Deeply shadowed cavities can achieve an effective albedo approaching the zero of a black body. The albedo is defined as the ratio between the reflected energy and the incident energy over a unit area, from which it can be inferred that there is some similarity between the albedo and the reflectance. Remote sensing of snow properties with sentinel3 versus modis 09. The high albedo of snow largely determines the climate of polar regions by controlling energy absorption at the surface. Early spring postfire snow albedo dynamics in high. Surface albedos inferred from satellite measurements have typical errors of a few percent, so a signal of reduced albedo will be difficult to detect. Spectral mixture analysis allows the retrieval of the subpixel variability of snow covered area, along with the snow s albedo. Since vast expanses of the earths polar regions are permanently covered by snow and ice e. This chapter summarizes the optical remote sensing techniques used for estimating snow grain size, snow albedo and level of pollution, using spaceborne observations. A critic may dismiss this as correlationdoesnotequalcausation because the underlying mechanisms linking albedo with nitrogen are unclear. Idso sb, jackson rd, reginato rj, kimball ba, nakayama fs 1975 the dependence of bare soil albedo on soil water content.
Satellite remote sensing of snow lce albedo over the himalayas n. Snow density is simulated over the domain to convert snow. The seasonal snow melt from the himalayan glaciers and snowpacks is one of. National operational hydrologic remote sensing center nohrsc snow maps over u. Pdf snow surface albedo estimation using terrestrial. Accuracy assessment of the modis 16day albedo product for. Star jpss environmental data record teams surface albedo. Data mining from remote sensing snow and vegetation product.
We still want to know the spatial extent of snow cover, snowpack properties such as grain size and albedo, snow depth, snow. Nolin abstract snow covered surfaces have a very high surface albedo, thereby allowing little energy to be absorbed by the. In addition, the local surface albedo and snow depth refers to a small area on the scale of a meter, whereas the remotelysensed albedo is. Feb 07, 2020 compute albedo from remote sensing data. The daily modis snow albedo product has been validated over the greenland ice sheet and shown to be biased low. In many ways, the research questions involving seasonal snow have not changed over the past several decades since the inception of remote sensing. It is essential to quantify the spatial representativeness of remote sensing products to better guide the sampling strategy in field experiments and match. Christina hsu and ritesh gautam code 6 nasa goddard space flight center, greenbelt, md, usa the himalayan glaciers and snowpacks play an important role in the hydrological cycle over asia. Recent advances in remote sensing of seasonal snow international. The role of radiation forcing versus atmosphere forcing requires a thorough knowledge of the surface albedo. The ratio of the up flux and down flux just above the snow surface, is called albedo. The time span is from december 2006 to february 2015. Any albedo in visible light falls within a range of about 0.
A synthesis of a variety of remote sensing and field measurements suggests that this albedo feedback from the northern hemisphere cryosphere falls between 0. Detecting intercepted snow on mountain needleleaf forest. Soil and vegetation albedos increase and snow albedo decreases kondrotyev, 1973. The snicar radiative transfer model can reproduce the observations that fresh shallow snow has a low albedo value, based on which a fresh snow. It focuses on the theoretical background of snow grain size and albedo pollution monitoring using spaceborne observations.
Glass albedo product from 1981 is produced from avhrr and modis data liang et al. Recent advances in remote sensing of seasonal snow journal. The aim of this work is to investigate whether snow albedo seasonality and trend under all sky conditions at johnsons glacier livingston island, antarctica can be tracked using the moderate resolution imaging spectroradiometer modis snow albedo daily product mod10a1. Albedo plays an important role in snow evolution modeling quantifying the amount of solar radiation absorbed and reflected by the snowpack, especially in midlatitude regions with semiarid conditions. When atmospheric turbidity is high, or the sun is low in the sky, the spectral distribution of solar radiation shifts to the red and infrared portion of the spectrum. Using remote sensing to quantify albedo of roofs in seven. Can black carbon in snow be detected by remote sensing. Using remote sensing to quantify albedo of roofs in seven california cities, part 2. Snow observatory aso, a coupled imaging spectrometer and scanning lidar, combined with distributed snow modeling, developed for the measurement of snow spectral albedo broadband albedo and snow depth swe. More precisely the terms of spectral and total albedo are differentiated. However, to simplify retrievals, many researchers assume that snow is a lambertian re ector. In terms of earth science, remote sensing refers to the ability of satellites to detect electromagnetic radiation from features on the earths surface or in the atmosphere. Agu chapman conference on remote sensing of the terrestrial. But, the constraints availability of model source codes, data sets, time restrict this thesis to limited electromagnetic spectrum optical remote sensing, spatial extents, and snow variables snow albedo and snow coverage.
Review on remote sensing of the snow cover and on wmo. Accurate estimates of the spatial distribution and albedo of snow cover are needed for climate models, that use surface albedo as a lower boundary condition. When seen from a distance, the ocean surface has a low albedo, as do most forests, whereas desert areas have some of the highest albedos among landforms. The conventional methods estimate snow albedo through a series of processing steps including atmospheric correction, surface angular modeling, and narrow band to broadband albedo conversions. Snow surface albedo estimation using terrestrial photography. Estimating snow albedo in tibetan plateau using modis. A handheld camera is an example of a remote sensing instrument. Spectral mixture analysis allows the retrieval of the subpixel variability of snowcovered area, along with the snows albedo. Pdf the use of satellite remote sensing for the mapping of snowcover characteristics has a. Radiative forcing and albedo feedback from the northern. A joint meeting on research on the use of remote sensing of snow and evaportranspiration was held november 1519,1983, at the eastwest center on the campus of the university of hawaii in honolulu with a field trip to an irrigationwater management site of the oahu sugar company.
Nov 21, 2014 the cryosphere, that region of the world where water is temporarily or permanently frozen, plays a crucial role on our planet. Data mining from remote sensing snow and vegetation product 311 figure 3. Bidirectional reflectance distribution function brdf of. Remote sensing offers a new and valuable tool for obtaining snow data for predicting. For remote sensing over snow covered surfaces, the bidirectional re ectance distribution function brdf of snow plays an important role that should be considered in inverse algorithms for the retrieval of snow properties. Snow density is simulated over the domain to convert snow depth to swe. Contrasting snow and ice albedos derived from modis. New methods to infer snow albedo from the misr instrument. Center for remote sensing, boston university, 725 commonwealth avenue, boston, ma 02215, usa. Request pdf remote sensing of snow and characterization of snow albedo for climate simulations accurate estimates of the spatial distribution and albedo of snow cover are needed for climate. The high albedo of snow presents a good contrast with most other.
The visible albedo for pure snow is not sensitive to these. In antarctica, where lightabsorbing impurities are few, snow albedo is. Recent developments in remote sensing techniques, and the acquisition of new data sets, have resulted in significant advances in our understanding of all components of the cryosphere and its processes. Remote sensing measurements have proven a high potential to provide valuable information regarding the mapping of land surface albedo at various spatial and temporal scales. The albedo of the snow surface is the property most easily measured by remote. Nov 03, 2005 remote sensing is a practical means for mapping snow albedo in high elevation area such as in the tibetan plateau. Nolin abstract snowcovered surfaces have a very high surface albedo, thereby allowing little energy to be absorbed by the. Remote sensing of environment university of new hampshire. Remote sensing of snow albedo, grain size, and pollution from. Effects of vertical inhomogeneity on snow spectral albedo and its implication for optical remote sensing of snow xiaobing zhou department of earth and environmental science, new mexico institute of mining and technology, socorro, new mexico, usa shusun li geophysical institute, university of alaska fairbanks, fairbanks, alaska, usa knut stamnes. The percentage of diffusely reflected sunlight relative to various surface conditions. The nearir solar irradiance thus plays an important role in snowmelt and in the energy balance at a snow surface.
Satellite remotesensing technology has virtually revolu tionized the study of snow cover. Such low albedo values contrast with the high values 0. Remote sensing is a practical means for mapping snow albedo in high elevation area such as in the tibetan plateau. Sensors free fulltext snow albedo seasonality and trend. Pdf monitoring of glacier albedo from optical remotesensing data. As the mod10a1 snow albedo product has never been used in antarctica. The gridded remote sensing albedo product often represents information concerning an area larger than the nominal spatial resolution because of the large viewing angles of the observations. Snow surface albedo estimation using terrestrial photography article pdf available in international journal of remote sensing 2524 december 2004 with 461 reads how we measure reads. A simple method to determine the timing of snow melt by. The albedo of fresh snow depends on snow depth, and is frequently less than 0. Comparison between snow albedo obtained from landsat tm. Nov 21, 2014 this chapter summarizes the optical remote sensing techniques used for estimating snow grain size, snow albedo and level of pollution, using spaceborne observations.
Remote sensing of environment national snow and ice data. Huete ar 1988 a soiladjusted vegetation index savi. Satellite remote sensing of snow is important for the studies of climate change because of the large impact of the cryosphere on to the climate system. Summary snow reflectance in the visible region of the electromagnetic spectrum depends on the amount and type of pollutants. Effects of vertical inhomogeneity on snow spectral albedo. This decreases the albedos of soils and vegetation but increases snow albedo miller, 1981. The cryosphere, that region of the world where water is temporarily or permanently frozen, plays a crucial role on our planet. Satellite remote sensing is the most extensive technique to determine the variability of snow albedo over medium to large areas. Remote sensing of snow and characterization of snow albedo for. Characterizing surface albedo of shallow fresh snow and.
Elements of remote sensing mcqs pdf download posted on august 19, 2018 april 18. We especially thank ash lashgari, eileen mccauley, and tony. Snow albedo forest grassland spatial representativeness this study assesses the moderateresolution imaging spectroradiometer modis brdf albedo 8 day standard. Narrowband to broadband conversions of land surface albedo. From multispectral and hyperspectral remote sensing at wavelengths from 0. Elements of remote sensing multiple choice questions. Contrasting snow and ice albedos derived from modis, landsat. Iii acknowledgements the authors thank the california air resources board for funding this project under contract 10321. Topology describes the geometric characteristic of objects which do not change under transformations and are independent of any coordinate system. Ndsi,ndvi, albedo,andlandsurfacetemperaturelstcanbe derivedfrommostopticalandthermalsatellitesensors. Remote sensing of the cryosphere wiley online books. Snow albedo is therefore much lower in the near ir.
Comparison between snow albedo obtained from landsat. Synergistic use of remote sensing for snow cover and snow. Recent advances in remote sensing of seasonal snow. Monitoring surface albedo is a key application of remote sensing and achieving consistency between instruments is crucial to accurate assessment of changing albedo. An example of demleft data and modisright in gif formatall these datasets are available from hdf files of snow product from july 2002 to january 2009, and vegetation product from 2003 to 2005 are adopted in this chapter, except for january 2004 which. Elements of remote sensing multiple choice questions and answers pdf free download for civil engineering students. The growth and decay of sea ice occur on a seasonal cycle. A high albedo value helps to reflect a huge amount of sunlight, which otherwise would have heated the earth s surface. We still want to know the spatial extent of snow cover, snowpack properties such as grain size and albedo, snow depth, snow water equivalent. Remote sensing, in simplest terms, means viewing something from a distance rather than by direct contact. Remote sensing of environment national snow and ice data center. Remote sensing landsat surface reflectance and albedo.
Isprs journal of photogrammetry and remote sensing. Effects of snow physical parameters on spectral albedo and. Surface albedo surfalb, defined as the ratio between solar radiation reflected by earths surface and solar radiation incident at the surface, is a function of both solar illumination and the surface reflective properties. Remote sensing of snow albedo, grain size, and pollution.
Estimation of snow extent and snow properties modis snow and. Remote sensing offers local, regional and global observations of seasonal snow, providing key information on snowpack processes. Modis snow albedo prototype albedo is calculated only for areas identified as cloudfree by the modis cloud mask and as snow covered by the modis snow. In addition, the local surface albedo and snow depth refers to a small area on the scale of a meter, whereas the remotelysensed albedo is derived for an area of 15 km. It focuses on the theoretical background of snow grain size and albedo pollution monitoring using. Thanks for contributing an answer to geographic information systems stack exchange. A flexible and inexpensive remote sensing tool for albedo estimation. For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article. Pdf retrieval of snow albedo and grain size using reflectance. Remote sensing of snow and characterization of snow albedo. The nearir albedo is very sensitive to snow grain size and moderately sensitive to solar zenith angle. The surface albedo is a key ingredient in the remote sensing of surface and atmospheric properties from space.