Preliminary results from the ISAMS NO channel: Thermospheric radiances

The Improved Stratospheric and Mesospheric Sounder (ISAMS) is producing the first global measurements of emission from the 1 yields 0 band of nitric oxide (NO). The emission from the lower thermosphere has been examined and is seen to increase dramatically at times corresponding to high solar activity. The temporal and geographical extent of the effect is reported, and possible mechanisms for the enhanced emission are discussed. The need for adequate representation of thermospheric NO emission in order to retrieve NO number densities at all heights from ISAMS data is discussed, as are prospects for science studies using such NO number density measurements

Ozone profile retrievals from the ESA GOME instrument

The potential of the ESA Global Ozone Monitoring Experiment (GOME) to produce ozone profile information has been examined by carrying out two sample retrievals using simulated GOME data. The first retrieval examines the potential of the GOME instrument to produce stratospheric ozone profiles using the traditional back-scatter ultraviolet technique, while the second examines the possibility of obtaining tropospheric profile information, and improving the quality of the stratospheric profile retrievals, by exploiting the temperature dependence of the ozone Huggins bands

Characterising the seasonal and geographical variability in tropospheric ozone, stratospheric influence and recent changes

The stratospheric contribution to tropospheric ozone (O3) has been a subject of much debate in recent decades but is known to have an important influence. Recent improvements in diagnostic and modelling tools provide new evidence that the stratosphere has a much larger influence than previously thought. This study aims to characterise the seasonal and geographical distribution of tropospheric ozone, its variability, and its changes and provide quantification of the stratospheric influence on these measures. To this end, we evaluate hindcast specified-dynamics chemistry–climate model (CCM) simulations from the European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model and the Canadian Middle Atmosphere Model (CMAM), as contributed to the International Global Atmospheric Chemistry – Stratosphere-troposphere Processes And their Role in Climate (IGAC-SPARC) (IGAC–SPARC) Chemistry Climate Model Initiative (CCMI) activity, together with satellite observations from the Ozone Monitoring Instrument (OMI) and ozone-sonde profile measurements from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) over a period of concurrent data availability (2005–2010). An overall positive, seasonally dependent bias in 1000–450 hPa (∼0–5.5 km) sub-column ozone is found for EMAC, ranging from 2 to 8 Dobson units (DU), whereas CMAM is found to be in closer agreement with the observations, although with substantial seasonal and regional variation in the sign and magnitude of the bias (∼±4 DU). Although the application of OMI averaging kernels (AKs) improves agreement with model estimates from both EMAC and CMAM as expected, comparisons with ozone-sondes indicate a positive ozone bias in the lower stratosphere in CMAM, together with a negative bias in the troposphere resulting from a likely underestimation of photochemical ozone production. This has ramifications for diagnosing the level of model–measurement agreement. Model variability is found to be more similar in magnitude to that implied from ozone-sondes in comparison with OMI, which has significantly larger variability. Noting the overall consistency of the CCMs, the influence of the model chemistry schemes and internal dynamics is discussed in relation to the inter-model differences found. In particular, it is inferred that CMAM simulates a faster and shallower Brewer–Dobson circulation (BDC) compared to both EMAC and observational estimates, which has implications for the distribution and magnitude of the downward flux of stratospheric ozone over the most recent climatological period (1980–2010). Nonetheless, it is shown that the stratospheric influence on tropospheric ozone is significant and is estimated to exceed 50 % in the wintertime extratropics, even in the lower troposphere. Finally, long-term changes in the CCM ozone tracers are calculated for different seasons. An overall statistically significant increase in tropospheric ozone is found across much of the world but particularly in the Northern Hemisphere and in the middle to upper troposphere, where the increase is on the order of 4–6 ppbv (5 %–10 %) between 1980–1989 and 2001–2010. Our model study implies that attribution from stratosphere–troposphere exchange (STE) to such ozone changes ranges from 25 % to 30 % at the surface to as much as 50 %–80 % in the upper troposphere–lower stratosphere (UTLS) across some regions of the world, including western Eurasia, eastern North America, the South Pacific and the southern Indian Ocean. These findings highlight the importance of a well-resolved stratosphere in simulations of tropospheric ozone and its implications for the radiative forcing, air quality and oxidation capacity of the troposphere

ISAMS observations of stratospheric aerosol

The Improved Stratospheric and Mesospheric (ISAMS) on board the Upper Atmosphere Research Satellite (UARS) incorporates a 12.1 micron window channel for the measurement of aerosol opacity. The retrieval scheme is discussed briefly and preliminary observations of the Mt. Pinatubo aerosol cloud are presented and compared with SAGE 2 observations at 1.02 microns. The effect of aerosol on other ISAMS channels and its spectral dependence is discussed

Measurements of stratospheric NO, NO2, and N2O5 by ISAMS: Preliminary observations and data validation

The Improved Stratospheric and Mesospheric Sounder (ISAMS) is a multichannel radiometer and forms part of the science payload of the Upper Atmosphere Research Satellite (UARS). ISAMS measures infrared emissions from the Earth's atmosphere in several wavelength bands. Three such bands include emission from nitric oxide, nitrogen dioxide, and dinitrogen pentoxide. In this paper, we briefly discuss how the ISAMS instrument measures NO, NO2, and N2O5. We also present preliminary data from these channels and describe preliminary validation work

Investigation of the summer 2018 European ozone air pollution episodes using novel satellite data and modelling

In the summer of 2018, Europe experienced an intense heat wave which coincided with several persistent large-scale ozone (O3) pollution episodes. Novel satellite data of lower tropospheric column O3 from the Global Ozone Monitoring Experiment-2 (GOME-2) and Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite showed substantial enhancements in 2018 relative to other years since 2012. Surface observations also showed ozone enhancements across large regions of continental Europe in summer 2018 compared to 2017. Enhancements to surface temperature and the O3 precursor gases carbon monoxide and methanol in 2018 were co-retrieved from MetOp observations by the same scheme. This analysis was supported by the TOMCAT chemistry transport model (CTM) to investigate processes driving the observed O3 enhancements. Through several targeted sensitivity experiments we show that meteorological processes, and emissions to a secondary order, were important for controlling the elevated O3 concentrations at the surface. However, mid-tropospheric (~500 hPa) O3 enhancements were dominated by meteorological processes. We find that contributions from stratospheric O3 intrusions ranged between 15&ndash;40 %. Analysis of back trajectories indicates that the import of O3-enriched air masses into Europe originated over the North Atlantic substantially increasing O3 in the 500 hPa layer during summer 2018.</p

Might Depression, Psychosocial Adversity, and Limited Social Assets Explain Vulnerability to and Resistance against Violent Radicalisation?

BACKGROUND: This study tests whether depression, psychosocial adversity, and limited social assets offer protection or suggest vulnerability to the process of radicalisation. METHODS: A population sample of 608 men and women of Pakistani or Bangladeshi origin, of Muslim heritage, and aged 18-45 were recruited by quota sampling. Radicalisation was measured by 16 questions asking about sympathies for violent protest and terrorism. Cluster analysis of the 16 items generated three groups: most sympathetic (or most vulnerable), most condemning (most resistant), and a large intermediary group that acted as a reference group. Associations were calculated with depression (PHQ9), anxiety (GAD7), poor health, and psychosocial adversity (adverse life events, perceived discrimination, unemployment). We also investigated protective factors such as the number social contacts, social capital (trust, satisfaction, feeling safe), political engagement and religiosity. RESULTS: Those showing the most sympathy for violent protest and terrorism were more likely to report depression (PHQ9 score of 5 or more; RR = 5.43, 1.35 to 21.84) and to report religion to be important (less often said religion was fairly rather than very important; RR = 0.08, 0.01 to 0.48). Resistance to radicalisation measured by condemnation of violent protest and terrorism was associated with larger number of social contacts (per contact: RR = 1.52, 1.26 to 1.83), less social capital (RR = 0.63, 0.50 to 0.80), unavailability for work due to housekeeping or disability (RR = 8.81, 1.06 to 37.46), and not being born in the UK (RR = 0.22, 0.08 to 0.65). CONCLUSIONS: Vulnerability to radicalisation is characterised by depression but resistance to radicalisation shows a different profile of health and psychosocial variables. The paradoxical role of social capital warrants further investigation