An assessment of tropopause characteristics of the ERA5 and ERA-Interim meteorological reanalyses

Abstract. The tropopause layer plays a key role in manifold processes atmospheric chemistry and physics. Here we compare the representation characteristics of lapse rate according to definition World Meteorological Organization (WMO) as estimated from European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data. Our study is based on 10-year records (2009 2018) ECMWF's state-of-the-art ERA5 its predecessor ERA-Interim. intercomparison reveals notable differences between ERA-Interim data, particular small spatiotemporal scales. monthly mean minus heights vary ?300 m at transition tropics extratropics (near 30? S N) 150 around Equator. Mean temperatures are mostly lower than ERA-Interim, with maximum difference up ?1.5 K tropics. Monthly standard deviations 350 or 60 % larger exceed those by 1.5 30 %. occurrence frequencies double-tropopause events 25 percentage points middle latitudes. We attribute data larger, more realistic variability improved resolution better geophysical forecast model well improvements assimilation scheme utilization additional observations ERA5. allows mesoscale features, gravity waves, which affect temperature profiles upper troposphere stratosphere (UTLS) thus height estimates. evaluated quality comparisons COSMIC MetOp Global Positioning System (GPS) satellite high-resolution radiosonde profiles. comparison indicates an uncertainty first (ERA-Interim) about ±150 ±200 (±250 m) ±120 (±170 coarser-resolution GPS different Consequently, will provide accurate information future tropopause-related studies.