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George Kallos With contribution from S. Solomos, I. Kushta, M. Astitha, C. Spyrou, I. Pytharoulis

UNIVERSITY OF ATHENS SCHOOL OF PHYSICS, DIVISION OF ENVIRONMENT AND METEOROLOGY ATMOSPHERIC MODELING AND WEATHER FORECASTING GROUP http://forecast.uoa.gr. Key Processes in Regional Atmospheric Modeling in the Mediterranean Region. George Kallos With contribution from

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George Kallos With contribution from S. Solomos, I. Kushta, M. Astitha, C. Spyrou, I. Pytharoulis

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  1. UNIVERSITY OF ATHENS SCHOOL OF PHYSICS, DIVISION OF ENVIRONMENT AND METEOROLOGY ATMOSPHERIC MODELING AND WEATHER FORECASTING GROUP http://forecast.uoa.gr Key Processes in Regional Atmospheric Modeling in the Mediterranean Region George Kallos With contribution from S. Solomos, I. Kushta, M. Astitha, C. Spyrou, I. Pytharoulis kallos@mg.uoa.gr

  2. MOTIVATION • Physiographic characteristics are partially responsible for the formation of particular climatic conditions in the Mediterranean Region. • Regional climatic patterns are defined as a result of balancing between large scale flow and mesoscale circulations. • The resulted circulation has a general trend from North to South (pressure gradient and differential heating between land and water). • Air masses reaching the Mediterranean region are not clearly defined as pure maritime or continental because their characteristics are modified relatively fast. • The air masses in the area have a mixture of natural and anthropogenic origin aerosols with varying optical and hygroscopic properties. • Therefore, cloud formation is a complicated process.

  3. MOTIVATION • Desert dust and sea salt are major sources of PM in the atmosphere. • Their impacts in the atmosphere are many and of course the feedbacks are considerable. • The impacts are ranging from modification of the radiative forcing to cloud formation and precipitation. • Therefore, perturbations in dust and/or sea salt particle production can have impacts on radiative properties, cloud formation and water budget. • These links are not one way but there are feedbacks that are critical for both meteorological and climatological – scale phenomena. • The links and feedbacks become more complicated because of the coexistence of anthropogenically-produced aerosols and chemical transformations.

  4. OBJECTIVES • Discuss the: • Long range transport of naturally (mainly Saharan dust and sea-salt) and anthropogenically - produced aerosols. • Aerosol-cloud interaction processes • Other processes needed to be taken in the account • New modeling tools

  5. Paths and scales of transport TRANSITION SEASONS SUMMER SEASON Kallos et al. 2007 JAMC, 46(8), pp. 1230–1251.

  6. PM AND GASEOUS POLLUTANTS IN THE ATMOSPHERE PROCESSES AFFECTING AIR QUALITY AND CLIMATE dust dust STRATOSPHERE dust Heterogeneous reactions SO2 + O3 DSO4 (dust+sulfate) NO2 DNO3 (dust+nitrate) HNO3 DNO3 (dust+nitrate) incoming-outgoing SW radiation hv & OH UPPER TROPOSPHERE warming SO2 H2SO4 SO2 HCl ash Nucleation Deposition LOWER TROPOSPHERE Cloud Modifications precipitation LW radiation NaCl Dust cooling of the surface

  7. AEROSOLS AND CLOUDS • Aerosols in general act as CCN and IN in the cloud formation processes according to their physicochemical properties. • As it is known, high concentrations of aerosols result in haze and small-cloud droplet formation that do not necessarily lead in precipitation. • Although, this is not always the case. • Under certain conditions and mixture of naturally and anthropogenically-produced aerosols, gigantic CCNs and/or IN formation with enhanced hygroscopicity may lead in stormy weather conditions (Levin et al., 2006; Rosenfeld et al., 2008)

  8. AEROSOLS AND CLOUDS Condensates (cloud,rain,ice,graupel,hail, pristine ice,aggregates) drop growth (collision, coalescence) activation Aerosol Natural particle emissions – transport

  9. COEXISTENCE OF MINERAL DUST, SULFATES AND CLOUD DROPLETS SEM analysis Izaña Sta. Cruz de Tenerife spongy carbonaceous anthropogenic particles general aspect of dust rounded quartz natural marine aerosols potassium sulphate particles clay particles (>10 µm) typical large and plate natural gypsum particles clay particles (around 1 µm) <5 µm Ca sulphates with crystalline habit fresh water diatom spore particles covering clay aggregates (Alastuey et al. 2005)

  10. COEXISTENCE OF MINERAL DUST, SULFATES AND CLOUD DROPLETS A photomicrograph of desert mineral dust with small sulfate particles on its surface. A photomicrograph of drops and aerosol particles collected inside clouds D: drops, P: dry interstitial particles (Levin et al. 1996, 2006)

  11. SAHARAN DUST AND ANTHROPOGENIC POLLUTANTS FORMATION OF VARIOUS GENERATIONS OF PM 1st GENERATION POLLUTANTS 3rdGENERATION POLLUTANTS

  12. MASS-SIZE DISTRIBUTION OF PM Interaction Molecular Processes Mechanical Processes Chemical transformation of gases, coalescence, condensation, homogeneous nucleation SULFATES FORMED ON DUST DUST + SEA SALT + SODIUM AEROSOL + CHLORIDE AEROSOL NITRATES FORMED ON DUST NITRATES SULFATES sedimentation 0.001 0.01 0.1 1 10 100 PARTICLE DIAMETER (μm) rain COARSE PARTICLES FINE PARTICLES

  13. Aerosol-Cloud Interaction (Rosenfeld, 2008)

  14. Aerosol effects on precipitation (Rosenfeld, 2008) Maritime & moderate (wet) continental clouds Accumulated rain Dry unstable situation Aerosol concentration

  15. Aerosol effects on precipitation Precipitation LOSS (evaporation+sublimation) GAIN (condensation+deposition) Precip = - Precipitation is often a small difference of large values Aerosols affect both generation and loss of hydrometeor mass

  16. WHY WE NEED NEW MODELING TOOLS? To study such complicated processes there is a need for advanced modeling tools that include physical and chemical properties directly coupled.

  17. ICLAMS • The Integrated Community Limited Area Modeling System – ICLAMS – has been developed (still under development) at the framework of CIRCE project (RL8) • It has been designed to be able to simulate links and feedbacks between air quality and regional climate • ICLAMS development is on RAMS.6 modeling system • RAMS is a multi-scale modeling system and can be configured to run with resolution from a few meters to tens of kilometers on a two-way interactive nesting mode • It has detailed cloud microphysical scheme with 8 microphysical categories, detailed surface parameterization and many other features that make it the most advanced limited area meteorological model • The cloud microphysical scheme includes prognostic equations for mass mixing ratios of the various forms of water species

  18. ICLAMS The new model development includes the following features: • Full dust cycle module following the formulation used in SKIRON/Dust with 8 dust particle bins following lognormal distribution Kallos et al., (2005, 2007). • Sea salt production mechanism with 2 size bins following Gong et al., (1999). • Gas and aqueous phase chemistry (SAPRC mechanism as implemented in CAMx). • Gas to particle conversion and heterogeneous chemistry following the ISOROPIA scheme and additional interactions with desert dust, sea salt and sulfates. • Impacts of aerosols and PMs on radiative transfer of the photochemically active bands. • Visible and Infrared corrections due to aerosols and PMs. • Treatment of CCN and GCCN as predictive quantities (4-D). • All these new elements are directly coupled and executed together with the meteorological modules.

  19. BASIC MODULES OF ICLAMS • The development is carried out on the RAMS ver. 6 • It has two-way interactive nesting capabilities • Explicit cloud microphysical scheme • It can be nested inside of global systems • It can run with configurations from a few meters horizontal resolution up to hemispheric • It also includes: • Detailed soil surface and water interaction processes • Detailed dust cycle description • Detailed sea salt cycle • Gas phase chemistry module with photochemical processes • Aqueous phase chemistry • Gas to particle conversion and heterogeneous chemical reactions • Dry and wet deposition modules • Aerosol-cloud-radiative transfer interaction module • It can be used mainly for case studies and scenario development related to aerosol cloud interaction

  20. ICLAMS Aerosol – Meteorology feedback The modeling system handles dust, sea salt and three-generation particle formation on a direct way. CCN, GCCN and IN are predictive quantities. Links and feedbacks between the direct and indirect aerosol effects are described. Currently the following model components have been developed and tested : Cloud effects: Prognostic CCN calculation based on aerosol number density and chemical composition.Three different approaches are used. All fine aerosols and 33% coarse are efficient CCN (Levin et al., 2005) A parameterization based on Koehler theory (Nenes et al., 2007) is used to calculate the number of natural particles that can be active CCNs and the number of cloud droplets nucleated based on the chemical composition of the aerosols, their size (lognormal distribution) and ambient conditions (temperature, updraft velocity). Cloud droplets spectrum is obtained by previously (offline) generated lookup tables from detailed parcel-bin model as a function of CCN and GCCN number concentration, updraft velocity and temperature. (Cotton et al., 2007). Prognostic cloud droplets spectrum is then used by the explicit microphysical scheme of RAMS (Meyers et al. 1997) to forecast the rest of the microphysical species (rain, pristine ice, snow, aggregates, graupel, hail) and precipitation. Radiative transfer : Calculation of the heating rates based on aerosol load and type. Two different options are available. Harrington radiation scheme Rapid Radiative Transfer Model (RRTM)

  21. MEIDEX experiment MEIDEX TEST CASE • On 28 January 2003, a dust storm passed over the north east Mediterranean region. • On 29 JAN 2003 heavy rain and hail dispersed over the Middle East coastline and a few km inland. • Flood events and agricultural disasters were reported. • Airborne measurements of this episode were obtained during the Mediterranean Israeli Dust Experiment (MEIDEX) Two cases have been considered: 1st case: Natural particles are treated as passive tracers. User specified constant CCN #. 2nd case: Dust plume and sea-salt sprayed interact with clouds. CCN and GCCN prognostic (from dust and sea salt concentrations and size distribution.

  22. MODEL SETUP RAMS6.0 with: • DUST MODULE (Zender at al., Marticorena and Bergameti) 8 Bin lognormal dust particles distribution - Dust cycle • SEASALT MODULE (Gong et al.) 2 Bin lognormal salt particles distribution - Seasalt cycle DOMAIN SETUP 3 grids (36km-12km-4km) , 31 vertical levels, 120 hours run Initial and boundary conditions – NCEP 1deg GFS analysis data REFERENCE RUN (1st case) • ICLOUD=5 (Constant # of CCN) Dust and Salt particles do not interact with the rest of the model TEST RUN (2nd case) • ICLOUD=7 (3-D prognostic CCN and GCCN field) Particles serve as efficient cloud condensation nuclei (CCN).

  23. LARGE SCALE FEAUTURES Wind speed 28JAN2003 1200UTC Dust load 28JAN2003 0900 UTC 3h accumulated precipitation 28JAN2003 1200 UTC • On 28 Jan 2003 a cold cyclone moved from Crete through Cyprus accompanied by a cold front . • A second air mass transported dust particles from NE Africa over the sea towards Israeli coastline.

  24. DUST CONCENTRATION at 1500UTC (all bins) 27JAN2003 1500 UTC 28JAN2003 1500 UTC 29JAN2003 1500 UTC 1071 m 6th model level 2087 m 9th model level 3440 m 12th model level

  25. 27JAN2003 28JAN2003 29JAN2003 SEA SALT CONCENTRATIONS at 1500 UTC (both bins) 97 m 2nd model level 530 m 4th model level 1071 m 6th model level

  26. Case 1 - CONSTANT CCN (ICLOUD=5) 1hr accumulated precip. 29JAN2003 06 UTC 1hr accumulated precip. 29JAN2003 10 UTC 1hr accumulated precip. 29JAN2003 13 UTC 1hr accumulated precip. 29JAN2003 18 UTC Case 2 - PROGNOSTIC CCN (ICLOUD=7) 1hr accumulated precip. 29JAN2003 06 UTC 1hr accumulated precip. 29JAN2003 10 UTC 1hr accumulated precip. 29JAN2003 13 UTC 1hr accumulated precip. 29JAN2003 18 UTC PRECIPITATION PATTERN

  27. Case 1 - CONSTANT CCN (ICLOUD=5) 3hr accumulated hail 29JAN2003 06 UTC 3hr accumulated hail 29JAN2003 09 UTC 3hr accumulated hail 29JAN2003 15 UTC 3hr accumulated hail 29JAN2003 21 UTC Case 2 - PROGNOSTIC CCN (ICLOUD=7) 3hr accumulated hail 29JAN2003 06 UTC 3hr accumulated hail 29JAN2003 09 UTC 3hr accumulated hail 29JAN2003 15 UTC 3hr accumulated hail 29JAN2003 21 UTC HAIL PATTERN

  28. MEIDEX OBSERVATIONS (Levin et al.) aircraft altitude particle concentration Total Particles have been measured at 15 locations along the aircraft flight (11:27–13:40 UTC 28JAN2003)

  29. ICLAMS PARTICLE CONCENTRATIONS MEIDEX experimental flight • For each one of the 15 measuring locations of MEIDEX experiment a time / height plot of modelled total particles (dust & salt) concentration is created. • Maximum particles concentration during the flight period (10:00 – 13:00 UTC) are ranging from 1000 #/cm3 near the ground to below 50#/cm3 above 3 Km. • These numbers compare well with the aircraft observations.

  30. COARSE & FINE PARTICLES Coarse particles – ICLAMS - 28JAN2003 Fine particles – ICLAMS - 28JAN2003 • During the dust storm simulation the concentration profile for coarse particles (d>1 μm) ranged from 40 (#/cm3) near the ground to less than 5(#/cm3) above 2km • The simulated concentration for fine particles (d<1 μm) ranged from 1000 (#/cm3) near the ground to less than 100 above 3km.

  31. 2nd CASE: Aerosols serve as efficient CCN • For simplicity we assume that all particles produced (dust and sea salt) are efficient CCN. • However the CCN field will not retain the lognormal characteristics of aerosol size distribution. • Dust and sea salt - born CCN will be added on the background value (400 #/cm3) in order to enhance the effect of the dust storm in cloud processes. • The rest of the RAMS microphysics scheme remains unchanged.

  32. CCN concentration (#/cm3) CCN concentration 28JAN2003 1700 UTC CCN concentration 29JAN2003 0500UTC CCN concentration 29JAN2003 1600UTC CCN concentration 30JAN2003 0000UTC ICLAMS CCN VERTICAL DISTRIBUTION Constant CCN field Prognostic 3D CCN field

  33. CLOUD CONCENTRATION VERTICAL CROSSECTION Constant CCN field Cloud concen. (#/cm3) 28JAN2003 16 UTC Cloud concen. (#/cm3) 29JAN2003 11 UTC prognostic CCN field Cloud concen. (#/cm3) 29JAN2003 11 UTC Cloud concen. (#/cm3) 28JAN2003 16 UTC

  34. TOTAL CONDENSATES VERTICAL CROSSECTION constant CCN field Total condensates (#/cm3) 29JAN2003 12 UTC Total condensates (#/cm3) 29JAN2003 15 UTC Prognostic CCN field Total condensates (#/cm3) 29JAN2003 12 UTC Total condensates (#/cm3) 29JAN2003 15 UTC

  35. ICE MIXING RATIO VERTICAL CROSSECTION Constant CCN field Ice mix ratio (gr/kgr) 28JAN2003 18 UTC Ice mix ratio (gr/kgr) 28JAN2003 21 UTC Prognostic CCN field Ice mix ratio (gr/kgr) 28JAN2003 18 UTC Ice mix ratio (gr/kgr) 28JAN2003 21 UTC

  36. MAXIMUM UPDRAFT VELOCITY CCN Latent heat Updrafts Condensation Significant delay on the updraft velocity maximum during cloud development and also increase in maximum value in 2nd mode run (yellow line )

  37. MAXIMUM UPDRAFT VELOCITY

  38. OTHER PROCESSES THAT NEED SPECIAL ATTENTION • Surface properties and energy partitioning: • SST • Soil thermophysical and hydraulic properties • How useful is the high resolution SST on regional scale modeling in the Mediterranean Region? • Energy partitioning on the sea surface • What is the role on soil texture on the accuracy of the models?

  39. HiRes SSTs (1/16 deg) Coarse SSTs (1/2 deg SEP 2004 OCT 2004 NOV 2004

  40. T+24 Front over the Ionian Sea

  41. 2-m Temperature and 6-hr accumulated precipitation RED: 1/16x 1/16 SSTs BLUE: 0.5x0.5 SSTs

  42. Sea-surface energy partitioning The SKIRON/Eta model calculates the surface parameters using a viscous sublayer scheme (Janjic 1994, MWR) • The viscous sublayer over the ocean is assumed to operate in 3 regimes: (i) smooth and transitional, (ii) rough, (iii) rough with spray, depending on the Reynolds number which is a function of u*

  43. Mean Differences in Heat Fluxes in Jan 2003 (VISCOUSyes-VISCOUSno) Stronger latent and sensible heat fluxes over the water without the use of the viscous sublayer. Higher precipitation amounts and stronger winds over the water without the use of the viscous sublayer. This is in agreement with theory

  44. Soil Characteristics - Thermophysical and Hydraulic Properties

  45. Effects of Soil Thermophysical Properties on Saharan ABL

  46. Some Concluding Remarks • Dust, sea salt and anthropogenically-produced aerosols are key players in radiation, cloud and precipitation formation. • The links and feedbacks are important on defining forcing and therefore studying regional climate. • In the new system - ICLAMS - such capabilities have been implemented: • Cloud formation through the treatment of CCN, GCCN and IN as predictive quantities. • Aerosol-cloud-radiation interactions. • Treatment of naturally and anthropogenically-produced particles with different properties. • Simulation of cloud-scale phenomena. • The sensitivity tests carried out clearly showed that the CCN originated mainly from desert dust. • The storm generation and evolution is highly related to spatiotemporal distribution of CCNs. • In general, high concentrations of natural particles tend to delay rainfall but can have higher amounts of precipitation in certain locations. • More development (production of CCG, GCCN and IN from anthropogenic sources) and testing efforts are under way at the framework of CIRCE project.

  47. ACKNOWLEDGEMENTS This work is funded by European Union FP6 project CIRCE

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