La Previsione del tempo atmosferico dal paradigma deterministico a quello probabilistico
Ten.Marcucci Francesca
Centro Nazionale Meteorologia e Climatologia Aeronautica
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The document summarizes research on using proximity-induced superconducting correlations in mesoscopic conductors to implement quantum detectors. It describes how superconducting correlations can modify the density of states in normal metals, and how this effect can be probed. It then introduces the Superconducting QUantum Interference Proximity Transistor (SQUIPT), a novel quantum interferometer that uses phase-controlled proximity effect to achieve high sensitivity flux detection with ultralow dissipation. Experimental results on SQUIPTs are presented and show good agreement with theoretical predictions. SQUIPTs could enable new cryogenic applications due to their simple operation, design flexibility, and extremely low power consumption.
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Il piano di marketing è necessario per definire, pianificare e raggiungere gli obbiettivi di una strategia di marketing. Evidenzia la mission aziendale che spesso non è mai considerata importante per un'azienda. Nel piano di marketing si analizza tramite l'analisi SWOT i punti di forza e di debolezza dell'impresa, i punti di forza e di debolezza della concorrenza. Tutto questo è riversato nell'audit di marketing. Il marketing mix porta il prodotto/servizio sul mercato attraverso l'analisi del prezzo, del portafoglio prodotto, della comunicazione e della distribuzione. Un budget deve essere definito per il raggiungimento degli obbiettivi. Il feedback aiuta l'impresa ad analizzare gli scostamenti ed eventualmente a rimettere mano per modificare il piano.
This document discusses the wave-particle duality of light and how light can behave as a fluid under certain conditions. It describes experiments observing superfluid behavior in coherent light fields in semiconductor microcavities, analogous to superfluidity in Bose-Einstein condensates. The experiments show evidence of superfluid flow for flow speeds below a critical speed, and scattering and Cerenkov wakes occurring above the critical speed, providing evidence that light can take on hydrodynamic properties when interacting coherently as a Bose gas of photons.
The document summarizes research on using proximity-induced superconducting correlations in mesoscopic conductors to implement quantum detectors. It describes how superconductivity can modify the density of states in normal metals through the proximity effect. It then introduces the Superconducting QUantum Interference Proximity Transistor (SQUIPT), a novel quantum interferometer that uses this effect for high-sensitivity magnetic flux detection, and presents theoretical predictions and experimental results demonstrating its behavior and advantages over DC SQUIDs.
The document summarizes research on using proximity-induced superconducting correlations in mesoscopic conductors to implement quantum detectors. It describes how superconducting correlations can modify the density of states in normal metals, and how this effect can be probed. It then introduces the Superconducting QUantum Interference Proximity Transistor (SQUIPT), a novel quantum interferometer that uses phase-controlled proximity effect to achieve high sensitivity flux detection with ultralow dissipation. Experimental results on SQUIPTs are presented and show good agreement with theoretical predictions. SQUIPTs could enable new cryogenic applications due to their simple operation, design flexibility, and extremely low power consumption.
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- Observing the cosmic microwave background radiation provides evidence of homogeneity across regions larger than the particle horizon, suggesting they were in causal contact earlier when the expansion rate was higher.
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This document discusses cosmological horizons in physics. It begins by explaining the particle horizon, which separates us from what we cannot observe because the light from beyond has not reached us yet. It then discusses other physical horizons that are closer than the particle horizon and depend on light propagation details in the universe. The document goes on to explain how observing further allows seeing back to when the universe was ionized, with the physical horizon being the surface of last scattering beyond which the universe was opaque due to scattering of photons by free electrons. It describes how detecting cosmic microwave background radiation photons provides strong evidence about the early hot phase of the universe.
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2) These synchronized oscillation patterns cover large areas of the brain and are present during both resting and cognitive task periods, suggesting they represent background brain activity modulated by environmental engagement.
3) A dissipative quantum field theory model is able to account for the dynamical formation of these synchronized oscillations through spontaneous symmetry breaking mechanisms generating long-range correlations mediated by massless quanta.
- The document discusses cosmological horizons in physics and cosmology.
- It describes the particle horizon, which separates what we can observe from what came before the light had time to reach us.
- It also describes the physical horizon, which is closer due to details of light propagation in an expanding universe. This physical horizon corresponds to the surface of last scattering from 380,000 years after the Big Bang.
- Observing the cosmic microwave background radiation provides evidence of homogeneity across regions larger than the particle horizon, suggesting they were in causal contact earlier when the expansion rate was higher.
The document discusses the physics of molecular motors and fluctuations in small engines. It covers topics like noise rectification mechanisms that allow directed motion from thermal fluctuations in biological motors like myosin and kinesin. Brownian motion results in efficient but random transport, while molecular motors achieve very efficient directed transport through mechanisms like thermal ratchets that can rectify thermal fluctuations through asymmetric potentials or periodic driving. The document also discusses applications to areas like biology-inspired nano-devices and single molecule experiments.
The document discusses cosmological horizons in physics. It explains that there exists a physical horizon beyond which the early universe was opaque due to electron scattering, known as the surface of last scattering. This horizon represents the farthest point in the universe we can observe by detecting cosmic microwave background radiation. The document also notes that the near-perfect isotropy of the CMB is surprising given that different regions of the early universe beyond the particle horizon would not have been in causal contact. This suggests the universe achieved thermal equilibrium prior to the surface of last scattering.
This document discusses cosmological horizons in physics. It begins by explaining the particle horizon, which separates us from what we cannot observe because the light from beyond has not reached us yet. It then discusses other physical horizons that are closer than the particle horizon and depend on light propagation details in the universe. The document goes on to explain how observing further allows seeing back to when the universe was ionized, with the physical horizon being the surface of last scattering beyond which the universe was opaque due to scattering of photons by free electrons. It describes how detecting cosmic microwave background radiation photons provides strong evidence about the early hot phase of the universe.
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The document discusses the modeling of economic complex systems using concepts and methods from physics. It provides three examples: 1) Filtering information from stock portfolio returns; 2) Analyzing high frequency strategic actions of economic actors in financial markets; 3) Empirical evidence of specialization among market members in financial markets. It also discusses hierarchical clustering analysis of correlation matrices to analyze complexity in financial markets.
COHERENCE, SELF-SIMILARITY AND BRAIN ACTIVITYnipslab
1) The document discusses coherence and self-similarity in brain activity, proposing that spatially extended domains of synchronized neural oscillations form rapidly in the brain and re-synchronize in frames at rates in the theta-alpha range.
2) These synchronized oscillation patterns cover large areas of the brain and are present during both resting and cognitive task periods, suggesting they represent background brain activity modulated by environmental engagement.
3) A dissipative quantum field theory model is able to account for the dynamical formation of these synchronized oscillations through spontaneous symmetry breaking mechanisms generating long-range correlations mediated by massless quanta.
La Previsione del tempo atmosferico dal paradigma deterministico a quello probabilistico - Ten.Marcucci Francesca
1. La Previsione del
tempo atmosferico
dal paradigma deterministico
a quello probabilistico
Ten.Marcucci Francesca
Centro Nazionale Meteorologia e Climatologia Aeronautica
4. Cosa è un MODELLO?
modello: tool per la simulazione (previsione) del comportamento di un
sistema dinamico
euristico: basato sull’esperienza
empirico: previsione basata sul “comportamento passato”
concettuale: framework per la comprensione di processi fisici
basato su un “physical reasoning”
analitico: soluzione esatta di eq. “semplificate” che descrivono il
sistema
numerico: integrazione delle equazioni tramite metodi numerici
(cond. Iniziali e al contorno)
Cosa è Numerical Weather Prediction (NWP)?
NWP: tecnica usata per ottenere una previsione oggettiva del tempo
futuro (fino max 2 settimane) risolvendo un sistema di equazioni che
descrivono l’evoluzione di variabili rappresentative dello stato
presente dell’atmosfera
5. La previsione: scienza e tecnologia
La previsione del tempo è
un’aspirazione che accompagna
l’uomo nella sua storia:
Aristotele: “µετέωρολογία ”, 350 a.C.
Organizzazione di un sistema coordinato di
stazioni di misura (Ferdinando II de’ Medici,
1654) e possibilità di ottenere i dati osservati in
“tempo reale” (invenzione del telegrafo, 1835)
Problema successivo: come fare
evolvere nel tempo lo stato del sistema
atmosferico?
6. La previsione: scienza e tecnologia
Vilhelm Bjerknes (1904)
postula la possibilità di
usare le equazioni della
fluidodinamica e della
termodinamica per
determinare l’evoluzione
dell’atmosfera
Lewis Fry Richardson
(1922) applica l’idea di
Bjerknes e produce la
prima previsione numerica
del tempo senza l’ausilio
del computer!
Richardson’s Forecast Factory:
64000 “computers umani”!
7. Invenzione del computer (1941-1945) e primi riusciti tentativi di
previsione numerica del tempo (J. von Neumann, J. Charney, 1955)
17. LA DIAGNOSI: Assimilazione dati
L’assimilazione dati e’ il processo attraverso il quale l’informazione
proveniente dalle osservazioni è incorporata in un modello numerico
per fornire la migliore stima dello stato iniziale dell’atmosfera
(ANALISI), dal quale far partire la previsione
ANALISI
PROGNOSI errore modello
DIAGNOSI errore background
OSSERVAZIONE
errore osservazione
Problema alle condizioni iniziali con errori e osservazioni
18. CICLO DI ASSIMILAZIONE INTERMITTENTE
00 06 12
tim e
Ana lysis Ana lysis Ana lysis
Initialisation Initialisation Initialisation Initialisation
Prediction Prediction Prediction Prediction
Initialisation Initialisation
Prediction Prediction
Forecasts
CICLO DI ASSIMILAZIONE CONTINUO
00 06 12
time
Continuous analysis/ model state
Initialisation Initialisation
Prediction Prediction
Forecasts
19. Interpolazione Statistica e Metodi Variazionali
K
xb (ri ) + ∑ Wik [ yo (rk ) − xb (rk )]
xa (ri ) =
k =1
-
OSS. BACKGROUND
-
ANALISI BACKGROUND
incremento innovazione
subscript quot;iquot; “model grid point”
subscript quot;kquot; “observation point”
K numero di osservazioni
Wik “analysis weight”
20. IL PESO “OTTIMALE”…
metodo “Optimal Interpolation” A=xa B=xb
T=Truth O=yo
K
= Bi − Ti + ∑ Wik [(Ok − Tk ) − (Bk − Tk )]
Ai − Ti
k =1
K K K
Α = Β + 2∑ Wik (Ok − Bk )(Bi − Ti ) + ∑∑ WikWil (Ok − Bk )(Ol − Bl )
k =1 k =1 l =1
Α = ( Ai − Ti ) Β = (Bi − Ti )
2
2
Wi = Bi [B + O ]
∂Α −1
=0
∂Wik
21. OPTIMAL INTERPOLATION:
NMC
“Spread-out” dell’incremento ENSEMBLE
dell’osservazione usando la struttura
…
spaziale di B
E’ necessario avere una
rappresentazione di B e O
soluzione diretta
è un metodo “UNIVARIATO”
non tutte le osservazioni possono
essere assimilate
… VERSO UN’ANALISI MULTIVARIATA
22. “L’ OBSERVATION OPERATOR” (H)
Permette di confrontare osservazioni (yo) e modello (xb)
K
xb (ri ) + ∑ Wik [ yo (rk ) − xb (rk )]
xa (ri ) =
k =1
= ≠ = Η xb
xb (ri ) xb ( rk )
xb
( x a − xb ) = W ( y − Hx b )
23. IL PESO “OTTIMALE”…
Funzione di densità di probabilità:
E’ necessario conoscere la statistica degli errori
Gli errori sono completamente descritti dalla densità di probabilità
P(εm,εb,εo,t)
Gli errori relativi ad osservazioni,modello e background possono essere
considerati indipendenti P = PmPbPo
Generalmente si ha una conoscenza limitata di P (es. Covarianza e bias),
ma in molti casi è sufficiente
OPTIMUM ANALYSIS = MAX PROBABILITY ?
25. Formalismo della stima variazionale
J ( x ) = ( x − xb )T B −1 ( x − xb ) + ( y − Hx )T R −1 ( y − Hx )
Jo
Jb
La grandezza relativa dei due termini determina l’ampiezza
dell’incremento del’analisi. La soluzione nel caso lineare è:
( x a − xb ) = BH T ( HBH T + Ο ) −1 ( y − Hx b )
incremento
Covarianza
y: array delle osservazioni innovazione
dell’errore di
x: variabile (modello/analisi)
H: “observation operator” linearizzato bakground in
B: background error covariance matrix funzione dell’
R: observation error covariance matrix osservazione
29. … riassumendo
L’“Analisi” è la condizione iniziale per NWP
La stima del background è la previsione
ottenuta dalla precedente analisi con
l’informazione aggiuntiva delle osservazioni
Un’accurata analisi è essenziale per il
processo di previsione
30. LA PROGNOSI
I moti atmosferici sono descritti di un
insieme di 3 equazioni differenziali:
Conservazione della massa (equazione di
continuità)
Conservazione della quantità di moto
(equazioni di Navier-Stokes)
Conservazione dell’energia (primo
principio della termodinamica)
Considero budgets di queste quantità per un
+
“volume di controllo”:
(a) “volume di controllo” fisso rispetto agli
assi
=> Euleriano (x,y,z,t)
(b) “volume di controllo” in moto con il
Equazione di stato dei gas ideali fluido e contenente sempre lo stesso
numero di particelle
=> Lagrangiano (xo,yo,zo,t)
31. Equazioni:
Mean free path
l →0 Navier-Stokes equations
Newton’s second law
ν →0
N →∞ Boltzmann equations kinematic viscosity
number of particles
~1.x10-6 m2s-1, water
~1.5x10-5 m2s-1, air
l →0
Euler equations
statistical distribution
individual particles continuum
32. Equazione del momento
Forze F- gradiente di pressione, gravitazione e attrito
dv
= −2Ω × v − α∇p − gk + τ
dt
α = volume specifico (= 1/ ρ ), p = pressione,
= forza centrifuga + gravitazionale,
g
τ = attrito
g varia ~0.5% dal polo alle’equatore e ~3% con altitudine
(fino a 100km).
33. SCALA SINOTTICA: importanza relativa dei singoli termini
MOTI ORIZZONTALI:
approx VENTO GEOSTROFICO
Numero di Rossby
36. •
• Velocità orizzontale del vento Temperatura
∂T
1 ∂T
∂T ∂T
1 ∂p' 1 ∂p0 ∂p'
∂u 1 ∂Eh
1
∂u ∂λ + v cosϕ ∂ϕ − ς ∂ς − ρc p∇ ⋅ v + QT
= − u
− + Mu
− vV −ς −
= − a cosϕ
∂t
∂ς ρacos ∂λ γ ∂λ ∂ς
acos ∂λ
ϕ ϕ
∂t
a vd
• Vapore acqueo
∂v 1 ∂p' 1 ∂p0 ∂p'
∂v 1 ∂Eh ∂q v
−Va −ς − − + Mv 1 ∂q v
∂q v ∂qv
= − − (S l + S f ) + M q v
+ v cosϕ − ς
∂ς ρa ∂ϕ γ ∂ϕ ∂ς u
= −
∂t a ∂ϕ a cosϕ ∂λ ∂ϕ
∂ς
∂t
• Velocità verticale • Contenuto acqua e ghiaccio nubi
g ρ0 ∂Pl , f
1 ∂ql , f
∂ql , f ∂ql , f ∂ql , f
∂w 1 ∂w ∂w ∂w g ρ0 ∂p'
+ v cosϕ − ς
u
= − − + S l, f + M ql , f
ϕ −ς +
= − u + vcos +
a cosϕ ∂λ ∂ϕ ∂ς λ ρ ∂ς
∂t
∂λ ∂ϕ ∂ς γ ρ ∂ς
ϕ
∂t acos
g ρ0 (T −T0 ) T0 p' Rv v l f •
+ −1q − q − q
+ − Densità totale dell’aria
Tp Rd
γ ρ T −1
Rv
0
T
ρ = p R d 1 + − 1 q v − q l − q f
• Perturbazione della pressione
Rd
∂p' ∂p' c
∂p' 1 ∂p' 1 ∂v ∂
(u cosϕ ) + f .
∂p0
, Eh = (u 2 + v 2 ) e Va =
1
ϕ −ς + gρ0w− pd p∇⋅ v ove γ ≡
= − u + vcos −
∂λ c d ∂ς a cosϕ ∂λ ∂ϕ
ϕ ∂ϕ ∂ς
∂t
acos 2
v
Science should me made as easy as possible,but not easier.
Albert Einstein
37. Scale dei Fenomeni Atmosferici
Le equazioni usate in
NWP rappresentano
l’evoluzione della media
spazio-temporale della
soluzione “vera”
Le equazioni (mediate)
sono “empiriche” ci
possono essere forti
interazioni tra scale
“risolte” e “non-risolte”
Le scale non risolte
sono rappresentate da
“sub-grid model”
(parametrizzazioni)
38.
39.
40. ATMOSFERA = SISTEMA CAOTICO
Lorenz (1963) scoprì che anche un modello
perfetto con condizioni iniziali pressoché perfette
perde significatività in un finito intrevallo di tempo
“Does the Flap of a Butterfly's Wing in Brazil set off a
Tornado in Texas? ”
Nel 1960 ciò era di interesse puramente
accademico (previsioni fino 2 giorni), ma ai nostri
giorni ( predicibilità 2 settimane), c’è la necessità di
estrarre la massima informazione
42. Teorema del caos (Lorenz, 1960s):
a) Sistemi instabili hanno predicibilità finita (caos)
b) Sistemi stabili hanno predicibilità infinita
43. Definizione di Caos Deterministico
(Lorenz, March 2006, 89)
WHEN THE PRESENT DETERMINES THE FUTURE
BUT
THE APPROXIMATE PRESENT DOES NOT
APPROXIMATELY DETERMINE THE FUTURE
44. Teoria del Caos ed effetto farfalla
dx dt = −σx1 +σx2
1
dx2 dt = −x1x3 + ρx1 − x2
dx dt = x x − βx
3 12 3
47. In presenza di un’instabilità, tutte le perturbazioni convergono verso la
perturbazione che cresce piu’ velocemente
(fastest growing perturbation – leading Vector)
Una singola previsione si
discosta più rapidamente
dalla “realtà” qualora l’errore
dell’analisi ha una forte
t=T2
componente lungo il leading
t=T1
singular vector del flusso
corrente
t=0
La qualità della previsione
varia giorno per giorno,senza
possibilità di conoscere a
priori quale previsione sarà
corretta ensemble
forecasting (incertezza della
previsione)
48. ENSEMBLE FORECASTING
Generalmente un singolo “control forecast” è integrato a
partire dall’analisi
Nell’ensemble forecasting sono generati piu’ forecast
perturbando leggermente le condizioni iniziali (o usando
differenti modelli)
Lo spread tra i membri dell’ensemble da un’informazione
sull’errore della previsione
Range di possibili soluzioni,la
media delle quali è generalmente più
accurata della singola previsione
deterministica
Base quantitatva per una
previsione probabilistica
49. Le perturbazioni iniziali devono essere rappresentative dell’ error of the
day e lo spread simile al forecast error
La mancanza di spread puo’ dare al previsore un’ingiustificata confidenza
nella previsione (errata)
Pero’ al momento della verifica fornisce una chiara evidenza di un errore
nel sistema di previsione, mentre nel caso deterministico non si può sapere
se ciò è da imputare al sistema o ad un errore nelle condizioni iniziali
51. Esempio di alta predicibilità a 6 giorni con error of the day
52. Forti instabilità del background (error of the day) tendono ad
avere forme simili (le perturbazioni si collocano in un
sottospazio di dimensione ridotta)
53. LA PARABOLA DEI 3 STATISTICI :
Forecast 1
Forecast 2
Forecast 3
Ensemble Forecast con 3 membri La media è una buona idea ?
Leonard Smith, Decidion Making
54. Cosa significa predire l’evoluzione della PDF?
EPS può essere usato per
stabilire la probabilità
di un evento
Alluvione in Piemonte
6 Nov 94 (top right)
EPS control (top left)
EPS probabilit forecasts
(bottom panels)
R.Buizza, Introduction to EPS
55. Cosa significa predire l’evoluzione della PDF?
Lo spread rispetto
al controllo può
essere usato per
identificare aree
con errore
potenzialmente
elevato
5-day control
forecast + ensemble
spread (left)
verifying analysis
and the control error
(right)
R.Buizza, Introduction to EPS
56. Cosa possiamo apprendere da un EPS ?
Qual’è il contributo
relativo dell’errore del
modello e dell’incertezza
iniziale?
Richardson (1998)
confronto di 2 modelli
(UKMO, ECMWF) con 2
diverse condizioni iniziali
(UKMO,ECMWF)
Il maggiore contributo a
UK(UK)-ECMWF(ECMWF)
proviene dalle condizioni
iniziali
R.Buizza, Introduction to EPS
63. Definition of the system instabilities: normal modes
Consider an N-dimensional autonomous system:
∂y
= A(y)
∂t
The method most commonly applied to study the stability of a
solution z of the system equations is based on normal modes,
whereby small disturbances are resolved into modes which
may be treated separately because each of them satisfies the
system equations. The system equations are linearized
around the constant solution z:
∂y ∂A( z)
= Al ( z) y Al ( z) =
∂t ∂z z
A normal mode is a solution of the linearized equations of the
form:
y( x, t ) = f ( x)eλt
64. Singular vector definition: the linear equations
Consider an N-dimensional autonomous system:
∂y
= A(y)
∂t
Denote by z’ a small perturbation around a time-evolving trajectory z:
∂A( z)
∂z′ Al ( z) =
= Al ( z) z′
∂z z
∂t
∂z
= A( z)
∂t
The time evolution of the small perturbation z’ is described to a good
degree of approximation by the linearized system Al(z) defined by
the trajectory. Note that the trajectory is not constant in time.
65. Singular vector definition: the linear propagator
The perturbation z’ at time t is given by the time
integration from the initial state z’(t=0) of the linear
system: t
z′(t ) = z0 + ∫ Al ( z)dτ
′
0
z′(t ) = L(t,0) z0
′
The solution can be written in terms of the linear
propagator L(t,0):
z′(t ) =< z′(t ); Ez′(t ) >=< L(t,0) z0 ; EL(t,0) z0 >
′ ′
2
The linear propagator is defined by the system equations
and depends on the trajectory characteristics. The E-
norm of the perturbation at time t is given by:
66. Singular vector definition: the adjoint operator
Given any two vectors x and y, the adjoint operator L*
of the linear operator L with respect to the
Euclidean norm <..,..> is the operator that satisfies
the following property:
< L* x; y >=< x; Ly >
Using the adjojnt operator L* the time-t E-norm of z’
can be written as:
z′(t ) =< Lz0 ; ELz0 >=< z0 ; L*ELz0 >
′ ′ ′ ′
2
67. Singular vector definition: the problem
The problem of the computation of the directions of
maximum growth can be stated as ‘finding the
directions in the phase-space of the system
characterized by the maximum ratio between the
time-t and the initial norms’. Formally, this problem
reduces to an eigenvector problem:
2
< x0 ; L*ELx0 >
x(t ) E
= maxx0∈Σ
maxx0∈Σ
< x0 ; Ex0 >
2
x0 E
2
< x0 ; L*ELx0 >
x(t ) E
= maxx0∈Σ
maxx0∈Σ
< x0 ; E0 x0 >
2
x0 E
0
The problem can be generalized by using two
different norms at initial and final time:
68. Singular vector definition: the eigenvalue problem
Apply the following coordinate transformation:
y = E0 2 x
1
Then the generalized problem reduces to:
2 − −
< y0 ; E0 1 2 L*ELE0 1 2 y0 >
x(t ) E
= maxy0
maxx0
< y0 ; y0 >
2
x0 E0
− −
E0 1 2 L*ELE0 1 2ν = σ 2υ
The directions of maximum growth are defined by the
following eigenvalue problem: