A strange problem about run_thermal_sail

[jianboqi]

Hello, I am using prosail for calculating brightness temperature (BT), I found a strange problem that the BT in hotspot direction is lower than other directions, I am not sure if this is a problem of prosail or my wrong use of prosail, could help to check? My code:

import prosail import matplotlib.pyplot as plt

emisVeg = 0.99 emisSoil = 0.97 T_Veg = 299.65 T_Soil = 306.65 LAI = 3 hot_spot = 0.03 solar_zenith = 30

LIDF = 57 #spherical T_VegSunlit = 296.65 T_SoilSunlit = 320.65 T_atm = 8

relativeAzi = 180 viewZeniths = range(60,0,-1) bts = [] for viewZenith in viewZeniths: re = prosail.run_thermal_sail(10,T_Veg,T_Soil,T_VegSunlit,T_SoilSunlit, T_atm, LAI, LIDF,hot_spot,solar_zenith,viewZenith, relativeAzi, emv=emisVeg, ems=emisSoil) bts.append(re[1])

relativeAzi = 0 viewZeniths = range(0,61,1) for viewZenith in viewZeniths: re = prosail.run_thermal_sail(10,T_Veg,T_Soil,T_VegSunlit,T_SoilSunlit, T_atm, LAI, LIDF, hot_spot,solar_zenith,viewZenith, relativeAzi, emv=emisVeg, ems=emisSoil) bts.append(re[1])

viewZeniths = [i for i in range(-60,0,1)]

viewZeniths += [i for i in range(0,61,1)]

plt.plot(viewZeniths, bts) plt.show()