Go back to linear BT correction (for continuity)

viirs_bright.py

@@ -11,46 +11,22 @@ from bright import bright_wavelength, bright_wavenumber
 centroid_wl = np.array([
     4.06703067365, # M13
     10.7343306552, # M15
-    11.8477889286, # M16
-]).reshape([3, 1])
-
-a2_wl = np.array([
-    -8.15959023e-07, # M13
-    -1.09287888e-05, # M15
-    -8.81835071e-06, # M16
-]).reshape([3, 1])
-a1_wl = np.array([
-    1.00115123e+00, # M13
-    1.00594659e+00, # M15
-    1.00441512e+00, # M16
-]).reshape([3, 1])
-a0_wl = np.array([
-    -3.39016267e-01, # M13
-    -6.71912517e-01, # M15
-    -4.58539806e-01, # M16
+    11.8477889286  # M16
 ]).reshape([3, 1])
 
 # center wavenumbers in inverse centimeters
-centroid_wn = np.array([
-    2460.21042115, # M13
-    934.694388302, # M15
-    846.281826259, # M16
-]).reshape([3, 1])
+centroid_wn = 1.0e4 / centroid_wl
 
-a2_wn = np.array([
-    -1.65753638e-07, # M13
-    -2.33816560e-06, # M15
-    -1.67985807e-06, # M16
-]).reshape([3, 1])
-a1_wn = np.array([
-    1.00057613e+00, # M13
-    1.00314524e+00, # M15
-    1.00235945e+00, # M16
+a1 = np.array([
+    1.0006825717,   # M13
+    1.00002170808,  # M15
+    0.999660182876, # M16
 ]).reshape([3, 1])
-a0_wn = np.array([
-    -3.39058355e-01, # M13
-    -7.28633110e-01, # M15
-    -5.21315259e-01, # M16
+
+a0 = np.array([
+    -0.272777656231, # M13
+     0.111109266746, # M15
+     0.165817224275, # M16
 ]).reshape([3, 1])
 
 # helper function to make an array 2-dimensional. the first dimension
@@ -77,7 +53,7 @@ def viirs_bright(rad):
     bt = bright_wavelength(centroid_wl, rad)
 
     # apply the temperature correction coeffiecients
-    bt = a0_wl + (bt * (a1_wl + (bt * a2_wl)))
+    bt = a1 * bt + a0
 
     # return an array shaped like the one passed in
     return bt.reshape(in_shape)
@@ -95,7 +71,7 @@ def viirs_bright_from_cris(rad):
     bt = bright_wavenumber(centroid_wn, rad)
 
     # apply the temperature correction coeffiecients
-    bt = a0_wn + (bt * (a1_wn + (bt * a2_wn)))
+    bt = a1 * bt + a0
 
     # return an array shaped like the one passed in
     return bt.reshape(in_shape)