Remote sensing of tropospheric total column water vapor: Intercomparison of POLDER, AMSR-E and MODIS retrievals

Abstract

Abstract. Since December 2004, the CNES Parasol (Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar) mission has been flying in the A-train with Aqua (NASA) providing more than 5 years of temporally and spatially coincident observations from POLDER, MODIS and AMSR-E which enable total column water vapor amount retrievals. We are providing here a temporal and statistical analysis of water vapor near-infrared retrievals from POLDER against MODIS and AMSR-E products derived from nearinfrared, thermal infrared and microwave observations over ocean. A temporal analysis of POLDER official product is conducted in view of AMSR-E and MODIS coincident retrievals over ocean. In a second step, an alternative approach based on the use of simple multilayer perceptron (MLP) neural network (NN) is developed to improve the mathematical parameterization used to retrieve water vapor amount from near-infrared observation. The retrievals are further improved when an estimate of the 910 nm surface reflectance is obtained through interpolation between PARASOL 865 nm and 1020 nm channels. This last improvement now allows for a unified land/ocean retrieval algorithm for PARASOL/POLDER.

Retrieval of liquid water cloud properties from POLDER-3 measurements using a neural network ensemble approach

“…POLDER-3 data have been used for a wide range of applications, including aerosol retrievals (Dubovik et al, 2011;Hasekamp et al, 2011;Waquet et al, 2013), retrieval of cloud properties (Riedi et al, 2010;Parol et al, 2013;van Diedenhoven et al, 2014b;Desmons et al, 2017), water vapour retrievals (Riedi et al, 2013), estimation of surface properties (Bréon and Maignan, 2017) and validation of surface reflection models (Kokhanovsky and Bréon, 2012).…”