DETERMINATION OF EFFECTIVE POLARIZABILITIES AND RADIATIVE FORCING OF ATMOSPHERIC AEROSOLS: IMPACTS ON VARIATIONS WITH WAVELENGTHS AND RELATIVE HUMIDITIES

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dc.contributor.authorUBA, SHUAIBU
dc.date.accessioned2017-07-24T13:49:58Z
dc.date.available2017-07-24T13:49:58Z
dc.date.issued2016-08
dc.descriptionA THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE SCHOOL, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF DOCTOR OF PHILOSOPHY ATMOSPHERIC PHYSICS DEPARTMENT OF PHYSICS FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY, ZARIA – NIGERIAen_US
dc.description.abstractIn this research, I reviewed and applied the Claussi Massoti together with Maxwell relations 2   n and derived the Lorentz – Lorentz relation. We computed the effective Polarizabilities for each atmospheric aerosol components. Hence, the effective polarizabilities for six types of model extracted from OPAC. The six models are: Artic, Antarctic, Maritime Tropical, Urban, Desert/Saharan and Continental Clean aerosols. The respective effective Polarizabilities were computed numerically within 61 wavelengths spectral ranges and eight different types of relative Humidities (RH 00%, 50%, 70%, 80%, 90%, 95%, 98%, and 99% ) respectively. The three wavelengths spectral range are: Part I (0.25 to 0.8 m), Near UV region to visible range. Part II (0.8 to 6.0 μm), Near infrared to medium spectral range and Part III (6.0 to 40.0 m), Far IR region. The results were analyzed graphically within the three different spectral regions. We have found that the range of effective polarizabilities for six models are as follows: continental clean aerosols 0.491 to 0.541Å3, Urban aerosols 0.00667 to 0.0073 Å3, for Antarctic aerosols, 0.0063 to 0.256 Å3, Artic aerosols 0.000333 to 0.00311 Å3, Maritime aerosols 0. 000144 to 0.000205 Å3 finally, for Saharan aerosols is 0.000663 to 0.0000909 Å3 respectively. Similarly for the Radiative Forcings (RF) were computed numerically using the concept of Chylek and Wong. The vibrational frequency were determined for each spectral region of the model. With changes of relative humidity in the atmosphere, condensation or evaporation of water take place on the aerosols and this at the same time changes the aerosols optical parameters It is evident that, when the relative humidity increases, the size of an aerosol particle increases through the accretion of water. At RH above 95%. together with the growth in size, the complex refractive index of the aerosol also varies. The research reveals that; the magnitude of Polarizabilities have shown clear decrease with increases in RH for all the aerosols models but have extraordinary values at different wavelength bands. The contributions mainly was due to the effect of the strongly oren_US
dc.identifier.urihttp://hdl.handle.net/123456789/9095
dc.language.isoenen_US
dc.subjectDETERMINATION,en_US
dc.subjectEFFECTIVE POLARIZABILITIE,en_US
dc.subjectRADIATIVE FORCING,en_US
dc.subjectATMOSPHERIC AEROSOLS,en_US
dc.subjectIMPACTS,en_US
dc.subjectVARIATIONS,en_US
dc.subjectVARIATIONS,en_US
dc.subjectRELATIVE HUMIDITIES,en_US
dc.titleDETERMINATION OF EFFECTIVE POLARIZABILITIES AND RADIATIVE FORCING OF ATMOSPHERIC AEROSOLS: IMPACTS ON VARIATIONS WITH WAVELENGTHS AND RELATIVE HUMIDITIESen_US
dc.typeThesisen_US
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