Airborne measurements of the nitric acid partitioning in persistent contrails

Abstract. This study reports the first systematic measurements of nitric acid (HNO 3 ) uptake in contrail ice particles at typical aircraft cruise altitudes. During the CIRRUS-III campaign cirrus clouds and almost 40 persistent contrails were probed with in situ instruments over Germany and Northern Europe in November 2006. Besides reactive nitrogen, water vapor, cloud ice water content, ice particle size distributions, and condensation nuclei were measured during 6 flights. Contrails with ages up to 12 h were detected at altitudes 10–11.5 km and temperatures 211–220 K. These contrails had a larger ice phase fraction of total nitric acid (HNO 3 ice /HNO 3 tot = 6%) than the ambient cirrus layers (3%). On average, the contrails contained twice as much HNO 3 ice as the cirrus clouds, 14 pmol/mol and 6 pmol/mol, respectively. Young contrails with ages below 1 h had a mean HNO 3 ice of 21 pmol/mol. The contrails had higher nitric acid to water molar ratios in ice and slightly higher ice water contents than the cirrus clouds under similar meteorological conditions. The differences in ice phase fractions and molar ratios between developing contrails and cirrus are likely caused by high plume concentrations of HNO 3 prior to contrail formation. The location of the measurements in the upper region of frontal cirrus layers might account for slight differences in the ice water content between contrails and adjacent cirrus clouds. The observed dependence of molar ratios as a function of the mean ice particle diameter suggests that ice-bound HNO 3 concentrations are controlled by uptake of exhaust HNO 3 in the freezing plume aerosols in young contrails and subsequent trapping of ambient HNO 3 in growing ice particles in older (age > 1 h) contrails.

[1]  Bernd Kärcher,et al.  Trapping of trace gases by growing ice surfaces including surface-saturated adsorption , 2009 .

[2]  Jessica R. Meyer,et al.  Ice water content of Arctic, midlatitude, and tropical cirrus - Part 2: Extension of the database and new statistical analysis , 2008 .

[3]  H. Schlager,et al.  Detection of reactive nitrogen containing particles in the tropopause region ? Evidence for a tropical nitric acid trihydrate (NAT) belt , 2008 .

[4]  V. Mitev,et al.  Evidence for ice particles in the tropical stratosphere from in-situ measurements , 2008 .

[5]  H. Schlager,et al.  A climatological view of HNO3 partitioning in cirrus clouds , 2008 .

[6]  A. Heymsfield.  On measurements of small ice particles in clouds , 2007 .

[7]  V. Mitev,et al.  In-situ observations and modeling of small nitric acid-containing ice crystals , 2007 .

[8]  Bernd Kärcher,et al.  Formation of nitric acid/water ice particles in cirrus clouds , 2006 .

[9]  H. Schlager,et al.  Nitric acid in cirrus clouds , 2006 .

[10]  J. Staehelin,et al.  Measurements of NO, NO y , N 2 O, and O 3 during SPURT: implications for transport and chemistry in the lowermost stratosphere , 2005 .

[11]  M. Lawrence,et al.  The impact of ice uptake of nitric acid on atmospheric chemistry , 2005 .

[12]  B. Kärcher.  Supersaturation, dehydration, and denitrification in Arctic cirrus , 2005 .

[13]  T. Peter,et al.  Microphysics and heterogeneous chemistry in aircraft plumes - high sensitivity on local meteorology and atmospheric composition , 2004 .

[14]  A. Weinheimer,et al.  Uptake of reactive nitrogen on cirrus cloud particles during INCA , 2004 .

[15]  T. L. Thompson,et al.  Evidence That Nitric Acid Increases Relative Humidity in Low-Temperature Cirrus Clouds , 2004, Science.

[16]  D. S. Sayres,et al.  Nitric Acid Uptake on Subtropical Cirrus Cloud Particles , 2003 .

[17]  N. Takegawa,et al.  Uptake of reactive nitrogen on cirrus cloud particles in the upper troposphere and lowermost stratosphere , 2003 .

[18]  J. Hendricks,et al.  Model studies on the sensitivity of upper tropospheric chemistry to heterogeneous uptake of HNO3 on cirrus ice particles , 2002 .

[19]  T. Berntsen,et al.  Impacts of NOx emissions from subsonic aircraft in a global three‐dimensional chemistry transport model including plume processes , 2002 .

[20]  M. Ammann,et al.  The adsorption of nitrogen oxides on crystalline ice , 2002 .

[21]  T. L. Thompson,et al.  In situ measurements of HNO3, NOy, NO, and O3 in the lower stratosphere and upper troposphere , 2001 .

[22]  H. Schlager,et al.  In Situ Observations of Particulate NOy in Cirrus Clouds for Different Atmospheric Conditions , 2001 .

[23]  M. Mishchenko,et al.  APPLICATION OF THE T-MATRIX METHOD TO THE MEASUREMENT OF ASPHERICAL (ELLIPSOIDAL) PARTICLES WITH FORWARD SCATTERING OPTICAL PARTICLE COUNTERS , 2000 .

[24]  H. Schlager,et al.  Distributions of NO, NO x , and NO y in the upper troposphere and lower stratosphere between 28° and 61°N during POLINAT 2 , 2000 .

[25]  B. Strauss,et al.  On the Transition of Contrails into Cirrus Clouds , 2000 .

[26]  Nicola J. Blake,et al.  Reactive nitrogen budget during the NASA SONEX Mission , 1999 .

[27]  W. R. Cofer,et al.  An assessment of aircraft as a source of particles to the upper troposphere , 1999 .

[28]  D. McKenna,et al.  Fast in situ stratospheric hygrometers: A new family of balloon‐borne and airborne Lyman α photofragment fluorescence hygrometers , 1999 .

[29]  Thomas Gerz,et al.  Transport and effective diffusion of aircraft emissions , 1998 .

[30]  U. Schumann,et al.  DILUTION OF AIRCRAFT EXHAUST PLUMES AT CRUISE ALTITUDES , 1998 .

[31]  H. Schlager,et al.  Observations and model calculations of jet aircraft exhaust products at cruise altitude and inferred initial OH emissions , 1998 .

[32]  A. Weinheimer,et al.  Uptake of NOy on wave‐cloud ice particles , 1998 .

[33]  B. Kärcher.  Aircraft‐generated aerosols and visible contrails , 1996 .

[34]  P. Fabian,et al.  Small-scale chemical evolution of aircraft exhaust species at cruising altitudes , 1996 .

[35]  M. E. Reinhardt,et al.  Measurements of jet aircraft emissions at cruise altitude I: The odd‐nitrogen gases NO, NO2, HNO2 and HNO3 , 1992 .

[36]  David W. Fahey,et al.  Evaluation of a catalytic reduction technique for the measurement of total reactive odd-nitrogen NOy in the atmosphere , 1985 .

[37]  L. M. Levin,et al.  Techniques for collection of representative aerosol samples , 1974 .