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Clouds Focus Area
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Clouds have a profound effect on the weather and climate of our planet due, in large part, to their interactions with radiation. Given that our understanding of these interactions is, at best, incomplete, the ARM Program has installed remote sensing instruments at its sites to measure the horizontal and vertical distributions (macroscopic properties) of cloud and the sizes and shapes of the particles that comprise the clouds (microphysical properties). Knowledge of these properties will provide researchers with the information they need to assess the impact of clouds on the Earth's climate system.
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Instruments that Measure Cloud Properties
Cloud properties over the ARM CART sites are sampled using a combination of active and passive remote sensors. The millimeter-wavelength cloud radar, which can penetrate multiple cloud layers and reveal their structure in unprecedented detail (except during periods of heavy rain), is the centerpiece of an array of ARM cloud instruments, each possessing unique, but complementary, features.
- MMCR - Millimeter-wavelength Cloud Radar at central facility; radar reflectivity, Doppler velocity, spectral width
- BLC - Belfort Laser Ceilometer at central facility; base height of first, second and third lowest cloud detected (up to 7.8 km)
- MPL - Micropulse Lidar at central facility; cloud base height (up to 15 km), backscatter ratio
- MWR - Microwave Radiometer at central and boundary facilities; column integrated liquid water and integrated water vapor
- WSI - Whole Sky Imager at central facility; cloud fraction, sky imagery
- RL - Raman Lidar at central facility; backscatter ratio, linear depolarization ratio
- VCEIL - Vaisala Ceilometer at central and boundary facilities; base height of first, second and third lowest cloud detected
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