Meteorology Tags

Meteorology Tags > Tag based links for Albedo

The following links have been tagged albedo by users just like you, because these resources are off-site we cannot guarantee the accuracy or quality of any third-party information.

Recovering Facial Shape Using a Statistical Model of Surface Normal Direction: Pattern Analysis and Machine Intelligence, IEEE Transactions on, Vol. 28, No. 12. (2006), pp. 1914-1930.In this paper, we show how a statistical model of facial shape can be embedded within a shape-from-sha ding algorithm. We describe how facial shape can be captured using a statistical model of variations in surface normal direction. To construct this model, we make use of the azimuthal equidistant projection to map the distribution of surface normals from the polar representation on a unit sphere to Cartesian points on a local tangent plane. The distribution of surface normal directions is captured using the covariance matrix for the projected point positions. The eigenvectors of the covariance matrix define the modes of shape-variatio n in the fields of transformed surface normals. We show how this model can be trained using surface normal data acquired from range images and how to fit the model to intensity images of faces using constraints on the surface normal direction provided by Lambert's law. We demonstrate that the combination of a global statistical constraint and local irradiance constraint yields an efficient and accurate approach to facial shape recovery and is capable of recovering fine local surface details. We assess the accuracy of the technique on a variety of images with ground truth and real-world imagesWAP Smith, ER Hancock

Source: Pattern Analysis and Machine Intelligence, IEEE Transactions on, Vol. 28, No. 12. (2006), pp. 1914-1930.
Landsat Thematic Mapper: Detection of Shifts in Community Composition of Coral Reefs: Conservation Biology, Vol. 15, No. 4. (2001), pp. 892-902.We assembled a time series of 20 Landsat thematic mapper images from 1982 to 1996 for Key Largo, Florida, to ascertain whether satellite imagery can detect temporal changes in coral reef communities. Selected reef and control areas were examined for changes in brightness, spectral reflectance, band ratios, spatial texture, and temporal texture ( pixel-to-pixel change over time). We compared the data to known changes in the reef ecosystem of Carysfort Reef and terrestrial sample sites. Changes in image brightness and spectral-band ratios were suggestive of shifts from coral- to algal-dominate d community structure, but the trends were not statistically significant. The spatial heterogeneity of the reef community decreased in the early 1980s at scales consistent with known ecological changes to the coral community on Carysfort Reef. An analysis of pixel-scale variation through time, termed temporal texture, revealed that the shallow reef areas are the most variable in regions of the reef that have experienced significant ecological decline. Thus, the process of reef degradation, which alters both the spatial patterning and variability of pixel brightness, can be identified in unclassified thematic mapper images. Mapeador Tematico Landsat: Deteccion de Desplazamiento s en la Composicion de Comunidades en Arrecifes de Coral Resumen: Ensamblamos una serie de tiempo de 200 imagenes del mapeador tematico Landsat de 1982 a 1996 para Cayo Largo, Florida para determinar si las imagenes de satelite pueden detectar cambios temporales en las comunidades de arrecifes de coral. Los arrecifes de coral y las areas control fueron examinados para cambios en resplandor, reflectancia espacial, proporciones de las bandas, textura espacial y textura temporal (cambios pixel a pixel a traves del tiempo). Comparamos los datos de cambios conocidos en el ecosistema de arrecife de Carysfort y en muestras de sitios terrestres. Cambios en el resplandor de la imagen y en las proporciones de las bandas espectrales sugirieron desplazamiento s en la estructura comunitaria dominante de coral a algas; sin embargo, las tendencias no fueron estadisticamen te significativas . La heterogeneidad espacial de la comunidad de arrecifes disminuyo en los inicios de los anos 1980s en escalas consistentes con cambios ecologicos conocidos en la comunidad de coral del arrecife Carysfort. El analisis de la variacion a nivel de pixel a traves del tiempo, e identificado como textura temporal, revelo que las areas de arrecifes bajos son las mas variables en regiones donde el arrecife ha experimentado disminuciones ecologicas significativas . Por lo tanto, el proceso de degradacion, que altera tanto los patrones espaciales como la variabilidad del resplandor de pixeles, puede ser identificado en el Mapeador Tematico sin clasificar.Phi llip Dustan, Eric Dobson, George Nelson

Source: Conservation Biology, Vol. 15, No. 4. (2001), pp. 892-902.
Global warming and climate forcing by recent albedo changes on Mars: Nature, Vol. 446, No. 7136., pp. 646-649.Lori Fenton, Paul Geissler, Robert Haberle

Source: Nature, Vol. 446, No. 7136., pp. 646-649.
Climate effects of global land cover change: Geophysical Research Letters, Vol. 32 (8 December 2005), L23705.S Gibbard, K Caldeira, G Bala, TJ Phillips, M Wickett

Source: Geophysical Research Letters, Vol. 32 (8 December 2005), L23705.
Seasonal and interannual variations of top-of-atmosph ere irradiance and cloud cover over polar regions derived from the CERES data set: Geophysical Research Letters, Vol. 33 (2006), L19804.Seiji Kato, Norman Loeb, Patrick Minnis, Jennifer Francis, Thomas Charlock, David Rutan, Eugene Clothiaux, Szedung Sun-Mack

Source: Geophysical Research Letters, Vol. 33 (2006), L19804.
Arctic Air Pollution: Origins and Impacts: Science, Vol. 315, No. 5818. (16 March 2007), pp. 1537-1540.Nota ble warming trends have been observed in the Arctic. Although increased human-induced emissions of long-lived greenhouse gases are certainly the main driving factor, air pollutants, such as aerosols and ozone, are also important. Air pollutants are transported to the Arctic, primarily from Eurasia, leading to high concentrations in winter and spring (Arctic haze). Local ship emissions and summertime boreal forest fires may also be important pollution sources. Aerosols and ozone could be perturbing the radiative budget of the Arctic through processes specific to the region: Absorption of solar radiation by aerosols is enhanced by highly reflective snow and ice surfaces; deposition of light-absorbin g aerosols on snow or ice can decrease surface albedo; and tropospheric ozone forcing may also be contributing to warming in this region. Future increases in pollutant emissions locally or in mid-latitudes could further accelerate global warming in the Arctic. 10.1126/scienc e.1137695Kathy Law, Andreas Stohl

Source: Science, Vol. 315, No. 5818. (16 March 2007), pp. 1537-1540.
Southern Hemisphere and Deep-Sea Warming Led Deglacial Atmospheric CO2 Rise and Tropical Warming: Science (27 September 2007), 1143791.Establ ishing what caused Earth's largest climatic changes in the past requires a precise knowledge of both the forcing and the regional responses. Here we establish the chronology of high and low latitude climate change at the last glacial termination by 14C dating benthic and planktonic foraminiferal stable isotope and Mg/Ca records from a marine core collected in the western tropical Pacific. Deep sea temperatures warmed by ~2oC between 19 and 17 ka B.P. (thousand years before present), leading the rise in atmospheric CO2 and tropical surface ocean warming by ~1000 years. The cause of this deglacial deep water warming does not lie within the tropics, nor can its early onset between 19-17 ka B.P. be attributed to CO2 forcing. Increasing austral spring insolation combined with sea-ice albedo feedbacks appear to be key factors responsible for this warming. 10.1126/scienc e.1143791Lowel l Stott, Axel Timmermann, Robert Thunell

Source: Science (27 September 2007), 1143791.
Changes in Earth's Reflectance over the Past Two Decades: Science, Vol. 304, No. 5675. (28 May 2004), pp. 1299-1301.We correlate an overlapping period of earthshine measurements of Earth's reflectance (from 1999 through mid-2001) with satellite observations of global cloud properties to construct from the latter a proxy measure of Earth's global shortwave reflectance. This proxy shows a steady decrease in Earth's reflectance from 1984 to 2000, with a strong climatological ly significant drop after 1995. From 2001 to 2003, only earthshine data are available, and they indicate a complete reversal of the decline. Understanding how the causes of these decadal changes are apportioned between natural variability, direct forcing, and feedbacks is fundamental to confidently assessing and predicting climate change. 10.1126/scienc e.1094070E Palle, PR Goode, P Montanes-Rodri guez, SE Koonin

Source: Science, Vol. 304, No. 5675. (28 May 2004), pp. 1299-1301.
Shortwave forcing of the Earth's climate: Modern and historical variations in the Sun's irradiance and the Earth's reflectance: Journal of Atmospheric and Solar-Terrestr ial Physics, Vol. 69, No. 13. (September 2007), pp. 1556-1568.Chan ges in the Earth's radiation budget are driven by changes in the balance between the thermal emission from the top of the atmosphere and the net sunlight absorbed. The shortwave radiation entering the climate system depends on the Sun's irradiance and the Earth's reflectance. Often, studies replace the net sunlight by proxy measures of solar irradiance, which is an oversimplifica tion used in efforts to probe the Sun's role in past climate change. With new helioseismic data and new measures of the Earth's reflectance, we can usefully separate and constrain the relative roles of the net sunlight's two components, while probing the degree of their linkage. First, this is possible because helioseismic data provide the most precise measure ever of the solar cycle, which ultimately yields more profound physical limits on past irradiance variations. Since irradiance variations are apparently minimal, changes in the Earth's climate that seem to be associated with changes in the level of solar activityȁ 4;the Maunder Minimum and the Little Ice age for example— ;would then seem to be due to terrestrial responses to more subtle changes in the Sun's spectrum of radiative output. This leads naturally to a linkage with terrestrial reflectance, the second component of the net sunlight, as the carrier of the terrestrial amplification of the Sun's varying output. Much progress has also been made in determining this difficult to measure, and not-so-well-kn own quantity. We review our understanding of these two closely linked, fundamental drivers of climate.P Goode, E Palle

Source: Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 69, No. 13. (September 2007), pp. 1556-1568.
Evaluation of surface albedo and snow cover in AR4 coupled climate models: Journal of Geophysical Research, Vol. 111 (15 August 2006), D15111.A Roesch

Source: Journal of Geophysical Research, Vol. 111 (15 August 2006), D15111.

If you would like to find additional social bookmark based links on the topic of albedo we recommend the Open Tag Directory > Albedo. If you would like to find related tags we recommend Tag Patterns > Albedo.