INCREASING THE SPATIO-TEMPORAL RESOLUTION OF OCO2 GHG SATELLITE DATA

Abstract

Green house gas (GHG) satellites such as Orbiting Carbon Observatory 2 (OCO2), Sentinel 5P (TROPOMI), GHGSat offer global coverage of measuring column averaged carbon- di-oxide (XCO2) and methane (XCH4). Though GHG satel- lites are a scalable method of measuring GHG emissions, they are limited by coarse spatial and/or temporal resolutions and missing data. Based on the statistical interpolation technique, fixed rank kriging (FRK) technique, in this work, we have de- veloped a novel nested kriging approach, N-FRK to address the above challenges of GHG satellite data, in particular of OCO2 satellite. Compared to the native spatio-temporal reso- lution of 16 days and 1.2x2.2km2 of OCO2 satellite, we have increased the temporal resolution to 1 day and spatial resolu- tion to 1.11x1.11km2 using N-FRK. The daily spatial maps at 111, 11.1, 1.11 km resolutions have been generated using FRK and N-FRK techniques and validated across 13 or subset of the 13 sensor sites of total carbon column observing net- work (TCCON) for the year 2019. As part of validation, we present the R2, root mean square error (RMSE), and bias met- rics and we see good agreement between the estimated data and sensor data.