Quick viewing(Text Mode)

SOLAR IRRADIATION of the EARTH's ATMOSPHERE” Sultana

SOLAR IRRADIATION of the EARTH's ATMOSPHERE” Sultana

LBT & Image ”SOLAR IRRADIATION OF THE ’S ATMOSPHERE”

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

”International Symposium on 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 and The EARTH

• The earth is our home planet • Sun is the source of 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 en- ergy irradiates the earth

2 Our SUN - The ”unQuiet” (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 that eject large amount of particles and in to space which can affect the earth • A typical solar flare is much larger than the earth

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

X-Ray Modeling of Solar Corona and Flares: “Halloween” (Oct 28, 2003) active region with big 8 minutes later ... X-class Flare erupts …. observed on the Earth

Ca Fe Ni X-ray photons

X-ray spectra of He-like Ca, Fe, Ni (SOXS Mission, PRL, India) leaves the Sun ….

8 hours later... particles         saturate SOHO/LASCO detector and reach the    30 R Earth (“ shower”) sun 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 spec- tra 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 103 102 e + Fe XXV -> Fe XXIV + hν: KLL satellite lines 101 100 a) Total 10-1 10-2 10-3 10-4 10-5 0 10 π e 2 2 b) J = (1/2) : 1s2s2p(SLJ) -> 1s 2s( S1/2) resonances 10-1 -2 10 v u r q t s 10-3 10-4 ) b 10-5 M

( 1 C 10 R 0 o 2 2 2 o

σ π 10 c) J = (1/2) : 1s2p (SLJ) -> 1s 2p( P 1/2) resonances 10-1 10-2 10-3 p i g k d b n 10-4 10-5 10-6 10-7 102 101 d) Jπ = (3/2)o: 1s2p2(SLJ) -> 1s22p(2Po ) resonances 100 3/2 10-1 o h f e l j a m 10-2 10-3 10-4 c 10-5 10-6 4550 4600 4650 4700 Photoelectron Energy (eV)

5 Solar Ejections - Radiation & Particles

• Solar storms ejects bursts of , , & heavy 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 , 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

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

• provides energy 1366 W/m2 on atmospheric surface - but 235 W/m2 is ab- sorbed, 67 W/m2 by air and 168 W/m2 by land & water • 168 W/m2 raises earth’s surface temer- ature to -18 C • However, the energy cycle between the atmosphere and the earth with the incom- ing radiation keeps the temperature stable for us

8 GREENHOUSE EFFECT - By Sun, Earth, & At- mosphere only • Atmospheric gases absorb 452 W/m2 thermal in- frared 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 sur- face is known as the greenhouse effect. The total amount of radiation energy entering the earth sys- tem is balanced exactly by the amount being radi- ated 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 ra- diated 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 - absorbs the photon and jumps to a higher level, but remains in the atomic or molecular system - Photon ABSORPTION X+Z + hν )* X+Z∗ 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 + hν )* X+Z+1 + e 4. Electron- 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 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 . 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

10-2 ) b M (

I .5 1 1.5 P 103 σ

102 O I + hν -> O II + e Nahar (1998) 101

100

10-1

10-2

10-3

10-4

0 .5 1 1.5 2 Photon Energy (Ry)

11 Atmospheric Opacities - Radiation Transport

Atmospheric Opacity (κν) depends on: i) Electron bound - bound transitions through pa- rameter oscillator strengths, fij πe2 κ (i → j) = N f φ ν mc i ij ν

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 radiation with 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 the same parameters, fij, σPI

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), Bel- gium, 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 colli- sional & radiative processes of Fe & Fe peak ele- ments • 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) Atomic 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

• 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 heat- ing of atmosphere • Model (Ramanathan et al., Nature 2007) suggests ABC has raised the temperature by 50% in the region, melting the Hi- malayan glaciers • However, it included model data for so- lar heating with uncertainty of about four- folds

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

• Higher opacity - less radiation and lower opacity - more radiation reaching 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 & 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

THE R−MATRIX CODES AT OSU

ATOMIC STRUCTURE: CIV3 OR SUPERSTRUCTURE GRASP

R−MATRIX R−MATRIX II DIRAC R−MATRIX

STG1 RAD DSTG1

STG2 DSTG2 *FULL ANG BREIT− RECUPD LS HAM DSTGH PAULI*

H STGH DIG

DSTG3

D H

STGB *STGF(J)* PFARM *DSTGFR* DSTGF DSTG4

B F

*ELEVID* STGBB STGBF / P *STGRC* /*PRCBPID* *STGBFRD*

ENERGY OSCILLATOR PHOTOIONIZATION RECOMBINATION COLLISION LEVELS STRENGTHS CROSS SECTIONS CROSS SECTIONS STRENGTHS

ASTROPHYSICAL AND SPECTRAL MODELS AND OPACITIES

20 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 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 radia- tive processes in atmosphere is available; how- ever, 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

Top View