TY - JOUR A1 - Vollmer, Michael A1 - Gedzelman, Stanley David T1 - Simulating irradiance during lunar eclipses: the spherically Symmetric case JF - In: Applied Optics 47 (2008) 34, H52-61 N2 - Irradiance during total lunar eclipses is simulated using a pinhole model. The Moon is illuminated by direct sunlight that is refracted into the Earth’s shadow as it passes through the atmosphere at the terminator but is depleted by scattering by molecules, extinction by aerosol particles, absorption by ozone, and obstruction by clouds and elevated land. On a spherical, sea-level Earth, and a cloudless, molecular atmosphere with no ozone, the eclipsed Moon appears red and calculated irradiance at the center of the umbra is reduced by a factor of about 2400 from direct moonlight. Selective absorption mainly of light around 600 nm by stratospheric ozone turns the periphery of the umbra pale blue. Typical distributions of aerosol particles, ozone, mountains, and clouds around the terminator reduce irradiance by an additional factor of the order of 100. © 2008 Optical Society of America Y1 - 2008 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.47.000H52 SP - H52 EP - H61 ER - TY - JOUR A1 - Gedzelman, Stanley David A1 - Vollmer, Michael T1 - Simulating irradiance and color during lunar eclipses using satellite data JF - In: Applied Optics 47 (2008) 34, pp. H149-H156 N2 - Irradiance and color during the total lunar eclipses of 2007 and 2008 are simulated using a ray tracing model that includes refraction, scattering by molecules, and observed or climatological distributions of aerosols, ozone, clouds, and topography around the terminator. Central portions of the umbra appear deep red for almost all eclipses due to preferential removal of short wavelengths in the spectrum of sunlight by scattering in the lower troposphere. The fringe of the umbra appears turquoise or blue due to selective removal of wavelengths around 600 nm by the Chappuis absorption bands of ozone in the stratosphere. Asymmetric distributions of clouds and aerosols, particularly for the 2008 eclipse, produce minimum calculated irradiance up to 17  arc min from the umbra center, while high ozone content over the arctic makes the northern edge of the umbra deepest blue. © 2008 Optical Society of America Y1 - 2008 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.47.00H149 SP - H149 EP - H156 ER - TY - JOUR A1 - Hernitschek, Nina A1 - Schmidt, Elmar A1 - Vollmer, Michael T1 - Lunar eclipse photometry: absolute luminance measurements and modeling JF - In: Applied optics 47 (2008) 34, pp. H62-H71 N2 - The Moon’s time-dependent luminance was determined during the 9 February 1990 and 3 March 2007 total lunar eclipses by using calibrated, industry standard photometers. After the results were corrected to unit air mass and to standard distances for both Moon and Sun, an absolute calibration was accomplished by using the Sun’s known luminance and a pre-eclipse lunar albedo of approximately 13.5%. The measured minimum level of brightness in the total phase of both eclipses was relatively high, namely −3.32 mvis and −1.7 mvis , which hints at the absence of pronounced stratospheric aerosol. The light curves were modeled in such a way as to let the Moon move through an artificial Earth shadow composed of a multitude of disk and ring zones, containing a relative luminance data set from an atmospheric radiative transfer calculation. © 2008 Optical Society of America Y1 - 2008 U6 - https://doi.org/10.1364/AO.47.000H62 SP - H62 EP - H71 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Influence of wind effects on thermal imaging results – Is the wind chill effect relevant ? T2 - In: InfraMation proceedings Vol. 8 (2007), 21-31 Y1 - 2007 SP - 21 EP - 31 ER - TY - JOUR A1 - Gedzelman, Stanley David A1 - Vollmer, Michael T1 - Atmospheric Optical Phenomena and Radiative Transfer JF - In: Bulletin of the American Meteorological Society. 89 (2008) 4, 471-485 N2 - We present simple radiative transfer models for the radiance and color of atmospheric optical phenomena. Skylight, halos, and rainbows are treated as singly scattered sunlight that is depleted by scattering as it passes through a plane-parallel atmosphere and a vertical rain shaft or a geometrically thin cloud layer. Skylight in a molecular atmosphere grades from deep blue at the zenith to pale blue near the horizon whenever the solar zenith angle sun ≤ 80°. Skylight near the horizon is orange resulting from wavelength-dependent scattering by air molecules and aerosol particles through a long oblique path through the atmosphere when the sun is low in the sky (sun ≥ 85°). Halos (and coronas) seen through clouds facing the sun are brightest for cloud optical depth τcld ≈ cos(sun), and fade to obscurity for τcld ≥ 5. Rainbows (and glories), seen by light that is backscattered from clouds, also appear most dramatic when 0.2 ≤ τcld ≤ 1, but remain visible even in the thickest clouds. Y1 - 2008 U6 - https://doi.org/10.1175/BAMS-89-4-471 SP - 471 EP - 485 ER - TY - JOUR A1 - Vollmer, Michael T1 - Effects of absorbing particles on coronas and glories JF - In: Applied optics 44 (2005) 27, 5658-5666 N2 - Light scattering from small particles changes if the particles are absorbing. Whereas the effect is small for coronas and Bishop's ring, glories show pronounced attenuation with increasing absorption. Results indicate suitable wavelength regions for studies of glory scattering from cloud tops. The behavior of core-shell particles could have applications for studying the atmosphere of Venus; in addition it provides more insight into the simple ray-path model of the glory. © 2005 Optical Society of America Y1 - 2005 U6 - https://doi.org/10.1364/AO.44.005658 SP - 5658 EP - 5666 ER - TY - CHAP A1 - Christmann, S. A1 - Vollmer, Michael T1 - Jahrgangsübergreifendes Projekt zum Wetter für die Grundschule T2 - In: Didaktik der Physik : Beiträge zur Frühjahrstagung Düsseldorf 2004 ; CD zur Frühjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft / V. Nordmeier ... (Hrsg.). - Berlin : Lehmanns Media, 2004. - 1 CD-ROM. - ISBN 3-86541-066-9 Y1 - 2004 ER - TY - JOUR A1 - Gedzelman, Stanley David A1 - Vollmer, Michael T1 - Crepuscular rays: laboratory experiments and simulations JF - In: Applied Optics Vol. 50 (2011) 28, pp. F142-F151 N2 - Model simulations of laboratory-generated and natural crepuscular rays are presented. Rays are created in the laboratory with parallel light beams that pass through artificial fogs and milk–water solutions. Light scattered by 90° in a dilute mixture of whole milk first increases in intensity with distance from the source to a maximum as a result of multiple scattering by mainly small angles before decreasing exponentially due to extinction as distance continues to increase. Crepuscular rays are simulated for three cloud configurations. In case 1, the Sun at the zenith is blocked by a cloud with an overhanging anvil. The rays appear white against blue sky and are brightest when atmospheric turbidity, β≈11 . Shading by the anvil separates maximum brightness from apparent cloud edge. In case 2, a ray passes through a rectangular gap in a cloud layer. The ray is faint blue in a molecular atmosphere but turns pale yellow as β and solar zenith angle, ϕsun , increase. At ϕsun=60° it appears most striking when the cloud is optically thick, β≈5 , and the beam width Δx≈1000 m . In these cases, increasing aerosol radius, raer , to about 1000 nm brightens, narrows, and shortens rays. In case 3, the twilight Sun is shaded by a towering cloud or mountain. The shaded rays are deeper blue than the sunlit sky because the light originates higher in the atmosphere, where short waves have suffered less depletion from scattering. The long optical path taken by sunlight at twilight makes color and lighting contrasts of the rays greatest when the air is quite clean, i.e., for β−1≪1 . In all cases, the brightest rays occur when sunlight passes through an optical thickness of atmosphere, τ≈O(1) . © 2011 Optical Society of America Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.50.00F142 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Rainbows, water droplets, and seeing—slow motion analysis of experiments in atmospheric optics JF - In: Applied optics Vol. 50 (2011) 28, pp. F21–F28 N2 - Many physics processes underlying phenomena in atmospheric optics happen on a rather short time scale such that neither the human eye nor video cameras are able to analyze the details. We report applications of high-speed imaging of laboratory experiments in atmospheric optics with subsequent slow motion analysis. The potential to study respective transient effects is investigated in general and for a few phenomena in detail, in particular for rainbow scattering due to single oscillating droplets during free fall, and for light propagation effects through atmospheric paths with turbulences, leading, e.g., to scintillation of stars or shimmering of mirage images. © 2011 Optical Society of America Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.50.000F21 SP - F21 EP - F28 ER - TY - CHAP A1 - Vollmer, Michael A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter T1 - Measurements of sun and moon with IR cameras: effects of air mass T2 - In: InfraMation proceedings. - Vol. 11 ( 2010) , 57-74 Y1 - 2010 SP - 74 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Two-color or ratio thermal imaging - potentials and limits T2 - In: InfraMation proceedings. - Vol. 11 (2010), pp.41-56 Y1 - 2010 SP - 41 EP - 56 ER - TY - CHAP A1 - Pinno, Frank A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Improved sensitivity for blower door thermography using image subtraction T2 - In: InfraMation proceedings. - Vol. 11 (2010), p. 29-40 Y1 - 2010 SP - 29 EP - 40 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - New book on IR imaging: the ultimate resource for all users T2 - In: InfraMation proceedings. - Vol. 11 (2010), pp 75-80 Y1 - 2010 SP - 75 EP - 80 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - IR imaging of gases: potential applications for CO2 cameras T2 - In: InfraMation proceedings. - Vol. 10 (2009), p.113-124 Y1 - 2009 SP - 113 EP - 124 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - IR imaging of gases: quantitative analysis T2 - In: InfraMation proceedings. - Vol. 10 (2009), p. 99-112 Y1 - 2009 SP - 99 EP - 112 ER - TY - CHAP A1 - Vollmer, Michael A1 - Vujković, M. A1 - Trellu, Y. A1 - Möllmann, Klaus-Peter T1 - IR feedback loops to spotlights: thermography and contemporary dancing T2 - In: InfraMation proceedings.- Vol. 10 (2009), p. 89-97 Y1 - 2009 SP - 89 EP - 97 ER - TY - CHAP A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Solar load and reflection effects and respective time constants in outdoor building inspections T2 - In: Inframation proceedings Vol. 10 (2009), 319-330 Y1 - 2009 SP - 319 EP - 330 ER - TY - JOUR A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Eine etwas andere, physikalische Sehweise - Visualisierung von Energieumwandlungen und Strahlungsphysik für die (Hochschul-)lehre JF - In: Physikalische Blätter 56 (2000) 9, 65-69 N2 - Max Planck legte 1900 mit dem nach ihm benannten Strahlungsgesetz das quantitative Fundament zu so genannten Wärmebildsystemen. 100 Jahre später gibt es — mit bedingt durch Fortschritte in der Halbleitertechnologie und Mikrosystemtechnik — Infrarotkameras, mit denen sowohl die von Planck untersuchten Strahlungsgesetze zur Hohlraumstrahlung als auch allgemein wissenschaftliche und technische Anwendungen der Temperaturstrahlung von Körpern untersucht werden können. Darüber hinaus bieten sich solche Systeme auch für didaktische Zwecke an, da physikalische Gesetzmäßigkeiten mit Energieaustauschprozesssen aus sehr vielen Gebieten der Physik durch eine etwas andere, physikalische Sehweise visualisiert und damit für Lehrzwecke eingesetzt werden können. Y1 - 2000 U6 - https://doi.org/10.1002/phbl.20000560915 SP - 65 EP - 69 ER - TY - JOUR A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Zauberei, Diffusion, industrielle Messtechnik und 100 Jahre Quantentheorie : Einige Freihandexperimente zur Optik und Wärmestrahlung JF - In: Physik in der Schule 38 (2000) 4, 260-262 Y1 - 2000 SP - 260 EP - 262 ER - TY - JOUR A1 - Vollmer, Michael T1 - Unschuldige Schule! : In den vergangenen Jahren hat zwar die Zahl der Physikstudenten dramatisch abgenommen, nicht aber die Zahl der Schüler, die in der Oberstufe Physik wählen JF - In: Physikalische Blätter 56 (2000) 6, 21-22 Y1 - 2000 U6 - https://doi.org/10.1002/phbl.20000560606 SP - 21 EP - 22 ER - TY - JOUR A1 - Vollmer, Michael T1 - Physikalische Texte zum Thema Atmosphärische Optik JF - In: Meteorologischer Kalender 2000(1999) Y1 - 1999 ER -