Transcript Slide 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 24-26.05.2012
Motivation
and content
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
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
Role of planetary boundary layers (PBLs):
TRADITIONAL VIEW
ocean
“Surface fluxes” through
AIR
and
WATER (or LAND) interfaces
fully characterise interaction between
ATMOSPHERE-OCEAN /LAND
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
http://www.jpgmag.com/photos/1006154
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).
http://www.jpgmag.com/photos/1006154
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.
Very shallow boundary layer separated form the
free atmosphere by capping inversion
PBL height visualised by smoke blanket (Johan The Ghost, Wikipedia)
PBL height and air quality
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)
http://www.jpgmag.com/photos/1006154
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.
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
http://www.jpgmag.com/photos/1006154
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)
TURBULENT CONVECTION
Cloud streets visualising updraughts in convective rolls
Photo J. Gratz
LES I. Esau
In the atmosphere
In LES
Development of convective clouds
Self-organised cells in the atmosphere
Гора Леммон, Аризона
Cloud systems over North Polar Ocean
Convective cells
Weak wind
 free convection
Convective rolls
Strong wind
 forced convection
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
Example of solved problem
NON-LOCAL THEORY OF CONVECTIVE
HEAT AND MASS TRANSFER
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)
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
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
2 orders of magnitude
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
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
Vertical cross-section of a convective cell at
weak wind over Australian desert (airborne
observations by Williams and Hacker, 1992)
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
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
Example of solved problem
NON-LOCAL THEORY OF
LONGLIVED STABLY-STRATIFIED
PLANETARY BOUNDARY LAYERS
(PBLs)
S. Galmarini, JRC
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 (2000-2010)
• 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
Temperature stratification in
(a) nocturnal and (b) long-lived stable PBLs
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
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
Features of ”scientific revolution”
(Tomas Kun, Structure of scientific revolutions, 1962)
XX
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)
XXI
+ 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
Towards ”scientific revolution”
Marie
Curie Chair – PBL (2004-07); ERC-IDEAS PBL-PMES (200913); RU-Gov. Mega-Grant – PBL (2011-13)
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)
Thank you
for your attention
and
WELCOME TO ADJOIN OUR
PARTNERSHIP!