Intercomparison of cloud top altitudes as derived using GOME and ATSR-2 instruments onboard ERS-2

Cloud top heights as derived using measurements of two instruments (GOME and ATSR-2) onboard the ESA ERS-2 space platform are intercompared. It was found that cloud altitudes obtained using thermal IR measurements of ATSR-2 highly correlate with those obtained from top-of-atmosphere backscattered solar light measurements of GOME in O2 A-band using both the semi-analytical cloud retrieval algorithm SACURA and the neural network cloud retrieval algorithm ROCINN. The average cloud top heights as obtained by these diverse techniques for the whole data set analyzed (931 GOME pixels) differ by 0.6 km on average, with larger values given by SACURA as applied to GOME data. We found that the standard deviation of SACURA-derived results for cloud top heights from those of ATSR-2 is equal to 1.8 km, while the standard deviation of ROCINN-derived results is equal to 2.2 km. The respective average deviations are 0.6 km (SACURA) and − 0.5 km (ROCINN).