Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Estimating the influence of lightning on upper tropospheric ozone using NLDN lightning data and CMAQ model
Abstract Lightning is a particularly significant NOx source in the middle and upper troposphere where it affects tropospheric chemistry and ozone. Because the version-4 Community Multiscale Air Quality Modeling System (CMAQ) does not account for NOx emission from lightning, it underpredicts NOx above the mixed layer. In this study, the National Lightning Detection Network™ (NLDN) lightning data are applied to the CMAQ model to simulate the influence of lightning-produced NOx (LNOx) on upper tropospheric NOx and subsequent ozone concentration. Using reasonable values for salient parameters (detection efficiency ∼95%, cloud flash to ground flash ratio ∼3, LNOx production rate ∼500 mol N per flash), the NLDN ground flashes are converted into total lightning NOx amount and then vertically distributed on 39 CMAQ model layers according to a vertical-distribution profile of lightning N mass. This LNOx contributes 27% of the total NOx emission during 15 July ∼7 September 2006. This additional NOx reduces the low-bias of simulated tropospheric O3 columns with respect to OMI tropospheric O3 columns from 10 to 5%. Although the model prediction of ozone in upper troposphere improves by ∼20 ppbv due to lightning-produced NOx above the southeastern and eastern U.S.A., the improved ozone prediction is still ∼20–25 ppbv lower than ozonesonde measurements.
Highlights ► Not accounting for lightning NOx, CMAQ underpredicts NOx above the mixed layer. ► We estimate LNOx emissions based on NLDN ground flashes and applied it to CMAQ. ► LNOx contributes 27% of the total NOx emission during 15 July–7 September 2006. ► LNOx improves upper tropospheric O3 by ∼20 ppbv above the southeastern and eastern U.S.A. ► The improved ozone prediction is still ∼20–25 ppbv lower than ozonesonde measurements.
Estimating the influence of lightning on upper tropospheric ozone using NLDN lightning data and CMAQ model
Abstract Lightning is a particularly significant NOx source in the middle and upper troposphere where it affects tropospheric chemistry and ozone. Because the version-4 Community Multiscale Air Quality Modeling System (CMAQ) does not account for NOx emission from lightning, it underpredicts NOx above the mixed layer. In this study, the National Lightning Detection Network™ (NLDN) lightning data are applied to the CMAQ model to simulate the influence of lightning-produced NOx (LNOx) on upper tropospheric NOx and subsequent ozone concentration. Using reasonable values for salient parameters (detection efficiency ∼95%, cloud flash to ground flash ratio ∼3, LNOx production rate ∼500 mol N per flash), the NLDN ground flashes are converted into total lightning NOx amount and then vertically distributed on 39 CMAQ model layers according to a vertical-distribution profile of lightning N mass. This LNOx contributes 27% of the total NOx emission during 15 July ∼7 September 2006. This additional NOx reduces the low-bias of simulated tropospheric O3 columns with respect to OMI tropospheric O3 columns from 10 to 5%. Although the model prediction of ozone in upper troposphere improves by ∼20 ppbv due to lightning-produced NOx above the southeastern and eastern U.S.A., the improved ozone prediction is still ∼20–25 ppbv lower than ozonesonde measurements.
Highlights ► Not accounting for lightning NOx, CMAQ underpredicts NOx above the mixed layer. ► We estimate LNOx emissions based on NLDN ground flashes and applied it to CMAQ. ► LNOx contributes 27% of the total NOx emission during 15 July–7 September 2006. ► LNOx improves upper tropospheric O3 by ∼20 ppbv above the southeastern and eastern U.S.A. ► The improved ozone prediction is still ∼20–25 ppbv lower than ozonesonde measurements.
Estimating the influence of lightning on upper tropospheric ozone using NLDN lightning data and CMAQ model
Wang, Lihua (Autor:in) / Newchurch, M.J. (Autor:in) / Pour-Biazar, Arastoo (Autor:in) / Kuang, Shi (Autor:in) / Khan, Maudood (Autor:in) / Liu, Xiong (Autor:in) / Koshak, William (Autor:in) / Chance, Kelly (Autor:in)
Atmospheric Environment ; 67 ; 219-228
04.11.2012
10 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Tropospheric sources of NOx: lightning and biology
| NTRS | 1984
Tropospheric sources of NO(x) - Lightning and biology
| NTRS | 1984