Abstract

Nitrous oxide (N2O) is an important greenhouse gas and it can also generate nitric oxide, which depletes ozone in the stratosphere. It is a common target species of ground-based Fourier transform infrared (FTIR) near-infrared (TCCON) and mid-infrared (NDACC) measurements. Both TCCON and NDACC net... Show moreNitrous oxide (N2O) is an important greenhouse gas and it can also generate nitric oxide, which depletes ozone in the stratosphere. It is a common target species of ground-based Fourier transform infrared (FTIR) near-infrared (TCCON) and mid-infrared (NDACC) measurements. Both TCCON and NDACC networks provide a long-term global distribution of atmospheric N2O mole fraction. In this study, the dry-air column-averaged mole fractions of N2O (X-N2O) from the TCCON and NDACC measurements are compared against each other at seven sites around the world (Ny-Alesund, Sodankyla, Bremen, Izana, Reunion, Wollongong, Lauder) in the time period of 2007-2017. The mean differences in X-N2O between TCCON and NDACC (NDACC-TCCON) at these sites are between -3.32 and 1.37 ppb (-1.1 %-0.5 %) with standard deviations between 1.69 and 5.01 ppb (0.5 %-1.6 %), which are within the uncertainties of the two datasets. The NDACC N2O retrieval has good sensitivity throughout the troposphere and stratosphere, while the TCCON retrieval underestimates a deviation from the a priori in the troposphere and overestimates it in the stratosphere. As a result, the TCCON X-N2O measurement is strongly affected by its a priori profile. Show less