PROJECT 1

Cal/Val MODIS with S-HIS (AIRS) radiances

CAL-VAR-IO

Authors: Annamaria, Tiziana, Tiziano, Teo

MODIS / SHIS Comparisons

A detailed comparison should account for:

• instrumental noise and scene variations

• Different spatial footprints

• Different view angles (MODIS is near nadir, SHIS is ~±35deg from nadir)

• Different observation altitudes (MODIS is 705km, SHIS is ~20km on ER2, ~14km on Proteus)

•Different spectral response (MODIS has different channels with different bandwidth, SHIS =~0.5 cm-1) and sampling

X

TORPEX 2003

FOV MODIS

FOV S-HIS

Average SHIS data within MODIS FOV(s) and compare

Average SHIS data within MODIS FOV(s) & compare

We convolve high resolution data with the response functions of the selected MODIS bands

Ex. of response functions of MODIS CO2 bands

Compare Residuals from calculations: (obs-calc)SHIS to (obs-calc)MODIS

• SHIS and MODIS calcs each done at correct altitudes, view angles, spectral resolution and sampling.

• Monochromatic calcs done using same forward model,atmospheric state, and surface property inputs.

MODISobs

S-HISobs S-HISsim

MODISsim

Difference Residuals: Spectral Resolutions made similar

MODISobs

S-HISobs S-HISsim

MODISsim

CONCLUSIONS:

• MODIS-(S-HIS):

1. GOOD RESULTS IN THE WINDOW AND H2OVAP

2. EXPECTED DISAGREEMENTS IN THE CO2 AND O3

• MODIS-(S-HIS) RESIDUALS:

1. GOOD CORRECTION IN THE O3 BAND

2. SIMULATIONS WITH TOO MUCH WV AT HIGH LEVELS