增加模块；增加主调用命令

prosail_method/modules/volscatt.py

@@ -0,0 +1,96 @@
+import numpy as np
+
+def volscatt(tts, tto, psi, ttl):
+    """
+    Volume scattering and interception functions for a given geometry.
+
+    Inputs:
+        tts  : solar zenith angle (deg)
+        tto  : observer zenith angle (deg)
+        psi  : relative azimuth angle (deg)
+        ttl  : leaf inclination angle (deg)
+
+    Returns:
+        chi_s : solar interception function
+        chi_o : observer interception function
+        frho  : function to multiply with leaf reflectance
+        ftau  : function to multiply with leaf transmittance
+    """
+    rd = np.pi / 180.0
+
+    costs = np.cos(rd * tts)
+    costo = np.cos(rd * tto)
+    sints = np.sin(rd * tts)
+    sinto = np.sin(rd * tto)
+    cospsi = np.cos(rd * psi)
+    psir = rd * psi
+    costl = np.cos(rd * ttl)
+    sintl = np.sin(rd * ttl)
+
+    cs = costl * costs
+    co = costl * costo
+    ss = sintl * sints
+    so = sintl * sinto
+
+    # Solar side
+    if abs(ss) > 1e-6:
+        cosbts = -cs / ss
+    else:
+        cosbts = 5
+
+    if abs(so) > 1e-6:
+        cosbto = -co / so
+    else:
+        cosbto = 5
+
+    if abs(cosbts) < 1:
+        bts = np.arccos(cosbts)
+        ds = ss
+    else:
+        bts = np.pi
+        ds = cs
+
+    chi_s = 2 / np.pi * ((bts - 0.5 * np.pi) * cs + np.sin(bts) * ss)
+
+    if abs(cosbto) < 1:
+        bto = np.arccos(cosbto)
+        doo = so
+    elif tto < 90:
+        bto = np.pi
+        doo = co
+    else:
+        bto = 0
+        doo = -co
+
+    chi_o = 2 / np.pi * ((bto - 0.5 * np.pi) * co + np.sin(bto) * so)
+
+    # Bidirectional scattering coefficient
+    btran1 = abs(bts - bto)
+    btran2 = np.pi - abs(bts + bto - np.pi)
+
+    if psir <= btran1:
+        bt1 = psir
+        bt2 = btran1
+        bt3 = btran2
+    else:
+        bt1 = btran1
+        if psir <= btran2:
+            bt2 = psir
+            bt3 = btran2
+        else:
+            bt2 = btran2
+            bt3 = psir
+
+    t1 = 2 * cs * co + ss * so * cospsi
+    t2 = 0
+    if bt2 > 0:
+        t2 = np.sin(bt2) * (2 * ds * doo + ss * so * np.cos(bt1) * np.cos(bt3))
+
+    denom = 2 * np.pi * np.pi
+    frho = ((np.pi - bt2) * t1 + t2) / denom
+    ftau = (-bt2 * t1 + t2) / denom
+
+    frho = max(frho, 0)
+    ftau = max(ftau, 0)
+
+    return chi_s, chi_o, frho, ftau