LBT & Image

”SOLAR IRRADIATION OF THEEARTH’S ATMOSPHERE”

Sultana N. NaharDepartment of AstronomyThe Ohio State University

Columbus, Ohio, USA

”International Symposium on Climate Change andFood Security of South Asia”

Dhaka, BangladeshAugust 24-29, 2008

Support: NASA, Ohio Supercomputer Cenrter,The Ohio State University

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Relation betweenThe SUN and The EARTH

• The earth is our home planet• Sun is the source of energy for our Earth• Earth is much smaller than the Sun;Sun’s radius is 110 times larger than thatof the earth• Only small fraction of sun’s emitted en-ergy irradiates the earth

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Our SUN - The ”unQuiet” Star(Observed by space observatory SOHO)

• Our Sun goes through a 11 years cycle of min-

imum to maximum active mode - Picture shows

white active regions & solar flares on the surface

• During active period it erupts with explosions

that eject large amount of particles and radiation

in to space which can affect the earth

•A typical solar flare is much larger than the earth

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SOLAR ACTIVITIES - Storms & Flares”Halloween” Solar Storm (Oct 28, 2003)

(Observed by Chandra, SOHO, SOXS)

������������

XX--Ray Modeling of Solar Corona and Flares:Ray Modeling of Solar Corona and Flares:“Halloween” Solar Storm (Oct 28, 2003)“Halloween” Solar Storm (Oct 28, 2003)

NOAA National Weather Service… at L1

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heliosphere

X-ray photons

30 Rsun

8 minutes later ... X-class Flareobserved on the Earth

coronal mass ejection leaves the Sun ….

8 hours later... particles saturate SOHO/LASCO detector and reach the Earth (“proton shower”)

active region with big sunspot erupts ….

XX--ray spectra of Heray spectra of He--like Ca, Fe, Ni like Ca, Fe, Ni (SOXS Mission, PRL, India)(SOXS Mission, PRL, India)

CaCa FeFeNiNi

• Sun spots are detected on the top left• SOHO mass detector, LASCO, detectslarge coronal mass ejection (lower left). 8hours later it is swarmed by the particles,proton shower (lower right)• X-ray emission peaks in radiation spec-tra of the solar flares• Emission bumps from He-like Ca, Fe, Niare noted

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Spectral Study of Iron (Fe XXV) lines -

Dielectronic Satellite or DES lines - in Solar

Storm(Nahar & Pradhan 2006)

Unified Spectrum of Dielectronic Satellite (DES) Lines

Photoelectron Energy (eV)

σ RC(M

b)

10-510-410-310-210-1100101102103

e + Fe XXV -> Fe XXIV + hν: KLL satellite lines

a) Total

10-5

10-4

10-3

10-2

10-1

100b) Jπ = (1/2)e: 1s2s2p(SLJ) -> 1s22s(2S1/2) resonances

v u r q t s

10-710-610-510-410-310-210-1100101

c) Jπ = (1/2)o: 1s2p2(SLJ) -> 1s22p(2Po1/2) resonances

p i g k d b n

4550 4600 4650 4700

10-610-510-410-310-210-1100101102

d) Jπ = (3/2)o: 1s2p2(SLJ) -> 1s22p(2Po3/2) resonances

o h f e l

c

j a m

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Solar Ejections - Radiation & Particles

• Solar storms ejects bursts of electrons, protons,

& heavy ions accelerated by massive explosions in-

side

• Our Earth’s atmosphere and magnetic field pro-

tects us from these massive bursts of particles and

radiation by reflections, absorptions, and captures

• For example, magnetic field capture charged par-

ticles, ozone layer blocks most ultraviolet, X-rays

and Gamma rays

•Most dangerous particles are ions which can dam-

age tissue, break strands of DNA, and lead to dis-

eases like cancer

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Distribution of Incoming Solar Radiation- Reflection, Scattering, Absorption

• Space is dark; Sky is blue due to light scattering

• 1) Reflection - 30% of incoming sun radiation is

reflected back to space (6% by air, 20% by clouds,

4% by the surface of the Earth)

• 2) Absorption - 19% absorbed by atmosphere

(16% by Atmospheric gases, 3% by Clouds)

• 3) Absorption by the Earth Surface - 51% of the

energy at the top of the atmosphere reaches the

earth surface and heats the oceans and land

• Solar radiation establishes the Thermal Structure

of the earth and its atmosphere

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GREENHOUSE EFFECT - By Sun,Earth, & Atmosphere only

• Sunlight provides energy 1366 W/m2 onatmospheric surface - but 235 W/m2 is ab-sorbed, 67 W/m2 by air and 168 W/m2 byland & water• 168 W/m2 raises earth’s surface temer-ature to -18 C• However, the energy cycle between theatmosphere and the earth with the incom-ing radiation keeps the temperature stablefor us

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GREENHOUSE EFFECT - By Sun, Earth, & At-mosphere only

• Atmospheric gases absorb 452 W/m2 thermal in-frared radiation emitted by the earth’s surface. Ofthe total 519 W/m2 (=67+452) it delivers 324 W/m2(62%) to earth and transmits the rest 195 W/m2(38%) to space• Total energy of 492 W/m2 [=168(sunlight) and324 (atmosphere)] raises earth surface temperatureto +14 C• This recycling of energy to warm the Earth’s sur-face is known as the greenhouse effect. The totalamount of radiation energy entering the earth sys-tem is balanced exactly by the amount being radi-ated into space, thus allowing the Earth maintain aconstant average temperature over time•Atmospheric compoments: 78.08% Nitrogen (N2),20.95% Oxygen (O2), 0.93% Argon, 0.038% Carbondioxide, some other traces.Any increase in the concentration of particular gasesin the atmosphere can prevent heat from being ra-diated out into space and upset this fine balance,raising the world’s temperature

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RADIATION ABSORPTION & EMISSION -ATOMIC & MOLECULAR PROCESSES

Details of Absorption & Emission lie with Sun lightinteractions with Atmospheric atoms and molecules

1. Photoexcitation - Electron absorbs the photonand jumps to a higher level, but remains in theatomic or molecular system- Photon ABSORPTION

X+Z + hν ⇀↽ X+Z∗

2. De-excitation - Electron gives out energy as aphoton and drops down to the ground level- Photon EMISSION

3. Photoionization/ Photo-Dissociation/ Photo-ElectricEffect - Electron absorbs photon energy and ejectsout of the atom - Photon ABSORPTION

X+Z + hν ⇀↽ X+Z+1 + e

4. Electron-Ion Recombination - A free electrongives out energy as a photon and combines to anion - Photon EMISSION

5. Collisional Excitation - Collisions among gaseousatoms and molecules give energies to excite otheratoms and molecules which then decay by emissionof photons - Photon EMISSION

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Sun’s Ultraviolet radiation breaks down O2 and

N2 moleculues to atoms, & then photo-ionize

them in ionosphere. The effect manifests itself in

radiation absorption & emmision

”PHOTOIONIZATION (PI) OF O & N”PI resonant peaks indicate enhancement of

ionization at particular energies

Photoionization Cross Sections of N and O

Photon Energy (Ry)

σ PI (M

b)

0 .5 1 1.5 2

10-4

10-3

10-2

10-1

100

101

102

103

O I + hν -> O II + e

Nahar (1998)

.5 1 1.5

10-2

10-1

100

101

102

103

N I + hν -> N II + e

Nahar & Pradhan (1997)

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Atmospheric Opacities - Radiation Transport

Atmospheric Opacity (κν) depends on:

i) Electron bound - bound transitions through pa-rameter oscillator strengths, fij

κν(i → j) =πe2

mcNifijφν

Ni = ion density in state i, φν is a profile factor

ii) Electron bound - free transitions through param-eter photoionization cross sections, σPI,

κν = NiσPI(ν)

• The opacity depends on interaction of radiationwith all atoms and molecules in the atmosphere

• Complete Atmospheric modeling will require opac-ities and parameters of all other processes

• Astrophysical modelings are carried out using thesame parameters, fij, σPI

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THE OPACITY PROJECT & THE IRON PROJECT:

AIM: Accurate Study of Atomic Processes in Astrophysical

Plasmas & Calculate Opacities

Elements: H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si,

S, Ar, Ca, Fe, Ni

International Collaborations: France, Germany, U.K.,U.S. (Ohio State U, NASA-Goddard, Rollins), Bel-gium, Venezuela, Canada

•THE OPACITY PROJECT (OP) (1982 -): studyradiative atomic processes and radiation transportin astrophysical plasmas - all elements from H to Fe

• THE IRON PROJECT - IP (1993 -): study colli-sional & radiative processes of Fe & Fe peak ele-ments

• Atomic & Opacity Databases: TOPbase, TIPbaseat CDS (France), Ohio Supercomouter Center (OSC)http://vizier.u-strasbg.fr/topbase/topbase.html,http://opacities.osc.edu

•NORAD (Nahar OSU Radiative Atomic Data) AtomicDatabase at the Ohio State U.:www.astronomy.ohio-state.edu/∼nahar/nahar radiativeatomicdata/index.html

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GLOBAL WARMINGGreenhouse Effect has increased the global

temperature by 0.57 ± 0.17 C (1890-2000)

• Increased CO2 is the main factor for it

• CH4, N2O, CFC, aerosol etc contributing as well

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EFFECTS OF GLOBAL WARMINGi) Glaciers melting has doubled, ii) Sea level rising

0.8mm/year – rise > 20 cm by 2100 (IPCC)

• Antarctic Ice sheet, seven times the size of

Manhattan, fall into ocean

• Polar snow caps retreating, sea levels rising.

Flooding, desertification, crop failures, fresh

water shortages & storms are increasing

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ATMOSPHERIC BROWN CLOUDS (ABC)(In South Asia - India, China, Bangladesh)

• Thick haze - in Humid Condition & in Winter(December to April) Monsoon with no rainfall towash the pollution• Airborne Particles & Pollution due to biomassburning, vehicle emissions, coal powered industrialsoot, burning of woods, dung, and crops

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EFFECTS OF BROWN CLOUDSAtmospheric Brown Cloud over India

• ABC reflects part of the sunlight backinto space which cools the surface, reducesevaporation, less the monsoon rainfall• It absorbs sunlight → raises solar heat-ing of atmosphere• Model (Ramanathan et al., Nature 2007)suggests ABC has raised the temperatureby 50% in the region, melting the Hi-malayan glaciers• However, it included model data for so-lar heating with uncertainty of about four-folds

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ATMOSPHERIC OPACITY(www.ipac.caltech.edu/Outreach/Edu)

• Higher opacity - less radiation and lower opacity

- more radiation reaching earths surface

• Opacity determines types of telescopes needed -

ground or earth based or space based

• Gamma, X-ray, UV are blocked while visible light

passes through

• Carbon dioxide, water vapor, other gases absorb

most of the infrared frequencies

• Part of radio frequencies is absorbed by water &

oxygen, and part passes through

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Detailed Solar Spectrum from Earth(Calculated by R. Kurucz)

Lines correspond to various photons absorptions

UV is absorbed highly - Optical (Blue to Red) is less - Yellow

is absorbed minimun (Reason for Sun to look Yellow) - Wide

Infrared range is absorbed, mostly by water

Best calculations for H2O opacity in atmoshpere used over

800 M transitions 19

High-Performance Large-Scale Atomic & Molecu-lar Calculations at the Ohio Supercomputer Center

R-Matrix Codes: VARIOUS COMPUTATIONAL STAGES

• R-matrix calculations has 3 branches to proceed - 1) LS coupling &

relativistic Breit-Pauli, 2) Large configuration interaction LS coupling,

3) Dirac relativistic

• Results - 1) Energy Levels, 2) Oscillator Strengths, 3) Photoioniza-

tion Cross sections, 4) Recombination Rate Coefficients, 5) Collision

Strengths; - Astrophysical Models

DSTG3

STGB *DSTGFR**STGF(J)*

ATOMIC STRUCTURE: CIV3 OR SUPERSTRUCTURE

R−MATRIX R−MATRIX II DIRAC R−MATRIX

ANG

BREIT−

*ELEVID*/*PRCBPID*

PFARM

STGBB STGBF

B

/*STGBFRD*

F

P *STGRC*

RAD

HAM

DIG

*FULL

PAULI*

LEVELS STRENGTHS CROSS SECTIONS CROSS SECTIONS STRENGTHS

ENERGY OSCILLATOR PHOTOIONIZATION RECOMBINATION COLLISION

STG2

RECUPD

STGH

DSTG2

DSTG4

STG1

GRASP

DSTG1

THE R−MATRIX CODES AT OSU

DSTGHLS

H

DSTGF

HD

ASTROPHYSICAL AND PLASMA SPECTRAL MODELS AND OPACITIES

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CONCLUSION

1. Sun is the main source of our energy and is keep-ing us in living conditions by its radiatioon

2. Atmosphere is the protecting envelope aroundus and hence its natural consistensies are to bemaintained

3. The relation between solar radiation and earth’satmospheric need to understood with accuracyand details and is an inherent to atmosphericmodelings

4. Numerical simulation of solar irradiation of Earth’satmosphere requires complex quantum-mechanicalcalculations for atomic and molecular processesusing high-performace computing

5. Large amount of atomic parameters for radia-tive processes in atmosphere is available; how-ever, more data for especially for molecules areneeded

6. A consorted MULTI-DISCIPLINARY effort isextremely crucial to solve the problem of GlobalWarming and protect our home planet.

7. PLAN: Calculation of Accurate Solar Opacitiesfor Atmospheric Modeling

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