easyclimate.field.ocean.oceanic_front

Quantify the intensity and location of two basin-scale oceanic frontal zones in the wintertime North Pacific, i.e. the subtropical and subarctic frontal zones (STFZ, SAFZ).

Functions

calc_intensity_STFZ(→ xarray.DataArray)

Calculate the intensity of the subtropical frontal zone (STFZ).

calc_intensity_SAFZ(→ xarray.DataArray)

Calculate the intensity of the subarctic frontal zone (SAFZ).

calc_location_STFZ(→ xarray.DataArray)

Calculate the location index of the subtropical frontal zone (STFZ).

calc_location_SAFZ(→ xarray.DataArray)

Calculate the location index of the subarctic frontal zone (SAFZ).

calc_location_line_STFZ(→ xarray.DataArray)

Calculate the location of the subtropical frontal zone (STFZ).

calc_location_line_SAFZ(→ xarray.DataArray)

Calculate the location of the subarctic frontal zone (SAFZ).

Module Contents

easyclimate.field.ocean.oceanic_front.calc_intensity_STFZ(sst_DtDy_data: xarray.DataArray, criteria=0.45 * 1e-05, lat_range=[24, 32], lon_range=[145, 215], lat_dim: str = 'lat', lon_dim: str = 'lon') → xarray.DataArray

Calculate the intensity of the subtropical frontal zone (STFZ). The intensity index defined reflects an average of the SST meridional gradient within a frontal zone.

\[\mathrm{ITS} = \sum_{i=1}^{N} \frac{G_i}{N}\]

where \(G_i\) is the value of zonally-averaged SST meridional gradient that is no less than an empirically-given critical value (here, \(0.45 \times 10^{-5} \mathrm{km^{-1}}\) for STFZ) at the \(i\)-th latitudinal grid point within the zone, and \(N\) is the number of total grid points that satisfy the criteria above.

Parameters

sst_DtDy_dataxarray.DataArray

The SST meridional gradient data.

criteria: float, default: 0.45 *1e-5.

Empirically-given critical value.

lat_range: list, default: [24, 32].

The latitude range of the oceanic frontal zone.

lon_range: list, default: [145, 215].

The longitude range of the oceanic frontal zone.

lat_dim: str, default: lat.

Latitude coordinate dimension name. By default extracting is applied over the lat dimension.

lon_dim: str, default: lon.

Longitude coordinate dimension name. By default extracting is applied over the lon dimension.

Returns

The intensity of the STFZ (xarray.DataArray).

Reference

  • Wang, L., Yang, X.-Q., Yang, D., Xie, Q., Fang, J. and Sun, X. (2017), Two typical modes in the variabilities of wintertime North Pacific basin-scale oceanic fronts and associated atmospheric eddy-driven jet. Atmos. Sci. Lett, 18: 373-380. Website: https://doi.org/10.1002/asl.766

easyclimate.field.ocean.oceanic_front.calc_intensity_SAFZ(sst_DtDy_data: xarray.DataArray, criteria=0.8 * 1e-05, lat_range=[36, 44], lon_range=[145, 215], lat_dim: str = 'lat', lon_dim: str = 'lon') → xarray.DataArray

Calculate the intensity of the subarctic frontal zone (SAFZ). The intensity index defined reflects an average of the SST meridional gradient within a frontal zone.

\[\mathrm{ITS} = \sum_{i=1}^{N} \frac{G_i}{N}\]

where \(G_i\) is the value of zonally-averaged SST meridional gradient that is no less than an empirically-given critical value (here, \(0.80 \times 10^{-5} \mathrm{km^{-1}}\) for SAFZ) at the \(i\)-th latitudinal grid point within the zone, and \(N\) is the number of total grid points that satisfy the criteria above.

Parameters

sst_DtDy_dataxarray.DataArray

The SST meridional gradient data.

criteria: float, default: 0.80 *1e-5.

Empirically-given critical value.

lat_range: list, default: [36, 44].

The latitude range of the oceanic frontal zone.

lon_range: list, default: [145, 215].

The longitude range of the oceanic frontal zone.

lat_dim: str, default: lat.

Latitude coordinate dimension name. By default extracting is applied over the lat dimension.

lon_dim: str, default: lon.

Longitude coordinate dimension name. By default extracting is applied over the lon dimension.

Returns

The intensity of the SAFZ (xarray.DataArray).

Reference

  • Wang, L., Yang, X.-Q., Yang, D., Xie, Q., Fang, J. and Sun, X. (2017), Two typical modes in the variabilities of wintertime North Pacific basin-scale oceanic fronts and associated atmospheric eddy-driven jet. Atmos. Sci. Lett, 18: 373-380. Website: https://doi.org/10.1002/asl.766

easyclimate.field.ocean.oceanic_front.calc_location_STFZ(sst_DtDy_data: xarray.DataArray, criteria=0.45 * 1e-05, lat_range=[24, 32], lon_range=[145, 215], lat_dim: str = 'lat', lon_dim: str = 'lon') → xarray.DataArray

Calculate the location index of the subtropical frontal zone (STFZ). The intensity index defined reflects an average of the SST meridional gradient within a frontal zone.

\[\mathrm{LCT} = \sum_{i=1}^{N} (G_i \times \mathrm{LAT}_i) / \sum_{i=1}^{N} G_i\]

where \(\mathrm{LAT}_i\) is the latitude at the \(i\)-th grid point within the front zone. Obviously, this definition reflects a weighted-average of \(\mathrm{LAT}_i\) with respect to \(G_i\), indicating that the location of a front is mainly determined by larger SST meridional gradients within the frontal zone.

Parameters

sst_DtDy_dataxarray.DataArray

The SST meridional gradient data.

criteria: float, default: 0.45 *1e-5.

Empirically-given critical value.

lat_range: list, default: [24, 32].

The latitude range of the oceanic frontal zone.

lon_range: list, default: [145, 215].

The longitude range of the oceanic frontal zone.

lat_dim: str, default: lat.

Latitude coordinate dimension name. By default extracting is applied over the lat dimension.

lon_dim: str, default: lon.

Longitude coordinate dimension name. By default extracting is applied over the lon dimension.

Returns

The location index of the STFZ (xarray.DataArray).

Reference

  • Wang, L., Yang, X.-Q., Yang, D., Xie, Q., Fang, J. and Sun, X. (2017), Two typical modes in the variabilities of wintertime North Pacific basin-scale oceanic fronts and associated atmospheric eddy-driven jet. Atmos. Sci. Lett, 18: 373-380. Website: https://doi.org/10.1002/asl.766

easyclimate.field.ocean.oceanic_front.calc_location_SAFZ(sst_DtDy_data: xarray.DataArray, criteria=0.8 * 1e-05, lat_range=[36, 44], lon_range=[145, 215], lat_dim: str = 'lat', lon_dim: str = 'lon') → xarray.DataArray

Calculate the location index of the subarctic frontal zone (SAFZ). The intensity index defined reflects an average of the SST meridional gradient within a frontal zone.

\[\mathrm{LCT} = \sum_{i=1}^{N} (G_i \times \mathrm{LAT}_i) / \sum_{i=1}^{N} G_i\]

where \(\mathrm{LAT}_i\) is the latitude at the \(i\)-th grid point within the front zone. Obviously, this definition reflects a weighted-average of \(\mathrm{LAT}_i\) with respect to \(G_i\), indicating that the location of a front is mainly determined by larger SST meridional gradients within the frontal zone.

Parameters

sst_DtDy_dataxarray.DataArray

The SST meridional gradient data.

criteria: float, default: 0.80 *1e-5.

Empirically-given critical value.

lat_range: list, default: [36, 44].

The latitude range of the oceanic frontal zone.

lon_range: list, default: [145, 215].

The longitude range of the oceanic frontal zone.

lat_dim: str, default: lat.

Latitude coordinate dimension name. By default extracting is applied over the lat dimension.

lon_dim: str, default: lon.

Longitude coordinate dimension name. By default extracting is applied over the lon dimension.

Returns

The location index of the SAFZ (xarray.DataArray).

Reference

  • Wang, L., Yang, X.-Q., Yang, D., Xie, Q., Fang, J. and Sun, X. (2017), Two typical modes in the variabilities of wintertime North Pacific basin-scale oceanic fronts and associated atmospheric eddy-driven jet. Atmos. Sci. Lett, 18: 373-380. Website: https://doi.org/10.1002/asl.766

easyclimate.field.ocean.oceanic_front.calc_location_line_STFZ(sst_DtDy_data: xarray.DataArray, criteria=0.45 * 1e-05, lat_range=[24, 32], lon_range=[145, 215], lat_dim: str = 'lat', lon_dim: str = 'lon') → xarray.DataArray

Calculate the location of the subtropical frontal zone (STFZ). The intensity index defined reflects an average of the SST meridional gradient within a frontal zone.

\[\mathrm{LCT} = (\sum_{i=1}^{N} (G_i \times \mathrm{LAT}_i)) / G_i\]

where \(\mathrm{LAT}_i\) is the latitude at the \(i\)-th grid point within the front zone. Obviously, this definition reflects a weighted-average of \(\mathrm{LAT}_i\) with respect to \(G_i\), indicating that the location of a front is mainly determined by larger SST meridional gradients within the frontal zone.

Parameters

sst_DtDy_dataxarray.DataArray

The SST meridional gradient data.

criteria: float, default: 0.45 *1e-5.

Empirically-given critical value.

lat_range: list, default: [24, 32].

The latitude range of the oceanic frontal zone.

lon_range: list, default: [145, 215].

The longitude range of the oceanic frontal zone.

lat_dim: str, default: lat.

Latitude coordinate dimension name. By default extracting is applied over the lat dimension.

lon_dim: str, default: lon.

Longitude coordinate dimension name. By default extracting is applied over the lon dimension.

Returns

The location of the STFZ (xarray.DataArray).

Reference

  • Wang, L., Yang, X.-Q., Yang, D., Xie, Q., Fang, J. and Sun, X. (2017), Two typical modes in the variabilities of wintertime North Pacific basin-scale oceanic fronts and associated atmospheric eddy-driven jet. Atmos. Sci. Lett, 18: 373-380. Website: https://doi.org/10.1002/asl.766

easyclimate.field.ocean.oceanic_front.calc_location_line_SAFZ(sst_DtDy_data: xarray.DataArray, criteria=0.8 * 1e-05, lat_range=[36, 44], lon_range=[145, 215], lat_dim: str = 'lat', lon_dim: str = 'lon') → xarray.DataArray

Calculate the location of the subarctic frontal zone (SAFZ). The intensity index defined reflects an average of the SST meridional gradient within a frontal zone.

\[\mathrm{LCT} = (\sum_{i=1}^{N} (G_i \times \mathrm{LAT}_i)) / G_i\]

where \(\mathrm{LAT}_i\) is the latitude at the \(i\)-th grid point within the front zone. Obviously, this definition reflects a weighted-average of \(\mathrm{LAT}_i\) with respect to \(G_i\), indicating that the location of a front is mainly determined by larger SST meridional gradients within the frontal zone.

Parameters

sst_DtDy_dataxarray.DataArray

The SST meridional gradient data.

criteria: float, default: 0.80 *1e-5.

Empirically-given critical value.

lat_range: list, default: [36, 44].

The latitude range of the oceanic frontal zone.

lon_range: list, default: [145, 215].

The longitude range of the oceanic frontal zone.

lat_dim: str, default: lat.

Latitude coordinate dimension name. By default extracting is applied over the lat dimension.

lon_dim: str, default: lon.

Longitude coordinate dimension name. By default extracting is applied over the lon dimension.

Returns

The location of the SAFZ (xarray.DataArray).

Reference

  • Wang, L., Yang, X.-Q., Yang, D., Xie, Q., Fang, J. and Sun, X. (2017), Two typical modes in the variabilities of wintertime North Pacific basin-scale oceanic fronts and associated atmospheric eddy-driven jet. Atmos. Sci. Lett, 18: 373-380. Website: https://doi.org/10.1002/asl.766