instruments:hatpro:hatpro
Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision | ||
instruments:hatpro:hatpro [2016/06/04 17:39] – susanne | instruments:hatpro:hatpro [2016/06/11 21:14] – susanne | ||
---|---|---|---|
Line 5: | Line 5: | ||
===== Introduction ===== | ===== Introduction ===== | ||
+ | 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 in order to derive the characteristic emission spectrum of the atmosphere or extraterrestrial objects. Microwave radiometers are utilized in a variety of environmental and engineering applications, | ||
- | Microwave radiometers are very sensitive receivers designed to measure thermal electromagnetic radiation emitted by material media like the atmosphere and are usually equipped with multiple receiving channels in order to derive the characteristic emission spectrum of the atmosphere. Microwave radiometers are utilized in a variety of environmental and engineering applications, | + | 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:// | ||
Line 12: | Line 13: | ||
{{: | {{: | ||
- | [[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 extraterestrial | + | First developments of microwave radiometer were dedicated to the measurement of radiation of extraterrestrial |
- | 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 the atmosphere, MW radiometers became part of their instrumentation. In 1962 the [[https:// |
+ | |||
+ | 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 hydrometeors (small cloud and rizzle drops) are efficient emitters in the microwave. | + | Besides the distinct absorption features of molecular transistion lines, there are also non-resonant |
- | 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 ===== | ||
- | |||
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, | ||
- | {{ :instruments:hatpro: | + | {{:stuff:mwr_design.png?200|Schematic diagram of a microwave radiometer}} \\ |
- | Schematic diagram of a microwave radiometer | + | Fig. 4: Schematic diagram of a microwave radiometer. |
===== Calibration ===== | ===== Calibration ===== | ||
Line 63: | Line 66: | ||
===== References ===== | ===== References ===== | ||
- | 1 Microwave Remote Sensing—Active and Passive”. By F. T. Ulaby. R. K. Moore and A. K. Fung. (Reading, Massachusetts: | + | [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. | + | [2] Thermal Microwave Radiation: Applications for Remote Sensing, C. Matzler, 2006, The Institution of Engineering and Technology, London, Chapter 1. |
- | 3 http:// | + | [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, | ||
+ | |||
- | - 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