Regional lightning NO<sub>x</sub> sources during the TROCCINOX experiment

Abstract

Abstract.A lightning NO x (LiNOx) source has been implemented in the deep convection scheme of the Meso-NH mesoscale model following a mass-flux formalism coherent with the transport and scavenging of gases inside the convective scheme. In this approach the vertical transport of NO inside clouds is calculated by the parameterization of deep convective transport, thus eliminating the need for apriori LiNOx profiles. Once produced inside the convective column, NO molecules are redistributed by updrafts and downdrafts and detrained in the environment when the conditions are favorable. The model was applied to three particular flights during the Tropical Convection, Cirrus and Nitrogen Oxides (TROCCINOX) campaign over the tropical area around Bauru on 3-4 March 2004. The convective activity during the three flights was investigated using brightness temperature at 10.7 µm observed from GOES-12 satellite. The use of a model-to-satellite approach reveals that the simulation appears rather realistic compared to the observations. The diurnal cycle of the simulated brightness temperature, CAPE, number of IC flashes, NO entrainment flux are in phase, with a succession of three marked peaks at 18:00 UTC (15:00 LT). These simulated peaks precede the observed afternoon one by about three hours. Comparison of the simulated NO x with observations along the flight tracks show that the model reproduces well the observed NO x levels when the LiNOx source is applied. The budget of entrainment, detrainment and LiNOx convective fluxes shows that the majority of the NO detrained back to the environment comes from lightning source inside the convective columns. Entrainment of NO from the environment and vertical transport from the boundary layer were not significant during the episode. The troposphere is impacted by detrainment fluxes of LiNOx from 4 km altitude to 16 km with maximum values around 14 km altitude. Detrainment fluxes varyCorrespondence to: C. Mari (celine.mari@aero.obs-mip.fr) between 75 kg(N)/s during nighttime to 400 kg(N)/s at the times of maximun convective activity. Extrapolation of the regional LiNOx source would yield a global LiNOx production around 5.7 Tg(N)/year which is within the current estimates but should not hide the overestimation of the number of flash rates by the model.

Role of lightning phenomenon over surface O3 and NOx at a semi-arid tropical site Hyderabad, India: inter-comparison with satellite retrievals

“…In the event on 11th May 2012, concentration of NO x started increasing after 18:00 h and reached a maximum hourly mean of 38 ppbv at about 21:00 h, which was greater than the control and monthly mean values (15 ppbv). Similar observations were reported for the formation of NO x in the middle and upper troposphere (Barthe and Barth 2008;Bond et al 2001;Choi et al 2009;Jacobson and Streets 2009;Jourdain et al 2010;Kaynak et al 2008;Labrador et al 2009;Mari et al 2006;Nath et al 2009;Zhang et al 2003). After dissipation of thunderstorm, the increased amount of NO x formed in the upper troposphere was transported downward to the lower troposphere.…”

Impact of West African Monsoon convective transport and lightning NO<sub>x</sub> production upon the upper tropospheric composition: a multi-model study

“…Convective processes are simulated with the Kain-Fritsch-Bechtold's (KFB) scheme of Bechtold et al (2001), and turbulent diffusion is calculated with the scheme by Louis (1979). The LiNO x parametrization is based on Mari et al (2006). In this approach, once produced inside the convective column, NO x molecules are redistributed by upward and downward transport and detrained in the environment and no a priori vertical placement of the emissions is prescribed.…”

“…MOCAGE LiNO x mixing ratios maxima are lower (100 pptv) but located at higher altitude (between 120 and 200 hPa) and at almost the same latitude as TM4. In MOCAGE, no vertical placement is prescribed and the NO x emitted within the cloud are transported according to the convective mass fluxes (Mari et al, 2006). The zonal LiNO x maximum (Fig.…”

Impact of West African Monsoon convective transport and lightning NO<sub>x</sub> production upon the upper tropospheric composition: a multi-model study

“…Convective processes are simulated with the Kain-Fritsch-Bechtold's (KFB) scheme of Bechtold et al (2001), and turbulent diffusion is calculated with the scheme by Louis (1979). The LiNO x parametrization is based on Mari et al (2006). In this approach, once produced inside the convective column, NO x molecules are redistributed by upward and downward transport and detrained in the environment and no a priori vertical placement of the emissions is prescribed.…”