Since January 1995, an ozone line at 110 GHz is observed with a ground‐based microwave radiometer at the Bordeaux Observatory, France (45°N), belonging to the Network for the Detection of ...Stratospheric Change (NDSC). Ozone profiles from 25 to 75 km are retrieved from the microwave emission spectra using the Optimal Estimation Method. Improvements on the data acquisition process and calibration procedure are presented. A comprehensive comparison with satellite (Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS), and Stratospheric Aerosol and Gas Experiment II (SAGE II)) and ground‐based instrument data (microwave radiometer in Bern, Switzerland, lidar at the Observatoire de Haute‐Provence, France) is given. The average profiles, using the statistically most significant data sets, deviate not more than 15% in the stratosphere and 30% in the mesosphere. We can thus assert that the Bordeaux radiometer is a well‐validated instrument providing consistent and high‐quality data.
We present profile measurements of key constituents relevant to stratospheric chemistry and dynamics such as ozone (O3), nitrous oxide (N2O), and chlorine monoxide (ClO) taken during the 2002–03 ...northern hemisphere winter by the Odin Sub‐Millimetre Radiometer (SMR), a limb‐sounding satellite sensor launched in February 2001. The observations of the chemically passive tracer N2O show a subsidence of lower stratospheric air masses inside the Arctic vortex in the range of 3–5 km, or 60–100 K in terms of potential temperature, for the period November 2002 to March 2003. Activated chlorine in the form of ClO was observed inside the vortex from the beginning of December until mid‐February. The accumulated chemical ozone loss over this period, derived from the correlation of ozone with N2O, is estimated to be 28 ± 9% on the 50 ppbv level of N2O, i.e., for lower stratospheric air masses subsiding from ∼23 down to 19 km, the lower limit of the Odin/SMR ozone measurement in the 501.8 GHz band.
A method for assimilating observations of long‐lived species such as ozone (O3) and nitrous oxide (N2O) in a three‐dimensional chemistry transport model (3D‐CTM) is described. The model is forced by ...the temperature and wind analyses from the European Centre for Medium‐Range Weather Forecasts (ECMWF). The O3 and N2O fields used in this study are obtained from the Sub‐Millimeter Radiometer (SMR) aboard the Odin satellite. The assimilation technique used is the sequential statistical interpolation approach. The parametrization of the error covariance matrix of the model forecast field is described. A sensitivity study of the system parameters is done in terms of the OMF (observation minus forecast) vector also called “innovation” vector and in terms of the χ2 (chi‐square) test. The effect of the correlation distances is critical for the assimilated field. The RMS (root mean square) of the OMF for the correlation distances is minimal for values of 1500 km in the meridional direction and 500 km in the zonal direction for both O3 and N2O. The treatment of the meridional distance as a function of latitude does not reveal an important improvement. The χ2 diagnostic shows that the asymptotic value of the model error (the model error of saturation) is optimal for the value of 12.5% for O3 and 18% for N2O. We demonstrate the applicability of the developed assimilation method for the Odin/SMR data. We also present first results of the assimilation of Odin/SMR ozone and nitrous oxide for the period from 22 December 2001 to 17 January 2002.
This paper presents observing system simulation experiments (OSSEs) to compare the relative capabilities of two geostationary thermal infrared (TIR) instruments to measure ozone (O3 ) and carbon ...monoxide (CO) for monitoring air quality (AQ) over Europe. The primary motivation of this study is to use OSSEs to assess how these infrared instruments can constrain different errors affecting AQ hindcasts and forecasts (emissions, meteorology, initial condition and the 3 parameters together). The first instrument (GEO-TIR) has a configuration optimized to monitor O3 and CO in the lowermost troposphere (LmT; defined to be the atmosphere between the surface and 3 km), and the second instrument (GEO-TIR2) is designed to monitor temperature and humidity. Both instruments measure radiances in the same spectral TIR band. Results show that GEO-TIR could have a significant impact (GEO-TIR is closer to the reference atmosphere than GEO-TIR2) on the analyses of O3 and CO LmT column. The information added by the measurements for both instruments is mainly over the Mediterranean Basin and some impact can be found over the Atlantic Ocean and Northern Europe. The impact of GEO-TIR is mainly above 1 km for O3 and CO but can also improve the surface analyses for CO. The analyses of GEO-TIR2 show low impact for O3 LmT column but a significant impact (although still lower than for GEO-TIR) for CO above 1 km. The results of this study indicate the beneficial impact from an infrared instrument (GEO-TIR) with a capability for monitoring O3 and CO concentrations in the LmT, and quantify the value of this information for constraining AQ models.
Measurements of mid-stratospheric formaldehyde (H
2CO) have been obtained from the limb-viewing sub-millimeter radiometer (SMR) instrument aboard the Odin satellite. The analysis is based upon the ...only weak (8
08→7
07) rotational transition line of H
2CO that can be measured by Odin/SMR at 576.7083150
GHz in the band dedicated to the measurement of carbon monoxide (CO). The signal-to-noise ratio is increased by averaging about 1000 spectra within 2-km width vertical layers in the stratosphere over periods from 1 to 7 days and within 3 latitude bands: Southern Hemisphere (90°S–45°S), tropics (30°S–30°N), and Northern Hemisphere (45°N–90°N). The faint H
2CO line can then be retrieved using the standard scientific ground-segment developed for the Odin/SMR measurements. The mid-stratospheric H
2CO shows maxima in the tropics for every period considered (January 2006, February 2005, March 2005, and September 2005). The spring-time extra-tropical mid-stratospheric H
2CO is more intense than the fall-time extra-tropical amounts. The simulations from the three-dimensional chemical-transport model Reprobus satisfactorily show these general features.
The LUNEX5 project in France Couprie, M E; Benabderrahmane, C; Betinelli, P ...
Journal of physics. Conference series,
03/2013, Volume:
425, Issue:
7
Journal Article
Peer reviewed
Open access
The LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) in France aims at investigating the generation of short, intense, and coherent ...pulses in the soft x-ray region (with two particular targeted wavelengths of 20 and 13 nm). It consists in a single Free Electron Laser (FEL) line with cryo-ready in-vacuum undulators using a Conventional Linear Accelerator (CLA) using the superconducting technology of 400 MeV or a Laser Wake Field Accelerator (LWFA) ranging from 0.4 to 1 GeV with multi-TW or PW lasers. The FEL line can be operated in the seeded (High order Harmonic in Gas seeding) and Echo Enable Harmonic Generation configurations, which performances will be compared. Two pilot user experiments for time-resolved studies of isolated species and magnetization dynamics will take benefit of LUNEX5 FEL radiation.
We present an observing simulated system experiment (OSSE) dedicated to evaluate the potential added value from the Sentinel-4 and the Sentinel-5P observations on tropospheric ozone composition. For ...this purpose, the ozone data of Sentinel-4 (Ultraviolet Visible Near-infrared) and Sentinel-5P (TROPOspheric Monitoring Instrument) on board a geostationary (GEO) and a low-Earth-orbit (LEO) platform, respectively, have been simulated
using the DISAMAR inversion package
for the summer 2003. To ensure the robustness of the results, the OSSE has been configured with conservative assumptions. We simulate the reality by combining two chemistry transport models (CTMs): the LOng Term Ozone Simulation – EURopean Operational Smog (LOTOS-EUROS) and the Transport Model version 5 (TM5). The assimilation system is based on a different CTM, the MOdèle de Chimie Atmosphérique à Grande Echelle (MOCAGE), combined with the 3-D variational technique. The background error covariance matrix does not evolve in time and its variance is proportional to the field values. The simulated data are formed of six eigenvectors to minimize the size of the dataset by removing the noise-dominated part of the observations. The results show that the satellite data clearly bring direct added value around 200 hPa for the whole assimilation period and for the whole European domain, while a likely indirect added value is identified but not for the whole period and domain at 500 hPa, and to a lower extent at 700 hPa. In addition, the ozone added value from Sentinel-5P (LEO) appears close to that from Sentinel-4 (GEO) in the free troposphere (200–500 hPa) in our OSSE.
The outcome of our study is a result of the OSSE design and the choice within each of the components of the system.
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