Hauke Harder

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[1] Measurements of isoprene and its oxidation products, methacrolein, methyl vinyl ketone and peroxymethacrylic nitric anhydride, were conducted between 13 June and 14 July 1999, at the Cornelia Fort Airpark during the Nashville intensive of the Southern Oxidant Study. Trends in isoprene and its oxidation products showed marked variability from(More)
Ozone (O3) is a photochemical oxidant, an air pollutant and a greenhouse gas. As the main precursor of the hydroxyl radical (OH) it strongly affects the oxidation power of the atmosphere. The remote marine boundary layer (MBL) is considered an important region in terms of chemical O3 loss; however surface-based atmospheric observations are sparse and the(More)
[1] OH and HO2 mixing ratios and total OH reactivity were measured together with photolysis frequencies, NOx, O3, many VOCs, and other trace gases during the midsummer 1999 SOS campaign in Nashville, Tennessee. These measurements provided an excellent opportunity to study OH and HO2 (collectively called HOx), and their sources and sinks in a polluted(More)
Recent data indicate positive effects of treating grain with citric (CAc) or lactic acid (LAc) on the hydrolysis of phytate phosphorus (P) and fermentation products of the grain. This study used a semicontinuous rumen simulation technique to evaluate the effects of processing of barley with 50.25 g/L (wt/vol) CAc or 76.25 g/L LAc on microbial composition,(More)
[1] The nitrate radical (NO3) is the dominant atmospheric oxidant during the night in most environments. During the day, however, NO3 has thus far been considered insignificant. Here we present daytime measurements of NO3 by Differential Optical Absorption Spectroscopy near Houston, Texas, during the Texas Air Quality Study 2000. On 3 consecutive days in(More)
Hydroxyl radicals in the tropical troposphere over the Suriname rainforest: airborne measurements M. Martinez, H. Harder, D. Kubistin, M. Rudolf, H. Bozem, G. Eerdekens, H. Fischer, C. Gurk, T. Klüpfel, R. Königstedt, U. Parchatka, C. L. Schiller, A. Stickler, J. Williams, and J. Lelieveld Department of Atmospheric Chemistry, Max Planck Institute for(More)
The rotational spectrum of NSF3 in the ground and v5 = 1 vibrational states has been investigated in the centimeter- and millimeter-wave ranges. R-branch (J + 1 <-- J) transitions for J = 0, 1 and Q-branch rotational transitions for the v5 = 1 vibrational state have been measured by waveguide Fourier transform microwave spectroscopy in the range 8-26.5 GHz.(More)
Chemistry, transport and dry deposition of trace gases in the boundary layer over the tropical Atlantic Ocean and the Guyanas during the GABRIEL field campaign A. Stickler, H. Fischer, H. Bozem, C. Gurk, C. Schiller, M. Martinez-Harder, D. Kubistin, H. Harder, J. Williams, G. Eerdekens, N. Yassaa, L. Ganzeveld, R. Sander, and J. Lelieveld Department of(More)
The present study aimed to investigate changes in the reticuloruminal pH and temperature dynamics in periparturient dairy cows. Reticuloruminal pH and temperature measurements were conducted from 7 d before until 8 d after parturition using indwelling sensors. Nine Simmental and 4 Brown Swiss dairy cows were fed a close-up total mixed ration (52.5% neutral(More)
Hydroxyl radicals in the tropical troposphere over the Suriname rainforest: comparison of measurements with the box model MECCA D. Kubistin, H. Harder, M. Martinez, M. Rudolf, R. Sander, H. Bozem, G. Eerdekens, H. Fischer, C. Gurk, T. Klüpfel, R. Königstedt, U. Parchatka, C. L. Schiller, A. Stickler, D. Taraborrelli, J. Williams, and J. Lelieveld Department(More)