Dresden 2011 – scientific programme

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UP: Fachverband Umweltphysik

UP 8: Measurement Techniques

UP 8.1: Invited Talk

Thursday, March 17, 2011, 14:00–14:30, HSZ 204

Development and application of a mobile LOPAP instrument — •Theo Brauers, Rolf Häseler, Frank Holland, and Andreas Wahner — Institut für Energie- und Klimaforschung (IEK-8: Troposphäre), Forschungszentrum Jülich, Jülich, D

The LOPAP (long path absorption) technique has been shown to be very sensitive for the detection of nitrous acid (HONO) in the atmosphere. Recently, we designed a new LOPAP instrument to be more versatile for mobile measurements and to meet the requirements for airborne application. The detection limit of the new instrument is below 1 ppt at a time resolution of 5 min to 7 min. As a first test, the instrument was successfully employed during the ZEPTER-1 campaign in July 2007 on board of the Zeppelin NT airship. During 15 flights on six days we measured HONO concentration profiles over southwest Germany, predominantly in the range between 100 m and 650 m above ground level. On average, a mixing ratio of 34 ppt was observed, almost independently of height. Within a second campaign, ZEPTER-2 in fall 2008, higher HONO mixing ratios were observed in the Lake Constance area. In this presentation, we will discuss the influence of these findings to the budget of HONO and to the OH photochemistry of the lower troposphere.