PROSAIL模型python版简单说明
PROSAIL模型是prospect 和sail模型的融合，其本来是用fortran语言，现在也有python版的，可以直接pip导入PROSAIL库。
其参数，下面的参数应该是很久没更新了，跟函数源代码标示略有不同。
| Parameter | Description of parameter | Units | Typical min | Typical max |
|---|---|---|---|---|
| N | Leaf structure parameter | N/A | 0.8 | 2.5 |
| cab | Chlorophyll a+b concentration | ug/cm2 | 0 | 80 |
| caw | Equivalent water thickiness | cm | 0 | 200 |
| car | Carotenoid concentration | ug/cm2 | 0 | 20 |
| cbrown | Brown pigment | NA | 0 | 1 |
| cm | Dry matter content | g/cm2 | 0 | 200 |
| lai | Leaf Area Index | N/A | 0 | 10 |
| lidfa | Leaf angle distribution | N/A | - | - |
| lidfb | Leaf angle distribution | N/A | - | - |
| psoil | Dry/Wet soil factor | N/A | 0 | 1 |
| rsoil | Soil brigthness factor | N/A | - | - |
| hspot | Hotspot parameter | N/A | - | - |
| tts | Solar zenith angle | deg | 0 | 90 |
| tto | Observer zenith angle | deg | 0 | 90 |
| phi | Relative azimuth angle | deg | 0 | 360 |
| typelidf | Leaf angle distribution type | Integer | - | - |
typelidf = 1: use the two parameter LAD parameterisation, whereaandbcontrol the average leaf slope and the distribution bimodality, respectively. Typical distributions
are given by the following parameter choices:
| LIDF type | LIDFa |
LIDFb |
|---|---|---|
| Planophile | 1 | 0 |
| Erectophile | -1 | 0 |
| Plagiophile | 0 | -1 |
| Extremophile | 0 | 1 |
| Spherical | -0.35 | -0.15 |
| Uniform | 0 | 0 |
typelidf = 2Ellipsoidal distribution, whereLIDFaparameter stands for mean leaf angle (0 degrees is planophile, 90 degrees is erectophile).LIDFbparameter is ignored.
The soil model
The soil model is a fairly simple linear mixture model, where two spectra are mixed and then a brightness term added:
rho_soil = rsoil*(psoil*soil_spectrum1+(1-psoil)*soil_spectrum2)
可以参考PROSAIL官网http://teledetection.ipgp.jussieu.fr/prosail/
模型原函数介绍，里面有模型的输入参数以及各个参数的含义
这仅仅是PROSAIL的主函数。
def run_prosail(n, cab, car, cbrown, cw, cm, lai, lidfa, hspot,
tts, tto, psi, ant=0.0, alpha=40., prospect_version="5",
typelidf=2, lidfb=0., factor="SDR",
rsoil0=None, rsoil=None, psoil=None,
soil_spectrum1=None, soil_spectrum2=None):
"""Run the PROSPECT_5B and SAILh radiative transfer models. The soil
model is a linear mixture model, where two spectra are combined together as
rho_soil = rsoil*(psoil*soil_spectrum1+(1-psoil)*soil_spectrum2)
By default, ``soil_spectrum1`` is a dry soil, and ``soil_spectrum2`` is a
wet soil, so in that case, ``psoil`` is a surface soil moisture parameter.
``rsoil`` is a soil brightness term. You can provide one or the two
soil spectra if you want. The soil spectra must be defined
between 400 and 2500 nm with 1nm spacing.
Parameters
----------
n: float
Leaf layers
cab: float
leaf chlorophyll concentration
car: float
leaf carotenoid concentration
cbrown: float
senescent pigment
cw: float
equivalent leaf water
cm: float
leaf dry matter
lai: float
leaf area index
lidfa: float
a parameter for leaf angle distribution. If ``typliedf``=2, average
leaf inclination angle.
tts: float
Solar zenith angle
tto: float
Sensor zenith angle
psi: float
Relative sensor-solar azimuth angle ( saa - vaa )
ant: float
leaf anthocyanin concentration (default set to 0)
alpha: float
The alpha angle (in degrees) used in the surface scattering
calculations. By default it's set to 40 degrees.
prospect_version: str
Which PROSPECT version to use. We have "5" and "D"
typelidf: int, optional
The type of leaf angle distribution function to use. By default, is set
to 2.
lidfb: float, optional
b parameter for leaf angle distribution. If ``typelidf``=2, ignored
factor: str, optional
What reflectance factor to return:
* "SDR": directional reflectance factor (default)
* "BHR": bi-hemispherical r. f.
* "DHR": Directional-Hemispherical r. f. (directional illumination)
* "HDR": Hemispherical-Directional r. f. (directional view)
* "ALL": All of them
rsoil0: float, optional
The soil reflectance spectrum
rsoil: float, optional
Soil scalar 1 (brightness)
psoil: float, optional
Soil scalar 2 (moisture)
soil_spectrum1: 2101-element array
First component of the soil spectrum
soil_spectrum2: 2101-element array
Second component of the soil spectrum
Returns
--------
A reflectance factor between 400 and 2500 nm
"""
factor = factor.upper()
if factor not in ["SDR", "BHR", "DHR", "HDR", "ALL"]:
raise ValueError, "'factor' must be one of SDR, BHR, DHR, HDR or ALL"
if soil_spectrum1 is not None:
assert (len(soil_spectrum1) == 2101)
else:
soil_spectrum1 = spectral_lib.soil.rsoil1
if soil_spectrum2 is not None:
assert (len(soil_spectrum1) == 2101)
else:
soil_spectrum2 = spectral_lib.soil.rsoil2
if rsoil0 is None:
if (rsoil is None) or (psoil is None):
raise ValueError, "If rsoil0 isn't define, then rsoil and psoil" + \
" need to be defined!"
rsoil0 = rsoil * (
psoil * soil_spectrum1 + (1. - psoil) * soil_spectrum2)
wv, refl, trans = run_prospect (n, cab, car, cbrown, cw, cm, ant=ant,
prospect_version=prospect_version, alpha=alpha)
[tss, too, tsstoo, rdd, tdd, rsd, tsd, rdo, tdo,
rso, rsos, rsod, rddt, rsdt, rdot, rsodt, rsost, rsot,
gammasdf, gammasdb, gammaso] = foursail (refl, trans,
lidfa, lidfb, typelidf,
lai, hspot,
tts, tto, psi, rsoil0)
if factor == "SDR":
return rsot
elif factor == "BHR":
return rddt
elif factor == "DHR":
return rsdt
elif factor == "HDR":
return rdot
elif factor == "ALL":
return [rsot, rddt, rsdt, rdot]
一般我们都默认‘SDR’返回反射率，函数能够返回一个数组，波长从400-2500,例如
import prosail
import numpy as np
import matplotlib.pyplot as plt
rr = prosail.run_prosail(1.5, 40., 8., 0.0, 0.01, 0.009, 3., -0.35, 0.01,
30., 10., 0., typelidf=1, lidfb=-0.15,
rsoil = 1., psoil=1., factor="SDR")
plt.plot(np.arange(400,2501),rr,'r-')
plt.show()
