Problems related to cloud properties of CERES clouds in spherical radiation budget systems

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Problems related to cloud properties of CERES clouds in spherical radiation budget systems

by xwgw » Mon Mar 18, 2024 7:48 am America/New_York

Help help
I would like to ask you, in the description of cloud properties in the CERES cloud and Earth radiation budget system, what is the effective height of the cloud and the effective pressure of the cloud respectively, whether it means that there is a cloud, whether the effective height of the cloud represents the height of the cloud. Because it also gives the height value of the cloud top, the pressure value, the temperature value, and the pressure value and the temperature value of the cloud base, these two should directly indicate the location of the cloud. Then, whether the height of the cloud base can be obtained through the temperature and pressure values of the cloud base. If so, can you give me some references or something?
I hope you can help. Thank you.


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Re: Problems related to cloud properties of CERES clouds in spherical radiation budget systems

by ASDC - » Fri Mar 29, 2024 4:03 pm America/New_York


Thank you for your interest in CERES data.

We have notified a member of the CERES Science team and they will answer your question shortly.

Thank you.


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Re: Problems related to cloud properties of CERES clouds in spherical radiation budget systems

by wfmiller » Fri Mar 29, 2024 4:41 pm America/New_York

The cloud effective height and pressure are values that is obtained strictly from the infrared radiance obtained by the imager. A certain amount of water droplets are needed before the infrared signal becomes strong enough to be detected by a passive instrument such as MODIS or VIIRS. This can be lower than the height that would be measured by an aircraft, radar or lidar. The cloud top height uses an empirical relationship between the effect height and top height measured by these other methods.

The Collection Guide,, provides definition of a lot of the variables in the SSF and applies to other product that use the SSF as input.

The algorithm to obtained the cloud base height was answered in the post. viewtopic.php?t=4989

Cloud effective temperature is the equivalent blackbody temperature of the cloud as seen from above. The temperature of the cloud generally decreases with increasing (decreasing) height( pressure). Thus, the radiation intensity from different layers of a cloud varies with temperature. An integration of that radiation over the cloud thickness, including the attenuation of radiation
from lower parts of the cloud by the upper layers, defines the effective temperature. That temperature corresponds to some location between the cloud base and top. Cloud retrieval obtains cloud effective temperature for each pixel first by removing the effects of the atmosphere and any contribution of the surface to the observed 10.8-μm radiance and then using the inverse
Planck function to convert the adjusted radiance to temperature.

Cloud retrieval assigns cloud effective height to each cloudy imager pixels by linearly interpolating to the calculated cloud effective temperature using the MOA profiles of temperature and height. A linear interpolation of the natural logarithm of pressures from the MOA profile levels that bracket the cloud effective height is performed. The logarithm of pressure is then converted back. A linear regression for each layer of the MOA profile is performed producing a slope and intercept.

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