S_TIDE计算乘潮水位

网上似乎没有公开的计算乘潮水位的程序，但是乘潮水位的计算又有重要的用途，鉴于此，S_TIDE v1.23(https://www.researchgate.net/project/A-non-stationary-tidal-analysis-toolbox-S-TIDE)添加了s_rtl函数来计算乘高/低潮水位。

例子见s_demo

load kushiro.mat

 [rHt,rLt]=s_rtl(kushiro(1:8767)/10,[1993,01,01,00,00,00],1,42.5,6,0.1,'symmetrical')

 %乘高潮水位（6小时,累积频率10%）201.59cm

 %乘低潮水位（6小时,累积频率10%）148.92cm

%输入和输出参数介绍

%the input: xin :observed water levels (missing values should be labeled as NaN)

%          stime: start time for observations (in the form similar to [2021,04,01,00,00,00])

%          dt:  sampling intervals for observation(in the unit of hour)

%          lat: latitude of observation

%          rdt: time intervals for riding tide level(in the unit of hour)

%          cp:  cumulative probability

%          tidetype: 'symmetrical' or 'asymmetrical'

%

%the output: rHt:riding high tide level

%            rLt:riding low tide level