Measurements > Land

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Measurements of land include a number of parameters covering albedo and reflectance, topography, temperature, soils and vegetation.
Albedo and reflectanceAlbedo is the fraction of solar energy that is diffusely reflected back from Earth to space. Measurements of albedo are essential for climate research studies and investigations of the Earth’s energy budget. Different parts of the Earth have different albedos. For example, ocean surfaces and rain forests have low albedos, which means that they reflect only a small portion of the Sun’s energy. Deserts, ice and clouds, however, have high albedos; they reflect a large portion of the incoming solar energy. The high albedo of ice helps to insulate the polar oceans from solar radiation.
Inland WatersObservations of inland water systems, for example lakes and rivers.
Landscape topographyMany modelling activities in Earth and environmental sciences, telecommunications and civil engineering increasingly require accurate, high resolution and comprehensive topographical databases with, indication of changes over time, where relevant. The information is also used by, amongst others, land use planners for civil planning and development, and by hydrologists to predict the drainage of water and likelihood of floods, especially in coastal areas.
Multi-purpose imagery (land)The spatial information that can be derived from satellite imagery is of value in a wide range of applications, particularly when combined with spectral information from multiple wavebands of a sensor. Satellite Earth observation is of particular value where conventional data collection techniques are difficult, such as in areas of inaccessible terrain, providing cost and time savings in data acquisition – particularly over large areas. At regional and global scales, low resolution instruments with wide coverage capability and imaging sensors on geostationary satellites are routinely exploited for their ability to provide global data on land cover and vegetation.
Soil moistureSoil moisture plays a key role in the hydrological cycle. Evaporation rates, surface runoff, infiltration and percolation are all affected by the level of moisture in the soil. Changes in soil moisture have a serious impact on agricultural productivity, forestry and ecosystem health. Monitoring soil moisture is critical for managing these resources and understanding long-term changes, such as desertification, and should be developed in proper coordination with other land surface variables. Applications include crop yield predictions, identification of potential famine areas, irrigation management, and monitoring of areas subject to erosion and desertification, as well as for the initialisation of NWP models.
Surface temperature (land)Land surface temperature varies widely with solar radiation. It is of help in interpreting vegetation and its water stress when the range of temperatures between day and night and from clear sky to cloud cover are compared. On a local scale, surface temperature imagery may be used to refine techniques for predicting ground frost and to determine the warming effect of urban areas (urban heat islands) on night-time temperatures. In agriculture, temperature information may be used, together with models, to optimise planting times and provide timely warnings of frost. Measurements of surface temperature patterns may also be used in studies of volcanic and geothermal areas and resource exploration.
VegetationChanges in land cover are important aspects of global environmental change, with implications for ecosystems, biogeochemical fluxes and global climate. Land cover change affects climate through a range of factors from albedo to emissions of greenhouse gases from the burning of biomass. Deforestation increases the amount of carbon dioxide (CO2) and other trace gases in the atmosphere.