Lidar observations at prioritized sites for GOSAT validation

The Thermal And Near infrared Sensor for carbon Observation-Fourier Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observing SATellite (GOSAT) measures the Short Wavelength InfraRed (SWIR) spectra of sunlight reflected by the earth surface and atmosphere. The column-averaged dry air mole fractions of carbon dioxide and methane (XCO2 and XCH4, hereafter GOSAT data) retrieved from the TANSO-FTS SWIR spectra could be influenced by aerosol and cirrus could particles. To investigate their influences on the GOSAT data, we deployed two-wavelength (532 and 1064 nm) polarization lidar systems at the Total Carbon Column Observing Network (TCCON) sites of Lauder in New Zealand, Tsukuba, Saga and Rikubetsu in Japan as prioritized validation sites. Vertical profiles of particle backscattering coefficients, backscatter wavelength exponent and total depolarization ratio were obtained by these lidar systems. Based on these physical parameters, we found that the particles had influence on GOSAT XCO2 at Tsukuba and Saga. These lidars detected increases in stratospheric aerosols by the volcanic eruptions of Sarychev Peak, Puyehue-Cordon Caulle, Nabro and Calbuco during 2009 through 2015, which might impact on GOSAT XCO2. Furthermore, we developed an improved version of lidar for validation of GOSAT-2 which will be launched in 2018. The improved lidar can measure the particle extinction-to-backscatter ratio and water vapor mixing ratio profiles up to 5 km in nighttime using N2 and H2O Raman scattering besides above-mentioned physical parameters. This lidar will be installed at Burgos in Philippines with a TCCON FTS in early 2017. We present the observational results of particles and their influences on the GOSAT data.