Cloud Processing of Trace Gases and Aerosols:
What are we missing / what should we do in the
future?
Mark G. Lawrence
Max Planck Institute for Chemistry, Mainz, Germany
Chemistry-Climate Interactions WorkshopSanta Fe, 10 February 2003
“At the Cleaners with Mark”
Mark G. Lawrence
Max Planck Institute for Chemistry, Mainz, Germany
Chemistry-Climate Interactions WorkshopSanta Fe, 10 February 2003
“Doing the Laundry with Mark”
Mark G. Lawrence
Max Planck Institute for Chemistry, Mainz, Germany
Chemistry-Climate Interactions WorkshopSanta Fe, 10 February 2003
Objectives
• Importance of clouds for atmospheric chemistry?
•Major outstanding issues?
• (Chemistry climate?)
Organized Picture of thewide range and complexity of
issues
TopicsBreak down into 2x2 different topics:
• Cloud type
– Shallow: • Stratiform, fair weather cumulus, and non-Cb
cirrus– Deep:
• Vertical motions exceeding 2-3 km: Cumulus convection (cu-congestus to MCSs and Hurricanes) and deep cirrus anvils (e.g., squall line)
• Chemical phase– Gases– Aerosols
Outline
• Shallow Clouds– Introduction/Effects– Issues
• Deep Clouds– Introduction/Effects– Issues
• Assessment of Priorities
Illustrations/Exampleslargely with MATCH results
Current studies often not explicitly listed
ISSUE
Importance (O3, AOT)
Difficulty (80-90% job)
G A G A
SHALLOW CLOUDS
Parameterization: Microphysics
Parameterization: Cloud Fraction
Liquid water chemistry: Role of internal/external mix
Liquid water chemistry: Uptake kinetics/amount
…
DEEP CLOUDS
Parameterization: Thermo/Location/Intensity
Vertical Transport: Entrainment
Vertical Transport: Detrainment
Vertical Transport: Downdrafts
…
Fill in withL/M/H
Fill in withL/M/H
Shallow Clouds
StratocumulusNorth
Atlantic
(From the Karlsruher Wolkenatlas)
StratocumulusGermany
(From the Karlsruher Wolkenatlas)
Fair Weather CumulusKarlsruhe
(From the Karlsruher Wolkenatlas)
Altocumulus LenticularisUtah
(From the Karlsruher Wolkenatlas)
Processing air
Cirrus
New Mexico
(From the Karlsruher Wolkenatlas)
New Mexico
Bolivia
Shallow Cloud Issues
• Parameterization
• Liquid Water Chemistry
• Ice Surface Chemistry
• Precipitation Scavenging
• Radiative Transfer / Photolysis Rates
Issues: Parameterization
• Microphysics– Currently mainly bulk schemes– Global models: mostly prognostic only for
total condensate, diagnostic for the rest – Cloud resolving models: typically bulk
schemes but prognostic for all condensate types
Large-ScaleProcesses
Cloud-ScaleProcesses
Control
Feedback
Issues: Parameterization
• Cloud cover– Diagnostic threshold (Slingo) schemes in
widest use– Often decoupled from microphysics,
though recent improvements…?– Always decoupled from advection (so far…)
Large-ScaleProcesses
Cloud-ScaleProcesses
Control
Feedback
Issues: Parameterization• Cloud cover – resolving cloud systems
<2% of rain cells (and <5% of clouds) exceed T42 (~105 km2), however…
From Wilcox, Thesis, 2002
Issues: Parameterization• Cloud cover – resolving cloud systems
…rain cells > T42 produce 70% of the total precipitationHouze/Mapes (Pacific):1% of clouds > 105 km2, but are 25% of total cloud cover
No coupling of clouds in one grid cell
with th
ose in the neighborin
g cells!
From Wilcox, Thesis, 2002
Issues: Liquid Water Chemistry
• Aerosols– Crucial for processing of all aerosol types
– Importance of internal/external mixtures (type, age, and size) and coating for determining hygroscopicity, nucleation, and optics?
– Collection/uptake of existing aerosols by droplets?
– Form of aerosols after evaporation (and evaporation process)?
– Coupling with gas phase chem (e.g., interaction of S and N cycles, halogen release, etc.)?
Issues: Liquid Water Chemistry
• Gases– Effects on O3 and HOx still under debate:
locally strong, globally moderate to weak
– Halogen and NMVOC reactions?
– Coupling with aerosol chem (e.g., SO2 oxidation, N2O5 hydrolysis)?
Issues: Ice Surface Chemistry
• Aerosols– Uptake/ageing of aerosols on ice?
Dependence on type/mixture?
• Gases– Halogen activation?
– HO2 + O3 (and other O3- or HOx-related reactions?)
– NMVOC reactions?
Issues: Precipitation Scavenging
• Aerosols– Major loss for all aerosol types
(some after processing)– Importance of aerosol type/mixture for
nucleation and collection?
Issues: Precipitation Scavenging
• Gases– Major loss process for reactive nitrogen, odd hydrogen, VOCs,
and halogens– Water solubilities generally known (except VOCs)– Ice uptake/retention very poorly characterized– Kinetic uptake limitations difficult to model (generally
neglected)
Issues: Precipitation Scavenging
• Example: Effect on soluble gases with a surface source
Based on Crutzen and Lawrence, J. Atmos. Chem., 2000
Hx in M/atm:
Hx = 0Hx = 103
Hx = 104
Hx = 105
Hx = 106
Issues: Precipitation Scavenging
• Example: Effect on soluble gases with a surface source
Based on Crutzen and Lawrence, J. Atmos. Chem., 2000
Hx in M/atm:
Hx = 103
Hx = 104
Hx = 105
Hx = 106
Hx = 1010
Issues: Precipitation Scavenging
• General– Precipitating fraction and stratiform/convective split– Preservation of information on scavenged areas– Slower sedimentation of smaller hydrometeors
Issues: Precipitation Scavenging
• Precipitating fraction
From Wilcox, Thesis, 2002
Issues: Precipitation Scavenging
• Preservation of Information / Artificial Mixing
t0 t0 + scav t0 + scav + adv t0 + t
Shorter t => worse artificial mixing!
Issues: Precipitation Scavenging
• Slower sedimentation of smaller hydrometeors
From Lawrence and Crutzen, Tellus, 2000
Issues: Radiative Transfer
• Effects on Photolysis Rates (and heating rates…)
– Effect on OH and CH4 small to moderate (~10%)
– Already simulated rather accurately (Landgraf/Crutzen)
From Landgraf, Thesis, 1998
MATCH-MPICsimulation
Deep Clouds
Organized
Convection
Cumulus CongestusMiam
i
Karlsruhe(From the Karlsruher
Wolkenatlas)
Near Karlsruhe
Cumulonimbus with and without Anvil
(From the NOAA Gallery)
Supercell Cumulonimbus
(From Houze‘s Cloud Atlas)
Squall Line
Hurricane Floyd
Mass-Balance
Subsidence
Downdrafts
Deep Convection: Characteristics
Updrafts
Eigenschaften der Eigenschaften der KonvektionKonvektion
Precipitation and Precipitation and slower slower
SedimentationSedimentation
PrecipitatiPrecipitationon
Anvils Anvils (Ice)(Ice)
LightniLightningng
Deep Convection: Characteristics
Deep Cloud Issues
• Parameterization
• Vertical (dry) Transport
• Precipitation Scavenging
• Lightning NOx
• Several components to deal with:– Thermodynamics (T/t, Q/t, Q1, Q2)– Microphysics– Cloud Cover / Precipitation Swath– Mass Fluxes / Tracer Transport– Proper treatment in offline models
(pre-stabilized thermodynamic profiles)
Issues: Parameterization
Large-ScaleProcesses
Moist-ConvectiveProcesses
Control
Feedback
Issues: Parameterization
• Wide range of philosophies and closures
• Focus of testing on thermodynamics; Tracers (e.g., CO, CH3I) may provide powerful tests
• Mesoscale organization rarely considered– CEMs: delays in response to large-scale forcing– First attempts by Donner, others? – Relevance for tracer transport unknown, likely substantial
Large-ScaleProcesses
Moist-ConvectiveProcesses
Control
Feedback
Issues: Vertical (dry) Transport
• Updraft Effects – Transport to the UT:– O3 and O3-precursors– HOx reservoirs– Stratosphere-relevant gases (halogenated gases, COS)– Aerosols – esp. Dust, BC, OC, and Sulfate precursors– Clean air masses
Example:
Southern Asian CO
from MATCH-MPIC
Issues: Vertical Transport
?Entrainment intothe Ensemble
?
Tropopause
Mu
Z
Issues: Vertical Transport
?Entrainment intothe Ensemble
Detrainment fromthe Ensemble
?
Mu
Z
?
Tropopause
Issues: Vertical Transport
?Entrainment intothe Ensemble
Detrainment fromthe Ensemble
?
Mu
Z
??
Tropopause
??
Issues: Vertical Transport
• Updraft Effects – Importance of Detrainment Region:
MATCH-MPIC O3:
Detrain-top----------
Base run
Issues: Vertical Transport
?
Downdrafts
• Strength
• Feeder Regions
( Organization)
• Entrainment
• Detrainment
?
Significance of downdrafts?
Issues: Vertical Transport
Mass-Balance Subsidence
• In same model column?
• As part of circ. cells (Hadley, Walker)?
Issues: Vertical Transport• Role of Subsidence, Balance with Updrafts:
From Lelieveld and Crutzen, Science, 1994
Issues: Vertical Transport• Role of Subsidence, Balance with Updrafts:
MATCH-MPIC O3:
Base run----------
No Conv Transp
Issues: Vertical Transport• Role of Subsidence, Balance with Updrafts:
Trop. Total Ozone (Tg)Run MATCH-MPIC1 MOGUNTIA2
No Convection 293 315
With Convection 328 (+12%) 253 (-20%)(Base Run)
1 This Study (when conv. precip is also turned off => 297 Tg)2 Lelieveld & Crutzen, Science, 1994 (only conv. transport turned off)
Cause for difference??
Issues: Vertical Transport
Degree/Amount ofPenetration into the TTL
(tropical tropopause layer)?
Issues: Vertical Transport
Penetration into the Stratosphere?• Tropical?• Extratropical?• Induced STF?
Issues: Precipitation Scavenging
• Scavenging Effects:– Major loss process for all aerosol types (some after processing)
– Major loss process for reactive nitrogen, odd hydrogen, and VOCs
– Important for stratosphere-relevant gases (soluble halogenates)
Issues: Precipitation Scavenging
Amount/Distribution?
Based on a MATCH simulation with NCEP reanalysis data
Issues: Precipitation Scavenging
Precipitation Swath?
Core/Anvil, Intensity?
Origin of scavenged air?
} }}
Issues: Precipitation Scavenging
Kinetic Uptake Limitations
Issues: Precipitation Scavenging
• Uptake in/on ice
• Retention in supercooled droplets upon freezing
Issues: Precipitation Scavenging• Importance of retention in ice and kinetic uptake limits
Based on Crutzen and Lawrence, J. Atmos. Chem., 2000
Hx in M/atm:
Hx = 103
Hx = 104
Hx = 105
Hx = 106
Hx = 1010
Ice
Issues: Precipitation Scavenging• Importance of retention in ice and kinetic uptake limits
Based on Crutzen and Lawrence, J. Atmos. Chem., 2000
Hx in M/atm:
Hx = 103
Hx = 104
Hx = 105
Hx = 106
Hx = 1010
Ice
Issues: Precipitation Scavenging• Importance of retention in ice
30 min 45 min 60 min
WRF - (Preliminary!)
Insoluble
Soluble
Degassed
Issues: Precipitation Scavenging• Importance of retention in ice WRF -
(Preliminary!)
Issues: Precipitation Scavenging
Artificial Mixing(preservation of info)
Issues: Lightning NOx
Issues: Lightning NOx
Influence on NOx and O3
(MATCHResults)
O3 Ratio:with/withoutLightning
NOx Ratio:with/withoutLightning
Issues: Lightning NOx
• Global Amount
• Regional Distribution
• Vertical Distribution
• Charge Separation
• NOx Production Mechanism
Issues: Lightning NOx
Global Amou
nt
REFERENCE(type of estimate)
P(NO)(1016 molecules
J-1)
P(NO)(1025
Molecules flash-1)
F(102 flashes s-1)
G(NO)(Tg (N) year-1)
Lawrence et al. (1995)(review)
- 2.3 (1-7) 1 (0.7-1.5) 2 (1-8)
Kumar et al. (1995)(observations)
0.5 1 2
Ridley et al. (1996)(observations)
- 1 2-5
Levy et al. (1996)(theoretical)
- - - 3-5
Price et al. (1997)(observations)
10 - 0.7-1 12.2 (5-20)
Price et al. (1997)(theoretical)
10 - - 13.2 (5-25)
Wang et al (1998)(laboratory)
- 3.1 0.3-1 2.5-8.3
Nesbitt et al. (2000)(observations)
- 0.87-6.2 0.57 0.9
Issues: Lightning NOx• Regional Distribution
MATCH-MPICOTD
Extratropics - underestimated
Tropics - overestimated
Flashes/km2/Month
Overarching Issues
Major Overarching Issues
• Do we need to unify/combine stratiform and convective cloud parameterizations?
• Do we need to keep separate cloudy and cloud-free variables for each grid cell?
• How do we include the effects of mesoscale organization?
• How do we properly compare CEM studies with 1D versions from global models?
• Which geographical regions need the most attention?
Priorities
ISSUE
Importance (O3, AOT)
Difficulty (80-90% job)
G A G A
SHALLOW CLOUDS
Parameterization: Microphysics L/M H H H
Parameterization: Cloud Fraction M H L/M L/M
Liquid water chemistry: Role of internal/external mix
- H - H
Liquid water chemistry: Uptake kinetics/amount L/M L/M L L/M
Liquid water chemistry: Aerosol processing details - H - H
Liquid water chemistry: Effects on O3/HOx L/M - M -
Liquid water chemistry: Halogens / NMVOCs L/M - H -
Liquid water chemistry: Gas-aerosol coupling L/M H H H
Ice surface chemistry L/M ? H H
Precipitation scavenging: Amount/Fraction M H M/H M/H
Precipitation scavenging: Ice uptake/retention M M(?) H H
Precipitation scavenging: (Liquid) kinetic limitations M M M M
Precipitation scavenging: Artificial mixing M H M/H M/H
Photolysis rates L L L L
DEEP CLOUDS
ISSUE
Importance (O3, AOT)
Difficulty (80-90% job)
G A G A
DEEP CLOUDS
Parameterization: Thermo/Location/Intensity H H M/H M/H
Vertical Transport: Entrainment M/H M M/H M/H
Vertical Transport: Detrainment M/H M M/H M/H
Vertical Transport: Downdrafts L L M M
Vertical Transport: Subsidence – connection to LS circ
M/H M H H
Vertical Transport: Penetration into the TTL M/H L/M M/H M/H
Vertical Transport: Penetration into the Strat / STE L/M L M/H M/H
Precipitation scavenging: Amount/Distribution /Swath M H M/H M/H
Precipitation scavenging: Ice uptake/retention M M(?) H H
Precipitation scavenging: (Liquid) kinetic limitations M M/H H H
Precipitation scavenging: Artificial mixing M H H H
Lightning NOx: Amount M - M -
Lightning NOx: Distribution M - L/M -
Extras
(type of estimate)
REFERENCEP(NO)
(1016 molecules J-1)P(NO)
(1025 Molecules flash-1)
F(102 flashes s-1)
G(NO)(Tg (N) year-1)
Tuck (1976) (theoretical)
- 1.1 5 4
Chameides et al.(1976) (theoretical)
3-17 6-14 4 18-41
Noxon (1976)(field observations)
- 10 5 37
Chameides (1979) (theoretical)
8-17 16-34 4 47-100
Dawson (1980) (theoretical)
- 0.8 5 3
Hill et al. (1980) (theoretical)
- 1.2 1 0.9
Levine et al.(1981)(laboratory )
5 ± 2 0.5 5 1.8 ± 0.7
Kowalczyk (1981) - - - 5.7
Peyrous and Lapeyre (1982)(laboratory)
1.6 3.2 4 9.4
Drapcho et al. (1983)(field observations)
- 40 1 30
Franzbau et al. (1989)(field observations)
- 300 1 220
Sisterson (1990)(theoretical)
- 8.2 2 12
Liaw et al. (1990) - - - 81
Issues: Precipitation Scavenging
• Precipitation Swath
• Core/Anvil fraction
• Uptake in/on ice
• Retention in supercooled water upon freezing
• Kinetic uptake limitations
• Preservation of information (artificial mixing)
(From the NOAA Gallery)
Tornadoes
Hail
Lightning
Issues: Parameterization
• Distribution/Intensity of deep convection
Based on a MATCH simulation with NCEP reanalysis data
From Lawrence and Crutzen, Tellus, 2000
Issues: Lightning NOxInfluence on NOx and O3
O3 Ratio:with/withoutLightning
NOx Ratio:with/withoutLightning
500 hPa
MATCH-MPIC
Einfluss der vertikale Verteilung von Blitzen
Verhältnisder Stickoxide:Amboss/gesamt Wolke
Verhältnisdes Ozons:Amboss/gesamt Wolke
Dru
ck (
hP
a)D
ruck
(h
Pa)
Vertical distribution: Implications for tropospheric chemistry.
Ratios of zonal averages for NOx, and O3 for July 1997.
NOx O3
Pick/base Pick/base