By Ulrich Schumann, Deutsches Zentrum für Luft- und Raumfahrt
(DLR)Institute of Atmospheric Physics, Oberpfaffenhofen, Germany
December 16, 2004 - 3:00 PM - FL1- EOL Atrium
The contributions of tropical continental deep convection to
lightning-produced nitrogen oxides (NOx) and to other trace gases
(including water vapor) and particles (ice crystal and aerosols) is
being investigated within the EU project TROCCINOX (Tropical
Convection, Cirrus, and Nitrogen Oxides Experiment),
http://www.pa.op.dlr.de/troccinox/. The project is being performed in
2002-2005 in cooperation with Brazilian partners. A first field
experiment has been performed in Brazil with the DLR Falcon in
February and March 2004, a second experiment is now being prepared to
be performed between mid-January and end of February 2005 including
measurements with the Falcon and the high-flying (up to 21 km
altitude) Russian Geophysica aircraft.
The results from the first field experiment allow to constrain the
possible range of the global source rate of lightning induced NOx.
Measurements have been performed with the DLR Falcon on the transfer
flights between Oberpfaffenhofen (Germany) and Gaviao Peixoto (S. P.,
Brazil) and during 14 local flights over Southern Brazil. The aircraft
was instrumented with in-situ sensors for NO, NOy, O3, CO, H2O, T, NO2
photolysis rate, and various aerosols. A differential absorption Lidar
measures aerosol properties and H2O profiles above or below the
aircraft. Lightning induced NOx has been measured in or near tropical
and subtropical thunderstorms at altitudes up to 12.5 km. In anvil
outflow of thunderstorms, spiky NO structures (maximum 65 nmol/mol)
above background were observed. Some of the spikes were notably wide
(order several 10 km) indicating outflow from a thunderstorm anvil,
others were narrow (order 200 m) clearly originating from fresh
lightning events. Model studies and analysis of the NOx outflow from
individual thunderstorm cases indicate global lightning-NOx production
rates between 2 and 9 Tg(N) yr-1.
Finally an outlook for using the new High Altitude and Long Range
Research Aircraft HALO (which is similar to HIAPER) will be presented.
For more information, contact Renee Ray at ext. 2050, rray@ucar.edu.
Tue, Nov 30, 2004 to Thu, Dec 16, 2004
