37 lines
1.4 KiB
Python
37 lines
1.4 KiB
Python
import numpy as np
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import xarray as xr
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''' 来自 Lee 等人 (2013) 的拉曼校正：
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《全球海洋中紫外-可见太阳辐射的穿透：来自海洋水色遥感的见解》
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J Geophys Res Oceans 2013;118:4241–55
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光谱插值在最近波段进行
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'''
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""" 拉曼校正查找表的类 """ # TODO 存储并在 ADF 中读取
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class Raman():
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def __init__(self):
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bands = [412,443,488,531,551,667]
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coords = {'bands': bands}
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self.alpha = xr.DataArray([0.003,0.004,0.011,0.015,0.017,0.018], dims='bands', coords=coords)
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self.beta1 = xr.DataArray([0.014,0.015,0.010,0.010,0.010,0.010], dims='bands', coords=coords)
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self.beta2 = xr.DataArray([-0.022,-0.023,-0.051,-0.070,-0.080,-0.081], dims='bands', coords=coords)
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def correct(self, Rrs):
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# Interpolate coefficients at nearest bands
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interp_opt = {'method':'nearest', 'kwargs':{'fill_value':'extrapolate'}}
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alpha = self.alpha.interp(bands=Rrs.bands, **interp_opt)
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beta1 = self.beta1.interp(bands=Rrs.bands, **interp_opt)
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beta2 = self.beta2.interp(bands=Rrs.bands, **interp_opt)
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# Select reference bands closest to 440 and 550
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Rrs440 = Rrs.sel(bands=440, method='nearest')
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Rrs550 = Rrs.sel(bands=550, method='nearest')
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# Compute Raman factor
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RF = alpha*Rrs440/Rrs550 + beta1*np.power(Rrs550,beta2)
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# Correct
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return Rrs/(1+RF)
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