scholarly journals Sensitivity of simulated summer monsoonal precipitation in Langtang Valley, Himalaya, to cloud microphysics schemes in WRF

2017 ◽  
Vol 122 (12) ◽  
pp. 6298-6318 ◽  
Author(s):  
A. Orr ◽  
C. Listowski ◽  
M. Couttet ◽  
E. Collier ◽  
W. Immerzeel ◽  
...  
Keyword(s):  
Cloud Microphysics ◽  
Monsoonal Precipitation ◽  
Langtang Valley

scholarly journals A Cloud Microphysics Parameterization for Shallow Cumulus Clouds Based on Lagrangian Cloud Model Simulations

2018 ◽  
Vol 75 (11) ◽  
pp. 4031-4047 ◽  
Author(s):  
Yign Noh ◽  
Donggun Oh ◽  
Fabian Hoffmann ◽  
Siegfried Raasch
Keyword(s):  
Cloud Model ◽  
Cloud Microphysics ◽  
Heaviside Function ◽  
Mixing Ratio ◽  
Cumulus Clouds ◽  
Cloud Droplets ◽  
Shallow Cumulus ◽  
Initial Stage ◽  
Accretion Rates ◽  
The Moment

Abstract Cloud microphysics parameterizations for shallow cumulus clouds are analyzed based on Lagrangian cloud model (LCM) data, focusing on autoconversion and accretion. The autoconversion and accretion rates, A and C, respectively, are calculated directly by capturing the moment of the conversion of individual Lagrangian droplets from cloud droplets to raindrops, and it results in the reproduction of the formulas of A and C for the first time. Comparison with various parameterizations reveals the closest agreement with Tripoli and Cotton, such as and , where and are the mixing ratio and the number concentration of cloud droplets, is the mixing ratio of raindrops, is the threshold volume radius, and H is the Heaviside function. Furthermore, it is found that increases linearly with the dissipation rate and the standard deviation of radius and that decreases rapidly with while disappearing at > 3.5 μm. The LCM also reveals that and increase with time during the period of autoconversion, which helps to suppress the early precipitation by reducing A with smaller and larger in the initial stage. Finally, is found to be affected by the accumulated collisional growth, which determines the drop size distribution.

Tropical cyclone simulations over Bay of Bengal with ARW model: Sensitivity to cloud microphysics schemes

2019 ◽  
Vol 230 ◽  
pp. 104651 ◽  
Author(s):  
P. Reshmi Mohan ◽  
C. Venkata Srinivas ◽  
V. Yesubabu ◽  
R. Baskaran ◽  
B. Venkatraman
Keyword(s):  
Tropical Cyclone ◽  
Bay Of Bengal ◽  
Cloud Microphysics ◽  
Model Sensitivity ◽  
Arw Model

scholarly journals 100 Years of Progress in Cloud Physics, Aerosols, and Aerosol Chemistry Research

2019 ◽  
Vol 59 ◽  
pp. 11.1-11.72 ◽  
Author(s):  
Sonia M. Kreidenweis ◽  
Markus Petters ◽  
Ulrike Lohmann
Keyword(s):  
Radiative Forcing ◽  
Cloud Microphysics ◽  
Climate System ◽  
Mitigation Strategies ◽  
Climate Projections ◽  
Weather Modification ◽  
Theoretical Understanding ◽  
Aerosol Cloud ◽  
Chemistry Research ◽  
Aerosol Cloud Interactions

Abstract This chapter reviews the history of the discovery of cloud nuclei and their impacts on cloud microphysics and the climate system. Pioneers including John Aitken, Sir John Mason, Hilding Köhler, Christian Junge, Sean Twomey, and Kenneth Whitby laid the foundations of the field. Through their contributions and those of many others, rapid progress has been made in the last 100 years in understanding the sources, evolution, and composition of the atmospheric aerosol, the interactions of particles with atmospheric water vapor, and cloud microphysical processes. Major breakthroughs in measurement capabilities and in theoretical understanding have elucidated the characteristics of cloud condensation nuclei and ice nucleating particles and the role these play in shaping cloud microphysical properties and the formation of precipitation. Despite these advances, not all their impacts on cloud formation and evolution have been resolved. The resulting radiative forcing on the climate system due to aerosol–cloud interactions remains an unacceptably large uncertainty in future climate projections. Process-level understanding of aerosol–cloud interactions remains insufficient to support technological mitigation strategies such as intentional weather modification or geoengineering to accelerating Earth-system-wide changes in temperature and weather patterns.

scholarly journals Ocean Emission Effects on Aerosol-Cloud Interactions: Insights from Two Case Studies

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Armin Sorooshian ◽  
Hanh T. Duong
Keyword(s):  
Case Studies ◽  
Field Experiments ◽  
Remote Sensing Data ◽  
Anthropogenic Pollution ◽  
Cloud Microphysics ◽  
Marine Aerosols ◽  
Aerosol Cloud ◽  
First Case ◽  
Wide Range ◽  
Aerosol Cloud Interactions

Two case studies are discussed that evaluate the effect of ocean emissions on aerosol-cloud interactions. A review of the first case study from the eastern Pacific Ocean shows that simultaneous aircraft and space-borne observations are valuable in detecting links between ocean biota emissions and marine aerosols, but that the effect of the former on cloud microphysics is less clear owing to interference from background anthropogenic pollution and the difficulty with field experiments in obtaining a wide range of aerosol conditions to robustly quantify ocean effects on aerosol-cloud interactions. To address these limitations, a second case was investigated using remote sensing data over the less polluted Southern Ocean region. The results indicate that cloud drop size is reduced more for a fixed increase in aerosol particles during periods of higher ocean chlorophyll A. Potential biases in the results owing to statistical issues in the data analysis are discussed.

AEROSOL SCAVENGING IN CLOUDS AS SEEN FROM SIMULATIONS USING 2000-BIN CLOUD MICROPHYSICS MODEL

2001 ◽  
Vol 32 ◽  
pp. 203-204
Author(s):  
M. Pinsky ◽  
Y. Segal ◽  
A.P. Khain ◽  
M. Shapiro
Keyword(s):  
Cloud Microphysics ◽  
Aerosol Scavenging

scholarly journals Global model simulations of the impact of ocean-going ships on aerosols, clouds, and the radiation budget

2007 ◽  
Vol 7 (19) ◽  
pp. 5061-5079 ◽  
Author(s):  
A. Lauer ◽  
V. Eyring ◽  
J. Hendricks ◽  
P. Jöckel ◽  
U. Lohmann
Keyword(s):  
Particulate Matter ◽  
Chemical Composition ◽  
Optical Thickness ◽  
Emission Inventory ◽  
Cloud Microphysics ◽  
Number Concentration ◽  
Climate Impacts ◽  
Aerosol Optical Thickness ◽  
Radiation Budget ◽  
International Shipping

Abstract. International shipping contributes significantly to the fuel consumption of all transport related activities. Specific emissions of pollutants such as sulfur dioxide (SO2) per kg of fuel emitted are higher than for road transport or aviation. Besides gaseous pollutants, ships also emit various types of particulate matter. The aerosol impacts the Earth's radiation budget directly by scattering and absorbing the solar and thermal radiation and indirectly by changing cloud properties. Here we use ECHAM5/MESSy1-MADE, a global climate model with detailed aerosol and cloud microphysics to study the climate impacts of international shipping. The simulations show that emissions from ships significantly increase the cloud droplet number concentration of low marine water clouds by up to 5% to 30% depending on the ship emission inventory and the geographic region. Whereas the cloud liquid water content remains nearly unchanged in these simulations, effective radii of cloud droplets decrease, leading to cloud optical thickness increase of up to 5–10%. The sensitivity of the results is estimated by using three different emission inventories for present-day conditions. The sensitivity analysis reveals that shipping contributes to 2.3% to 3.6% of the total sulfate burden and 0.4% to 1.4% to the total black carbon burden in the year 2000 on the global mean. In addition to changes in aerosol chemical composition, shipping increases the aerosol number concentration, e.g. up to 25% in the size range of the accumulation mode (typically >0.1 μm) over the Atlantic. The total aerosol optical thickness over the Indian Ocean, the Gulf of Mexico and the Northeastern Pacific increases by up to 8–10% depending on the emission inventory. Changes in aerosol optical thickness caused by shipping induced modification of aerosol particle number concentration and chemical composition lead to a change in the shortwave radiation budget at the top of the atmosphere (ToA) under clear-sky condition of about −0.014 W/m² to −0.038 W/m² for a global annual average. The corresponding all-sky direct aerosol forcing ranges between −0.011 W/m² and −0.013 W/m². The indirect aerosol effect of ships on climate is found to be far larger than previously estimated. An indirect radiative effect of −0.19 W/m² to −0.60 W/m² (a change in the atmospheric shortwave radiative flux at ToA) is calculated here, contributing 17% to 39% of the total indirect effect of anthropogenic aerosols. This contribution is high because ship emissions are released in regions with frequent low marine clouds in an otherwise clean environment. In addition, the potential impact of particulate matter on the radiation budget is larger over the dark ocean surface than over polluted regions over land.

scholarly journals Convective formation of pileus cloud near the tropopause

2006 ◽  
Vol 6 (5) ◽  
pp. 1185-1200 ◽  
Author(s):  
T. J. Garrett ◽  
J. Dean-Day ◽  
C. Liu ◽  
B. Barnett ◽  
G. Mace ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Deep Convection ◽  
Cloud Microphysics ◽  
In Situ Measurements ◽  
Ice Crystals ◽  
Total Water ◽  
Wave Analysis ◽  
Cold Temperatures ◽  
Face Experiment

Abstract. Pileus clouds form where humid, vertically stratified air is mechanically displaced ahead of rising convection. This paper describes convective formation of pileus cloud in the tropopause transition layer (TTL), and explores a possible link to the formation of long-lasting cirrus at cold temperatures. The study examines in detail in-situ measurements from off the coast of Honduras during the July 2002 CRYSTAL-FACE experiment that showed an example of TTL cirrus associated with, and penetrated by, deep convection. The TTL cirrus was enriched with total water compared to its surroundings, but was composed of extremely small ice crystals with effective radii between 2 and 4 μm. Through gravity wave analysis, and intercomparison of measured and simulated cloud microphysics, it is argued that the TTL cirrus originated neither from convectively-forced gravity wave motions nor environmental mixing alone. Rather, it is hypothesized that a combination of these two processes was involved in which, first, a pulse of convection forced pileus cloud to form from TTL air; second, the pileus layer was punctured by the convective pulse and received larger ice crystals through interfacial mixing; third, the addition of this condensate inhibited evaporation of the original pileus ice crystals where a convectively forced gravity wave entered its warm phase; fourth, through successive pulses of convection, a sheet of TTL cirrus formed. While the general incidence and longevity of pileus cloud remains unknown, in-situ measurements, and satellite-based Microwave Limb Sounder retrievals, suggest that much of the tropical TTL is sufficiently humid to be susceptible to its formation. Where these clouds form and persist, there is potential for an irreversible repartition from water vapor to ice at cold temperatures.

Seasonal variability of cloud microphysics retrieved from NOAA/AVHRR

1999 ◽  
Vol 24 (7) ◽  
pp. 945-948
Author(s):  
K. Kawamoto ◽  
T. Nakajima
Keyword(s):  
Seasonal Variability ◽  
Cloud Microphysics ◽  
Noaa Avhrr

Evaluation of convective cloud microphysics in numerical weather predictionmodel with dual-wavelength polarimetric radar observations

2021 ◽  
Author(s):  
Gregor Köcher ◽  
Florian Ewald ◽  
Martin Hagen ◽  
Christoph Knote ◽  
Eleni Tetoni ◽  
...  
Keyword(s):  
Particle Size ◽  
Weather Prediction ◽  
Cloud Microphysics ◽  
Dual Wavelength ◽  
Size Distributions ◽  
Polarimetric Radar ◽  
Particle Size Distributions ◽  
Numerical Weather ◽  
High Impact Weather ◽  
Radar Signals

<p>The representation of microphysical processes in numerical weather prediction models remains a main source of uncertainty until today. To evaluate the influence of cloud microphysics parameterizations on numerical weather prediction, a convection permitting regional weather model setup has been established using 5 different microphysics schemes of varying complexity (double-moment, spectral bin, particle property prediction (P3)). A polarimetric radar forward operator (CR-SIM) has been applied to simulate radar signals consistent with the simulated particles. The performance of the microphysics schemes is analyzed through a statistical comparison of the simulated radar signals to radar measurements on a dataset of 30 convection days.</p> <p>The observational data basis is provided by two polarimetric research radar systems in the area of Munich, Germany, at C- and Ka-band frequencies and a complementary third polarimetric C-band radar operated by the German Weather Service. By measuring at two different frequencies, the<br />dual-wavelength ratio is derived that facilitates the investigation of the particle size evolution. Polarimetric radars provide in-cloud information about hydrometeor type and asphericity by measuring, e.g., the differential reflectivity ZDR.</p> <p>Within the DFG Priority Programme 2115 PROM, we compare the simulated polarimetric and dual-wavelength radar signals with radar observations of convective clouds. Deviations are found between the schemes and observations in ice and liquid phase, related to the treatment of particle size distributions. Apart from the P3 scheme, simulated reflectivities in the ice phase are too high. Dual-wavelength signatures demonstrate issues of most schemes to correctly represent ice particle size distributions. Comparison of polarimetric radar signatures reveal issues of all schemes except the spectral bin scheme to correctly represent rain particle size distributions. The polarimetric information is further exploited by applying a hydrometeor classification algorithm to obtain dominant hydrometeor classes. By comparing the simulated and observed distribution of hydrometeors, as well as the frequency, intensity and area of high impact weather situations (e.g., hail or heavy convective precipitation), the influence of cloud microphysics on the ability to correctly predict high impact weather situations is examined.</p>

Repräsentierung von Mischphasenwolken im spektralen gekoppelten Wolkenmikrophysikmodells COSMO-SPECS und Vergleich mit Fernerkundungsbeobachtungen

2021 ◽  
Author(s):  
Roland Schrödner ◽  
Johannes Bühl ◽  
Patric Seifert ◽  
Fabian Senf ◽  
Oswald Knoth ◽  
...  
Keyword(s):  
Cloud Microphysics

<p>Während der Feldkampagnen CyCyare (Limassol, Zypern) und DACAPO-PESO (Punta Arenas, Chile) wurden Fernerkundungsmethoden zur Untersuchung von Mischphasenwolken eingesetzt. Die beiden Standorte zeigen unterschiedliche Aerosolbelastungen mit sehr sauberen, marinen Luftmassen über dem Süden Chiles und höheren Aerosolmassen- und -anzahlkonzentrationen über Zypern, die häufig staubbelastet sind. Die Beobachtungen deuten auf unterschiedliche Wolkeneigenschaften hin. Um die Eigenschaften und die Entwicklung der beobachteten Wolken sowie ihre Beziehung zum umgebenden Aerosol weiter zu untersuchen, wurde das detaillierte gekoppelte mikrophysikalische Wolkenmodell COSMO-SPECS für ausgewählte reale Fallstudien angewendet.</p> <p>Das SPECtral bin cloud microphysicS Modell SPECS wurde entwickelt, um Wolkenprozesse unter Verwendung von fixed-bin Größenverteilungen von Aerosolpartikeln und von flüssigen und gefrorenen Hydrometeoren zu simulieren. Es wurde in das numerische Wettervorhersagemodell COSMO implementiert und ersetzt dort die vorhandene Wolkenmikrophysik. COSMO-SPECS wurde bisher für idealisierte Fallstudien mit horizontal periodischen Randbedingungen verwendet. Mit der Berücksichtigung seitlicher Randbedingungen für die Hydrometerspektren können nun auch hochauflösende reale Fallstudien auf genesteten Gittern durchgeführt werden. Dabei wird der meteorologische Treiber COSMO mit seiner Standard-Zweimoment-Wolkenmikrophysik in mehreren Schritten auf immer feineren Gittern mit zunehmender horizontaler Auflösung angewendet. Schließlich wird das COSMO-SPECS-Modellsystem auf den innersten Gebiet mit einer horizontalen Auflösung von einigen hundert Metern angewandt, wobei Randbedingung verwendet werden, die aus dem feinsten antreibenden COSMO-Gebiet stammen. Zu diesem Zweck müssen die nicht-größenaufgelösten Hydrometeorfelder des antreibenden Modells in die entsprechenden Hydrometormassen- und -anzahlverteilungen der Hydrometerspektren von SPECS übersetzt werden.</p> <p>In dieser Arbeit präsentieren wir Ergebnisse für ausgewählte Fallstudien von Mischphasenwolken, die während CyCyare und DACAPO-PESO beobachtet wurden. Mit einer Reihe von Modellsimulationen wurde die Abhängigkeit der resultierenden Wolkeneigenschaften und der Niederschlagsbildung von der INP- und Aerosolkonzentration sowie spezifischer mikrophysikalischer Prozesse untersucht. Die Ergebnisse der Modellsimulationen wurden mit den vorhandenen LIDAR- und Wolkenradarbeobachtungen an den beiden Standorten verglichen.</p>

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