VLIDORT User's Guide

time)*100%. Tests were made for several values of NSTREAMS (the number of half-spacediscrete ordinates or computational streams). The atmosphere/surface scenario in these tests isthat used in the standard environment wrappers that come with the LIDORT package: a 23-layeratmosphere with aerosol in the lowest six layers and a Lambertian surface (see section 6.2 fordetails). Table 3.3 refers to efficiency of intensity-only computations, whereas in Table 3.4timings were compared for calculations with intensity, two column Jacobians and one surfaceJacobian; in Table 3.5 calculation timings for intensity, three profile Jacobians and one surfaceJacobian were compared.Table 3.3 Efficiency of ObsGeo vs. Lattice computations for intensity (% ratio of CPU values).# of computational streams (half-space)# of geometries 2 4 6 81 101.2 99.7 100.2 100.42 95.4 96.0 98.2 88.63 85.6 88.8 94.0 95.14 72.0 75.9 83.7 87.05 60.0 69.8 84.8 85.66 52.1 68.4 80.7 83.77 41.2 62.8 77.3 82.48 34.3 57.4 73.5 80.8Table 3.4 Efficiency of ObsGeo vs. Lattice computations for intensity, 2 atmospheric columnJacobians and 1 surface Jacobian (% ratio of CPU values).# of computational streams (half-space)# of geometries 2 4 6 81 101.5 100.0 100.1 100.42 90.8 92.3 96.7 88.43 75.7 81.6 86.1 89.44 59.9 66.0 79.4 86.65 46.5 66.0 76.5 81.36 36.0 54.9 70.2 77.97 28.7 47.6 64.6 74.88 23.0 41.5 59.0 71.7Table 3.5 Efficiency of ObsGeo vs. Lattice computations for intensity, 3 atmospheric profileJacobians and 1 surface Jacobian (% ratio of CPU values).# of computational streams (half-space)# of geometries 2 4 6 81 102.7 99.9 100.2 100.32 88.5 88.2 94.0 86.13 73.7 77.3 83.3 83.24 59.7 64.1 71.6 75.75 48.6 55.3 67.4 71.76 39.1 49.6 61.8 67.87 31.7 44.1 57.1 62.98 25.9 39.0 51.8 59.551