HDO/H<sub>2</sub>O ratio retrievals from GOSAT

Abstract

Abstract. We report a new shortwave infrared (SWIR) retrieval of the column-averaged HDO/H2O ratio from the Japanese Greenhouse Gases Observing Satellite (GOSAT). From synthetic simulation studies, we have estimated that the inferred δD values will typically have random errors between 20‰ (desert surface and 30° solar zenith angle) and 120‰ (conifer surface and 60° solar zenith angle). We find that the retrieval will have a small but significant sensitivity to the presence of cirrus clouds, the HDO a priori profile shape and atmospheric temperature, which has the potential of introducing some regional-scale biases in the retrieval. From comparisons to ground-based column observations from the Total Carbon Column Observing Network (TCCON), we find differences between δD from GOSAT and TCCON of around −30‰ for northern hemispheric sites which increase up to −70‰ for Australian sites. The bias for the Australian sites significantly reduces when decreasing the spatial co-location criteria, which shows that spatial averaging contributes to the observed differences over Australia. The GOSAT retrievals allow mapping the global distribution of δD and its variations with season, and we find in our global GOSAT retrievals the expected strong latitudinal gradients with significant enhancements over the tropics. The comparisons to the ground-based TCCON network and the results of the global retrieval are very encouraging, and they show that δD retrieved from GOSAT should be a useful product that can be used to complement datasets from thermal-infrared sounder and ground-based networks and to extend the δD dataset from SWIR retrievals established from the recently ended SCIAMACHY mission.

The MUSICA MetOp/IASI H<sub>2</sub>O and δD products: characterisation and long-term comparison to NDACC/FTIR data

“…Schneider and Hase, 2011a;Boesch et al, 2013) or between δD measurements and model simulations (e.g. Schneider et al, 2010;Lacour et al, 2012).…”

Variations of oxygen-18 in West Siberian precipitation during the last 50 years

“…Ground-based remote sensing of δ 18 O in water vapour has been realized recently but so far, only a small number of measurements have been carried out. For this reason we consider global observations of deuterium (δD) in total column water vapour retrieved from the GOSAT satellite (Boesch et al, 2013;Frankenberg et al, 2013) for the period April 2009 to June 2011. We select only measurements which pass a series of quality criteria involving the absence of clouds and the retrieval precision for different species Risi et al, 2013).…”

Empirical validation and proof of added value of MUSICA's tropospheric δD remote sensing products

“…Schneider et al, 2006b;Worden et al, 2006;Lacour et al, 2012;Schneider et al, 2012;Boesch et al, 2013), so far no rigorous empirical quality assessment has been presented. The few existing studies consist of very few indirect comparisons (Worden et al, 2011) or use a δD reference that itself is not comprehensively validated Boesch et al, 2013). This situation is rather unsatisfactory: since δD remote sensing measurements are very difficult and the nature of the data is very complex, there is urgent need to support the theoretical quality assessment studies by elaborated empirical validation exercises.…”

“…Schneider et al (2012) present tropospheric H 2 O and δD remotely sensed from the ground at 10 globally distributed FTIR (Fourier transform infrared) stations of the NDACC (Network for the Detection of Atmospheric Composition Change, http://www.acd.ucar.edu/irwg/). Space-based remote sensing observations of tropospheric δD are possible by thermal nadir sensors (Worden et al, 2006;Lacour et al, 2012) and sensors detecting reflected solar light in the near infrared (Frankenberg et al, 2009(Frankenberg et al, , 2013Boesch et al, 2013).…”