1. Air-sea/land interaction: physics and observation of planetary boundary layers and quality of environment
Mega-Grant, started November 1st 2011
University of Nizhny Novgorod, Russia
INSTITUTIONS-COLLABORATORS
Institute of Applied Physics RAS; Faculty of Geography of Moscow State University; Russian State Hydrometeorological University; A.M. Obukhov Institute of Atmospheric Physics RAS – RUSSIA // Danish Meteorological Institute – DENMARK // Finnish Meteorological Institute; Dept of Physics of University of Helsinki – Finland // Ben-Gurion University of the Negev – ISRAEL // Nansen Environmental and Remote Sensing Centre – NORWAY…
WELCOME TO ADJOIN OUR PARTNERSHIP!
Mega-grants for environmental challenges

2. Motivation
and content

3. Geophysical turbulence and planetary boundary layers (PBLs)
Physics
Geo-sciences
New concepts of random
and self-organised motions
in geophysical turbulence
PBLs link atmosphere,
hydrosphere, lithosphere
and cryosphere within
weather & climate systems
Revision of basic theory
of turbulence and PBLs
Improved “linking algorithms”
in weather & climate models
Progress in understanding and modelling
weather & climate systems

4. Geospheres in climate system
Atmosphere, hydrosphere, lithosphere and cryosphere are coupled through turbulent planetary boundary layers PBLs (dark green lenses)
PBLs include 90% biosphere and entire anthroposphere

5. Role of planetary boundary layers (PBLs): TRADITIONAL VIEW
“Surface fluxes” through
AIR
and
WATER (or LAND) interfaces
fully characterise interaction between
ATMOSPHERE-OCEAN / LAND
atmosphere
ocean
Monin-Obukhov similarity theory (1954) (conventional framework for determining surface fluxes in operational models) disregards non-local features of both convective and long-lived stable PBLs

6. Role of PBLs: MODERN VIEW
Because of very stable stratification in the atmosphere and ocean beyond the PBLs and convective zones, strong density increments inherent in the PBL outer boundaries prevent entities delivered by surface fluxes or anthropogenic emissions to efficiently penetrate from the PBL into the free atmosphere or deep ocean.
Hence the PBL heights and the fluxes due to entrainment at the PBL outer boundaries essentially control extreme weather events (e.g., heat waves associated with convection; or strongly stable stratification events triggering air pollution).
This concept (equally relevant to the hydrosphere) brings forth the problem of determining the PBL depth and the turbulent entrainment in numerical weather prediction, air/water quality and climate modelling.
Atmosphere
Atmosphere
PBL
Ocean PBL
Ocean

7. PBL height visualised by smoke blanket (Johan The Ghost, Wikipedia)
Very shallow boundary layer separated form the free atmosphere by capping inversion
PBL height visualised by smoke blanket (Johan The Ghost, Wikipedia)

8. PBL height and air quality

9. Tasks
Geophysical turbulence and PBLs Non-local nature  Revision of traditional theory  Improved practical applications (SZ) Atmospheric electricity Convective PBLs, thunderstorms, upper atmosphere  role in global electric circuit  applications (EM) Air-sea interaction Processes at air-sea interface (theory, lab and field experiments)  application to hurricanes, storms (YuT) Internal waves Interaction with turbulence, wave-driven transports (ocean, ionosphere)  role in climate machine (AK) Chemical weather / climate Fires and modelling air pollution  troposphere and middle atmosphere (AF) New methods of radio-physical observations Instruments to respond new challenges  turbulence, organised structures, chemical composition  commercialisation (AF, AU) Education and young-scientist programme  new PhD, Dr.Sci.

10. PBL and turbulence problems
Self-organisation of turbulent convection Failure of the MO similarity theory  non-local resistance and heat/mass transfer laws (free and forced convection regimes); growth rate of and turbulent entrainment into convective PBLs Non-local nature of stably stratified PBLs ”Long-lived stable” and “conventionally neutral” very shallow and therefore sensitive (typical of Polar areas and over ocean); diagnostic and prognostic PBL-height equations Dead locks in and new concept of turbulence closure Potential energy, self-preservation of stably stratified turbulence  no critical Richardson number; new “weak turbulence” regime with diminishing heat transfer (everywhere in the atmosphere and hydrosphere beyond PBLs and convective zones)

11. Turbulent convection
Cloud streets visualising updraughts in convective rolls
Photo J. Gratz
LES I. Esau
In the atmosphere
In LES

12. Development of convective clouds Self-organised cells in the atmosphere
Гора Леммон, Аризона

13. Cloud systems over North Polar Ocean
Convective cells
Weak wind
 free convection‏
Convective rolls
Strong wind
 forced convection

14. Revision of the theory is demanded
Self-organisation
Self-organisation in viscous convection is known since
Benard (1900) and Rayleigh (1916)
It is obviously presents in turbulent convection but missed in essentially local classical theories:
Heat and mass transfer law Nu ~ Ra1/3
Prandtl theory of free convection Wc = (βFsz)1/3
Monin-Obukhov similarity theory L = τ 3/2 (βFs)-1
and in all parameterizations based on these theories
Revision of the theory is demanded

15. Non-local theory of convective heat and mass transfer
Example of solved problem
Non-local theory of convective heat and mass transfer

16. Organised cell in turbulent convection (disregarded in classical theory)
Air-borne measurements, calm sunny day over Australian desert: arrows – winds; lines – temperatures (Williams and Hacker, 1992)

17. Heat and mass transfer in free convection: non-local theory
Self-organisation
Convective wind pattern includes the convergence flow towards the plume axes at the surface
Near-surface internal boundary layer
”minimum friction velocity U* (Businger,1973)
Strongly enhanced heat/mass transfer

18. Heat-transfer coefficient
Blue symbols observations
Red symbols LES
Line theory
Classical theory (Nu = C0 Ra1/3)
disregards dependence on h/z0
and underestimates heat transfer over rough surfaces up to orders of magnitude

19. Convective heat/mass transfer: conclusions
Classical (local) theory disregards self-organisation of turbulent convection and strongly underestimates heat/mass transfer in nature
Developed Non-local theory of free convection (cells, weak winds) Essential dependence of heat/mass transfer on the ratio of boundary-layer depth to roughness length (h/z0u) New turbulent entrainment equation accounting for IGW mechanism
Under development  Non-local theory of forced convection (rolls at strong winds)
Applications to modelling air flows over  warm pool area in Tropical Ocean (free convection / known)  openings in Polar ocean (forced convection / prospective)  urban heat islands, deserts, etc. (prospective

20. Convection: principal statement
Convective structures are supplied with energy through inverse energy cascade (from smaller to larger eddies). They resemble secondary circulations rather then large turbulent eddies 2h
Cloud streets visualising convective rolls stretched along the strong wind (Queensland, North Coast, Australia, Wikimedia Commons; photo by Mick Petroff )
In both figures h ~ 103 м is the height of convective layer
Vertical cross-section of a convective cell at weak wind over Australian desert (airborne observations by Williams and Hacker, 1992)

21. turbulence in stable stratification
Very shallow long-lived stable boundary layer over cold Lake Teletskoe (Altay, Russia) on 28 August 2010 (photo by S. Zilitinkevich). Smoke blanket visualises upper boundary of the layer

22. Example of solved problem
Non-local theory of long-lived stably-stratified Planetary boundary layers (PBLs)
S. Galmarini, JRC

23. Stable and neutral PBLs
Traditional theory (adequate over land at mid latitudes)
is valid in the presence of pronounced diurnal course of temperature
recogniseed only two types of stably or neutrally stratified PBL, REGARDLESS STATIC STABILITY AT PBL OUTER BOUNDARY:
stable (factually nocturnal stable – capped by residual layer)
neutral (factually truly neutral – capped by residual layer)
Non-local theory ( )
accounted for the free flow-PBL interaction through IGW or structures
led to discovery of additional types of PBL:
long-lived stable (50 % at high latitudes)
conventionally neutral (40 % over ocean)
both proved to be much shallower than mid-latitudinal PBLs

24. Temperature stratification in (a) nocturnal and (b) long-lived stable PBLs

25. The effect of the free flow stability on the PBL height
● LES
● observations
Traditional (local) theory
New non-local theory (Z et al., 2007)‏
Nocturnal
PBL
Marine
PBL
Polar PBL

26. Stable PBLs: Conclusions
Non-local nature
due to long-lived structures and/or internal waves
Triggering air pollution
the shallower PBL  the heavier air pollution
Sensitivity to thermal impacts
the shallower PBL  the stronger microclimate response
 triggering global warming in stable PBLs:
in winter- and night-time at Polar and high latitudes

27. Features of ”scientific revolution” (Tomas Kun, Structure of scientific revolutions, 1962‏)
TRADITIONAL PARADIGM
Forward cascade
Fluid flow = mean (regular) + turbulence (chaotic)
Applicable to neutrally- and weakly-stratified flows
Crises of traditional theory ALTERNATIVE PARADIGM
Forward (randomisation) and inverse (self-organisation) cascades
Fluid flow = mean (regular) + Kolmogorov’s turbulence (chaotic)
+ anarchic turbulence (with inverse cascade)
+ organised structures (regular)
NON-LOCAL THEORY
Self-organisation of turbulent convection
Structures and internal waves in stable PBLs
Non-local closures Much work to be done Numerous simple unsolved problems XX
XXI

28. Co-authors from > 30 groups / 15 countries
Towards ”scientific revolution” Marie Curie Chair – PBL ( ); ERC-IDEAS PBL-PMES ( ); RU-Gov. Mega-Grant – PBL ( )
Co-authors from > 30 groups / 15 countries
Finland (FMI, U-Helsinki); Russia((Nizhny Novgorod State Univ., Obukhov Inst. Atmos. Phys., Rus. State Hydro-met. Univ.)
Sweden (MIUU, MISU, SMHI); Norway (NERSC-Bergen);
Denmark (RISOE National Lab, DMI-Copenhagen); Israel (Ben-Gurion Univ., Weizmann Inst. Advance Studies);
UK (Univ. College London, Brit. Antarctic Sur. Cambridge);
USA (Arizona State Univ., Univ. Notre Dame, NCAR, NOAA); Brazil (UNIPAMA, Univ.-Rio Grande, Univ.-Santa Maria); Greece (Nat. Obs., Univ.-Athens); Germany (Univ.-Freiburg); Estonia (Tech. Univ.-Tallinn); Switzerland (SFIT, EPF-Lausanne);
France (Univ.-Nantes); Croatia (Univ.-Zagreb)

29. WELCOME TO ADJOIN OUR PARTNERSHIP!
Thank you
for your attention
and
WELCOME TO ADJOIN OUR PARTNERSHIP!