Nessun titolo diapositiva

1
Earth's atmosphere and cosmic rays (the point of
view of an atmospheric physicist).
Vincenzo Rizi (vincenzo.rizi_at_aquila.infn.it) Dipar
timento di Fisica Università Degli Studi -
LAquila -Italy
Rossella Caruso, Aurelio Grillo, Marco Iarlori,
Sergio Petrera, Dipartimento di Fisica
Università Degli Studi - LAquila
Italy, Laboratori Nazionali del Gran Sasso,
Istituto Nazionale di Fisica Nucleare
First International Workshop on Air
Fluorescence Salt Lake City Utah October 5-8,
2002
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Summary

• Planetary atmosphere as a calorimeter
  atmospheric parameters and nitrogen fluorescence
  yield.
• In particular, the effect of atmosphere
  parameterization and/or local meteorological
  measurable parameters.
• Atmospheric transmission of fluorescence light
  and determination of energy release by UHECR.
• Role of the aerosol transmission
• Estimation of aerosol transmission (with real
  data).
• Advantages of Raman lidar in measuring the
  aerosol transmission.

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Residence times
Individual species
Turbulent mixing dominant at low altitudes
(lt120km) i.e., mixing ratios constant with
altitude
2x107 years
3x103 years
78.084
Relevant for inversion of Lidar Raman data, see
later!
accumulative
20.946
Trace gases 0.036
6 years
0.934
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National Space Science Data Center NASA Goddard
Space Flight Center Greenbelt, MD 20771, USA
Atmospheric models and their use in the
estimation of air fluorescence yield and light
transmission.
Models of preference for specialized
tropospheric/lower stratosphere
work. Homogeneous mixing Perfect
gas Hydrostatic equilibrium
Partial list of available models ...
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U.S. Standard Atmosphere 1976 NOAA/NASA/U.S.Air
Force (lt32km) ? ICAO standard atmosphere steady
state atmosphere for moderate solar activity
based on rocket and satellite data perfect gas
theory parameters listed atmospheric
temperature, pressure, density, in 1966
supplement 5 northern latitudes for summer and
winter. Availability the Fortran code can be
obtained from Public Domain Aeronautical
software. References U.S. Standard Atmosphere,
1976, U.S. Government Printing Office,
Washington, D.C., 1976.
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Atmospheric Handbook 1984 NOAA/National
Geophysical Data Center (NGDC) compilation by
V.E. Derr parameters listed atmospheric
parameters for scattering calculations Availabi
lity from NGDC via anonymous ftp.
References V. E. Derr, Atmospheric Handbook
Atmospheric Data Tables Available on Computer
Tape, World Data Center A for Solar-Terrestrial
Physics, Report UAG-89, Boulder, Colorado, 1984.
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COSPAR (Committee on Space Research)
International Reference Atmosphere CIRA
1986 compilations (Fleming et al., 1988) of
ground-based and satellite measurements (Oort,
1983, Labitzke et al., 1985) parameters listed
temperature, pressure, densities ... monthly mean
values for the latitude range 80N to
80S Availability from NSSDC's anonymous FTP
site References E. L. Fleming, et al., Monthly
Mean Global Climatology of Temperature, Wind,
Geopotential Height and Pressure for 0-120 km,
NASA, Technical Memorandum 100697, Washington,
D.C., 1988. A. H. Oort, Global Atmospheric
Circulation Statistics 1958-1983, NASA,
Professional Paper 14, 180 pp., Washington, D.C.,
1983. K. Labitzke, J. J. Barnett, and B. Edwards
(eds.), Middle Atmosphere Program, MAP Handbook,
Volume 16, University of Illinois, Urbana, 1985.
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How these atmospheres compare parameters
relevant for air fluorescence yield and light
transmission?
Seasonal variability
For a typical GAP site
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Seasonal variability
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Seasonal variability
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Dipartimento di Fisica Università Degli Studi -
LAquila Italy
REAL DATA Local atmospheric parameters recorded
by means of balloon borne meteorological
radiosoundings.
Vaisala radiosondes measure upper air
temperature, humidity and pressure, and upper air
windspeed and direction, as they rise to their
maximum altitude of 30 km.
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(No Transcript)
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LAquila, Italy 42.35N, 13.22E, 683m a.s.l.
Seasonal variability ? sensors systematics
Same atmosphere of a typical GAP site?!
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LAquila, Italy 42.35N, 13.22E, 683m a.s.l.
Seasonal variability ? sensors systematics
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Outlines - atmospheric models
below 20km mid-latitude seasonal variability
pressure up to 20 temperature
2?8 density 4?8
Outlines - meteorological observations
below 20km ?42N (LAquila - Italy) seasonal
variabilitysensors systematics pressure 2 ?
10 temperature 4 ? 8
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Atmospheric local parameters variability and air
fluorescence yield
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Nitrogen fluorescence
A.N. Bunner, 1964.
Keilhauer, B. et al., Auger technical note
GAP-20012-022
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?, Fluorescence Yield (photons per meter per
electron)
Kakimoto et al., A measurement of the air
fluorescence yield, Nucl. Instr. And Meth. A,
372, 527-533, 1996. Nagano, M. and A.A. Watson,
Observations and implications of the UHECR, Rev.
Of Modern Phys. 72, 2000
AIR FL(uorescence) Y(ield) approach Paolo
Privitera
N, Atmospheric number density T, Atmospheric
temperature ?s, ?s, constants
O-th approx.!
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Approaches to minimize the errors
from atmospheric parameters variability
Adiabatic model, combined with local ground
temperature and pressure measurements.
Martin, G., and J.A.J. Matthews,GAP 1999-037,
1999
and/or
Local balloon borne meteorological
radiosoundings. Forschungszentrum Karlsruhe -
Institut für Kernphysik Keilhauer, B., et al.,
GAP 2002-022, 2002
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Atmospheric transmission of fluorescence light.
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AFD light measurements
CR
Io?(s)
z
Ts
s
AFD
IAFD(s)
CR cosmic ray AFD Auger Fluorescence Detector Ts
transmission functions s range z altitude
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AFD light measurements
In a single pixel
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air fluorescence yield
Energy of CR
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E shower energy T atmospheric transmission
It can be easily estimated with sufficient
precision !?
High variability direct measurements with Raman
lidar OR strong assumption ...
Total atmospheric transmission
s range along the line of sight
The absorption can be neglected because of the FD
optical transmission !?
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Single scattering approx.!
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The lidar should/could measure the needed
quantities.
LIDAR
backscattering (bcks.)
Laser wavelength
Elastic bcks. molecular/Rayleigh aerosol/Mie
Anelastic bcks. Raman (N2, O2 ...)
Laser
Telescope
DAQ
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Laser photons
Back-scattered photons
Atmosphere
Atmospheric attenuation scattering and absorption
laser photons
collected photons
Scattering processes Rayleigh-Mie
scattering Raman scattering Resonant scattering
solid angle subtended by the receiver ?1/z2 z is
the altitude/range
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Advantages of Raman lidar vs. Elastic lidar.
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Elastic/Rayleigh Lidar signal
upward travel
downward travel
backscattering
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Key features of Klett method.
Recasting the lidar equation
Mandatory assumption!
Unknown!
Solving for
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Key features of Fernald method.
Mandatory assumption!
Unknown!
The Lidar Ratio (LR) is the inverse of the back
scattering phase function.
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Solving for
See Scannin lidar based atmospheric monitoring
for fluorescent detectors of cosmic showers, D.
Veberic, A. Filipcic, M. Horvat, D. Zavrtanik,
M. Zavrtanik, submitted, 2002.
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Anelastic/Raman Lidar signal
upward travel
backscattering
downward travel
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Key features of Raman method.
Unknown!
Assumption!
Unnecessary if Raman signals from O2 and N2 are
measured!
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Estimation of aerosol transmission with real
data.
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UV Raman Vertical lidar - Dipartimento di Fisica
- Università Degli Studi - LAquila ?o351nm
?Raman382nm (N2) September 2001 LAquila 42oN
(rural site) 1/2 hour measurements
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1st step from Raman N2 k-1
2nd step from Elastic
(ext. Coeff.) (bcks coeff.)
Taer(z)
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Elastic
The aerosol transmission function retrieved from
real lidar signals (at Univ. AQ) The continuous
lines refer to the case in which only the elastic
signal is used (the lidar ratio is assumed), the
dashed lines with symbols show the transmission
calculated using the Raman signal.
Raman
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Outlines

• elastic lidar
• More infos on backscattering than extinction.
• For simple non-scanning lidar system
• the aerosol extinction profiles (i.e.,
  transmission function)
• derived by inverting the elastic signal, and
  assuming
• the lidar ratio, might have large systematic
  errors.

• anelastic lidar
• reliable aerosol transmission with no
  assumptions.
• A combined Raman/Rayleigh-Mie lidar
• measures aerosol extinction and backscattering
  independently.

• best configuration
• Scanning Raman/Rayleigh-Mie lidar

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Aerosol variability data from RAMAN LIDAR
LAquila - Italy (42oN) clear sky above 1500m
(virtual Auger FD site)
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Lidar ratio (LR) seasonal altitude variation.
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Aerosol extinction seasonal variation.
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Aerosol attenuation length seasonal variation.
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Aerosol transmission seasonal variation.
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Aerosol transmission seasonal variation.
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Aerosol extinction and transmission day
variation.
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Outlines - aerosol contribution to light
transmission
Most of the aerosol in the planetary boundary
layer (lt3km a.s.l.) clear sky from 1500m
a.s.l. relative transmission mean value
0.85 seasonal variability up to 15 (3?) day
variability (over 3hours - night) 6
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Status of Raman channel integration in Auger
lidar.
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Technical details of Raman lidar
INFN Torino/Nova Gorica Polytechnic LIDAR
Pino TO
Elastic Raman O2 Raman N2
laser
L field lens BS beam splitter NO notch
filter ND neutral density filter IF
interference filter PMT photomultiplier
telescope
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Lidar Auger Malargue - Argentina
VERY PRELIMINARY!
Malargue Lidar - zenit angle 90 March 7, 2002 -
LR50, raw resolution 30m
Lower limit estimation!.
MALARGUE height a.s.l.