Determining stages of cirrus life-cycle evolution: A cloud classification scheme

Abstract. Cirrus clouds impose high uncertainties on climate prediction, as knowledge on important processes is still incomplete. For instance it remains unclear how cloud microphysical and radiative properties change as the cirrus evolves. Recent studies classify cirrus clouds into categories including "in situ", "orographic", "convective" and "liquid origin" clouds and investigate their specific impact. Following this line, we present a novel scheme for the classification of cirrus clouds that addresses the need to determine specific stages of cirrus life-cycle evolution. Our classification scheme is based on airborne Differential Absorption and High Spectral Resolution Lidar measurements of atmospheric water vapor, aerosol depolarization, and backscatter, together with model temperature fields and simplified parameterizations of freezing onset conditions. It identifies regions of supersaturation with respect to ice (ISSR), heterogeneous and homogeneous nucleation, depositional growth, and ice sublimation and sedimentation with high spatial resolution. Thus the whole cirrus life-cycle can be traced. In a case study of a gravity lee wave influenced cirrus cloud, encountered during the ML-CIRRUS flight campaign, the applicability of our classification is demonstrated. Revealing the structure of cirrus clouds, this valuable tool might help to examine the influence of life-cycle stages on the cloud's net radiative effect and to investigate the specific variability of optical and microphysical cloud properties in upcoming research.

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Determining stages of cirrus evolution: a cloud classification scheme

Atmospheric Measurement Techniques ◽

10.5194/amt-10-1653-2017 ◽

2017 ◽

Vol 10 (5) ◽

pp. 1653-1664 ◽

Cited By ~ 5

Author(s):

Benedikt Urbanek ◽

Silke Groß ◽

Andreas Schäfler ◽

Martin Wirth

Keyword(s):

Classification Scheme ◽

Cirrus Clouds ◽

Radiative Properties ◽

Temperature Fields ◽

High Spectral Resolution ◽

Cloud Properties ◽

Lidar Measurements ◽

Lee Wave

Abstract. Cirrus clouds impose high uncertainties on climate prediction, as knowledge on important processes is still incomplete. For instance it remains unclear how cloud microphysical and radiative properties change as the cirrus evolves. Recent studies classify cirrus clouds into categories including in situ, orographic, convective and liquid origin clouds and investigate their specific impact. Following this line, we present a novel scheme for the classification of cirrus clouds that addresses the need to determine specific stages of cirrus evolution. Our classification scheme is based on airborne Differential Absorption and High Spectral Resolution Lidar measurements of atmospheric water vapor, aerosol depolarization, and backscatter, together with model temperature fields and simplified parameterizations of freezing onset conditions. It identifies regions of supersaturation with respect to ice (ice-supersaturated regions, ISSRs), heterogeneous and homogeneous nucleation, depositional growth, and ice sublimation and sedimentation with high spatial resolution. Thus, all relevant stages of cirrus evolution can be classified and characterized. In a case study of a gravity lee-wave-influenced cirrus cloud, encountered during the ML-CIRRUS flight campaign, the applicability of our classification is demonstrated. Revealing the structure of cirrus clouds, this valuable tool might help to examine the influence of evolution stages on the cloud's net radiative effect and to investigate the specific variability of optical and microphysical cloud properties in upcoming research.

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Classifying stages of cirrus life-cycle evolution

EPJ Web of Conferences ◽

10.1051/epjconf/201817605021 ◽

2018 ◽

Vol 176 ◽

pp. 05021

Author(s):

Benedikt Urbanek ◽

Silke Groß ◽

Andreas Schäfler ◽

Martin Wirth

Keyword(s):

Life Cycle ◽

Water Vapor ◽

Relative Humidity ◽

Classification Scheme ◽

Airborne Lidar ◽

Temperature Fields ◽

Lidar Measurements ◽

Life Cycle Evolution ◽

Ice Sublimation ◽

Model Temperature

Airborne lidar backscatter data is used to determine in- and out-of-cloud regions. Lidar measurements of water vapor together with model temperature fields are used to calculate relative humidity over ice (RHi). Based on temperature and RHi we identify different stages of cirrus evolution: homogeneous and heterogeneous freezing, depositional growth, ice sublimation and sedimentation. We will present our classification scheme and first applications on mid-latitude cirrus clouds.

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Dynamic Processes in Cirrus Clouds: Concepts and Models

Cirrus ◽

10.1093/oso/9780195130720.003.0022 ◽

2002 ◽

Author(s):

David O’C. Starr ◽

Markus Quante

Keyword(s):

Cirrus Clouds ◽

Radiative Properties ◽

Cirrus Cloud ◽

Early Model ◽

Minimum Requirement ◽

Microphysical Properties ◽

Cloud Properties ◽

Cloud Models ◽

New Concepts

Advancement in the understanding of cirrus clouds and their life cycle comes through symbiotic use of models, observations, and related concepts (fig. 18.1). Models of cirrus clouds represent an integration of our knowledge of cirrus cloud properties and processes. They provide a capacity to extend knowledge and enhance understanding in ways that complement existing observational capabilities. Models can be used to develop new theories, such as parameterizations, and focus science issues and observational requirements and developments. For example, early model results of Starr and Cox (1985a) and Starr (1987b) predicted that fine cellular structure (~lkm or less) would be found in the upper part of extended stratiform cirrus clouds. This prediction was confirmed when high-frequency sensors were deployed both for active remote sensing (Sassen et al. 1990a, 1995) and later for in-situ measurements (Quante and Brown 1992; Gultepe et al. 1995; Quante et al. 1996). Sampling rates of 10Hz, or better, are now accepted as a minimum requirement for resolving cirrus cloud internal structure and circulation where 1-Hz or coarser measurements were previously used. Similarly, discrepancies between observed cloud radiative properties and calculations (theory) based on corresponding in-situ observations of cloud microphysical properties (Sassen et al. 1990b) led to the development of improved observing capabilities for small ice crystals (Arnott et al. 1994; Miloshevich and Heymsfield 1997; Lawson et al. 1998). Such sensors are now regarded as part of the standard complement when doing in-situ microphysical measurements in cirrus. At the same time, observations are absolutely essential in developing and evaluating cloud models. No cloud modeler wants to apply a model or theory too far beyond the limits of what can be observationally confirmed, at least in gross terms. The third aspect of this triad is concepts. Although models and observations can lead to predictions or diagnosis of unexpected relationships, they are each limited by the concepts that were used in their design and/or implementation. In the end, new concepts arising from analogy to other phenomena and/or from synergistic integration of existing knowledge can lead to new understanding, new models, new instruments, and new sampling strategies (fig. 18.1). Chapter 17 focuses on observations of internal cloud circulation and structure.

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Radiative Properties of Aerosols and Clouds from Observations and Models over the Southeast Atlantic

10.5194/egusphere-egu2020-13086 ◽

2020 ◽

Author(s):

Ian Chang ◽

Keyword(s):

Climate Models ◽

Current Model ◽

Regional Climate ◽

Regional Climate Models ◽

Radiative Properties ◽

High Spectral Resolution ◽

Airborne Measurements ◽

Cloud Properties ◽

Satellite Retrievals ◽

Aerosol Radiative Effects

<p>The southeast Atlantic serves as a natural laboratory for studying aerosol-cloud-radiation interactions due to the abundant presence of quasi-permanent stratocumulus and overlying biomass burning smoke aerosols during austral winters. Aerosol and cloud properties from the Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) and Solar Spectral Flux Radiometer (SSFR) on board NASA P-3 and High Spectral Resolution Lidar (HSRL) on board NASA ER-2 during the NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign are used to compare with satellite retrievals. Aerosol and cloud properties from regional climate models such as WRF-Chem, WRF-Chem (with CAM5), ALADIN, GEOS-CHEM, EAM-E3SM, MERRA-2, and GEOS-5 with aerosol schemes are also compared against airborne measurements and satellite retrievals to evaluate and address the current model deficiencies in the southeast Atlantic. A preliminary estimate of the direct aerosol radiative effects over the southeast Atlantic will be presented.</p>

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Rapid phenotypic evolution following shifts in life cycle complexity

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.2304 ◽

2018 ◽

Vol 285 (1871) ◽

pp. 20172304 ◽

Cited By ~ 10

Author(s):

Ronald M. Bonett ◽

John G. Phillips ◽

Nicholus M. Ledbetter ◽

Samuel D. Martin ◽

Luke Lehman

Keyword(s):

Life Cycle ◽

Vertebral Column ◽

Life Stages ◽

Phenotypic Evolution ◽

Trait Evolution ◽

Life Cycle Stages ◽

Biphasic Life Cycle ◽

History Of ◽

Life Cycle Evolution

Life cycle strategies have evolved extensively throughout the history of metazoans. The expression of disparate life stages within a single ontogeny can present conflicts to trait evolution, and therefore may have played a major role in shaping metazoan forms. However, few studies have examined the consequences of adding or subtracting life stages on patterns of trait evolution. By analysing trait evolution in a clade of closely related salamander lineages we show that shifts in the number of life cycle stages are associated with rapid phenotypic evolution. Specifically, salamanders with an aquatic-only (paedomorphic) life cycle have frequently added vertebrae to their trunk skeleton compared with closely related lineages with a complex aquatic-to-terrestrial (biphasic) life cycle. The rate of vertebral column evolution is also substantially lower in biphasic lineages, which may reflect the functional compromise of a complex cycle. This study demonstrates that the consequences of life cycle evolution can be detected at very fine scales of divergence. Rapid evolutionary responses can result from shifts in selective regimes following changes in life cycle complexity.

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An automated cirrus classification

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-6157-2018 ◽

2018 ◽

Vol 18 (9) ◽

pp. 6157-6169 ◽

Cited By ~ 3

Author(s):

Edward Gryspeerdt ◽

Johannes Quaas ◽

Tom Goren ◽

Daniel Klocke ◽

Matthias Brueck

Keyword(s):

Formation Mechanism ◽

Cirrus Clouds ◽

Radiative Properties ◽

Radiation Budget ◽

Cloud Formation ◽

Back Trajectory ◽

Formation Mechanisms ◽

Cirrus Cloud ◽

Cloud Properties

Abstract. Cirrus clouds play an important role in determining the radiation budget of the earth, but many of their properties remain uncertain, particularly their response to aerosol variations and to warming. Part of the reason for this uncertainty is the dependence of cirrus cloud properties on the cloud formation mechanism, which itself is strongly dependent on the local meteorological conditions. In this work, a classification system (Identification and Classification of Cirrus or IC-CIR) is introduced to identify cirrus clouds by the cloud formation mechanism. Using reanalysis and satellite data, cirrus clouds are separated into four main types: orographic, frontal, convective and synoptic. Through a comparison to convection-permitting model simulations and back-trajectory-based analysis, it is shown that these observation-based regimes can provide extra information on the cloud-scale updraughts and the frequency of occurrence of liquid-origin ice, with the convective regime having higher updraughts and a greater occurrence of liquid-origin ice compared to the synoptic regimes. Despite having different cloud formation mechanisms, the radiative properties of the regimes are not distinct, indicating that retrieved cloud properties alone are insufficient to completely describe them. This classification is designed to be easily implemented in GCMs, helping improve future model–observation comparisons and leading to improved parametrisations of cirrus cloud processes.

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Evidence for complex life cycle constraints on salamander body form diversification

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1703877114 ◽

2017 ◽

Vol 114 (37) ◽

pp. 9936-9941 ◽

Cited By ~ 29

Author(s):

Ronald M. Bonett ◽

Andrea L. Blair

Keyword(s):

Life Cycle ◽

Phenotypic Diversity ◽

Life Cycles ◽

Complex Life Cycle ◽

Body Form ◽

Life Cycle Stages ◽

Biphasic Life Cycle ◽

Evolution Of Life ◽

Adult Body ◽

Life Cycle Evolution

Metazoans display a tremendous diversity of developmental patterns, including complex life cycles composed of morphologically disparate stages. In this regard, the evolution of life cycle complexity promotes phenotypic diversity. However, correlations between life cycle stages can constrain the evolution of some structures and functions. Despite the potential macroevolutionary consequences, few studies have tested the impacts of life cycle evolution on broad-scale patterns of trait diversification. Here we show that larval and adult salamanders with a simple, aquatic-only (paedomorphic) life cycle had an increased rate of vertebral column and body form diversification compared to lineages with a complex, aquatic-terrestrial (biphasic) life cycle. These differences in life cycle complexity explain the variations in vertebral number and adult body form better than larval ecology. In addition, we found that lineages with a simple terrestrial-only (direct developing) life cycle also had a higher rate of adult body form evolution than biphasic lineages, but still 10-fold lower than aquatic-only lineages. Our analyses demonstrate that prominent shifts in phenotypic evolution can follow long-term transitions in life cycle complexity, which may reflect underlying stage-dependent constraints.

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