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ISS in front of a background of small-scale cirrus and cumulus clouds.Source: NASA

Ice Cloud Studies:

Cirrus clouds play a crucial role in the global climate system, in that they reflect near-infrared radiation back to space, whilst reflecting thermal emission from the Earth’s surface back to Earth. The understanding of these processes is critical in order to constrain global climate circulation models. In order to observe cloud ice from space, a far-infrared radiometer placed above the cirrus cloud layer observes upwardly emitted radiation from water vapour in the mid-troposphere. Scattering of a fraction of this radiation back toward the ground reduces the brightness temperature of the observed regions relative to clear sky.

  • Strong absorption of these frequencies by water means that the Earth’s surface, and indeed the lower tropospheric layers, are invisible and therefore do not contribute to background variability.
  • Ice particle sizes are comparable to the observed radiation wavelength and scattering occurs in the Mie regime. The observed emission is therefore a strong indicator of particle size.
  • The spectral signature of the reduction in brightness temperature is different for changes in Ice-Water Path (IWP) on the one hand and mean scattering particle size on the other. Independent and direct retrieval of these two parameters is therefore possible.
  • Scattering is the dominant mechanism at these wavelengths rather than absorption. A FIR instrument is therefore sensitive to high altitude IWP clouds because the brightness temperature will saturate more slowly as a result of scattering.
  • Off-nadir polarization sensitive radiometry can measure particle shape and orientation. Falling ice particles tend to align themselves to the direction of movement. Observations would therefore measure particle size that varies as a function of polarization orientation.
Traditionally, experiments have been proposed for these studies based on scanning radiometers, with single-pixel heterodyne receivers, and limited to frequencies below ~850 GHz.
Large arrays of kinetic inductance detectors present novel instrument opportunities, removing the need for a scanning mechanism, and greatly increasing the available frequency range and sensitivity.

2nd SPACEKIDs workshop

2nd international SPACEKIDs Workshop

The second, and final community workshop will be held on 10th March at the European Space Technology Centre, Noorwijk, Netherlands.

 

2nd SPACEKIDs workshop

2nd international SPACEKIDs Workshop

The second, and final community workshop will be held on 10th March at the European Space Technology Centre, Noorwijk, Netherlands.

 

Announcement of first SPACEKIDs workshop

The first SPACEKIDS workshop has been announced.

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SPACEKIDS Kicks-Off

The SPACEKIDS project "Kick-Off" meeting was held in Cardiff on  28th-29th January, 2013.

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