SOLAR IRRADIATION OF THE EARTH\'S ATMOSPHERE

LBT & Image

”SOLAR IRRADIATION OF THE EARTH’S ATMOSPHERE”

Sultana N. Nahar Department of Astronomy The Ohio State University Columbus, Ohio, USA

”International Symposium on Climate Change and Food Security of South Asia” Dhaka, Bangladesh August 24-29, 2008 Support: NASA, Ohio Supercomputer Cenrter, The Ohio State University

1

Relation between The 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 that of the earth • Only small fraction of sun’s emitted energy irradiates the earth 2

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

• Our Sun goes through a 11 years cycle of minimum 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 3

SOLAR ACTIVITIES - Storms & Flares ”Halloween” Solar Storm (Oct 28, 2003) (Observed by Chandra, SOHO, SOXS)

X-Ray Modeling of Solar Corona and Flares: “Halloween” Solar Storm (Oct 28, 2003) active region with big sunspot erupts ….

8 minutes later ... X-class Flare observed on the Earth

Ca Fe

Ni

X-ray photons

X-ray spectra of HeHe-like Ca, Fe, Ni (SOXS Mission, PRL, India)

coronal mass ejection leaves the Sun …. 8 hours later... particles saturate SOHO/LASCO

       detector and reach the    30 R Earth (“proton shower”) sun heliosphere NOAA National Weather Service … at L1   

• Sun spots are detected on the top left • SOHO mass detector, LASCO, detects large coronal mass ejection (lower left). 8 hours later it is swarmed by the particles, proton shower (lower right) • X-ray emission peaks in radiation spectra of the solar flares • Emission bumps from He-like Ca, Fe, Ni are noted 4

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 3

10 102 101 100 10-1 10-2 10-3 10-4 10-5 100

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

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

10-1 10-2

v

u

r

q

t

s

σRC(Mb)

10-3 10-4 10-5 101 100 10-1 10-2 10-3 10-4 10-5 10-6 10-72 10 101 100 10-1 10-2 10-3 10-4 10-5 10-6 4550

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

i

g

k

d

b

n

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

h

f

e

l

j

a

m

c

4600

4650

Photoelectron Energy (eV)

5

4700

Solar Ejections - Radiation & Particles

• Solar storms ejects bursts of electrons, protons, & heavy ions accelerated by massive explosions inside • Our Earth’s atmosphere and magnetic field protects us from these massive bursts of particles and radiation by reflections, absorptions, and captures • For example, magnetic field capture charged particles, ozone layer blocks most ultraviolet, X-rays and Gamma rays • Most dangerous particles are ions which can damage tissue, break strands of DNA, and lead to diseases like cancer 6

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 7

GREENHOUSE EFFECT - By Sun, Earth, & Atmosphere only

• Sunlight provides energy 1366 W/m2 on atmospheric surface - but 235 W/m2 is absorbed, 67 W/m2 by air and 168 W/m2 by land & water • 168 W/m2 raises earth’s surface temerature to -18 C • However, the energy cycle between the atmosphere and the earth with the incoming radiation keeps the temperature stable for us 8

GREENHOUSE EFFECT - By Sun, Earth, & Atmosphere only • Atmospheric gases absorb 452 W/m2 thermal infrared radiation emitted by the earth’s surface. Of the 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) and 324 (atmosphere)] raises earth surface temperature to +14 C • This recycling of energy to warm the Earth’s surface is known as the greenhouse effect. The total amount of radiation energy entering the earth system is balanced exactly by the amount being radiated into space, thus allowing the Earth maintain a constant average temperature over time • Atmospheric compoments: 78.08% Nitrogen (N2), 20.95% Oxygen (O2), 0.93% Argon, 0.038% Carbon dioxide, some other traces. Any increase in the concentration of particular gases in the atmosphere can prevent heat from being radiated out into space and upset this fine balance, raising the world’s temperature

9

RADIATION ABSORPTION & EMISSION ATOMIC & MOLECULAR PROCESSES Details of Absorption & Emission lie with Sun light interactions with Atmospheric atoms and molecules 1. Photoexcitation - Electron absorbs the photon and jumps to a higher level, but remains in the atomic or molecular system - Photon ABSORPTION ) X +Z∗ X +Z + hν * 2. De-excitation - Electron gives out energy as a photon and drops down to the ground level - Photon EMISSION

3. Photoionization/ Photo-Dissociation/ Photo-Electric Effect - Electron absorbs photon energy and ejects out of the atom - Photon ABSORPTION ) X +Z+1 + e X +Z + hν * 4. Electron-Ion Recombination - A free electron gives out energy as a photon and combines to an ion - Photon EMISSION 5. Collisional Excitation - Collisions among gaseous atoms and molecules give energies to excite other atoms and molecules which then decay by emission of photons - Photon EMISSION 10

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 103

N I + hν -> N II + e 102

Nahar & Pradhan (1997)

101 100 10-1

σPI (Mb)

10-2 .5

103

1

1.5

O I + hν -> O II + e Nahar (1998)

102 101 100 10-1 10-2 10-3 10-4 0

.5

1 Photon Energy (Ry)

11

1.5

2

Atmospheric Opacities - Radiation Transport Atmospheric Opacity (κν ) depends on: i) Electron bound - bound transitions through parameter oscillator strengths, fij πe2 Nifijφν κν (i → j) = mc Ni = ion density in state i, φν is a profile factor ii) Electron bound - free transitions through parameter photoionization cross sections, σP I , κν = NiσPI(ν) • The opacity depends on interaction of radiation with all atoms and molecules in the atmosphere • Complete Atmospheric modeling will require opacities and parameters of all other processes • Astrophysical modelings are carried out using the same parameters, fij , σP I

12

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), Belgium, Venezuela, Canada •THE OPACITY PROJECT (OP) (1982 -): study radiative atomic processes and radiation transport in astrophysical plasmas - all elements from H to Fe • THE IRON PROJECT - IP (1993 -): study collisional & radiative processes of Fe & Fe peak elements • Atomic & Opacity Databases: TOPbase, TIPbase at CDS (France), Ohio Supercomouter Center (OSC) http://vizier.u-strasbg.fr/topbase/topbase.html, http://opacities.osc.edu

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

13

GLOBAL WARMING Greenhouse 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

14

EFFECTS OF GLOBAL WARMING i) 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

15

ATMOSPHERIC BROWN CLOUDS (ABC) (In South Asia - India, China, Bangladesh) • Thick haze - in Humid Condition & in Winter (December to April) Monsoon with no rainfall to wash the pollution • Airborne Particles & Pollution due to biomass burning, vehicle emissions, coal powered industrial soot, burning of woods, dung, and crops

16

EFFECTS OF BROWN CLOUDS Atmospheric Brown Cloud over India

• ABC reflects part of the sunlight back into space which cools the surface, reduces evaporation, less the monsoon rainfall • It absorbs sunlight → raises solar heating of atmosphere • Model (Ramanathan et al., Nature 2007) suggests ABC has raised the temperature by 50% in the region, melting the Himalayan glaciers • However, it included model data for solar heating with uncertainty of about fourfolds 17

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 18

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 & Molecular 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) Photoionization Cross sections, 4) Recombination Rate Coefficients, 5) Collision Strengths; - Astrophysical Models THE R−MATRIX CODES AT OSU

ATOMIC STRUCTURE: CIV3 OR SUPERSTRUCTURE

*FULL BREIT− PAULI*

GRASP

R−MATRIX

R−MATRIX II

DIRAC R−MATRIX

STG1

RAD

DSTG1

STG2

DSTG2

ANG

RECUPD

LS

DSTGH

HAM

STGH

H

DIG

DSTG3 D

H STGB

*STGF(J)*

B

*ELEVID* /*PRCBPID*

STGBB

PFARM

*DSTGFR*

DSTGF

DSTG4

F

STGBF / *STGBFRD*

P

*STGRC*

ENERGY

OSCILLATOR

PHOTOIONIZATION

RECOMBINATION

COLLISION

LEVELS

STRENGTHS

CROSS SECTIONS

CROSS SECTIONS

STRENGTHS

ASTROPHYSICAL AND PLASMA SPECTRAL MODELS AND OPACITIES

20

CONCLUSION 1. Sun is the main source of our energy and is keeping us in living conditions by its radiatioon 2. Atmosphere is the protecting envelope around us and hence its natural consistensies are to be maintained 3. The relation between solar radiation and earth’s atmospheric need to understood with accuracy and details and is an inherent to atmospheric modelings 4. Numerical simulation of solar irradiation of Earth’s atmosphere requires complex quantum-mechanical calculations for atomic and molecular processes using high-performace computing 5. Large amount of atomic parameters for radiative processes in atmosphere is available; however, more data for especially for molecules are needed 6. A consorted MULTI-DISCIPLINARY effort is extremely crucial to solve the problem of Global Warming and protect our home planet. 7. PLAN: Calculation of Accurate Solar Opacities for Atmospheric Modeling 21