Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object,in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth and other planets. Remote sensing is used in numerous fields,including geophysics,geography,land surveying and most Earth science disciplines. It also has military,intelligence,commercial,economic,planning,and humanitarian applications,among others.
The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972,the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat 1 in 1975. The most recent,Landsat 9,was launched on 27 September 2021.
Landsat 1 (LS-1),formerly named ERTS-A and ERTS-1,was the first satellite of the United States' Landsat program. It was a modified version of the Nimbus 4 meteorological satellite and was launched on July 23,1972,by a Delta 900 rocket from Vandenberg Air Force Base in California.
Satellite images are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell images by licensing them to governments and businesses such as Apple Maps and Google Maps.
Landsat 3 is the third satellite of the Landsat program. It was launched on March 5,1978,with the primary goal of providing a global archive of satellite imagery. Unlike later Landsat satellites,Landsat 3 was managed solely by NASA. Landsat 3 decommissioned on September 7,1983,beyond its design life of one year. The data collected during Landsat 3's lifetime was used by 31 countries. Countries that cannot afford their own satellite are able to use the data for ecological preservation efforts and to determine the location of natural resources.
The Cooperative Institute for Research in Environmental Sciences (CIRES) is a research institute that is sponsored jointly by the National Oceanic and Atmospheric Administration (NOAA) Office of Oceanic and Atmospheric Research (OAR) and the University of Colorado Boulder (CU). CIRES scientists study the Earth system,including the atmosphere,hydrosphere,cryosphere,biosphere,and geosphere,and communicate these findings to decision makers,the scientific community,and the public.
The normalized difference vegetation index (NDVI) is a widely-used metric for quantifying the health and density of vegetation using sensor data. It is calculated from spectrometric data at two specific bands:red and near-infrared. The spectrometric data is usually sourced from remote sensors,such as satellites.
Snow hydrology is a scientific study in the field of hydrology which focuses on the composition,dispersion,and movement of snow and ice. Studies of snow hydrology predate the Anno Domini era,although major breakthroughs were not made until the mid eighteenth century.
GNSS reflectometry involves making measurements from the reflections from the Earth of navigation signals from Global Navigation Satellite Systems such as GPS. The idea of using reflected GNSS signals for earth observation was first proposed in 1993 by Martin-Neira. It was also investigated by researchers at NASA Langley Research Center and is also known as GPS reflectometry.
Atmospheric correction is the process of removing the scattering and absorption effects of the atmosphere on the reflectance values of images taken by satellite or airborne sensors. Atmospheric effects in optical remote sensing are significant and complex,dramatically altering the spectral nature of the radiation reaching the remote sensor. The atmosphere both absorbs and scatters various wavelengths of the visible spectrum which must pass through the atmosphere twice,once from the sun to the object and then again as it travels back up the image sensor. These distortions are corrected using various approaches and techniques,as described below.
Frank Wentz is the CEO and director of Remote Sensing Systems,a company he founded in 1974,which specializes in satellite microwave remote sensing research. Together with Carl Mears,he is best known for developing a satellite temperature record from MSU and AMSU. Intercomparison of this record with the earlier UAH satellite temperature record,developed by John Christy and Roy Spencer,revealed deficiencies in the earlier work;specifically,the warming trend in the RSS version is larger than the University of Alabama in Huntsville (UAH) one. From 1978 to 1982,Wentz was a member of NASA's SeaSat Experiment Team involved in the development of physically based retrieval methods for microwave scatterometers and radiometers. He has also investigated the effect of climate change on satellite-derived evaporation,precipitation and surface wind values. His findings are different from most climate change model predictions.
Sea ice concentration is a useful variable for climate scientists and nautical navigators. It is defined as the area of sea ice relative to the total at a given point in the ocean. This article will deal primarily with its determination from remote sensing measurements.
JoBea Way Holt is an American planetary scientist who has worked for NASA. Holt studied the carbon cycle in Earth's atmosphere. She is also a member of the Climate Project,and is the author of several books and research papers.
Chandra Prasad Giri is a Nepalese-American author,scientist,and businessman. He specializes in remote sensing and sensor technologies in mapping and monitoring of land cover and mangrove forests. Giri is currently chief of the Sensing and Spatial Analysis branch of the United States Environmental Protection Agency and adjunct professor at Duke University in North Carolina. Prior to this,he worked as senior scientist at the United States Geological Survey,Columbia University,the Asian Institute of Technology,the United Nations Environment Programme,and the Nepal Government. Prior to this he worked as a school teacher at Dangi Secondary School,Dangihat,Morang,Nepal and Dhulabari Secondary School,Dhulabari,Jhapa,Nepal
BAITSSS is biophysical Evapotranspiration (ET) computer model that determines water use,primarily in agriculture landscape,using remote sensing-based information. It was developed and refined by Ramesh Dhungel and the water resources group at University of Idaho's Kimberly Research and Extension Center since 2010. It has been used in different areas in the United States including Southern Idaho,Northern California,northwest Kansas,Texas,and Arizona.
Dr. Y. S. Rao is a professor at the Centre of Studies in Resources Engineering,Indian Institute of Technology Bombay,Mumbai,India. He is working in the field of microwave remote sensing and land based applications for more than 34 years. His early research was focused on the use of Synthetic Aperture Radar (SAR) interferometry for landslides and land deformation monitoring,Digital Elevation Model generation,snow and glacier monitoring. He is also actively involved in developing several techniques for soil moisture estimation using passive and active microwave remote sensing data for more than 25 years. His current research involves SAR Polarimetry for crop characterization,classification,biophysical parameter retrieval using linear and compact-pol SAR data. Apart from applications,he has also contributed in the field of Polarimetric SAR system calibration and software tool development.
Eni G. Njoku is a Nigerian-American scientist specializing in microwave remote sensing. He worked at the Jet Propulsion Laboratory (JPL),California Institute of Technology,where he was responsible for developing techniques for sea surface temperature and soil moisture remote sensing using microwave radiometers. He produced the first microwave-derived sea surface temperature maps from space,and developed the first application of deployable mesh antennas for satellite Earth observation. From 2008-2013,he served as project scientist of NASA's first soil moisture mission,the Soil Moisture Active Passive (SMAP) mission,launched in 2015.
Qihao Weng is an American geographer,urban,environmental sustainability,and remote sensing scientist. He has been a Chair Professor at the Hong Kong Polytechnic University since July 2021,and was the Director of the Center for Urban and Environmental Change and is a professor of geography in the Department of Earth and Environmental Systems at the Indiana State University.
Dorothy K. Hall is a scientific researcher known for her studies on snow and ice,which she studies through a combination of satellite data and direct measurements. She is a fellow of the American Geophysical Union.
Ralph Bernstein is a German–born American engineer known for his contributions to digital imaging,image processing,and geosciences. He is a member of the American Society for Photogrammetry and Remote Sensing (ASPRS).
