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Christopher S Bretherton - One of the best experts on this subject based on the ideXlab platform.
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cloud aerosol and boundary layer structure across the northeast pacific Stratocumulus cumulus transition as observed during cset
Monthly Weather Review, 2019Co-Authors: Christopher S Bretherton, Virendra P Ghate, Robert Wood, Isabel L Mccoy, Johannes Mohrmann, Andrew Gettelman, Charles G Bardeen, Bruce Albrecht, Paquita ZuidemaAbstract:AbstractDuring the Cloud System Evolution in the Trades (CSET) field study, 14 research flights of the National Science Foundation G-V sampled the Stratocumulus–cumulus transition between Northern ...
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the gass euclipse model intercomparison of the Stratocumulus transition as observed during astex les results
Journal of Advances in Modeling Earth Systems, 2013Co-Authors: J J Van Der Dussen, Irina Sandu, Andrew S Ackerman, Christopher S Bretherton, Peter N Blossey, S R De Roode, Marcin J Kurowski, A P Lock, Roel Neggers, A P SiebesmaAbstract:Large-eddy simulations of a Lagrangian transition from a vertically well-mixed Stratocumulus-topped boundary layer to a situation in which shallow cumuli penetrate an overlying layer of thin and broken Stratocumulus are compared with aircraft observations collected during the Atlantic Stratocumulus Transition Experiment. Despite the complexity of the case and the long simulation period of 40 h, the six participating state-of-the-art models skillfully and consistently represent the observed gradual deepening of the boundary layer, a negative buoyancy flux at the top of the subcloud layer and the development of a double-peaked vertical velocity variance profile. The moisture flux from the subcloud to the Stratocumulus cloud layer by cumulus convection exhibits a distinct diurnal cycle. During the night the moisture flux at the Stratocumulus cloud base exceeds the surface evaporation flux, causing a net drying of the subcloud layer, and vice versa during daytime. The spread in the liquid water path (LWP) among the models is rather large during the first 12 h. From additional sensitivity experiments it is demonstrated that this spread is mainly attributable to differences in the parameterized precipitation rate. The LWP differences are limited through a feedback mechanism in which enhanced drizzle fluxes result in lower entrainment rates and subsequently a reduced drying at cloud top. The spread is furthermore reduced during the day as cloud layers with a greater LWP absorb more solar radiation and hence evaporate more.
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mechanisms of marine low cloud sensitivity to idealized climate perturbations a single les exploration extending the cgils cases
Journal of Advances in Modeling Earth Systems, 2013Co-Authors: Christopher S Bretherton, Peter N Blossey, Christopher R JonesAbstract:[1] Climate change sensitivities of subtropical cloud-topped marine boundary layers are analyzed using large-eddy simulation (LES) of three CGILS cases of well-mixed Stratocumulus, cumulus under Stratocumulus, and shallow cumulus cloud regimes, respectively. For each case, a steadily forced control simulation on a small horizontally doubly periodic domain is run 10–20 days into quasi-steady state. The LES is rerun to steady state with forcings perturbed by changes in temperature, free-tropospheric relative humidity (RH), CO2 concentration, subsidence, inversion stability, and wind speed; cloud responses to combined forcings superpose approximately linearly. For all three cloud regimes and 2× CO2 forcing perturbations estimated from the CMIP3 multimodel mean, the LES predicts positive shortwave cloud feedback, like most CMIP3 global climate models. At both Stratocumulus locations, the cloud remains overcast but thins in the warmer, moister, CO2-enhanced climate, due to the combined effects of an increased lower-tropospheric vertical humidity gradient and an enhanced free-tropospheric greenhouse effect that reduces the radiative driving of turbulence. Reduced subsidence due to weakening of tropical overturning circulations partly counteracts these two factors by raising the inversion and allowing the cloud layer to deepen. These compensating mechanisms may explain the large scatter in low cloud feedbacks predicted by climate models. CMIP3-predicted changes in wind speed, inversion stability, and free-tropospheric RH have lesser impacts on the cloud thickness. In the shallow cumulus regime, precipitation regulates the simulated boundary-layer depth and vertical structure. Cloud-droplet (aerosol) concentration limits the boundary-layer depth and affects the simulated cloud feedbacks.
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open cellular structure in marine Stratocumulus sheets
Journal of Geophysical Research, 2008Co-Authors: Robert Wood, Kimberly K Comstock, Christopher S Bretherton, C Cornish, J M Tomlinson, Don R Collins, C W FairallAbstract:[1] Geostationary and Sun-synchronous satellite data and in situ observations from ship cruises are used to investigate the formation of open cellular structure in marine Stratocumulus clouds over the southeast Pacific (SEP). Open cellular convection either forms spontaneously as pockets of open cells (POCs) within overcast Stratocumulus, or is advected into the region from midlatitude regions. POC formation occurs most frequently during the latter part of the night, demonstrating that this transition is not caused by solar absorption-driven decoupling. The transition preferentially occurs in clouds with low 11–3.9 μm nighttime brightness temperature difference (BTD) which is found to be well correlated with both in situ measured accumulation mode aerosol concentration and cloud droplet concentration estimates derived from MODIS. Besides indicating that nighttime BTD is an excellent proxy for Stratocumulus cloud droplet concentration Nd, this also suggests that low aerosol concentrations favor POC formation. Indeed, extremely low accumulation mode aerosol concentrations are found during the passage of open cell events over the ship. Free-tropospheric moisture is not found to be an important factor in POC formation. Significant subseasonal variability occurs in the fractional coverage of open cellular convection over the broader SEP. This coverage is well correlated with a MODIS-derived drizzle proxy (MDP) proportional to the ratio of liquid water path (LWP) to Nd for predominantly overcast regions. Both LWP and Nd variability influences the MDP. Periods of low MDP have significant positive large-scale Nd anomalies and are preceded by offshore winds at 850 hPa, which suggests a potential continental influence upon open cell formation over the SEP. Together, the results suggest important two-way interactions between aerosols and drizzle in marine Stratocumulus and a role for drizzle in modulating the large-scale albedo of these cloud systems.
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the three dimensional structure and kinematics of drizzling Stratocumulus
Monthly Weather Review, 2007Co-Authors: Kimberly K Comstock, Sandra E. Yuter, Robert Wood, Christopher S BrethertonAbstract:Abstract Drizzling marine Stratocumulus are examined using observations from the 2001 East Pacific Investigation of Climate Stratocumulus (EPIC Sc) field experiment. This study uses a unique combination of satellite and shipborne Doppler radar data including both horizontal and vertical cross sections through drizzle cells. Stratocumulus cloud structure was classified as closed cellular, open cellular, or unclassifiable using infrared satellite images. Distributions of drizzle cell structure, size, and intensity are similar among the cloud-structure categories, though the open-cellular distributions are shifted toward higher values. Stronger and larger drizzle cells preferentially occur when the cloud field is broken (open-cellular and unclassifiable categories). Satellite observations of cloud structure may be useful to indicate the most likely distribution of rain rates associated with a set of scenes, but infrared data alone are not sufficient to develop routine precipitation retrievals for marine stra...
Bjorn Stevens - One of the best experts on this subject based on the ideXlab platform.
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large eddy simulations of euclipse gass lagrangian Stratocumulus to cumulus transitions mean state turbulence and decoupling
Journal of the Atmospheric Sciences, 2016Co-Authors: Stephan R De Roode, Irina Sandu, Andrew S Ackerman, Peter N Blossey, J J Van Der Dussen, A P Lock, Dorota Jarecka, Pier A Siebesma, Bjorn StevensAbstract:AbstractResults of four Lagrangian Stratocumulus-to-shallow-cumulus transition cases as obtained from six different large-eddy simulation models are presented. The model output is remarkably consistent in terms of the representation of the evolution of the mean state, which is characterized by a Stratocumulus cloud layer that rises with time and that warms and dries relative to the subcloud layer. Also, the effect of the diurnal insolation on cloud-top entrainment and the moisture flux at the top of the subcloud layer are consistently captured by the models. For some cases, the models diverge in terms of the liquid water path (LWP) during nighttime, which can be explained from the difference in the sign of the buoyancy flux at cloud base. If the subcloud buoyancy fluxes are positive, turbulence sustains a vertically well-mixed layer, causing a cloud layer that is relatively cold and moist and consequently has a high LWP. After some simulation time, all cases exhibit subcloud-layer dynamics that appear to ...
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on the factors modulating the Stratocumulus to cumulus transitions
Journal of the Atmospheric Sciences, 2011Co-Authors: Irina Sandu, Bjorn StevensAbstract:AbstractLarge-eddy simulation (LES) is used to explore the role of various processes in regulating the Stratocumulus to cumulus transition (SCT). Simulations are based on a composite case derived from a Lagrangian analysis of 2 yr of data from the northeastern Pacific. The simulations reproduce well the observed transition from a compact Stratocumulus layer to more broken fields of cumulus, simply as a response to increasing sea surface temperatures (SSTs) along the transition. In so doing they support earlier theoretical work that argued that the SCT was a response of boundary layer circulations to increased forcing by surface latent heat fluxes. Although the basic features of the SCT imposed by the increase in SST are robust, a variety of other factors affect the detailed character of the SCT. For example, enhanced precipitation or increased downwelling longwave radiative fluxes can accelerate the reduction in cloud cover that accompanies the SCT, while a gradual decrease in the large-scale divergence c...
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the structure and mesoscale organization of precipitating Stratocumulus
Journal of the Atmospheric Sciences, 2008Co-Authors: Verica Savicjovcic, Bjorn StevensAbstract:Abstract Large-eddy simulations are used to explore the structure and mesoscale organization of precipitating Stratocumulus. The simulations incorporate a simple, two-moment, bulk representation of microphysical processes, which by varying specified droplet concentrations allows for comparisons of simulations that do and do not develop precipitation. The boundary layer is represented over a large (25.6 km × 25.6 km) horizontal domain using a relatively fine mesh, thereby allowing for the development of mesoscale circulations while retaining an explicit representation of cloud radiative, dynamical and microphysical interactions on scales much smaller than the dominant eddy scale. Initial conditions are based on measurements made as part of the Second Dynamics and Chemistry of the Marine Stratocumulus field study (DYCOMS-II). The simulations show that precipitation is accompanied by sharp reductions in cloudiness and changes in flow topology. Mesoscale features emerge in all of the simulations but are ampli...
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accumulation mode aerosol pockets of open cells and particle nucleation in the remote subtropical pacific marine boundary layer
Journal of Geophysical Research, 2006Co-Authors: Ian Faloona, Gabor Vali, Bjorn Stevens, Markus D Petters, Jefferson R Snider, Lynn M RussellAbstract:[1] We analyze a marine boundary layer cloud field encountered during the second research flight of the second Dynamics and Chemistry of Marine Stratocumulus Experiment. The cloud field is distinguished by the presence of pockets of open cells. Differences between the pockets and the surrounding Stratocumulus clouds are studied utilizing in situ and satellite data. The pockets are characterized as regions where cloud radar echo tops are unusually variable, accumulation mode aerosol concentrations are low, and Aitken mode particles with a mode diameter at 0.02 μm dominate aerosol number concentration. The Aitken mode particles are thought to be generated by a nucleation event which occurred within the marine boundary layer. The low accumulation mode concentrations associated with the pockets are proposed to be necessary for their maintenance.
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observations of entrainment in eastern pacific marine Stratocumulus using three conserved scalars
Journal of the Atmospheric Sciences, 2005Co-Authors: Ian Faloona, Bjorn Stevens, Donald H Lenschow, Alan R Bandy, T L Campos, M Van Zanten, Byron Blomquist, Donald C Thornton, Hermann GerberAbstract:Abstract Fast measurements of three scalars, ozone, dimethyl sulfide (DMS), and total water, are used to investigate the entrainment process in the Stratocumulus-topped boundary layer (STBL) observed over the eastern subtropical Pacific during the second Dynamics and Chemistry of Marine Stratocumulus Experiment (DYCOMS-II). Direct measurement of the flux profiles by eddy covariance is used to estimate the entrainment velocity, the average rate at which the boundary layer grows diabatically via incorporation of overlying free tropospheric air. The entrainment velocities observed over the course of the mission, which took place during July 2001, ranged from 0.12 to 0.72 cm s−1, and appear to outpace the estimated large-scale subsidence as the boundary layer advects over warmer sea surface temperatures. Observed entrainment velocities display only a weak correlation with the buoyancy Richardson number defined at the inversion, which suggests that processes other than inversion strength, such as wind shear, m...
Joao Paulo Teixeira - One of the best experts on this subject based on the ideXlab platform.
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on the parameterization of convective downdrafts for marine Stratocumulus clouds
Monthly Weather Review, 2020Co-Authors: Handa Yang, Marcin J Kurowski, Jan Kleissl, Kay Suselj, Joao Paulo TeixeiraAbstract:AbstractThe role of nonlocal transport on the development and maintenance of marine Stratocumulus (Sc) clouds in coarse-resolution models is investigated, with a special emphasis on the downdraft c...
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sensitivity to physical and numerical aspects of large eddy simulation of Stratocumulus
Monthly Weather Review, 2019Co-Authors: Georgios Matheou, Joao Paulo TeixeiraAbstract:AbstractA series of numerical experiments where both physical and numerical model parameters are varied with respect to a reference setup is used to investigate the physics of a Stratocumulus cloud...
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steady state large eddy simulations to study the Stratocumulus to shallow cumulus cloud transition
Journal of the Atmospheric Sciences, 2012Co-Authors: Daniel Chung, Georgios Matheou, Joao Paulo TeixeiraAbstract:AbstractThis study presents a series of steady-state large-eddy simulations (LESs) to study the Stratocumulus to shallow cumulus cloud transition. To represent the different stages of what can be interpreted as an Eulerian view of the transition, each simulation is assigned a unique sea surface temperature (SST) and run until statistically steady. The LES runs are identical in every other aspect. These idealized boundary-driven steady-state LESs allow for a simple parametric assessment of cloud-controlling factors in isolation from initial conditions and time-lag effects inherent in the Lagrangian view of the transition. The analysis of the thermodynamic energy budget reveals that, as the cloud regime transitions from Stratocumulus to shallow cumulus, changes in the cloud radiative cooling term are balanced by changes in the subsidence warming term. This leads to a linear regression between the cloud fraction (CF) and an integral that scales, to a first-order approximation, as the lower-tropospheric stabi...
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tropical and subtropical cloud transitions in weather and climate prediction models the gcss wgne pacific cross section intercomparison gpci
Journal of Climate, 2011Co-Authors: Joao Paulo Teixeira, S Cardoso, M Bonazzola, Jason C Cole, Anthony D Delgenio, Charlotte A Demott, Charmaine Franklin, Cecile Hannay, Christian JakobAbstract:AbstractA model evaluation approach is proposed in which weather and climate prediction models are analyzed along a Pacific Ocean cross section, from the Stratocumulus regions off the coast of California, across the shallow convection dominated trade winds, to the deep convection regions of the ITCZ—the Global Energy and Water Cycle Experiment Cloud System Study/Working Group on Numerical Experimentation (GCSS/WGNE) Pacific Cross-Section Intercomparison (GPCI). The main goal of GPCI is to evaluate and help understand and improve the representation of tropical and subtropical cloud processes in weather and climate prediction models. In this paper, a detailed analysis of cloud regime transitions along the cross section from the subtropics to the tropics for the season June–July–August of 1998 is presented. This GPCI study confirms many of the typical weather and climate prediction model problems in the representation of clouds: underestimation of clouds in the Stratocumulus regime by most models with the co...
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boundary layer clouds in a global atmospheric model simple cloud cover parameterizations
Journal of Climate, 2002Co-Authors: Joao Paulo Teixeira, Timothy F HoganAbstract:Abstract Subtropical boundary layer clouds have a fundamental role on the radiative budget of the atmosphere and on the modulation of the tropical circulations. The development of realistic parameterizations of these clouds in global atmospheric models is a major challenge. Unfortunately, this has been a difficult problem to solve in an acceptable way. In this paper, new and simple parameterization schemes for subtropical clouds are implemented in the U.S. Navy Operational Global Atmospheric Prediction System's (NOGAPS) forecast model. The parameterizations are partially based on large eddy simulation (LES) results and provide a substantial improvement when compared with observations and with the previous scheme. The global distribution of boundary layer clouds and of surface shortwave radiation is more realistic with this new scheme, particularly over the Stratocumulus regions. The transition from Stratocumulus to cumulus is well captured, the seasonal and diurnal cycles of Stratocumulus are realistic, a...
Yefim L. Kogan - One of the best experts on this subject based on the ideXlab platform.
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a cumulus cloud microphysics parameterization for cloud resolving models
Journal of the Atmospheric Sciences, 2013Co-Authors: Yefim L. KoganAbstract:AbstractA microphysical parameterization for shallow cumulus and boundary layer Stratocumulus clouds has been developed. Similar to the Khairoutdinov and Kogan parameterization for Stratocumulus clouds, the new parameterization is based on an explicit microphysical large-eddy simulation (LES) model as a data source and benchmark for comparison. The predictions of the bulk model using the new parameterization were tested in simulations of shallow cumulus and boundary layer Stratocumulus clouds; in both cases the new parameterization matched the predictions of the explicit microphysics LES quite accurately. These results show the importance of the choice of the dataset in parameterization development and the need for it to be balanced by realistic dynamic conditions. The strong sensitivity to representation of rain evaporation is also demonstrated. Accurate formulation of this process, tuned for the case of cumulus convection, has substantially improved precision of rain production.
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fidelity of analytic drop size distributions in drizzling stratiform clouds based on large eddy simulations
Journal of the Atmospheric Sciences, 2009Co-Authors: Yefim L. Kogan, Z N Kogan, David B. MechemAbstract:Abstract Cloud microphysical parameterizations and retrievals rely heavily on knowledge of the shape of drop size distributions (DSDs). Many investigations assume that DSDs in the entire or partial drop size range may be approximated by known analytical functions. The most frequently employed approximations of function are of the type of gamma, lognormal, Khrgian–Mazin, and Marshall–Palmer. At present, little is known about the accuracy of these approximations. The authors employ a DSD dataset generated by the Cooperative Institute for Mesoscale Meteorological Studies Large-Eddy Simulation (CIMMS LES) explicit microphysics model for Stratocumulus cases observed during the Atlantic Stratocumulus Transition Experiment (ASTEX) field project. The fidelity of analytic lognormal- and gamma-type DSD functions is evaluated according to how well they represent the higher-order moments of the drop spectra, such as precipitation flux and radar reflectivity. It is concluded that for boundary layer marine drizzling st...
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A New Cloud Physics Parameterization in a Large-Eddy Simulation Model of Marine Stratocumulus
Monthly Weather Review, 2000Co-Authors: Marat Khairoutdinov, Yefim L. KoganAbstract:Abstract A new bulk microphysical parameterization for large-eddy simulation (LES) models of the Stratocumulus-topped boundary layer has been developed using an explicit (drop spectrum resolving) microphysical model as a data source and benchmark for comparison. The liquid water is divided into two categories, nonprecipitable cloud water and drizzle, similar to traditional Kessler-type parameterizations. The cloud condensation nucleus (CCN) count, cloud/drizzle water mixing ratios, cloud/drizzle drop concentrations, and the cloud drop integral radius are predicted in the new scheme. The source/sink terms such as autoconversion/accretion of cloud water into/by drizzle are regressed using the cloud drop size spectra predicted by an explicit microphysical model. The results from the explicit and the new bulk microphysics schemes are compared for two cases: nondrizzling and heavily drizzling Stratocumulus-topped boundary layers (STBLs). The evolution of the STBL (characterized by such parameters as turbulence...
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Modeling of Stratocumulus Cloud Layers in a Large Eddy Simulation Model with Explicit Microphysics
Journal of the Atmospheric Sciences, 1995Co-Authors: Yefim L. Kogan, Z N Kogan, M. P. Khairoutdinov, D.k. Lilly, Qingfu LiuAbstract:Abstract A new large eddy simulation (LES) Stratocumulus cloud model with an explicit formulation of micro-physical processes has been developed, and the results from three large eddy simulations are presented to illustrate the effects of the Stratocumulus-topped boundary layer (STBL) dynamics on cloud microphysical parameters. The simulations represent cases of a well-mixed and a radiatively driven STBL. Two of the simulations differ only in the ambient aerosol concentration and show its effect on cloud microphysics. The third simulation is based on the data obtained by Nicholls, and the simulation results from this case are contrasted with his measurements. Cloud-layer dynamical parameters and cloud droplet spectra are in reasonably good agreement with observations. As demonstrated by the results of three large eddy simulations presented in the paper, the cloud microphysical parameters are significantly affected by cloud dynamics. This is evidenced by the sensitivity of the cloud drop spectra itself, as...
Robert Wood - One of the best experts on this subject based on the ideXlab platform.
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cloud aerosol and boundary layer structure across the northeast pacific Stratocumulus cumulus transition as observed during cset
Monthly Weather Review, 2019Co-Authors: Christopher S Bretherton, Virendra P Ghate, Robert Wood, Isabel L Mccoy, Johannes Mohrmann, Andrew Gettelman, Charles G Bardeen, Bruce Albrecht, Paquita ZuidemaAbstract:AbstractDuring the Cloud System Evolution in the Trades (CSET) field study, 14 research flights of the National Science Foundation G-V sampled the Stratocumulus–cumulus transition between Northern ...
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observations pertaining to precipitation within the northeast pacific Stratocumulus to cumulus transition
Monthly Weather Review, 2019Co-Authors: Mampi Sarkar, Paquita Zuidema, Virendra P Ghate, Bruce A Albrecht, Johannes Mohrmann, Jorgen Jensen, Robert WoodAbstract:AbstractThree genuine Stratocumulus-to-cumulus transitions sampled during the Cloud System Evolution over the Trades (CSET) campaign are documented. The focus is on Lagrangian evolution of in situ ...
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the competing effects of stability and humidity on subtropical Stratocumulus entrainment and cloud evolution from a lagrangian perspective
Journal of the Atmospheric Sciences, 2018Co-Authors: Ryan Eastman, Robert WoodAbstract:AbstractThe evolution of subtropical Stratocumulus clouds and the boundary layer is studied on daily time scales from the Lagrangian perspective, following the flow. Measures of humidity above the ...
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the subtropical Stratocumulus topped planetary boundary layer a climatology and the lagrangian evolution
Journal of the Atmospheric Sciences, 2017Co-Authors: Ryan Eastman, Robert Wood, Kuan Ting OAbstract:AbstractPrior work has shown that deeper planetary boundary layers (PBLs) are associated with cloud breakup and reduced droplet concentration in subtropical Stratocumulus cloud decks, motivating a need for a thorough understanding of PBL mechanics. Here, 169 000 boundary layer trajectories are calculated in four eastern subtropical ocean basins following reanalysis winds at 925 mb (1 mb = 1 hPa). These trajectories combined with a twice-daily cloud-top-height-inferred PBL depth product allow for a comprehensive Lagrangian analysis of the Stratocumulus (Sc)-topped PBL as the cloud deck transitions from Sc to trade cumulus (Cu). Month-to-month variations of this PBL product are strongly positively correlated with an independent PBL product derived from GPS radio occultation.A climatology shows the PBL deepening offshore in every region. The yearly cycle of PBL depth varies in opposition to the yearly cycle of lower-tropospheric stability (LTS), but high-frequency variation between LTS and PBL depth is more ...
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open cellular structure in marine Stratocumulus sheets
Journal of Geophysical Research, 2008Co-Authors: Robert Wood, Kimberly K Comstock, Christopher S Bretherton, C Cornish, J M Tomlinson, Don R Collins, C W FairallAbstract:[1] Geostationary and Sun-synchronous satellite data and in situ observations from ship cruises are used to investigate the formation of open cellular structure in marine Stratocumulus clouds over the southeast Pacific (SEP). Open cellular convection either forms spontaneously as pockets of open cells (POCs) within overcast Stratocumulus, or is advected into the region from midlatitude regions. POC formation occurs most frequently during the latter part of the night, demonstrating that this transition is not caused by solar absorption-driven decoupling. The transition preferentially occurs in clouds with low 11–3.9 μm nighttime brightness temperature difference (BTD) which is found to be well correlated with both in situ measured accumulation mode aerosol concentration and cloud droplet concentration estimates derived from MODIS. Besides indicating that nighttime BTD is an excellent proxy for Stratocumulus cloud droplet concentration Nd, this also suggests that low aerosol concentrations favor POC formation. Indeed, extremely low accumulation mode aerosol concentrations are found during the passage of open cell events over the ship. Free-tropospheric moisture is not found to be an important factor in POC formation. Significant subseasonal variability occurs in the fractional coverage of open cellular convection over the broader SEP. This coverage is well correlated with a MODIS-derived drizzle proxy (MDP) proportional to the ratio of liquid water path (LWP) to Nd for predominantly overcast regions. Both LWP and Nd variability influences the MDP. Periods of low MDP have significant positive large-scale Nd anomalies and are preceded by offshore winds at 850 hPa, which suggests a potential continental influence upon open cell formation over the SEP. Together, the results suggest important two-way interactions between aerosols and drizzle in marine Stratocumulus and a role for drizzle in modulating the large-scale albedo of these cloud systems.
