instruments:hatpro:hatpro
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instruments:hatpro:hatpro [2016/05/27 14:31] – [Calibration] stefan | instruments:hatpro:hatpro [2016/06/11 21:11] – susanne | ||
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===== Introduction ===== | ===== Introduction ===== | ||
- | The atmosphere in the [[https:// | + | Microwave radiometers are very sensitive receivers designed to measure thermal electromagnetic radiation emitted by material media like the atmosphere. They are usually equipped with multiple receiving channels |
+ | |||
+ | Using the [[https:// | ||
For weather and climate monitoring, microwave radiometers are operated from space [1] [2] as well as from the ground [3]. As [[https:// | For weather and climate monitoring, microwave radiometers are operated from space [1] [2] as well as from the ground [3]. As [[https:// | ||
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{{: | {{: | ||
- | [[http:// | + | Fig. 1: [[http:// |
===== History of microwave radiometer measurements ===== | ===== History of microwave radiometer measurements ===== | ||
+ | First developments of microwave radiometer were dedicated to the measurement of radiation of extraterrestrial origin in the 1930s and 1940s [1]. The first operational microwave radiometer was designed by [[https:// | ||
- | The first operational microwave radiometer was designed by [[https:// | + | Soon after satellites were first used for observing the atmosphere, MW radiometers became part of their instrumentation. In 1962 the [[https:// |
- | Soon after satellites were first used for observing | + | Here we could keep the graphic from the original article |
+ | https:// | ||
+ | Fig. 2 | ||
===== Principle of operation ===== | ===== Principle of operation ===== | ||
- | Solids, liquids (e.g. the earth' | + | Solids, liquids (e.g. the earth' |
- | The emission and absorption of hydrometeors does not provide characteristic absorption line features as found for atmospheric gases. Liquid | + | Besides the distinct |
- | Larger rain drops as well as larger frozen hydrometeors (snow, graupel, hail) also scatter microwave radiation especially at higher frequencies (>90 GHz). These scattering effects can be used to distinguish between rain and cloud water content [10] but also to constrain the columnar amount of snow and ice particles from space [11] and from the ground [12]. | + | Larger rain drops as well as larger frozen hydrometeors (snow, graupel, hail) also scatter microwave radiation especially at higher frequencies (>90 GHz). These scattering effects can be used to distinguish between rain and cloud water content |
- | + | {{: | |
- | {{ : | + | Fig. 3: Microwave spectrum: The black lines show the simulated spectrum (in brightness temperatures TB) for a ground-based receiver; the colored lines are the spectrum obtained from a satellite instrument over the ocean measuring at horizontal (blue) and vertical (red) linear polarization. Solid lines indicate simulations for clear-sky (cloud-free) conditions, dotted lines show a clear-sky case with a single layer liquid cloud. The vertical lines indicate typical frequencies used by satellite sensors like the [[https:// |
- | Microwave spectrum: The black lines show the simulated spectrum (in brightness temperatures TB) for a ground-based receiver; the colored lines are the spectrum obtained from a satellite instrument over the ocean measuring at horizontal (blue) and vertical (red) linear polarization. Solid lines indicate simulations for clear-sky (cloud-free) conditions, dotted lines show a clear-sky case with a single layer liquid cloud. The vertical lines indicate typical frequencies used by satellite sensors like the [[https:// | + | |
===== Design ===== | ===== Design ===== | ||
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The principal components of a microwave radiometer often follow a similar design and can be grouped into: antenna system, microwave radio-thermal receiver, recording and storage devices and a final processing unit. Usually ground-based radiometers are also equipped with environmental sensors (rain, temperature, | The principal components of a microwave radiometer often follow a similar design and can be grouped into: antenna system, microwave radio-thermal receiver, recording and storage devices and a final processing unit. Usually ground-based radiometers are also equipped with environmental sensors (rain, temperature, | ||
- | {{ : | + | {{: |
- | Schematic | + | Fig. 2Schematic |
===== Calibration ===== | ===== Calibration ===== | ||
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===== References ===== | ===== References ===== | ||
+ | [1] Microwave Remote Sensing—Active and Passive”. By F. T. Ulaby. R. K. Moore and A. K. Fung. (Reading, Massachusetts: | ||
+ | |||
+ | [2] Thermal Microwave Radiation: Applications for Remote Sensing, C. Matzler, 2006, The Institution of Engineering and Technology, London, Chapter 1. | ||
+ | |||
+ | [3] http:// | ||
+ | |||
+ | [4] Passive Microwave Remote Sensing of the Earth, Physical Foundations, | ||
+ | |||
+ | [5] Czekala et al. (2001), Discrimination of cloud and rain liquid water path by groundbased polarized microwave radiometry, Geophy. Res. Lett., DOI: 10.1029/ | ||
+ | |||
+ | [6] Bennartz, R., and P. Bauer (2003), Sensitivity of microwave radiances at 85–183 GHz to precipitating ice particles, Radio Sci., 38(4), 8075, doi: | ||
+ | |||
+ | [7| Kneifel et al. (2010), Snow scattering signals in ground-based passive microwave radiometer measurements, | ||
+ | |||
- | - http:// | ||
- | - http:// | ||
- | - http:// | ||
- | - Thermal Microwave Radiation: Applications for Remote Sensing, C. Matzler, 2006, The Institution of Engineering and Technology, London, Chapter 1. | ||
- | - Eugene A. Sharkov, “Passive Microwave Remote Sensing of the Earth”, Physical Foundations, | ||
- | - Cimini et al., 2009 | ||
- | - Klein and Gasiewski, 2000 | ||
- | - Eugene A. Sharkov, “Passive Microwave Remote Sensing of the Earth”, Physical Foundations, | ||
- | - http:// | ||
- | - Czekala et al., Discrimination of cloud and rain liquid water path by groundbased polarized microwave radiometry, GRL, 2001, DOI: 10.1029/ | ||
- | - Bennartz, R., and P. Bauer (2003), Sensitivity of microwave radiances at 85–183 GHz to precipitating ice particles, Radio Sci., 38(4), 8075, doi: | ||
- | - Kneifel et al., Snow scattering signals in ground-based passive microwave radiometer measurements, | ||
instruments/hatpro/hatpro.txt · Last modified: 2021/01/22 22:17 by 127.0.0.1