Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility...
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![Page 1: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/1.jpg)
Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to
Environmental Parameters
Jay MaceTrevor FergusonStephanie AveySteve Cooper
Photo Credit: patternsofnature.files.wordpress.com
![Page 2: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/2.jpg)
The Southern Ocean is one of the cloudiest regions on Earth…
… and primarily populated by geometrically thin layers based in the boundary layer.
![Page 3: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/3.jpg)
Methodology:
1. Using WS climatology provided at GISS, collect A-Train hydrometeor layer statistics as a function of WS along the CloudSat Track
2. Aggregate the RL-GEOPROF data for that weather state over a period of time to characterize the layer properties
3. Examine regional similarities in hydrometeor layer distributions within a WS.
Use 3-years of A-Train data (2007,8,9) across the Pacific Basin
WS3: Anvils and Isolated Convection
![Page 4: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/4.jpg)
WS 5: Polar and High Latitudes
Dominated by low level clouds of moderate optical thickness – often with cirrus above.
![Page 5: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/5.jpg)
North:
South:
WS 5: Polar and High Latitudes
![Page 6: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/6.jpg)
The Inversion Algorithm
• Assumption: Bimodal PSD– cloud mode and precipitation modes
• Input: CloudSat Z Profile, 94 GHz Tb (New Product!), MODIS 0.55, 1.6, 2.1 um reflectances
• Output: Cloud LWC, re, Nd, and Precip LWC, re, Nd in each range bin.
• Prior data from RICO and MASE
Forward Models:
Radar Forward Model: Posselt and Mace (2013). Mie backscatter and extinction. Direct integration of modified gamma PSD’s. Accounts for air and droplet attenuation.
MODIS reflectances simulated using Radiant 2.0 eigenmatrix solver (Christi and Gabriel, 2004)
Microwave: Kummerow et al. (1993) with modifications by Lebsock. W-Band ocean emissivity developed by Greg Elsaesser at CSU.
The A-Train Observations:
• Cloudsat CPR is sensitive to precip when precip is present but cloud otherwise• MODIS Vis and NIR Reflectances sensitive to Cloud properties primarily but precip
contributes• Passive Microwave (from Cloudsat Noise - New!) responds to water path – mostly
cloud but precip contributes
Together these measurements have independent (but tangled) information on the cloud and precipitation coexisting within a profile.
![Page 7: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/7.jpg)
Southern Ocean Attenuation Comparison:Observed by Cloudsat – calculated from retrieved microphysics
![Page 8: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/8.jpg)
Examples: Warm Shallow Cumulus in the SE Pacific20070106, orbit 03691
NonPrecipitating Case94 GHz Tb: 246 KMODIS 550 nm: 0.62MODIS 1.6 um: 0.48MODIS 2.1 um: 0.31
Cloud Number: 80 cm-1 ±±60%
Cloud LWC: 0.2 g m-3
±70%Cloud re: 10 um ±30%
Precipitating Case94 GHz Tb: 259 KMODIS 550 nm: 0.63MODIS 1.6 um: 0.45MODIS 2.1 um: 0.23
Cloud Number: 80 cm-1 ±±120%
Cloud LWC: 0.3 g m-3
±130%Cloud re: 20 um ±180%
Precip Rate: 80 mm/day ±40%
![Page 9: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/9.jpg)
![Page 10: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/10.jpg)
![Page 11: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/11.jpg)
Examine the Co-Dependence of Albedo and Precipitation Susceptibility in Warm Shallow Clouds of the Southern Ocean
Periods Considered: Winter, 2008, ~11,000 Profiles Summer, 2007, ~32,000 Profiles
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Co-Dependence of Albedo and Precipitation Susceptibility: Seasonal Comparison
Summer Winter
# Profiles: 11140# Profiles: 32389
Summer Microphysics Stats
• Ncld=90 cm-3
• LWP=120 g m-2
• Prate=22 mm day-1
• Albedo=0.4• Prate> 1mm/day: 68%• Prate> 10 mm/day: 20%
Winter Microphysics Stats
• Ncld=9 cm-3
• LWP=98 g m-2
• Prate=23 mm day-1
• Albedo=0.2• Prate> 1mm/day: 89%• Prate> 10 mm/day: 32%
![Page 13: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/13.jpg)
Consistency with Feingold et al., (2013)Feingold et al. (2013) show that• Cloud environments dominated by autoconversion are sensitive to Nd • Cloud environments dominated by accretion are less sensitive to Nd• S0 maximum increases for autoconversion dominated environments• Accretion dominated environments transition rapidly to lower S0
Lower Nd, Transitions to accretion dominated regime at lower S0 for LWP > 250 g/m2
Higher Nd, remains in autoconversion dominated regime with higher S0 and no obvious transition
Summer Winter
![Page 14: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/14.jpg)
Summary
• Atrain provides unique information regarding the relationships between warm cloud properties and light precipitation properties
• Information is distributed between radar, passive microwave, solar reflectance.• Uncertainties in cloud properties are substantial in the presence of precipitation
when cloud property retrievals rely more on passive measurements.
• Southern Ocean clouds and precipitation show large seasonal amplitudes in cloud and precipitation properties
• Results consistent with seasonal oscillations in sulfate aerosol and sensitivity to sea salt aerosol due to surface winds
• Results suggest • 1st indirect effect (albedo susceptibility) remains active in summer and winter• 2nd aerosol indirect effect (precip susceptibility) diminishes in winter consistent
with Feingold et al. modeling work.
Photo Credit: patternsofnature.files.wordpress.com
![Page 15: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/15.jpg)
“If you look deeply, you can see the clouds in the rain …” Thich Naht Hanh, Zen Buddhist Monk
![Page 16: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/16.jpg)
Left Profile: • More LWC information. • Cloud droplets are bigger
relative to precip, so radar contributes to information
Right Profile: • Less LWC information.
• Cloud droplets are smaller relative to precip and passive data contributes more than radar.
![Page 17: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/17.jpg)
Graciosa Island
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re=25 umN=15 cm-3
re=110 umN=0.2 cm-3
re=15 umN=20 cm-3
re=110 umN=0.08 cm-3
![Page 19: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/19.jpg)
NonPrecipitating Case Precipitating Case
Examples: Warm Shallow Cumulus in the SE Pacific
Cloud Droplet Number
![Page 20: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/20.jpg)
NonPrecipitating Case Precipitating Case
Examples: Warm Shallow Cumulus in the SE Pacific
LWC Info Content
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From Klein et al., (2013)
The ubiquitous low cloud cover over the Southern Ocean remains a challenge for climate model simulations
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NonPrecipitating Case Precipitating Case
Examples: Warm Shallow Cumulus in the SE Pacific
Cloud Liquid Water
![Page 23: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/23.jpg)
NonPrecipitating Case Precipitating Case
Examples: Warm Shallow Cumulus in the SE Pacific
Cloud Effective Radius
![Page 24: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/24.jpg)
NonPrecipitating Case Precipitating Case
Examples: Warm Shallow Cumulus in the SE Pacific
LWC Sensitivity
Note the magnitudes
Note the relative contributions
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Summer
Winter
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SummerLow Wind
SummerHigh Wind
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WinterLow Wind
WinterHigh Wind
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SummerLow Wind
WinterLow Wind
![Page 29: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/29.jpg)
SummerHigh Wind
WinterHigh Wind
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Knowledge of precipitation processes within dynamical environment are central to understanding ….
Advanced cloud parameterizations (Weber and Quas, 2012) attempt to represent subgrid statistics of precip processes with little knowledge of what actually exists in nature (Morrison and Gettelemen, 2008)
Our Goal: Build on Lebsock et al. to derive simultaneous cloud-precip property statistics within dynamical regimes of the Southern Ocean.
![Page 31: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/31.jpg)
Examine the Co-Dependence of Albedo and Precipitation Susceptibility in Warm Shallow Clouds of the Southern Ocean
Albedo Susceptibility (Platnick and Twomey, 1994):
SA=dA/dlnN
Painemal and Minnis, 2012 Sorooshian et al, 2009
Precipitation Susceptibility (Feingold and Stevens, 2009):
SA=dlnP/dlnN
![Page 32: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/32.jpg)
Co-Dependence of Albedo and Precipitation Susceptibility: Summer – Low Wind vs. High Wind
Low Wind Tercile (<5 m/s) High Wind Tercile (>12 m/s)
# Profiles: 10796# Profiles: 10796
Summer Low Wind Microphysics Stats
• Ncld=99 cm-3
• LWP=110 g m-2
• Prate=18 mm day-1
• Albedo=0.39• Prate> 1 mm/day: 64%• Prate> 10 mm/day: 17%
Summer High Wind Microphysics Stats
• Ncld=133 cm-3
• LWP=125 g m-2
• Prate=23 mm day-1
• Albedo=0.40• Prate> 1 mm/day: 70%• Prate> 10 mm/day: 22%
![Page 33: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/33.jpg)
Co-Dependence of Albedo and Precipitation Susceptibility: Winter - Low Wind vs. High Wind
Low Wind Tercile High Wind Tercile
# Profiles: 3715# Profiles: 3715
Winter Low Wind Microphysics Stats
• Ncld=7 cm-3
• LWP=86 g m-2
• Prate=15 mm day-1
• Albedo=0.18• Prate> 1 mm/day: 88%• Prate> 10 mm/day: 28%
Winter High Wind Microphysics Stats
• Ncld=13 cm-3
• LWP=107 g m-2
• Prate=37 mm day-1
• Albedo=0.21• Prate> 1 mm/day: 90%• Prate> 10 mm/day: 39%
![Page 34: Derived Properties of Warm Marine Low Clouds over the Southern Ocean: Precipitation Susceptibility and Sensitivity to Environmental Parameters Jay Mace.](https://reader038.fdocuments.in/reader038/viewer/2022110207/56649d925503460f94a79625/html5/thumbnails/34.jpg)
So, What is going on?
• Sulfate aerosol decreases significantly from Summer to Winter
Ayers and Gras (1991)Cape Grim (41 S)
Kloster et al (2005)Amsterdam Is. (37 S)
• Sea salt aerosol increases with wind speed
O’Dowd et al., 1997
Feingold et al., 2013: Is the precipitation process dominated by autoconversion (Nd dependent) or accretion? LES suggest that S diminishes with decreasing Nd at a given LWP.