Full-physics carbon dioxide retrievals from the Orbiting Carbon Observatory-2 (OCO-2) satellite by only using the 2.06 µm band

<p<Passive remote sensing of atmospheric carbon dioxide uses spectroscopic measurements of sunlight backscattered by the Earth's surface and atmosphere. The current state-of-the-art retrieval methods use three different spectral bands, the oxygen A band at <span class="inline-form...
Ausführliche Beschreibung

<p<Passive remote sensing of atmospheric carbon dioxide uses spectroscopic measurements of sunlight backscattered by the Earth's surface and atmosphere. The current state-of-the-art retrieval methods use three different spectral bands, the oxygen A band at <span class="inline-formula"<0.76</span< <span class="inline-formula"<µ</span<m and the weak and strong <span class="inline-formula"<CO<sub<2</sub<</span< absorption bands at <span class="inline-formula"<1.61</span< and <span class="inline-formula"<2.06</span< <span class="inline-formula"<µ</span<m, respectively, to infer information on light scattering and the carbon dioxide column-averaged dry-air mole fraction <span class="inline-formula"<<i<X</i<CO<sub<2</sub<</span<. In this study, we propose a one-band <span class="inline-formula"<<i<X</i<CO<sub<2</sub<</span< retrieval technique which uses only the <span class="inline-formula"<2.06</span< <span class="inline-formula"<µ</span<m band measurements from the Orbiting Carbon Observatory-2 (OCO-2) satellite. We examine the data quality by comparing the OCO-2 <span class="inline-formula"<<i<X</i<CO<sub<2</sub<</span< with collocated ground-based measurements from the Total Carbon Column Observing Network (TCCON). Over land and ocean the OCO-2 one-band retrieval shows differences from TCCON observations with a standard deviation of <span class="inline-formula"<∼1.30</span< ppm and a station-to-station variability of <span class="inline-formula"<∼0.50</span< ppm. Moreover, we compare one-band and three-band retrievals over Europe, the Middle East, and Africa and see high correlation between the two retrievals with a SD of <span class="inline-formula"<0.93</span< ppm. Compared to the three-band retrievals, <span class="inline-formula"<<i<X</i<CO<sub<2</sub<</span< retrievals using only the <span class="inline-formula"<2.06</span< <span class="inline-formula"<µ</span<m band have similar retrieval accuracy, precision, and data yield.</p< Ausführliche Beschreibung