0000000000075911
AUTHOR
Paul Konopka
Evidence for heterogeneous chlorine activation in the tropical UTLS
Airborne in-situ observations of ClO in the tropics were made during the TROCCINOX (Aracatuba, Brazil, February 2005) and SCOUT-O<sub>3</sub> (Darwin, Australia, November/December 2005) field campaigns. While during most flights significant amounts of ClO (≈10–20 parts per trillion, ppt) were present only in aged stratospheric air, instances of enhanced ClO mixing ratios of up to 40 ppt – significantly exceeding those expected from gas phase chemistry – were observed in air masses of a more tropospheric character. Most of these observations are associated with low temperatures or with the presence of cirrus clouds (often both), suggesting that cirrus ice particles and/or liquid …
Tropical troposphere to stratosphere transport of carbon monoxide and long-lived trace species in the Chemical Lagrangian Model of the Stratosphere (CLaMS)
Variations in the mixing ratio of trace gases of tropospheric origin entering the stratosphere in the tropics are of interest for assessing both troposphere to stratosphere transport fluxes in the tropics and the impact of these transport fluxes on the composition of the tropical lower stratosphere. Anomaly patterns of carbon monoxide (CO) and long-lived tracers in the lower tropical stratosphere allow conclusions about the rate and the variability of tropical upwelling to be drawn. Here, we present a simplified chemistry scheme for the Chemical Lagrangian Model of the Stratosphere (CLaMS) for the simulation, at comparatively low numerical cost, of CO, ozone, and long-lived trace substances…
Transport of Antarctic stratospheric strongly dehydrated air into the troposphere observed during the HALO-ESMVal campaign 2012
Abstract. Dehydration in the Antarctic winter stratosphere is a well-known phenomenon that is annually observed by satellites and occasionally observed by balloon-borne measurements. However, in situ measurements of dehydrated air masses in the Antarctic vortex are very rare. Here, we present detailed observations with the in situ and GLORIA remote sensing instrument payload aboard the German aircraft HALO. Strongly dehydrated air masses down to 1.6 ppmv of water vapor were observed as far north as 47° S in an altitude between 12 and 13 km in the lowermost stratosphere. The dehydration can be traced back to individual ice formation events above the Antarctic Peninsula and Plateau, where ice…
Observations of meteoric material and implications for aerosol nucleation in the winter Arctic lower stratosphere derived from in situ particle measurements
Number concentrations of total and non-volatile aerosol particles with size diameters >0.01 μm as well as particle size distributions (0.4–23 μm diameter) were measured in situ in the Arctic lower stratosphere (10–20.5 km altitude). The measurements were obtained during the campaigns European Polar Stratospheric Cloud and Lee Wave Experiment (EUPLEX) and Envisat-Arctic-Validation (EAV). The campaigns were based in Kiruna, Sweden, and took place from January to March 2003. Measurements were conducted onboard the Russian high-altitude research aircraft Geophysica using the low-pressure Condensation Nucleus Counter COPAS (COndensation PArticle Counter System) and a modified F…
Nitric Acid Trihydrate (NAT) formation at low NAT supersaturation in Polar Stratospheric Clouds (PSCs)
International audience; A PSC was detected on 6 February 2003 in the Arctic stratosphere by in-situ measurements onboard the high-altitude research aircraft Geophysica. Low number densities (~10-4cm-3) of small nitric acid (HNO3) containing particles (dTNAT, these NAT particles have the potential to grow further and to remove HNO3 from the stratosphere, thereby enhancing polar ozone loss. Interestingly, the NAT particles formed in less than a day at temperatures just slightly below TNAT (T>TNAT-3.1K). This unique measurement of PSC formation at extremely low NAT saturation ratios (SNAT?10) constrains current NAT nucleation theories. We suggest, that the NAT particles have formed heterogeneo…
Detection of reactive nitrogen containing particles in the tropopause region? Evidence for a tropical nitric acid trihydrage (NAT) belt
The detection of nitric acid trihydrate (NAT, HNO<sub>3</sub>&times;3H<sub>2</sub>O) particles in the tropical transition layer (TTL) harmonizes our understanding of polar stratospheric cloud formation. Large reactive nitrogen (NO<sub>y</sub>) containing particles were observed on 8 August 2006 by instruments onboard the high altitude research aircraft M55-Geophysica near and below the tropical tropopause. The particles, most likely NAT, have diameters less than 6 &mu;m and concentrations below 10<sup>-4</sup> cm<sup>&minus;3</sup>. The NAT particle layer was repeatedly detected at altitudes between 15.1 and 17.5 km ove…