data [2009 - 2018] obtained from the New European
    Wind Atlas (NEWA), a free, web-based application developed, owned and operated
    by the NEWA Consortium. For additional information see www.neweuropeanwindatlas.eu.'
  driver: intake_xarray.xzarr.ZarrSource
  metadata:
    catalog_dir: /opt/eooffshore/notebooks/datasets/data/intake-catalogs/
    tags:
    - atmosphere
    - wind
    - newa
    - iwb
    - ocean
    title: NEWA products for the IWB M3 buoy area (2009 - 2018)
    url: https://map.neweuropeanwindatlas.eu/

View the Irish Weather Buoy Network - M4 buoy NEWA Zarr store metadata

catalog.eooffshore_ics_newa_m4

eooffshore_ics_newa_m4:
  args:
    storage_options: null
    urlpath: /data/eo/zarr/newa/eooffshore_ics_newa_m4.zarr
  description: EOOffshore Project 2009 - 2018 Concatenated NEWA wind variable products
    for surrounding the area surrounding the Irish Weather Buoy Network (IWB) M4 buoy
    within the Irish Continental Shelf. Data [2009 - 2018] obtained from the New European
    Wind Atlas (NEWA), a free, web-based application developed, owned and operated
    by the NEWA Consortium. For additional information see www.neweuropeanwindatlas.eu.'
  driver: intake_xarray.xzarr.ZarrSource
  metadata:
    catalog_dir: /opt/eooffshore/notebooks/datasets/data/intake-catalogs/
    tags:
    - atmosphere
    - wind
    - newa
    - iwb
    - ocean
    title: NEWA products for the IWB M4 buoy area (2009 - 2018)
    url: https://map.neweuropeanwindatlas.eu/

Load each catalog NEWA Zarr store

Intake catalog entries typically specify a driver to be used when loading the corresponding data set. The NEWA entries specify intake_xarray.xzarr.ZarrSource, a driver implementation provided by the intake-xarray library. This enables NetCDF and Zarr data sets to be loaded using xarray, a library for processing N-D labeled arrays and datasets. As xarray labels take the form of dimensions, coordinates and attributes on top of NumPy-like arrays, it is particularly suited to data sets such as NEWA whose variables feature latitude/longitude grid coordinates.

This intake driver will load the associated dataset into an xarray.Dataset. To enable support for potentially large data sets, the to_dask() function is used to load the underlying variable arrays with Dask, a parallel, out-of-core computing library. The ZarrSource implementation will load the data set variables into Dask arrays, which will be loaded and processed in parallel as chunks during subsequent computation. As discussed above, variable chunk sizes may be specified during Zarr store creation.

This utility class is used for Zarr loading and preparation. The 10m NEWA wind variables (WS10 and WD10) are added to the corresponding wind variables containing data at multiple heights (WS and WD), and the height dimension is reindexed to include the 10m data.

@dataclass
class EooffshoreDataset:
    name: str
    catalog: Catalog = field(repr=False, hash=False, compare=False)
    dataset_id: str
    dataset: xr.Dataset = field(init=False, hash=False, compare=False, repr=False)

    def __post_init__(self):
        """Load the dataset from the Intake catalog"""
        ds = self.catalog[self.dataset_id].to_dask()
        
        # Enable consistent variable naming
        ds = ds.rename({'WS': 'wind_speed', 
                        'WD': 'wind_direction', 
                        'PD': 'power_density',
                        'XLAT': 'latitude',
                        'XLON': 'longitude'}
                      )
        # Not required
        ds = ds.drop(['south_north', 'west_east'])

        # Add provided 10m wind variable data to corresponding variable with a height dimension
        wind_variables = {}
        for variable_name_10m, variable_name in {'WS10': 'wind_speed', 'WD10': 'wind_direction'}.items(): 
            wind_variables[variable_name] = xr.concat((ds[variable_name], ds[variable_name_10m].assign_coords(height=10).expand_dims(['height'])), dim='height').sortby('height')
        ds = ds.reindex({'height': wind_variables['wind_speed'].height}).chunk({'height':1})
        for variable_name, wind_variable in wind_variables.items():
            ds[variable_name] = wind_variable
        
        self.dataset = ds

Here, each NEWA store is loaded into an xarray.Dataset:

  • The wind_speed, wind_direction and power_density variables have associated coordinate dimensions:

    • height

    • west_east (longitude) and south_north (latitude) - the corresponding coordinate grid

    • time - hourly

  • A low number of time chunks have been specified, to support subsequent computation across time for smaller AOI grid coordinates.

newa_irishsea = EooffshoreDataset(name='NEWA Irish Sea', catalog=catalog, dataset_id='eooffshore_ics_newa_irishsea')
newa_celticsea = EooffshoreDataset(name='NEWA Celtic Sea', catalog=catalog, dataset_id='eooffshore_ics_newa_celticsea')
newa_m3 = EooffshoreDataset(name='NEWA M3', catalog=catalog, dataset_id='eooffshore_ics_newa_m3')
newa_m4 = EooffshoreDataset(name='NEWA M4', catalog=catalog, dataset_id='eooffshore_ics_newa_m4')

newa_irishsea.dataset

<xarray.Dataset>
Dimensions:         (height: 5, time: 87648, south_north: 67, west_east: 35)
Coordinates:
  * height          (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude        (south_north, west_east) float32 dask.array<chunksize=(67, 35), meta=np.ndarray>
    longitude       (south_north, west_east) float32 dask.array<chunksize=(67, 35), meta=np.ndarray>
  * time            (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Data variables:
    power_density   (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 67, 35), meta=np.ndarray>
    RHO             (time, south_north, west_east) float32 dask.array<chunksize=(40000, 67, 35), meta=np.ndarray>
    Times           (time) |S20 dask.array<chunksize=(40000,), meta=np.ndarray>
    wind_direction  (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 67, 35), meta=np.ndarray>
    WD10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 67, 35), meta=np.ndarray>
    wind_speed      (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 67, 35), meta=np.ndarray>
    WS10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 67, 35), meta=np.ndarray>
    crs             (time) |S1 dask.array<chunksize=(40000,), meta=np.ndarray>
Attributes: (12/116)
    ADAPT_DT_MAX:                    15.0
    ADAPT_DT_MIN:                    3.0
    ADAPT_DT_START:                  13.0
    AER_ANGEXP_OPT:                  1
    AER_ANGEXP_VAL:                  1.2999999523162842
    AER_AOD550_OPT:                  1
    ...                              ...
    WEST-EAST_GRID_DIMENSION:        Attribute edlided: Unsupported attribute...
    W_DAMPING:                       1
    YSU_TOPDOWN_PBLMIX:              0
    eooffshore_zarr_creation_time:   2022-05-13T15:25:40Z
    eooffshore_zarr_details:         EOOffshore Project: Concatenated NEWA wi...
    history:                         2021-10-27 13:36:24 GMT Hyrax-1.16.0 htt...
newa_celticsea.dataset

<xarray.Dataset>
Dimensions:         (height: 5, time: 87648, south_north: 40, west_east: 54)
Coordinates:
  * height          (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude        (south_north, west_east) float32 dask.array<chunksize=(40, 54), meta=np.ndarray>
    longitude       (south_north, west_east) float32 dask.array<chunksize=(40, 54), meta=np.ndarray>
  * time            (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Data variables:
    power_density   (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 40, 54), meta=np.ndarray>
    RHO             (time, south_north, west_east) float32 dask.array<chunksize=(40000, 40, 54), meta=np.ndarray>
    Times           (time) |S20 dask.array<chunksize=(40000,), meta=np.ndarray>
    wind_direction  (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 40, 54), meta=np.ndarray>
    WD10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 40, 54), meta=np.ndarray>
    wind_speed      (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 40, 54), meta=np.ndarray>
    WS10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 40, 54), meta=np.ndarray>
    crs             (time) |S1 dask.array<chunksize=(40000,), meta=np.ndarray>
Attributes: (12/116)
    ADAPT_DT_MAX:                    15.0
    ADAPT_DT_MIN:                    3.0
    ADAPT_DT_START:                  13.0
    AER_ANGEXP_OPT:                  1
    AER_ANGEXP_VAL:                  1.2999999523162842
    AER_AOD550_OPT:                  1
    ...                              ...
    WEST-EAST_GRID_DIMENSION:        Attribute edlided: Unsupported attribute...
    W_DAMPING:                       1
    YSU_TOPDOWN_PBLMIX:              0
    eooffshore_zarr_creation_time:   2022-05-13T15:11:52Z
    eooffshore_zarr_details:         EOOffshore Project: Concatenated NEWA wi...
    history:                         2021-10-27 13:36:09 GMT Hyrax-1.16.0 htt...
newa_m3.dataset

<xarray.Dataset>
Dimensions:         (height: 5, time: 87648, south_north: 19, west_east: 20)
Coordinates:
  * height          (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude        (south_north, west_east) float32 dask.array<chunksize=(19, 20), meta=np.ndarray>
    longitude       (south_north, west_east) float32 dask.array<chunksize=(19, 20), meta=np.ndarray>
  * time            (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Data variables:
    power_density   (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 19, 20), meta=np.ndarray>
    RHO             (time, south_north, west_east) float32 dask.array<chunksize=(40000, 19, 20), meta=np.ndarray>
    Times           (time) |S20 dask.array<chunksize=(40000,), meta=np.ndarray>
    wind_direction  (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 19, 20), meta=np.ndarray>
    WD10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 19, 20), meta=np.ndarray>
    wind_speed      (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 19, 20), meta=np.ndarray>
    WS10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 19, 20), meta=np.ndarray>
    crs             (time) |S1 dask.array<chunksize=(40000,), meta=np.ndarray>
Attributes: (12/116)
    ADAPT_DT_MAX:                    15.0
    ADAPT_DT_MIN:                    3.0
    ADAPT_DT_START:                  13.0
    AER_ANGEXP_OPT:                  1
    AER_ANGEXP_VAL:                  1.2999999523162842
    AER_AOD550_OPT:                  1
    ...                              ...
    WEST-EAST_GRID_DIMENSION:        Attribute edlided: Unsupported attribute...
    W_DAMPING:                       1
    YSU_TOPDOWN_PBLMIX:              0
    eooffshore_zarr_creation_time:   2022-05-13T15:39:49Z
    eooffshore_zarr_details:         EOOffshore Project: Concatenated NEWA wi...
    history:                         2021-10-27 13:38:03 GMT Hyrax-1.16.0 htt...
newa_m4.dataset

<xarray.Dataset>
Dimensions:         (height: 5, time: 87648, south_north: 20, west_east: 20)
Coordinates:
  * height          (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude        (south_north, west_east) float32 dask.array<chunksize=(20, 20), meta=np.ndarray>
    longitude       (south_north, west_east) float32 dask.array<chunksize=(20, 20), meta=np.ndarray>
  * time            (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Data variables:
    power_density   (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 20, 20), meta=np.ndarray>
    RHO             (time, south_north, west_east) float32 dask.array<chunksize=(40000, 20, 20), meta=np.ndarray>
    Times           (time) |S20 dask.array<chunksize=(40000,), meta=np.ndarray>
    wind_direction  (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 20, 20), meta=np.ndarray>
    WD10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 20, 20), meta=np.ndarray>
    wind_speed      (time, height, south_north, west_east) float32 dask.array<chunksize=(40000, 1, 20, 20), meta=np.ndarray>
    WS10            (time, south_north, west_east) float32 dask.array<chunksize=(40000, 20, 20), meta=np.ndarray>
    crs             (time) |S1 dask.array<chunksize=(40000,), meta=np.ndarray>
Attributes: (12/116)
    ADAPT_DT_MAX:                    15.0
    ADAPT_DT_MIN:                    3.0
    ADAPT_DT_START:                  13.0
    AER_ANGEXP_OPT:                  1
    AER_ANGEXP_VAL:                  1.2999999523162842
    AER_AOD550_OPT:                  1
    ...                              ...
    WEST-EAST_GRID_DIMENSION:        Attribute edlided: Unsupported attribute...
    W_DAMPING:                       1
    YSU_TOPDOWN_PBLMIX:              0
    eooffshore_zarr_creation_time:   2022-05-13T15:52:39Z
    eooffshore_zarr_details:         EOOffshore Project: Concatenated NEWA wi...
    history:                         2021-10-27 13:38:07 GMT Hyrax-1.16.0 htt...

NEWA wind speed (2009 - 2018)

Each variable in the NEWA data sets, for example, wind speed, is loaded into an xarray.DataArray:

  • The arrays are transposed here to produce more intuitive time chunk visualisations. This is not required for computation.

newa_irishsea.dataset.wind_speed.transpose('height', 'time', 'south_north', 'west_east')

<xarray.DataArray 'wind_speed' (height: 5, time: 87648, south_north: 67,
                                west_east: 35)>
dask.array<transpose, shape=(5, 87648, 67, 35), dtype=float32, chunksize=(1, 40000, 67, 35), chunktype=numpy.ndarray>
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   (south_north, west_east) float32 dask.array<chunksize=(67, 35), meta=np.ndarray>
    longitude  (south_north, west_east) float32 dask.array<chunksize=(67, 35), meta=np.ndarray>
  * time       (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Attributes:
    grid_mapping:   crs
    long_name:      Wind Speed
    standard_name:  wind_speed
    units:          m s-1
newa_celticsea.dataset.wind_speed.transpose('height', 'time', 'south_north', 'west_east')

<xarray.DataArray 'wind_speed' (height: 5, time: 87648, south_north: 40,
                                west_east: 54)>
dask.array<transpose, shape=(5, 87648, 40, 54), dtype=float32, chunksize=(1, 40000, 40, 54), chunktype=numpy.ndarray>
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   (south_north, west_east) float32 dask.array<chunksize=(40, 54), meta=np.ndarray>
    longitude  (south_north, west_east) float32 dask.array<chunksize=(40, 54), meta=np.ndarray>
  * time       (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Attributes:
    grid_mapping:   crs
    long_name:      Wind Speed
    standard_name:  wind_speed
    units:          m s-1
newa_m3.dataset.wind_speed.transpose('height', 'time', 'south_north', 'west_east')

<xarray.DataArray 'wind_speed' (height: 5, time: 87648, south_north: 19,
                                west_east: 20)>
dask.array<transpose, shape=(5, 87648, 19, 20), dtype=float32, chunksize=(1, 40000, 19, 20), chunktype=numpy.ndarray>
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   (south_north, west_east) float32 dask.array<chunksize=(19, 20), meta=np.ndarray>
    longitude  (south_north, west_east) float32 dask.array<chunksize=(19, 20), meta=np.ndarray>
  * time       (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Attributes:
    grid_mapping:   crs
    long_name:      Wind Speed
    standard_name:  wind_speed
    units:          m s-1
newa_m4.dataset.wind_speed.transpose('height', 'time', 'south_north', 'west_east')

<xarray.DataArray 'wind_speed' (height: 5, time: 87648, south_north: 20,
                                west_east: 20)>
dask.array<transpose, shape=(5, 87648, 20, 20), dtype=float32, chunksize=(1, 40000, 20, 20), chunktype=numpy.ndarray>
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   (south_north, west_east) float32 dask.array<chunksize=(20, 20), meta=np.ndarray>
    longitude  (south_north, west_east) float32 dask.array<chunksize=(20, 20), meta=np.ndarray>
  * time       (time) datetime64[ns] 2009-01-01 ... 2018-12-31T23:00:00
Dimensions without coordinates: south_north, west_east
Attributes:
    grid_mapping:   crs
    long_name:      Wind Speed
    standard_name:  wind_speed
    units:          m s-1

Calculate mean wind speed over time dimension for all heights at AOI grid coordinates

Using Dask, the data set loading process is lazy, where no data is loaded inititally. Instead, data loading is delayed until execution time, where variables will be loaded and processed in parallel according to the corresponding chunks specification. Dask arrays implement a subset of the NumPy ndarray interface using blocked algorithms, and the original variable arrays will be split into smaller chunk arrays, enabling computation on arrays larger than memory using all available cores. The blocked algorithms are coordinated using Dask graphs.

To perform some analysis at known AOI latitude/longitude coordinates, the xarray.DataArray.sel(..., method='nearest') function may be used to select a subset of the data array (or data set) at coordinates nearest to the specified parameters. Here, mean wind speed over the time dimension is determined for the specified coordinates, where Dask graph execution is triggered by calling compute(). The resulting variable values will be contained in a NumPy ndarray.

Graph execution is managed by a task scheduler. The default scheduler (used for executing this notebook) executes computations with local threads. However, execution may also be performed on a distributed cluster without any change to the xarray code used here.

newa_irishsea.dataset.wind_speed.isel(west_east=0, south_north=0).mean(dim='time').compute()

<xarray.DataArray 'wind_speed' (height: 5)>
array([8.081513, 9.090129, 9.398023, 9.641414, 9.994202], dtype=float32)
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   float32 52.15
    longitude  float32 -6.238
newa_celticsea.dataset.wind_speed.isel(west_east=0, south_north=0).mean(dim='time').compute()

<xarray.DataArray 'wind_speed' (height: 5)>
array([ 8.580611,  9.392164,  9.646666,  9.849321, 10.153699],
      dtype=float32)
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   float32 51.05
    longitude  float32 -8.522
newa_m3.dataset.wind_speed.isel(west_east=0, south_north=0).mean(dim='time').compute()

<xarray.DataArray 'wind_speed' (height: 5)>
array([ 9.164568,  9.935695, 10.173062, 10.357634, 10.630132],
      dtype=float32)
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   float32 50.95
    longitude  float32 -10.89
newa_m4.dataset.wind_speed.isel(west_east=0, south_north=0).mean(dim='time').compute()

<xarray.DataArray 'wind_speed' (height: 5)>
array([ 9.485068, 10.272412, 10.511473, 10.694211, 10.965795],
      dtype=float32)
Coordinates:
  * height     (height) float64 10.0 50.0 75.0 100.0 150.0
    latitude   float32 54.75
    longitude  float32 -10.26

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MÉRA Wind Data for Irish Continental Shelf region

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Sentinel-1 Wind Data for Irish Continental Shelf region