High ice water content (HIWC) regions with small ice crystals, where ice water contents (IWCs) are greater than 1.5 g m^-3 and median mass diameters (MMDs) less than about 300 micrometers, occur above tropical mesoscale convective systems (MCSs) and can have detrimental impacts on aircraft engines. Data collected by the French Falcon aircraft and the National Research Council of Canada Convair-580 during the 2014 and 2015 High Altitude Ice Crystals and High Ice Water Content (HAIC/HIWC) projects are revisited here along with coordinated modeling studies to investigate processes that can produce such HIWCs. In particular, data collected from 2014 in the vicinity of Darwin Australia and from 2015 in the vicinity of Cayenne French Guyana are used to determine how bulk microphysical properties (e.g., number concentration, IWC, median volume diameter) and characteristics of ice crystal size distributions (i.e., multimodal nature, parameters fit to gamma distributions for each mode) vary with environmental conditions such as temperature, vertical velocity, MCS age, distance from MCS core, and surface characteristics. It is determined that temperature and vertical velocity are the biggest controls of small ice crystals, but younger cells, stronger convective strengths and closer proximity to convective cores also increase the relative importance of small crystals.

Numerical simulations conducted using the Weather Research and Forecasting model with four different bulk microphysics schemes generally reproduce the observed temperature, dew-point, and wind structure. However, comparison of regime-specific observations against properties simulated over Cayenne using a variety of existing parameterization schemes show that although the coverage and evolution of convection is well predicted, simulations overestimate the intensity and spatial extent of observed airborne X-band radar reflectivity and do not well depict the peak of observed size distributions with maximum dimensions between 0.1 and 1 mm. To explore formation mechanisms for large numbers of small ice crystals, a series of simulations varying the representation of secondary ice production (SIP) processes were conducted. Simulations including one of three SIP mechanisms separately (i.e., the Hallett–Mossop mechanism, fragmentation during ice–ice collisions, and shattering of freezing droplets) did not replicate the observed ratio of number concentration divided by IWC. However, the simulation including all three SIP processes produced HIWC regions consistent with observations in terms of number concentration and radar reflectivity, which was not replicated using the original P3 two-ice category configuration that only included the Hallett-Mossop mechanism. In summary, observations and simulations show primary ice production plays a key role in generating HIWC regions at temperatures < -40 Celsius, shattering of freezing droplets dominates ice particle production in HIWC regions between -15 and 0 Celsius during the early stage of convection, and fragmentation during ice–ice collisions dominates between -15 and 0 Celsius during the later stage of convection and between -40 and -20 Celsius over the whole convection period. This study thus shows the dominant role of SIP processes in the formation of numerous small crystals in HIWC regions. Implications for future measurement and modeling needs are discussed.

How to cite: McFarquhar, G., Huang, Y., Hu, Y., Brechner, P., Korolev, A., Morrison, H., Milbrandt, J., Wolde, M., Nguyen, C., and Protat, A.: Observational and Modeling Studies of High Ice Water Content Clouds: Implications for Process–Oriented Understanding, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-22, https://doi.org/10.5194/egusphere-egu23-22, 2023.

The HIAPER Cloud Radar (HCR) is a 94 GHz W-band radar deployed in an underwing pod on the NCAR HIAPER aircraft. We use dual polarized Doppler observations collected in three major field campaigns:

• The Cloud Systems Evolution in the Trades (CSET) study focused on the characterization of the cloud fields in the stratocumulus and the fair-weather cumulus regimes within the subtropical easterlies over the northern Pacific.
• Motivated by challenges in their modeling, Southern Ocean clouds were observed south of Tasmania during the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES).
• Deep convective clouds in a tropical environment were the focus in the Organization of Tropical East Pacific Convection (OTREC) field campaign.

In this study we classify clouds sampled by HCR in these very different environments into twelve categories, based on the clouds’ convective and stratiform characteristics. We calculate dimensional and convective properties of the clouds in the different categories and contrast and compare derived statistics. We analyze updraft regions observed in all cloud categories, their dimensions and velocities. Characteristics of precipitation shafts from the precipitating clouds, such as precipitation fraction or strength are also provided.

How to cite: Romatschke, U.: Cloud properties from airborne radar observations collected in field campaigns, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2868, https://doi.org/10.5194/egusphere-egu23-2868, 2023.

Tropical Tropopause Layer clouds have a significant impact on the Earth's radiative budget and regulate the amount of water vapor entering the stratosphere. They are a key component of the climate system but their observation is still challenging. The Strateole-2 project aims at a  better understanding of dynamical, transport, and processes in the Tropical Tropopause Layer (TTL) using long-duration super-pressure balloons flying for several months in the lower stratosphere along the equator belt. From October 2021 to late January 2022, three microlidars flew onboard stratospheric balloons, slowly drifting just a few kilometers above the clouds. These observations have unprecedented sensitivity to thin cirrus and provide a fine scale description of cloudy structures both in time and space. Statistical comparisons with spaceborne lidar CALIOP are discussed, highlighting the unique ability of the microlidar to detect optically thin clouds. The modulation of outgoing longwave radiation by tropical clouds is also investigated using the balloon-borne observations. 

How to cite: Lesigne, T., Ravetta, F., Podglajen, A., Tran, D., Bureau, J., Mariage, V., Pelon, J., and Hauchecorne, A.: Characterization of Tropical Tropopause Layer clouds combining balloon-borne and space-borne observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7035, https://doi.org/10.5194/egusphere-egu23-7035, 2023.

Cirrus in mid latitudes (<= 60° N) are often affected by aviation and pollution while cirrus in high latitudes (> 60° N) develop in a more pristine atmosphere. In this study, we compare the microphysical properties of cirrus measured in mid latitudes and cirrus measured in high latitudes. The analyzed properties are: the ice crystal number concentration (N), effective diameter (ED) and ice water content (IWC) of cirrus from in situ measurements during the CIRRUS-HL campaign in June and July 2021. We use a combination of cloud probes covering ice crystals sizes between 2 and 6400 µm. The differences in cirrus properties are investigated with dependence on altitude and latitude and we show that there exist differences between mid-latitude and high-latitude cirrus. An increase in ED and a reduction in N is observed in high-latitude cirrus compared to mid-latitude cirrus.

In order to investigate the cirrus properties in relation to the region of formation, we also combine our measurements with 10-day backward trajectories to identify the location of cirrus formation and the cirrus type: in situ or liquid origin cirrus. According to the latitude of cloud formation and latitude of the measurement, we classify the cirrus in three groups: cirrus formed and measured at mid latitudes (M-M), cirrus formed at mid latitudes and measured at high latitudes (M-H) and cirrus formed and measured at high latitudes (H-H). This analysis shows that part of the cirrus measured at high latitudes are actually formed at mid latitudes and therefore influenced by mid-latitude air masses. We discuss the differences of the cirrus properties under this new classification. Our study helps to advance the understanding of upper-tropospheric cirrus properties at mid and high latitudes in summer and the influence of anthropogenic perturbations.

How to cite: De La Torre Castro, E., Jurkat-Witschas, T., Afchine, A., Hahn, V., Kirschler, S., Krämer, M., Lucke, J., Spelten, N., Wernli, H., Zöger, M., and Voigt, C.: Differences in microphysical properties of cirrus at high and mid latitudes from airborne measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15602, https://doi.org/10.5194/egusphere-egu23-15602, 2023.

Mixed-phase clouds are essential elements in Earth’s weather and climate system. Atmospheric observation of mixed-phase clouds occasionally demonstrated a strong discrepancy between the ice particle and ice nucleating particle number concentration of several orders of magnitude at modest supercooling [1, 4, 6]. Various secondary ice production (SIP) mechanisms have been hypothesized which can increase the ice particle number concentration by multiplication of primary ice particles [2, 3].

In this study, we focus on SIP as a result of droplet-ice collisions, commonly known as rime-splintering or Hallett-Mossop (HM) process. During riming supercooled droplets collide with an ice particle and freeze upon impact and lead to the formation of secondary ice particles. Our main objectives are to quantify the number of secondary ice particles and to learn more about the underlying physics. Therefore, we conducted laboratory experiments at IDEFIX (Ice Droplets splintEring on FreezIng eXperiment) in which small droplets collide with a fixed ice particle of 1 mm in diameter. IDEFIX is designed to simulate atmospheric relevant conditions regarding temperature, humidity, impact velocities and collision rates. The riming process was observed with high-speed video microscopy and infrared thermography to visualize the growing rimer structures and the surface temperature of the riming ice particle, respectively. Further, the secondary ice particles were counted via inertial impaction on a supercooled sugar solution in the ice counting device (cut off diameter of 2 µm) developed at IMK-AAF, KIT.

The following parameters were investigated: the air temperature was varied between -4°C and -10°C, the ice-droplet impact velocities were set either to 1 ms^-1 or 3 ms^-1, and the lognormal droplet size distribution was adjusted to have the mode diameter between 18 µm and 30 µm with the standard deviation between 1.6 µm and 8.4 µm. Under these conditions, the collisions rates between droplets and rimer were between 10² and 10³ mm^-1s^-1 , as determined from the video records and with a rimer heat balance model [5] using measured surface temperature as input data. Thus, the simulated riming process is typical for convective clouds; both dry and wet growth could be realized in IDEFIX. We found no efficient and reproducible secondary ice production during riming within the range of the investigated parameters. The amount of secondary ice particles produced in all our experiments was well below the values expected from the HM mechanism [3, 7], where several hundreds of secondary ice particles per mg rime were found at optimal conditions. Six potential SIP cases (out of 31) could be identified where ice was detected in the ice counting device. Four of them could be attributed to rime spicules break-off due to sublimation.

[1] Crosier, J., et al. 2011, DOI: 10.5194/acp-11-257-2011.

[2] Field, P.R., et al. 2016, DOI: 10.1175/amsmonographs-d-16-0014.1.

[3] Korolev, A. and T. Leisner 2020, DOI: 10.5194/acp-20-11767-2020.

[4] Luke, E.P., et al. 2021, DOI: 10.1073/pnas.2021387118.

[5] Pruppacher, H.R. and J.D. Klett, Microphysics of Clouds and Precipitation. 2010, Springer Dordrecht.

[6] Taylor, J.W., et al. 2016, DOI: 10.5194/acp-16-799-2016.

How to cite: Hartmann, S., Seidel, J., Keinert, A., Kiselev, A., Leisner, T., and Stratmann, F.: Secondary ice production - No evidence of a productive rime-splintering mechanisms during dry and wet growth, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11199, https://doi.org/10.5194/egusphere-egu23-11199, 2023.

In recent years our understanding of cirrus cloud processes has been significantly advanced. However, a large uncertainty regarding the influence of cirrus formation mechanisms on the microphysical properties, and hence radiative properties of cirrus clouds still remains. This leads to uncertainty in global climate models and climate change projections. In this work we aim to identify different cirrus formation regimes and analyze their influence on cirrus microphysical properties. We combine DARDAR-Nice satellite observations with Lagrangian back trajectories of meteorological and aerosol reanalysis data on the Northern Hemisphere. Our goal is to classify observed cirrus clouds by means of their trajectories and investigate the trajectories' influence on observed cirrus microphysical properties. With our data-driven nested clustering approach we identify different meteorological regimes that lead to cirrus formation. We are also able to isolate the effect of dust ice nucleating particle (INP) exposure along the trajectory from meteorological variability.

We identify four different meteorological clusters that lead to characteristic cirrus cloud microphysical properties and can be associated with liquid origin and in-situ formed cirrus clouds. Furthermore, we find that dust concentrations in cirrus cloud back trajectories are significantly higher compared to cloud free trajectories with comparable meteorological conditions. This indicates the importance of dust acting as INP during heterogeneous nucleation. The magnitude of the dust concentration, however, has only a negligible effect on cirrus microphysical properties.

How to cite: Jeggle, K., Neubauer, D., and Lohmann, U.: Identification of cirrus formation regimes using cluster analysis of back trajectories and satellite data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5002, https://doi.org/10.5194/egusphere-egu23-5002, 2023.

Ice cloud and floating snow play critical roles in Earth’s energy budget and hydrological cycle. Their diurnal variation is tightly coupled with convection development life cycle, hence it also greatly impacts the diurnal cycle of surface precipitation and top of the atmosphere radiation. Due to the high degree of freedom of ice crystal microphysical properties, remote sensing of ice/snow cloud is challenging for passive spaceborne sensors.

In this work, we present a global diurnal ice/snow cloud product by merging three spaceborne passive microwave sensor observations together (GPM-GMI, NPP-ATMS, and MT-SAPHIR). This dataset includes ice water path (cloud ice + falling snow), cloud top height (CTH) and cloud bottom height (CBH) at pixel level between 2015 – 2016, and monthly gridded values at 2deg X 2deg X 2 hours grid scale. The convolutional neural network (CNN) approach is adopted for the algorithm development by learning from collocated CloudSat observations, and the Monte Carlo dropout method is used for uncertainty estimation. A customized loss-function is developed to retrieve cloud mask and mass together.

We evaluated the retrieval at collocated pixels as well as against other independent field campaign and ground-based measurements. Diurnal and semi-diurnal distributions of the IWP will be presented. We will also demonstrate how we use this product to evaluate model performance on capturing the general distribution and diurnal variation of the frozen hydrometeors in the atmosphere.

How to cite: Gong, J., Wang, C., Wu, D., Wang, Y., Ding, L., and Barahona, D.: A Global Merged Diurnal Ice/Snow Cloud Product from Spaceborne Passive Microwave Observations and Its Applications to Model Evaluation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8660, https://doi.org/10.5194/egusphere-egu23-8660, 2023.

The cloud thermodynamic phase (ice / mixed-phase / liquid) is a crucial parameter to understand the earth radiation budget, hydrological cycle and atmospheric thermodynamic processes. The phase partitioning of clouds and their parameterization in global climate models have therefore become of particular interest.

To improve our understanding of the frequency of occurrence and temporal evolution of cloud phase, geostationary passive sensors can be very useful due to their wide field of regard and high temporal resolution. However, the retrieval of cloud phase using passive instruments is challenging since the spectral signature of the phase is weak compared to other parameters of the clouds and atmosphere. Especially the distinction between ice and mixed-phase clouds is difficult and previous efforts to retrieve cloud phase often only distinguished between ice and liquid phase.

We present a new method to detect clouds and retrieve their phase using the passive instrument SEVIRI aboard the geostationary satellite Meteosat Second Generation. The method uses probabilities derived from active observations (the Lidar-Radar product DARDAR) of cloud top phase. Combining these probabilities for different SEVIRI channels gives probabilities for the presence of a cloud and for its cloud top phase. Our probabilistic approach includes a measure of uncertainty and allows us to distinguish between ice, mixed-phase, supercooled liquid, and warm liquid clouds. The method is tested against active satellite measurements and shows good agreement. Finally, we discuss its advantages and limitations. In the future, we plan to use our method to study the microphysical (such as optical thickness and effective radii) and macrophysical (such as temporal evolution and extent) properties of ice and mixed-phase clouds.

How to cite: Mayer, J., Bugliaro, L., Ewald, F., and Voigt, C.: A probabilistic approach to determine the thermodynamic cloud phase using passive satellites, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13062, https://doi.org/10.5194/egusphere-egu23-13062, 2023.

The large cirrus outflows that arise from deep convection play a vital role in modulating the energy balance of the Earth’s atmosphere. One important question is how much do the initial conditions of the deep convection influence the subsequent evolution of the detrained cirrus, and if these initial conditions are important, over what timescales do they matter? Characterising how these cirrus outflows evolve over their entire lifetime, and how they might change in response to anthropogenic emissions is important in order to understand their role in the climate system and to constrain past and future climate change.

Building on the ‘Time Since Convection’ product used in Horner & Gryspeerdt (2023), this work investigates how the initial conditions of the deep convection influence the subsequent evolution of the detrained cirrus- in particular, how does the timing, location, and meteorological environment of the deep convection alter the detrained cirrus, and for how long are these initial conditions important for the cirrus properties- is there a ‘memory’ of the initial conditions of the deep convection imprinted on the properties of the cirrus hours or days after the initial deep convection has dissipated? To answer this question, data from the DARDAR, ISCCP, and CERES products are used to build a composite picture of the radiative and microphysical properties of the clouds, which is investigated under varying initial conditions.

The initial state of the convection is found to have a considerable impact on cirrus development under a variety of conditions. The diurnal cycle, particularly the timing of the convection, is a strong control on the cloud radiative effect, particularly in regions of strong convective activity. The initial aerosol perturbation is also shown to play a role in cirrus development, both in the large scale properties of the cirrus and the microphysical properties.

This demonstrates a potential time dependent impact of aerosol and convection on cloud properties and provides a template for future studies of cloud development incorporating diverse sets of measurements.

How to cite: Horner, G. and Gryspeerdt, E.: Do detrained cirrus clouds have memory of the deep convection they came from?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15307, https://doi.org/10.5194/egusphere-egu23-15307, 2023.

Ice multiplication processes have been recognized to play an important role in the forming of cloud ice crystals, and multiple mechanisms have been proposed to describe ice multiplication. Ice multiplication processes have been investigated for a variety of cloud types, but mostly for stratiform clouds or shallow cumulus, which do not reach temperatures of homogeneous freezing. In this study, sensitivity experiments are performed to study the role of ice multiplication in the developing stages of deep convective clouds. A double-moment cloud physics scheme was adopted. Except as the default Hallett-Mossop rime splintering process, two additional ice multiplication processes, which are droplet shattering during the freezing of supercooled drops and the collisional breakup of ice particles, are implemented. Moreover, two different parameterization schemes for the collisional breakup of ice particles. Simulation results reveal that the ice multiplication processes have a significant impact on the cloud microphysical properties and thermodynamic phase distribution within the cloud. At the cloud top, the fingerprint of ice multiplication is weaker. Collisional breakup is found to dominate ice multiplication, and the collisional breakup process rate is larger than rime splintering and droplet shattering process rates by 4 and 3 orders of magnitude, respectively. The ice enhancement factor (the ratio of ice mass or number in simulations with and without ice multiplication) has a strong vertical variation, with the maximum around -10°C and -25°C. Besides, the cascade effect on ice cloud number concentration was also investigated.

How to cite: Han, C., Hoose, C., and Dürlich, V.: Ice multiplication in simulated deep convective clouds with the ICON model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5327, https://doi.org/10.5194/egusphere-egu23-5327, 2023.

Warm conveyor belts (WCB) lead to formation of horizontally wide spread Cirrus clouds in the upper troposphere. However, the contribution of different ice formation processes and the resulting micro- and macrophysical properties of the Cirrus ,e.g., their radiative effects are still poorly understood. We want to especially address the research question of in-situ vs. liquid origin ice formation.

Common microphysics bulk schemes only consider a single ice class which includes sources from multiple formation mechanisms. We developed and implemented a two-moment microphysics scheme in the atmosphere model ICON that distinguishes between different ice modes of origin including homogeneous nucleation, deposition freezing, immersion freezing, homogeneous freezing of water droplets and secondary ice production from rime splintering, frozen droplet shattering and collisional break-up, respectively. Each ice mode is described by its own size distribution, prognostic moments and unique formation mechanism while still interacting with all other ice modes and microphysical classes like cloud droplets, rain and rimed cloud particles.

Using this novel microphysics scheme we can determine the contribution of the various ice formation mechanisms to the total ice content. For the first time this allows us to directly investigate the competition of in-situ and liquid origin Cirrus as well as homogeneous and heterogeneous ice nucleation with regards to environmental conditions and choice of microphysical parameterisations.

We performed an ensemble of simulations for selected WCB cases to cover a range of microphysical properties and compared the results of our liquid origin vs in-situ analysis with other Cirrus categorization algorithms.

How to cite: Lüttmer, T. and Spichtinger, P.: A novel approach to investigate Cirrus cloud formation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9818, https://doi.org/10.5194/egusphere-egu23-9818, 2023.

     The global aviation fleet modifies cloudiness through contrail formation and their subsequent competition with natural cirrus for ambient water vapor, along with enhanced ice-nuclei concentrations from aircraft soot emissions. Contrails form in the upper troposphere at temperatures below 233 K and pressures below 300 hPa, when plume gases from jet engines, having appreciable water vapor content, saturate with respect to liquid water (Schmidt-Appleman Criterion, SAC). Realistic assessments of the aviation-induced modifications to global cloud cover demand improved representation of contrails and their interaction with background cloudiness in climate models. We have implemented a process-based parametrization of contrail cirrus, that applies to both young (≤ 5 h) and aged contrails, in the UK Met Office Unified Model, version 12.0. Contrail cirrus is introduced as a new prognostic cloud class, forming in the parametrized, fractional ice supersaturated area which then undergoes advection, depositional growth, sublimation and sedimentation. The proxy for the fractional supersaturated area is calculated using the same total water PDF as used for natural cirrus but with a different critical relative humidity, r_cc - a value at which part of the model grid box is at least ice-saturated. The persistence of contrails being allowed in the ice supersaturated areas, the simulated coverage is not confined to flight corridors, but is advected to air traffic free zones as well. The simulated annual mean global coverage due to young contrails is 0.13%, with the main traffic areas of Europe and North America having the maximum coverage. Similar to natural cirrus, the contrail ice particles reflect the solar short-wave (SW) radiation and trap outgoing long-wave (LW) radiation, thereby modifying the radiative balance of the Earth’s atmosphere. Contrail cirrus is radiatively active in the model with forcing studies enabled via a ‘double radiation call’ approach, wherein parallel runs of the radiation scheme ‘with’ (prognostic) and ‘without’ (diagnostic) the contrail radiative effects isolates the contrail-induced perturbations. Contrails are seen to induce a short-wave cooling and long-wave warming and the net (SW+LW) direct top-of-atmosphere radiative forcing by young contrails amounts globally to 0.5 mWm^-2, with the peak forcing seen along the main air traffic areas of North America, Europe and East Asia. The implementation of this process-based parametrization in the UM enables the simulation of the life cycle of persistent contrails, and can provide valuable insights to the aviation-induced modifications to the global cloud cover.

How to cite: Francis, T., Rap, A., Van Weverberg, K., Manners, J., Furtado, K., Zhang, W., Forster, P., and Morcrette, C.: Implementing a process-based contrail parametrization in the Unified Model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2964, https://doi.org/10.5194/egusphere-egu23-2964, 2023.

Warm conveyor belts (WCB) are regions of large-scale coherent airflow within extratropical cyclones that rapidly ascend from the boundary layer to the upper troposphere. During their ascent, WCBs transport water vapour and cloud condensate to the upper troposphere, and thereby significantly contribute to the moisture content of the extra-tropical upper troposphere-lower stratosphere (UTLS) as well as upper tropospheric cloudiness. UTLS moisture content and cloudiness are important for the radiative budget of the Earth and future changes thereof, but are often poorly represented in numerical models and reanalysis products. A detailed quantitative understanding of the processes governing water transport in WCBs provides vital clues to the origin of these biases and for evaluating predicted future changes in WCB moisture transport. Furthermore, recent studies have found that deep and embedded convection play an important role in WCBs. This points to the necessity of high-resolution simulations, that are well validated with observational data to provide a “benchmark” for coarser-resolution global (climate) models. Here we investigate the physical processes governing WCB moisture transport in simulations of a case-study from the WISE campaign with a particular focus on (i) the impact of grid spacing (including the use of convection parameterisations) on WCB moisture transport, (ii) the microphysical processes controlling moisture loss from the WCB, and (iii) the cloud microphysical properties of the cirrus clouds in the WCB outflow.

To this end we conducted two ICON simulations of an extratropical cyclone using (i) a global (~13km resolution), convection-parameterizing and (ii) a doubly nested (~13km, ~6km and ~3km resolution) convection permitting set up. In both set-ups online trajectories are calculated that capture convective ascent and allow for a Lagrangian analysis of WCB moisture transport and WCB cloud structure.

The Lagrangian metrics show large differences in ascent timescales and the efficiency with which water is transported from the boundary-layer to the UTLS. It is shown that this impacts the UTLS moisture content in the WCB outflow region. Local changes in UTLS moisture content induced by different representations of convection are shown to project onto larger-scale structures in the moisture and cloud fields over the 1-2 days after WCB ascent.

How to cite: Schwenk, C. and Miltenberger, A.: Physical processes controlling warm conveyor belt moisture transport to the UTLS and dependence on model resolution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6987, https://doi.org/10.5194/egusphere-egu23-6987, 2023.