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 [2016/06/05 21:58] – susanne | instruments:hatpro:hatpro [2016/06/11 21:11] – susanne | ||
---|---|---|---|
Line 14: | Line 14: | ||
{{: | {{: | ||
- | [[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:// | 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:// | ||
- | 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:// |
- | ===== Principle of operation ===== | + | Here we could keep the graphic from the original article |
- | Solids, liquids (e.g. the earth' | + | https:// |
+ | Fig. 2 | ||
- | The emission | + | ===== Principle of operation ===== |
+ | Solids, liquids (e.g. the earth' | ||
- | Larger rain drops as well as larger frozen | + | Besides the distinct absorption features of molecular transistion lines, there are also non-resonant contributions by hydrometeors (liquid drops and frozen particles). Liquid water emission increases with frequency, hence, measuring |
+ | 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 exploitinh polarized measurements [5] but also to constrain the columnar amount of snow and ice particles from space [6] and from the ground [7]. | ||
- | {{ : | + | {{: |
- | 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:// | + | 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:// |
===== Design ===== | ===== Design ===== | ||
Line 36: | Line 39: | ||
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 ===== | ||
Line 73: | Line 76: | ||
[4] Passive Microwave Remote Sensing of the Earth, Physical Foundations, | [4] Passive Microwave Remote Sensing of the Earth, Physical Foundations, | ||
- | - Cimini et al., 2009 | + | [5] Czekala et al. (2001), Discrimination of cloud and rain liquid water path by groundbased polarized microwave radiometry, |
- | - Klein and Gasiewski, 2000 | + | |
- | - Eugene A. Sharkov, “Passive Microwave Remote Sensing of the Earth”, Physical Foundations, | + | [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: |
- | - http:// | + | |
- | - Czekala et al., Discrimination of cloud and rain liquid water path by groundbased polarized microwave radiometry, | + | [7| Kneifel et al. (2010), 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