Extract Ocean Winds (Image Analyst Tools)

Summary

Estimates wind direction and magnitude on the ocean surface.

The input is a synthetic aperture radar (SAR) dataset and the output is a two-band raster with U and V components, which provide a map of ocean surface winds.

Usage

The Input Radar Data parameter value needs to be calibrated to sigma nought before running this tool. Use the Apply Radiometric Calibration tool to perform this conversion.
The Input Radar Data parameter value must be either a dual polarization or quad polarization single look complex (SLC) product. Dual-polarization examples are HH+HV or VV+VH. Quad-polarization examples are HH, HV, VV, and VH.
The tool can only detect winds over the ocean surface. If there are any land in the SAR scene, it must be masked out using the Generate Masked SAR Raster tool, before using this tool.
To reduce noise within the Input Radar Data parameter value, use either the Remove Thermal Noise or Despeckle tool before running this tool. This will help improve wind extraction performance.
To convert the output of this tool from U-V components to a Magnitude-Direction, use the Vector Field raster function.

Label	Explanation	Data type
Input Radar Data	The input SAR dataset. The input must be either a dual polarization or quad polarization SLC product.	Raster Dataset; Raster Layer
Output Raster	The output two-band raster dataset that has U and V components.	Raster Dataset

Label

Explanation

Data type

Input Radar Data

The input SAR dataset.

The input must be either a dual polarization or quad polarization SLC product.

Raster Dataset; Raster Layer

Output Raster

The output two-band raster dataset that has U and V components.

Raster Dataset

ExtractOceanWinds(in_radar_data, out_raster)

Name	Explanation	Data type
in_radar_data	The input SAR dataset. The input must be either a dual polarization or quad polarization SLC product.	Raster Dataset; Raster Layer
out_raster	The output two-band raster dataset that has U and V components.	Raster Dataset

Name

Explanation

Data type

in_radar_data

The input SAR dataset.

The input must be either a dual polarization or quad polarization SLC product.

Raster Dataset; Raster Layer

out_raster

The output two-band raster dataset that has U and V components.

Raster Dataset

Code sample

ExtractOceanWinds example 1 (Python window)

This example takes an SLC image and outputs the U and V wind components.

import arcpy
arcpy.env.workspace = r"C:\Data\SAR"

arcpy.ia.ExtractOceanWinds("S1A_S1_SLC__1SDV_20150319T064010_20150319T064029_005097_00668C_0667_IW1_CalS0.crf", "Wind_UV.crf")

ExtractOceanWinds example 2 (stand-alone script)

This example takes an SLC image and outputs the U and V wind components.

# Import system modules
import arcpy
from arcpy.ia import *

# Set local variables
in_radar = r"C:\SAR\S1A_S1_SLC__1SDV_20150319T064010_20150319T064029_005097_00668C_0667_IW1_CalS0.crf"
out_radar = r"C:\Output\Wind_UV.crf"

# Run
arcpy.ia.ExtractOceanWinds(in_radar, out_radar)

Environments

This tool does not use any geoprocessing environments.

Licensing information

Basic: Requires Image Analyst
Standard: Requires Image Analyst
Advanced: Requires Image Analyst

References

Zhang, B., Mouche, A., Lu, Y., Perrie, W., Zhang, G., & Wang, H. (2019). A geophysical model function for wind speed retrieval from C-band HH-polarized synthetic aperture radar. IEEE Geoscience and Remote Sensing Letters, 16(10), 1521–1525. https://doi.org/10.1109/LGRS.2019.2905578.
Hersbach, H. (2008). CMOD5.N: A C-band geophysical model function for equivalent neutral wind (ECMWF Technical Memorandum No. 554). European Centre for Medium-Range Weather Forecasts.
Zhang, B., Perrie, W., Vachon, P. W., Li, X., Pichel, W. G., Guo, J., & He, Y. (2012). Ocean vector winds retrieval from C-band fully polarimetric SAR measurements. IEEE Transactions on Geoscience and Remote Sensing, 50(11), 4252–4261. https://doi.org/10.1109/TGRS.2012.2194157.