Actually-measured marine environment data assimilation method based on sequence recursive filtering three-dimensional variation

A method for determining an underwater marine environment based on sequence recursive filtering three-dimensional variation, comprising:

• using a plurality of sensors on an underwater vehicle to measure and generate actually-measured marine environment data proximate the underwater vehicle;
• receiving the marine environment data from the plurality of sensors in a computer system of the underwater vehicle, the computer having a processor, the processor configured to:
• carry out preprocessing and quality control on the actually-measured marine environment data by filtering out invalid data and abnormal data in the actually-measured marine environment data and then converting the actually-measured marine environment data into a format necessary for assimilation;
• calculate a target function value by adopting the preprocessed actually-measured marine environment data and background field data by a parallel recursive filter by giving a filtering parameter;
• calculate a gradient value of the target function based on the target function value and a source code of a gradient of the target function generated by a tangent and adjoint model compiler;
• calculate a minimum value of the target function by inputting the target function value and the gradient value of the target function in a limited Broyden-Fletcher-Glodfarb-Shanno minimization algorithm to calculate the minimum value of the target function, wherein a state variable corresponding to the minimum value is a long wave estimate of observation data;
• extract space multi-scale information from the actually-measured data by subtracting the long wave estimate from the actually-measured marine environment data to serve as new actually-measured marine environment data, adjust the filtering parameter to decrease it, replace the actually-measured marine environment data with the new actually-measured marine environment data, and repeat the steps of calculating a target function value, calculate a gradient value of the target function and calculate a minimum value of the target function to sequentially extract the secondary long wave and short wave information from the actually-measured marine environment data;
• and
• update the background field data to form a final data assimilation analysis field.