Publications

Impact of the Pacific sector sea ice loss on the sudden stratospheric warming characteristics

Orsolini, Yvan Joseph Georges Emile G.

Impact of the major SSWs of February 2018 and January 2019 on the middle atmospheric nitric oxide abundance

The Arctic middle atmosphere was affected by major sudden stratospheric warmings (SSW) in February 2018 and January 2019, respectively. In this article, we report for the first time the impact of these two events on the middle atmospheric nitric oxide (NO) abundance. The study is based on measurements obtained during two dedicated observation campaigns, using the Sub-Millimetre Radiometer (SMR) aboard the Odin satellite, measuring NO globally since 2003. The SSW of February 2018 was similar to other, more dynamically quiet, Arctic winters in term of NO downward transport from the upper mesosphere–lower thermosphere to lower altitudes (referred to as energetic particle precipitation indirect effect EPP-IE). On the contrary, the event of January 2019 led to one of the strongest EPP-IE cases observed within the Odin operational period. Important positive NO anomalies were indeed observed in the lower mesosphere–upper stratosphere during the three months following the SSW onset, corresponding to NO volume mixing ratios more than 50 times higher than the climatological values. These different consequences on the middle atmospheric composition are explained by very different dynamical characteristics of these two SSW events.

Impact of the Eastern Eurasian autumn snow cover on high latitude climate variability. NILU F

Orsolini, Y. J.

Impact of the autumn snow cover on high latitude climate variability. NILU F

Orsolini, Y. J. et al.

Impact of the 2007 Arctic sea ice reduction in coupled ocean-atmosphere autumn hindcasts. NILU F

Orsolini, Y. J. et al.

Impact of the 2007 Arctic sea ice reduction in coupled ocean-atmosphere autumn hindcasts. NILU F

Orsolini, Y. J.

Impact of synthetic space-borne NO2 observations from the Sentinel-4 and Sentinel-5P missions on tropospheric NO2 analyses

We present an Observing System Simulation Experiment (OSSE) dedicated to the evaluation of the added value of the Sentinel-4 and Sentinel-5P missions for tropospheric nitrogen dioxide (NO2). Sentinel-4 is a geostationary (GEO) mission covering the European continent, providing observations with high temporal resolution (hourly). Sentinel-5P is a low Earth orbit (LEO) mission providing daily observations with a global coverage. The OSSE experiment has been carefully designed, with separate models for the simulation of observations and for the assimilation experiments and with conservative estimates of the total observation uncertainties. In the experiment we simulate Sentinel-4 and Sentinel-5P tropospheric NO2 columns and surface ozone concentrations at 7 by 7 km resolution over Europe for two 3-month summer and winter periods. The synthetic observations are based on a nature run (NR) from a chemistry transport model (MOCAGE) and error estimates using instrument characteristics. We assimilate the simulated observations into a chemistry transport model (LOTOS-EUROS) independent of the NR to evaluate their impact on modelled NO2 tropospheric columns and surface concentrations. The results are compared to an operational system where only ground-based ozone observations are ingested. Both instruments have an added value to analysed NO2 columns and surface values, reflected in decreased biases and improved correlations. The Sentinel-4 NO2 observations with hourly temporal resolution benefit modelled NO2 analyses throughout the entire day where the daily Sentinel-5P NO2 observations have a slightly lower impact that lasts up to 3–6 h after overpass. The evaluated benefits may be even higher in reality as the applied error estimates were shown to be higher than actual errors in the now operational Sentinel-5P NO2 products. We show that an accurate representation of the NO2 profile is crucial for the benefit of the column observations on surface values. The results support the need for having a combination of GEO and LEO missions for NO2 analyses in view of the complementary benefits of hourly temporal resolution (GEO, Sentinel-4) and global coverage (LEO, Sentinel-5P).

Impact of springtime snow over the Himalayan-Tibetan Plateau on the onset of the Indian summer monsoon in coupled seasonal forecasts.

Orsolini, Y.; Senan, R.; Weisheimer, A.; Vitart, F.; Balsamo, G.; Stockdale, T.N.; Dutra, E.; Doblas-Reyes, F.J.; Basang, D.

Impact of springtime snow over the Himalayan-Tibetan Plateau on the onset of the Indian summer monsoon in coupled seasonal forecasts.

Orsolini, Y.

Impact of springtime Himalayan-Tibetan Plateau snowpack on the onset of the Indian summer monsoon in coupled seasonal forecasts.

Orsolini Y.J.; Senan, R.; Weisheimer, A.; Vitart, F.; Balsamo, G.; Doblas-Reyes, F. J.; Stockdale, T. N.; , Dutra, E.

Impact of springtime Himalayan-Tibetan Plateau snowpack on the onset of the Indian summer monsoon in coupled seasonal forecasts.

Orsolini, Y.

Impact of springtime Himalayan-Tibetan Plateau snowpack on the onset of the Indian summer monsoon in coupled seasonal forecasts.

Orsolini, Y.J.; Senan, R.; Weisheimer, A.; Vitart, F.; Balsamo, G.; Stockdale, T. N.; Dutra, E.; Doblas-Reyes, F. J.

Impact of spaceborne carbon monoxide observations from the S-5P platform on tropospheric composition analyses and forecasts.

Abida, R.; Attié, J.-L.; El Amraoui, L.; Ricaud, P.; Lahoz, W.; Eskes, H.; Segers, A.; Curier, L.; de Haan, J.; Kujanpää, J.; Nijhuis, A. O.; Tamminen, J.; Timmermans, R.; Veefkind, P.