Convective Cloud Research

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Convective Cloud Research Current Projects 1.
CSIP 2. COPS 3. ICEPIC 4. RICO 5. APPRAISE 6.
VOCALS (AG) 7. In-cloud temperature
probe Possible Future Projects Response to
themes -- storms network of sensors... Constrain
-- microphysics in UM (and WRF and
MESO-NH?) Aerosol-Clouds (Amazon) -- Major
international effort ICE-T and New Mexico -- Ice
in convective clouds and influence of
aerosols Projects involve many people in ICAS
from tea maker (me) to Head of ICAS and Director
of NCAS. Everyone important. ICAS is an excellent
group.
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Research on initiation of convection 1.
Convecitve Storm Initiation Project (CSIP)
Southern England, summers of 2004 and 2005 2.
Convective Orograpically-induced Precipitation
Study (COPS) Black Forest, Germany, summer of
2007. Flash Floods caused by intense rainfall
associated with a thunderstorm In the US, more
people die yearly in floods (127 on average) than
by lightning (73), tornadoes (65), or hurricanes
(16) In the UK Country in chaos after flash
floods and storms a familiar headline now --
return time to severe events decreasing
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Map of CSIP
Thanks to Cyril Morcrette
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Map of COPS
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• Objective Determine location and timing of the
  initiation and development of
• convective storms.
• Lids important.
• Ways of overcoming Lids
• Convergence lines created by orography, land/sea
  contrasts, surface moisture gradients,
  differential heating
• Heating impact of clouds
• In complex terrain e.g. up-valley flow,
  elevated heat island
• Gravity waves and cold pools (secondary
  convection)
• Mesoscale convergence lines and dry intrusions
• Combination of processes

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• COPS objective understand influence of aerosols
  on convective precipitation
• - link to MMOCCAA and future expts
• Venting of aerosols out of valleys into clouds
• Role of tranformation of aerosols by previous
  clouds
• Saharan dust outbreaks

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ICEPIC Study of the initiation and development
of ice and precipitation in cumulus clouds. 1.
First ice -- do the numbers match up with
concentration of ice nuclei? Don't know. Didn't
manage this. Only way to do this in individual
Cumulus clouds is to study clouds that are
anchored to a feature - New Mexico(2012). Or
statistically, as in RICO - ICE-T (2012?). Also
see APPRAISE for mixed-phase layer clouds. 2.
There are many more ice particles than ice nuclei
-- why? We showed quantitatively that the
Hallett-Mossop process of secondary ice
production can explain the observed rate of
production of ice. MAC3 model results confirm
that the HM process is important. However, MAC3
also shows that supercooled raindrops are
important and we didn't observe these. 3.
Explain quantitatively with models the production
of precipitation -- that means getting the
riming rate correct having explained 2. The rain
rate produced by MAC3 was comparable with the
observed rate. BUT, the concentration of
aerosols was critical.
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ICEPIC (cont) 4. The UM has errors in the
quantity of precipitation. The interaction of
the parametrized autoconversion and ice
nucleation process can lead to an excessively
rapid glaciation and vertical development of the
simulated clouds. For example, in simulations of
New Mexico clouds, autoconversion first occurred
at and above the freezing level and the raindrops
were then rapidly frozen by accreting primary
ice crystals formed by the parametrized primary
nucleation. These frozen raindrops then grew
further by riming and, because this occurs with
the temperature range of -3 to -8 C, acted as
efficient centres of secondary ice nucleation
via the Hallett-Mossop process. Similar for
ICEPIC clouds. Critical to get autoconversion
right - see results from RICO. Also freezing --
see APPRAISE and future NM, ICE-T and CONSTRAIN?
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RICO Study of the processes responsible for the
formation of warm rain in shallow maritime
cumulus clouds. (Rain In Cumulus over the
Ocean) Result Can quantitatively explain the
formation of rain in shallow maritim cumulus by
collision and coalescence with MAC3 model using
the observed aerosol size distribution.
Observations
MAC3 Model
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APPRAISE Aerosol Properties, Processes And
InfluenceS on the Earth's climate

Core position Zhiqiang Cui -- bin microphysics
in LEM. Almost complete. Important
Aerosol Interactions in Mixed Phase Clouds

• determine the nucleating ability of specific ice
  nuclei and the initiation and
• development of ice in mixed phase clouds.
• determine how aerosol particles control the
  cloud microphysics, preciptiation
• and dynamics in mixed phase clouds.
• determine the type and phase partitioning of
  absorbing material above below and within
• clouds and the role of this material in ice
  nucleation.
• reduce the uncertainty in the contribution of
  indirect radiative forcing by better
• understanding of the role of aerosols in the
  microphysics of mixed phase cloud.
• Few flights last winter most of the flying is in
  January and February 2009 over Chilbolton

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The VOCALS-UK Consortium will deliver new
insights into the influence of marine
stratocumulus clouds on global and regional
climate and provide much needed improvements in
our ability to quantify the processes that
influence stratocumulus clouds and mans
influences on them.
Alan Gadian
BAe-146
Do-228
C-130

• Multi-platform sampling along the 20S cross
  section will deliver
• a synthesised data set for testing of climate
  model representations of the SEP boundary layer.
• A series of important case studies

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VOCALS Bridging the scales between climate and
cloud processes
VOCALS

• VOCALS will act to bridge the gap between climate
  models and key cloud processes by
• Diagnosing and testing important aspects of
  Climate model performance in Sc cloud regions
  nested model resolution is key to this
• Developing new process knowledge and
  parameterising it in a way that is effective for
  climate models
• It will provide process studies with a
  
  climate backdrop to the VOCALS
  
  experiment an important
  context

Courtesy Hugh Coe
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In-Cloud temperature probe
Joint UFAM/FAAM/NCAR/Met Office project to
produce a temperature probe that works in
cloud. Ophir radiometric probe is primary
candidate