Uptake of reactive nitrogen on cirrus cloud particles in the upper troposphere and lowermost stratosphere

2003 ◽  
Vol 30 (4) ◽  
Author(s):  
Y. Kondo ◽  
O. B. Toon ◽  
H. Irie ◽  
B. Gamblin ◽  
M. Koike ◽  
...  
Keyword(s):  
Reactive Nitrogen ◽  
Cirrus Cloud ◽  
Upper Troposphere ◽  
Cloud Particles

scholarly journals Uptake of reactive nitrogen on cirrus cloud particles during INCA

2004 ◽  
Vol 31 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Ziereis ◽  
A. Minikin ◽  
H. Schlager ◽  
J. F. Gayet ◽  
F. Auriol ◽  
...  
Keyword(s):  
Reactive Nitrogen ◽  
Cirrus Cloud ◽  
Cloud Particles

scholarly journals Balloon-borne match measurements of midlatitude cirrus clouds

2014 ◽  
Vol 14 (14) ◽  
pp. 7341-7365 ◽  
Author(s):  
A. Cirisan ◽  
B. P. Luo ◽  
I. Engel ◽  
F. G. Wienhold ◽  
M. Sprenger ◽  
...  
Keyword(s):  
Temperature Fluctuations ◽  
Cloud Microphysics ◽  
Cirrus Clouds ◽  
Climate Feedback ◽  
Small Scale ◽  
Model Parameters ◽  
Cirrus Cloud ◽  
Air Mass ◽  
Upper Troposphere ◽  
Weather Model

Abstract. Observations of high supersaturations with respect to ice inside cirrus clouds with high ice water content (> 0.01 g kg−1) and high crystal number densities (> 1 cm−3) are challenging our understanding of cloud microphysics and of climate feedback processes in the upper troposphere. However, single measurements of a cloudy air mass provide only a snapshot from which the persistence of ice supersaturation cannot be judged. We introduce here the "cirrus match technique" to obtain information about the evolution of clouds and their saturation ratio. The aim of these coordinated balloon soundings is to analyze the same air mass twice. To this end the standard radiosonde equipment is complemented by a frost point hygrometer, "SnowWhite", and a particle backscatter detector, "COBALD" (Compact Optical Backscatter AerosoL Detector). Extensive trajectory calculations based on regional weather model COSMO (Consortium for Small-Scale Modeling) forecasts are performed for flight planning, and COSMO analyses are used as a basis for comprehensive microphysical box modeling (with grid scale of 2 and 7 km, respectively). Here we present the results of matching a cirrus cloud to within 2–15 km, realized on 8 June 2010 over Payerne, Switzerland, and a location 120 km downstream close to Zurich. A thick cirrus cloud was detected over both measurement sites. We show that in order to quantitatively reproduce the measured particle backscatter ratios, the small-scale temperature fluctuations not resolved by COSMO must be superimposed on the trajectories. The stochastic nature of the fluctuations is captured by ensemble calculations. Possibilities for further improvements in the agreement with the measured backscatter data are investigated by assuming a very slow mass accommodation of water on ice, the presence of heterogeneous ice nuclei, or a wide span of (spheroidal) particle shapes. However, the resulting improvements from these microphysical refinements are moderate and comparable in magnitude with changes caused by assuming different regimes of temperature fluctuations for clear-sky or cloudy-sky conditions, highlighting the importance of proper treatment of subscale fluctuations. The model yields good agreement with the measured backscatter over both sites and reproduces the measured saturation ratios with respect to ice over Payerne. Conversely, the 30% in-cloud supersaturation measured in a massive 4 km thick cloud layer over Zurich cannot be reproduced, irrespective of the choice of meteorological or microphysical model parameters. The measured supersaturation can only be explained by either resorting to an unknown physical process, which prevents the ice particles from consuming the excess humidity, or – much more likely – by a measurement error, such as a contamination of the sensor housing of the SnowWhite hygrometer by a precipitation drop from a mixed-phase cloud just below the cirrus layer or from some very slight rain in the boundary layer. This uncertainty calls for in-flight checks or calibrations of hygrometers under the special humidity conditions in the upper troposphere.

scholarly journals Cloud discrimination in probability density functions of limb scattered sunlight measurements

2013 ◽  
Vol 6 (4) ◽  
pp. 6491-6516
Author(s):  
E. N. Normand ◽  
A. E. Bourassa ◽  
D. A. Degenstein
Keyword(s):  
Probability Density ◽  
Lower Stratosphere ◽  
Infrared Imaging ◽  
Imaging System ◽  
Probability Density Functions ◽  
Density Functions ◽  
Cirrus Cloud ◽  
Upper Troposphere ◽  
Solar Occultation ◽  
Continuum Measurement

Abstract. A technique characterizing the distribution of cirrus cloud top occurrences from the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb scattering radiance profiles is presented. The technique involves computing scattering residual profiles by comparing normalized measured radiance and modelled molecular radiance profiles where enhancements in the measured radiance indicate the presence of clouds. Probability density functions of scattering residuals show the distribution is not a continuum measurement; there is a distinction between the cloudy and cloud-free conditions. Observations show high cloud top occurrences in the upper troposphere and lower stratosphere region above Indonesia and Central America. Results obtained using this technique with OSIRIS measurements are compared to those obtained by Sassen et al. (2008) with CALIPSO nadir measurements and to those obtained by Wang et al. (1996) with SAGE II solar occultation measurements.

scholarly journals Selected topics on interactions between cirrus clouds and embedded contrails

2012 ◽  
Vol 12 (9) ◽  
pp. 25237-25254
Author(s):  
K. Gierens
Keyword(s):  
Water Vapour ◽  
Cirrus Clouds ◽  
Ice Crystals ◽  
Tip Vortex ◽  
Cirrus Cloud ◽  
Upper Troposphere ◽  
Wing Tip Vortex ◽  
Wing Tip ◽  
Emission Index

Abstract. Persistent contrails and natural cirrus clouds often coexist in the upper troposphere and contrails can be embedded within cirrus clouds. The present paper deals with some questions regarding the interaction of cirrus clouds and embedded contrails. I have selected only questions that can be answered by analytical means. I find that (1) the emission index for water vapour is only slightly changed when an aircraft crosses a cirrus cloud, (2) that contrail formation is not affected by an ambient cirrus, (3) that cirrus ice crystals entrained into the trailing wing tip vortex do not efficiently retard the sublimation of contrail ice crystals, and (4) that cirrus can start to dissolve an embedded contrail after a couple of hours by aggregation.

scholarly journals A decadal cirrus clouds climatology from ground-based and spaceborne lidars above the south of France (43.9° N–5.7° E)

2013 ◽  
Vol 13 (14) ◽  
pp. 6951-6963 ◽  
Author(s):  
C. Hoareau ◽  
P. Keckhut ◽  
V. Noel ◽  
H. Chepfer ◽  
J.-L. Baray
Keyword(s):  
Observation Time ◽  
Cirrus Clouds ◽  
Cirrus Cloud ◽  
Upper Troposphere ◽  
Cloud Parameters ◽  
Cloud Properties ◽  
Total Observation Time ◽  
The Mean ◽  
Ground Based Lidar ◽  
Total Observation

Abstract. This study provides an analysis of cirrus cloud properties at midlatitude in the southern part of France from ground-based and spaceborne lidars. A climatology of cirrus cloud properties and their evolution over more than 12 yr is presented and compared to other mid-latitude climatological studies. Cirrus clouds occur ~37% of the total observation time and remain quasi-constant across seasons with a variation within ~5% around the mean occurrence. Similar results are obtained from CALIOP and the ground-based lidar, with a mean difference in occurrence of ~5% between both instruments. From the ground-based lidar data, a slight decrease in occurrence of ~3% per decade is observed but found statistically insignificant. Based on a clustering analysis of cirrus cloud parameters, three distinct classes have been identified and investigations concerning their origin are discussed. Properties of these different classes are analysed, showing that thin cirrus in the upper troposphere represent ~50% of cloud cover detected in summer and fall, decreasing by 15–20% for other seasons.

Reactive nitrogen in the global upper troposphere from NASA DC8 and MOZAIC aircraft campaigns

2021 ◽  
Author(s):  
Nana wei ◽  
eloise a. marais ◽  
paul o. wennberg ◽  
hannah m. allen ◽  
john d. crounse ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Air Quality ◽  
Global Climate ◽  
Reactive Nitrogen ◽  
Commercial Aircraft ◽  
Upper Troposphere ◽  
Initial Analysis ◽  
Aircraft Observations ◽  
Pernitric Acid

<p>Reactive nitrogen in the upper troposphere (~8-12 km) impacts global climate, air quality and the oxidizing capacity of the whole troposphere. Here we use aircraft observations from instruments onboard the NASA DC8 aircraft for campaigns from 1997 (SONEX) to the recent ATom campaign (2016-2018) and the MOZAIC commercial aircraft campaign (2003-2005) to address uncertainties in the dynamics of reactive nitrogen (NO<sub>y</sub> = NO<sub>x</sub> + NO<sub>x</sub> reservoir compounds) in the global upper troposphere (UT). Our initial analysis of the DC8 aircraft observations is consistent with previous work in that PAN is the dominant NO<sub>y</sub> component (average: 43%; range: 40-60%), followed by NO<sub>x </sub>(on average, 21%), with smaller contributions (on average, 3.5-12.5%) from pernitric acid (HNO<sub>4</sub>), organonitrate (RONO<sub>2</sub>) and nitric acid (HNO<sub>3</sub>). We go on to compare multiyear mean NO<sub>y</sub> from MOZAIC to the combination of all NASA DC8 campaigns to determine whether we can build a near-global climatology of NO<sub>y</sub> and its components to compare to GEOS-Chem to assess our understanding of these very important atmospheric components.</p>

scholarly journals A Raman lidar at La Reunion (20.8° S, 55.5° E) for monitoring water vapor and cirrus distributions in the subtropical upper troposphere: preliminary analyses and description of a future system

2011 ◽  
Vol 4 (5) ◽  
pp. 6449-6496
Author(s):  
C. Hoareau ◽  
P. Keckhut ◽  
J.-L. Baray ◽  
L. Robert ◽  
Y. Courcoux ◽  
...  
Keyword(s):  
Water Vapor ◽  
Cirrus Cloud ◽  
La Réunion ◽  
Raman Lidar ◽  
Data Set ◽  
Upper Troposphere ◽  
Future System ◽  
Rayleigh Lidar ◽  
Term Monitoring

Abstract. A ground based Rayleigh lidar has provided continuous observations of tropospheric water vapor profiles and cirrus cloud using a preliminary Raman channels setup on an existing Rayleigh lidar above La Reunion over the period 2002–2005. With this instrument, we performed a first measurement campaign of 350 independent water vapor profiles. A statistical study of the distribution of water vapor profiles is presented and some investigations concerning the calibration are discussed. The data set having several long acquisition measurements during nighttime, an analysis of the diurnal cycle of water vapor has also been investigated. Analysis regarding the cirrus clouds is presented and a classification has been performed showing 3 distinct classes. Based on these results, the characteristics and the design of a future lidar system to be implemented at the new Reunion Island altitude observatory (2200 m) for long-term monitoring is presented and numerical simulations of system performance have been realized to compare both instruments.

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