CloudSat CPR Operating Characteristics, Orbit, and Data Footprint
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The CloudSat radar samples at 625 kHz.

At this frequency the burst rate is given by: 1/6.25 = 0.16 sec / burst
(this sample interval creates a CloudSat "ray" - also referred to as a "profile")

The CloudSat Pulse Repetition Frequency (PRF) = 4300

from this we can compute: (4300 pulses / sec) * (0.16 sec/burst) = 688 pulses/burst

(Note: Approx. 21 pulses/burst of overhead are used for calibration and "dead time")

The CloudSat antenna pattern will provide an instantaneous footprint of approximately 1.4 km
(at Mean Sea Level)

The CPR instrument will be flown in a sun-synchronous orbit
at an 89o inclination angle, and a nominal altitude of 705 km.

These orbital characteristics will produce an along-track velocity of approximately 7 km/sec


Using this velocity, and the sample rate of 0.16 sec/profile, we can approximate that a CPR profile will be generated every 1.1 km along track
.

Each profile will have 125 vertical "bins"
, each bin will be approximately 240m thick

As shown in graphic: Determining the Shape of the CloudSat "Footprint", The footprint for a single profile
will be approximately 1.4km (across-track) X 2.5km (along-track)

A CloudSat data "Granule"
is defined as one orbit.

A granule is determined by the first profile that falls on or past the equator on the descending node
.

Approximately 20 seconds, or 125 profiles, will be appended to the beginning and end of each granule.

The start time of the granule will be the time of the first profile appended to the beginning of the granule
, and the granule termination time will be the time of the last profile that was appended to the end of the granule. (Note: the overlap was added to facilitate the generation of several CloudSat standard data products.)

An overview of the cloudsat granule and footprint dimensions is given in the CloudSat data sampling - conceptual diagram.

The CloudSat data products are time stamped with
the sample time at the start of the 0.16 second profile.