A parametrization of the ice water content observed in frontal and convective clouds

Bower, Keith; MOSS, SJ; JOHNSON, DW; LATHAM, J; Brown, Philip R. A.; BLYTH, AM; CARDWELL, J

doi:10.1256/smsqj.53604

Cited by 12 publications

(17 citation statements)

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“…(1) Korolev [2003] (2) Cober [2001] (3) Mossop [1970] (4) Moss & Johnson [1992] (5) Isaac & Shemenauer [1979] (6) K11−Punta Arenas (7) K11−Cape Verde (8) K11−RV Polarstern (9) K11−Stellenbosch (10) K11−Leipzig (11) Bower [1996] (12) Hu [2010] (13) Naud Table 1. Colored markers are used to denote previous observational estimates of T5050 derived from the probability of observing ice or liquid cloud as a function of temperature.…”

Section: Aircraftmentioning

confidence: 99%

“…The probability of observing either ice or liquid clouds as a function of temperature derived from aircraft data and surface-based lidar is shown for comparison to the model diagnosed T5050s [Bower et al, 1996;Cober et al, 2001;Isaac and Schemenauer, 1979;Kanitz et al, 2011;Korolev et al, 2003;Moss and Johnson, 1994;Mossop et al, 1970]. Data from Korolev et al [2003] were revised as discussed in Storelvmo et al [2015] to account for large ice particles shattering upon entering the inlets of cloud particle probes.…”

Section: Aircraftmentioning

confidence: 99%

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On the relationships among cloud cover, mixed‐phase partitioning, and planetary albedo in GCMs

McCoy

Tan

Hartmann

et al. 2016

J Adv Model Earth Syst

144

137

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In this study, it is shown that CMIP5 global climate models (GCMs) that convert supercooled water to ice at relatively warm temperatures tend to have a greater mean-state cloud fraction and more negative cloud feedback in the middle and high latitude Southern Hemisphere. We investigate possible reasons for these relationships by analyzing the mixed-phase parameterizations in 26 GCMs. The atmospheric temperature where ice and liquid are equally prevalent (T5050) is used to characterize the mixed-phase parameterization in each GCM. Liquid clouds have a higher albedo than ice clouds, so, all else being equal, models with more supercooled liquid water would also have a higher planetary albedo. The lower cloud fraction in these models compensates the higher cloud reflectivity and results in clouds that reflect shortwave radiation (SW) in reasonable agreement with observations, but gives clouds that are too bright and too few. The temperature at which supercooled liquid can remain unfrozen is strongly anti-correlated with cloud fraction in the climate mean state across the model ensemble, but we know of no robust physical mechanism to explain this behavior, especially because this anti-correlation extends through the subtropics. A set of perturbed physics simulations with the Community Atmospheric Model Version 4 (CAM4) shows that, if its temperature-dependent phase partitioning is varied and the critical relative humidity for cloud formation in each model run is also tuned to bring reflected SW into agreement with observations, then cloud fraction increases and liquid water path (LWP) decreases with T5050, as in the CMIP5 ensemble.

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Section: Aircraftmentioning

confidence: 99%

Section: Aircraftmentioning

confidence: 99%

On the relationships among cloud cover, mixed‐phase partitioning, and planetary albedo in GCMs

McCoy

Tan

Hartmann

et al. 2016

J Adv Model Earth Syst

144

137

View full text Add to dashboard Cite

show abstract

“…Given the poor constraints on ice nucleation, GCMs may either parameterize the transition from liquid to ice as a simple function of temperature [Bower et al, 1996;Cesana et al, 2015;Choi et al, 2014] or attempt a more rigorous approach including nucleation and growth [Cesana et al, 2015;Komurcu et al, 2014]. Careful study and intercomparison of ice nucleation parameterizations between GCMs have shown that nucleation and processes subsequent to nucleation contribute equally to the uncertainty in mixed-phase behavior of several GCMs with advanced microphysics parameterizations [Komurcu et al, 2014].…”

Section: Diagnosis Of Gcm Mixed-phase Behaviormentioning

confidence: 99%

“…Careful study and intercomparison of ice nucleation parameterizations between GCMs have shown that nucleation and processes subsequent to nucleation contribute equally to the uncertainty in mixed-phase behavior of several GCMs with advanced microphysics parameterizations [Komurcu et al, 2014]. Although ice microphysics are complex, one would expect to find that warmer temperatures on average lead to higher abundances of liquid and lower abundances of ice, provided that the concentration of IN does not vary significantly with temperature [Bower et al, 1996;Hu et al, 2010;Kanitz et al, 2011;Tan et al, 2014].…”

Section: Diagnosis Of Gcm Mixed-phase Behaviormentioning

confidence: 99%

Mixed‐phase cloud physics and Southern Ocean cloud feedback in climate models

et al. 2015

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Increasing optical depth poleward of 45° is a robust response to warming in global climate models. Much of this cloud optical depth increase has been hypothesized to be due to transitions from ice‐dominated to liquid‐dominated mixed‐phase cloud. In this study, the importance of liquid‐ice partitioning for the optical depth feedback is quantified for 19 Coupled Model Intercomparison Project Phase 5 models. All models show a monotonic partitioning of ice and liquid as a function of temperature, but the temperature at which ice and liquid are equally mixed (the glaciation temperature) varies by as much as 40 K across models. Models that have a higher glaciation temperature are found to have a smaller climatological liquid water path (LWP) and condensed water path and experience a larger increase in LWP as the climate warms. The ice‐liquid partitioning curve of each model may be used to calculate the response of LWP to warming. It is found that the repartitioning between ice and liquid in a warming climate contributes at least 20% to 80% of the increase in LWP as the climate warms, depending on model. Intermodel differences in the climatological partitioning between ice and liquid are estimated to contribute at least 20% to the intermodel spread in the high‐latitude LWP response in the mixed‐phase region poleward of 45°S. It is hypothesized that a more thorough evaluation and constraint of global climate model mixed‐phase cloud parameterizations and validation of the total condensate and ice‐liquid apportionment against observations will yield a substantial reduction in model uncertainty in the high‐latitude cloud response to warming.

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“…However, INA microorganisms can benefit from a process of ice multiplication that is restricted to a very specific temperature range, if their primary ice can grow to become ice precipitation aloft. Between À3 and À8°C, the number of ice particles in clouds can be amplified by the Hallett-Mossop (H-M) process of ice multiplication (Hallett & Mossop, 1974;Harris-Hobbs & Cooper, 1987), which involves rime splintering of ice precipitation leading to ice concentrations that are several orders of magnitude greater than what would be expected due to primary ice nucleation alone (Bower et al, 1996). Indeed, such impacts from biological ice nuclei on the H-M process have been simulated (Phillips et al, 2009).…”

Section: The Impact Of Biological Ice Nuclei On Cold Cloudsa Contentimentioning

confidence: 99%

Bioprecipitation: a feedback cycle linking Earth history, ecosystem dynamics and land use through biological ice nucleators in the atmosphere

Morris

Conen

Huffman

et al. 2013

Global Change Biology

255

225

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Landscapes influence precipitation via the water vapor and energy fluxes they generate. Biologically active landscapes also generate aerosols containing microorganisms, some being capable of catalyzing ice formation and crystal growth in clouds at temperatures near 0 °C. The resulting precipitation is beneficial for the growth of plants and microorganisms. Mounting evidence from observations and numerical simulations support the plausibility of a bioprecipitation feedback cycle involving vegetated landscapes and the microorganisms they host. Furthermore, the evolutionary history of ice nucleation-active bacteria such as Pseudomonas syringae supports that they have been part of this process on geological time scales since the emergence of land plants. Elucidation of bioprecipitation feedbacks involving landscapes and their microflora could contribute to appraising the impact that modified landscapes have on regional weather and biodiversity, and to avoiding inadvertent, negative consequences of landscape management.

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A parametrization of the ice water content observed in frontal and convective clouds

Cited by 12 publications

References 0 publications

On the relationships among cloud cover, mixed‐phase partitioning, and planetary albedo in GCMs

On the relationships among cloud cover, mixed‐phase partitioning, and planetary albedo in GCMs

Mixed‐phase cloud physics and Southern Ocean cloud feedback in climate models

Bioprecipitation: a feedback cycle linking Earth history, ecosystem dynamics and land use through biological ice nucleators in the atmosphere

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