Upper tropospheric slightly ice-subsaturated regions: Frequency of occurrence and statistical evidence for the appearance of contrail cirrus

Li, Yun; Mahnke, Christoph; Rohs, Susanne; Bundke, Ulrich; Spelten, N.; Dekoutsidis, Georgios; Groß, Silke; Voigt, Christiane; Schumann, U.; Petzold, A.; Krämer, M.

doi:10.5194/acp-2022-632

Cited by 1 publication

(6 citation statements)

References 39 publications

(77 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4.1 already suggested that ML cirrus are more affected by contrail cirrus. As Li et al (2022), we observe that in situ origin cirrus are more strongly influenced by contrails than liquid origin clouds. Liquid origin clouds are formed at lower altitudes where liquid droplets and ice crystals can coexist.…”

Section: Relating Ice Cloud Microphysical Properties To the Location ...mentioning

confidence: 54%

“…Gayet et al (2004) high number concentrations and lower EDs for several hours after their formation (Voigt et al, 2017;. In general, it is difficult to distinguish aged contrails from thin natural cirrus unaffected by aviation (Li et al, 2022) or embedded contrails in natural cirrus (Unterstrasser et al, 2017a, b), in particular, as the influence of air traffic over Europe is omnipresent (Voigt et al, 2017;.…”

Section: Overview and Differences In Microphysical Properties Of Cirr...mentioning

confidence: 99%

“…The evolution of the liquid origin cirrus has sufficient time to consume the available water vapor when the cloud reaches the cirrus regime. Li et al (2022) found that the Schmidt-Appleman criterion for contrail formation (SAC) is mostly not fulfilled in liquid origin clouds due to the warmer temperatures at which they are located. Therefore, it is more difficult to find the appropriate conditions for a contrail to develop within a liquid origin cloud.…”

Section: Relating Ice Cloud Microphysical Properties To the Location ...mentioning

confidence: 99%

“…Microphysical properties of contrails have been measured in many studies (e.g. Baumgardner et al (1998); Voigt et al (2010Voigt et al ( , 2011; Chauvigné et al (2018); Li et al (2022). Young contrails initially have ice crystal concentrations larger than 100 cm −3 and ice crystal sizes of a few micrometers (Petzold et al, 1997;Gayet et al, 2012;Jeßberger et al, 2013;Kleine et al, 2018).…”

mentioning

confidence: 99%

“…A reduction of ED was observed from measurements near flight corridors by Kristensson et al (2000). Recent studies also showed a reduction in the effective radius of contrails embedded in natural cirrus (Wang et al, 2022;Li et al, 2022). However, depending on atmospheric conditions, when contrails are embedded in natural cirrus, the evolution of the contrail is perturbed by the cirrus and ice crystals from contrail and cirrus coexist, making it difficult to distinguish between them (Unterstrasser et al, 2017a, b).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Differences in microphysical properties of cirrus at high and mid-latitudes

Castro

Jurkat‐Witschas

Afchine³

et al. 2023

Preprint

View full text Add to dashboard Cite

Abstract. Despite their proven significance for the atmospheric radiative energy budget, the effect of cirrus on climate and the magnitude of their modification by human activity is not well quantified. Besides anthropogenic pollution sources on the ground, aviation has a large local effect on cirrus microphysical and radiative properties via the formation of contrails and their transition to contrail cirrus. To investigate the anthropogenic influence on natural cirrus, we compare the microphysical properties of cirrus measured at mid-latitude regions (ML, < 60° N) that are often affected by aviation and pollution with cirrus measured in the same season in comparatively pristine high latitudes (HL, ≥ 60° N). The number concentration, effective diameter, and ice water content of the observed cirrus are derived from in situ measurements covering ice crystal sizes between between 2 and 6400 µm collected during the CIRRUS-HL campaign (CIRRUS in High Latitudes) in June and July 2021. We analyse the dependence of cirrus microphysical properties on altitude and latitude and demonstrate that the median ice number concentration is by an order of magnitude larger in the measured mid-latitude cirrus with 0.0086 cm-3 compared to 0.001 cm-3 in high-latitude cirrus. Ice crystals in mid-latitude cirrus are on average smaller than in high-latitude cirrus, with a median effective diameter of 165 µm compared to 210 µm and the median ice water content in mid-latitude cirrus is higher (0.0033 g m-3) than in high-latitude cirrus (0.0019 g m-3). In order to investigate the cirrus properties in relation to the region of formation, we combine the airborne observations with 10-day backward trajectories to identify the location of cirrus formation and the cirrus type: in situ or liquid origin cirrus, depending on whether there is only ice or also liquid water present in the cirrus history, respectively. The cirrus formed and measured at mid-latitudes (M-M) have particularly high ice number concentration and low effective diameter. This is very likely a signature of contrails and contrail cirrus, which is often observed in the in situ origin cirrus type. In contrast, the largest effective diameter and lowest number concentration were found in the cirrus formed and measured at high latitudes (H-H) along with the highest relative humidity over ice (RHi). On average, in-cloud RHi was above saturation in all cirrus. While most of the H-H cirrus were of in situ origin, the cirrus formed at mid-latitudes and measured at high latitudes (M-H) were mainly of liquid origin. A pristine Arctic background atmosphere with scarce availability of ice nuclei and the extended growth of few nucleated ice crystals may explain the observed RHi and size distributions. The M-H cirrus are a mixture of the properties of M-M and H-H cirrus (preserving some of the initial properties acquired at mid-latitudes and transforming under Arctic atmospheric conditions). Our analyses indicate that part of the cirrus found at high latitudes are actually formed at mid-latitudes, and therefore affected by mid-latitude air masses, which have a greater anthropogenic influence.

show abstract

Section: Relating Ice Cloud Microphysical Properties To the Location ...mentioning

confidence: 54%