Editing Atmospheric physics (section)

== Remote sensing ==
{{Weather}}
[[Image:weather radar.jpg|thumb|Brightness can indicate reflectivity as in this 1960 [[weather radar]] image (of [[1960 Atlantic hurricane season#Hurricane Abby|Hurricane Abby]]). The radar's frequency, pulse form, and antenna largely determine what it can observe.]]
{{Main|Remote sensing}}
Remote sensing is the small or large-scale acquisition of information of an object or phenomenon, by the use of either recording or real-time sensing device(s) that is not in physical or intimate contact with the object (such as by way of [[aircraft]], [[spacecraft]], [[satellite]], [[buoy]], or [[ship]]). In practice, remote sensing is the stand-off collection through the use of a variety of devices for gathering information on a given object or area which gives more information than sensors at individual sites might convey.<ref>COMET program (1999). [http://www.comet.ucar.edu/nsflab/web/remote/121.htm Remote Sensing.] {{Webarchive|url=https://web.archive.org/web/20130507000326/http://www.comet.ucar.edu/nsflab/web/remote/121.htm |date=2013-05-07 }} [[University Corporation for Atmospheric Research]]. Retrieved on 2009-04-23.</ref> Thus, [[Earth observation]] or [[weather satellite]] collection platforms, ocean and atmospheric observing [[weather buoy]] platforms, monitoring of a pregnancy via [[ultrasound]], [[magnetic resonance imaging]] (MRI), [[positron-emission tomography]] (PET), and [[space probes]] are all examples of remote sensing. In modern usage, the term generally refers to the use of imaging sensor technologies including but not limited to the use of instruments aboard aircraft and spacecraft, and is distinct from other imaging-related fields such as [[medical imaging]].

There are two kinds of remote sensing. Passive sensors detect natural radiation that is emitted or reflected by the object or surrounding area being observed. Reflected sunlight is the most common source of radiation measured by passive sensors. Examples of passive remote sensors include film [[photography]], infrared, [[charge-coupled devices]], and [[radiometer]]s. Active collection, on the other hand, emits energy in order to scan objects and areas whereupon a sensor then detects and measures the radiation that is reflected or backscattered from the target. [[radar]], [[lidar]], and [[SODAR]] are examples of active remote sensing techniques used in atmospheric physics where the time delay between emission and return is measured, establishing the location, height, speed and direction of an object.<ref>Glossary of Meteorology (2009). [http://amsglossary.allenpress.com/glossary/search?id=radar1 Radar.] [[American Meteorological Society]]. Retrieved on 2009-24-23.</ref>

Remote sensing makes it possible to collect data on dangerous or inaccessible areas. Remote sensing applications include monitoring [[deforestation]] in areas such as the [[Amazon Basin]], the [[effects of climate change]] on [[glacier]]s and Arctic and Antarctic regions, and [[depth sounding]] of coastal and ocean depths. Military collection during the [[Cold War]] made use of stand-off collection of data about dangerous border areas. Remote sensing also replaces costly and slow data collection on the ground, ensuring in the process that areas or objects are not disturbed.

Orbital platforms collect and transmit data from different parts of the [[electromagnetic spectrum]], which in conjunction with larger scale aerial or ground-based sensing and analysis, provides researchers with enough information to monitor trends such as [[El Niño]] and other natural long and short term phenomena. Other uses include different areas of the [[earth science]]s such as [[natural resource management]], agricultural fields such as land usage and conservation, and national security and overhead, ground-based and stand-off collection on border areas.<ref>[[NASA]] (2009). [http://hurricanes.nasa.gov/earth-sun/technology/remote_sensing.html Earth.] {{webarchive|url=https://web.archive.org/web/20060929081013/http://hurricanes.nasa.gov/earth-sun/technology/remote_sensing.html |date=2006-09-29 }} Retrieved on 2009-02-18.</ref>