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Current Epoch: Epoch 10

Start: 16 Dec 2021 (Day 350) 14:27:41 | End: Present

Active Release: R05

R04 products will be available until all R05 products have been released.

CloudSat Epoch Information

Epoch 10

After a second reaction wheel anomaly on 26 August 2020 CloudSat returned to operation in December of 2021 in ACT-TWO (Attitude Control Through Two Wheel Operations) DO-Op (Daylight-Only Operations) mode, no longer in formation with CALIPSO.

Start: 16 Dec 2021 (Day 350) 14:27:41
End: Present

Epoch 09

Starting on July 5th, 2019 and continuing through August 26th, 2020, the apparent height of the surface in the radar profiles is not consistent with the Digital Elevation Map (DEM) that has been used with all CloudSat operational products throughout the mission. The mismatch is a result of an error in the satellite pointing or timing data or both. While still under investigation, the present the cause has not been isolated. Rather than further delaying the release of these data, they are being released as-is with the pointing/timing error. Fundamentally, this means there is a substantially larger uncertainty in the location where the radar beam intersects the surface that may be as large as 10 km.

Start: 11 Jul 2019 (Day 192) 00:00:00
End: 26 Aug 2020 (Day 239) 19:25:23

Epoch 08

CloudSat is joined by CALIPSO, forming the C-Train.

Start: 10 Oct 2018 (Day 283) 00:00:00
End: 10 Jul 2019 (Day 191) 23:59:59

Epoch 07

CloudSat exited the A-Train on February 22nd, 2018 after a reaction wheel anomaly.

Start: 3 May 2018 (Day 123) 07:25:00
End: End: 10 Oct 2018 (Day 283) 00:00:00

Epoch 06

Although CloudSat continues to only operate during the sunlit portion of the orbit, epoch 06 started when CloudSat returned to the A-Train formation on May 15th, 2012. Data products once again use MODIS and CALIPSO ancillary data although the overlap with CALIPSO is degraded because fewer formation flying maneuvers are performed.

Start: 15 May 2012 (Day 136) 00:49:00
End: 12 Jan 2018 (Day 12) 15:15:56

Epoch 05

A battery anomaly on April 17th, 2011 caused the spacecraft to stop collecting data and lose formation with the A-Train. The radar was turned back on in November 2011 and now collects data only during the sunlit portion of the orbit. Epoch 05 represents this new operating paradigm. In addition, the spacecraft remained outside of the A-Train formation so all data products were processed in radar-only mode without MODIS or CALIPSO data. The impact of the missing MODIS data on the CloudSat products is still being assessed and the combined radar/lidar products (2B-GEOPROF-LIDAR, 2B-CLDCLASS-LIDAR, and 2B-FLXHR-LIDAR) are not available.

Start: 27 Oct 2011 (Day 300) 23:28:21
End: 15 May 2012 (Day 136) 00:49:00

Epoch 04

Marks the beginning of a period where the CPR pulse rate will be periodically reduced, or increased, to manage the power draw on the battery (due to the reduced power margin as the battery ages). The increased or reduced pulsing with induce a slight change in sensitivity. The number of pulses can be found in the 1B-CPR field RayStatus_pulsesTx. The pulse rate will likely continue to be adjusted, seasonally, for the duration of the mission.

Start: 15 Feb 2011 (Day 46) 18:06:30
End: 17 Apr 2011 (Day 107) 18:17:31

Epoch 03

Epoch 02 ended when a battery anomaly forced the CPR offline. It was brought back into operations with a slightly reduced pulse rate that decreases the radar sensitivity by approximately 0.25 dB. Epoch 03 tags the modified operating parameters.

Start: 15 Jan 2010 (Day 15) 18:24:56
End: 15 Feb 2011 (Day 46) 18:06:30

Epoch 02

Increased specular reflection due to the nadir-pointing instrument caused an increase in ground clutter, so the spacecraft orientation was changed again so that the CPR pointed 0.16 degrees in the forward (along-track) direction.

Start: 15 Aug 2006 (Day 227) 20:56:31
End: 7 Dec 2009 (Day 341) 11:43:22

Epoch 01

The pointing error was corrected and the spacecraft was oriented so that the CPR pointed to nadir.

Start: 7 Jul 2006 (Day 188) 14:14:02
End: 15 Aug 2006 (Day 227) 20:56:31

Epoch 00

During the initial phase of the mission it was unknown that the CPR was pointing off-nadir 1.7021 degrees in the forward (along-track) direction and 0.1314 degress to the right (across-track).

Start: 2 Jun 2006 (Day 153) 13:42:23
End: 7 Jul 2006 (Day 188) 14:14:02

MODIS-AUX

Product Availability: Available during A-Train Epochs except for anomalies and maneuver data gaps

Captioned Figure 1
An example image showing a MODIS pass over the eye of a tropical cyclone.

The MODIS-AUX data set is an intermediate product that contains a subset of ancillary MODIS radiance and cloud mask data that overlaps and surrounds each CloudSat cloud profiling radar (CPR) footprint. Input data are obtained from the 1B-CPR and AN-MODIS products, and the MODIS-AUX data are used as input to the 2B-GEOPROF, 2B-CLDCLASS, 2B-TAU, and 2B-FLXHR algorithms in the CloudSat data processing system. The MODIS-AUX product is created by the Generic-AUX Subset-to-Reference algorithm.

Primary Publication(s)

No publications found.

  • MODIS-AUX P_R05 (Current)
  • MODIS-AUX P_R04

Process Description and Interface Control Document (PDICD)

E09 Data Issues (Updated July 17, 2023)
MODIS-AUX P_R05 PDICD (Rev. 1) (Updated November 8, 2017)

Process Description and Interface Control Document (PDICD)

MODIS-AUX P_R04 PDICD (Updated July 18, 2007)

Algorithm Specifications (for latest R05)

Geolocation Fields

Field Type Dimensions Units Valid Range Missing Missing Op. Factor Offset
MODIS_latitude FLOAT32 nbin,nray [-90.0, 90.0] -999.0 eq
MODIS_longitude FLOAT32 nbin,nray [-180.0, 180.0] -999.0 eq
Profile_time FLOAT32 nray seconds [0.0, 6000.0] 1.0 0.0
UTC_start FLOAT32 scalar seconds [0.0, 86400.0] 1.0 0.0
TAI_start FLOAT64 scalar seconds [0.0, 600000000.0] 1.0 0.0

Data Fields

Field Type Dimensions Units Valid Range Missing Missing Op. Factor Offset
MODIS_granule_index INT8 nbin,nray [1, 25] -99 ==
MODIS_pixel_index_along_track INT16 nbin,nray [1, 2030] -999 ==
MODIS_pixel_index_across_track INT16 nbin,nray [1, 1354] -999 ==
Solar_zenith INT16 nbin,nray [0, 18000] -32767 eq
Solar_azimuth INT16 nbin,nray [-18000, 18000] -32767 eq
Sensor_zenith INT16 nbin,nray [0, 18000] -32767 eq
Sensor_azimuth INT16 nbin,nray [-18000, 18000] -32767 eq
Cloud_Mask INT8 scalar [0, 1] 0 eq
EV_1KM_RefSB UINT16 scalar [0, 32767] -32768 ge
EV_1KM_RefSB_ref_offsets FLOAT32 nbin,nray -999.0 eq
EV_1KM_RefSB_ref_scales FLOAT32 nbin,nray -999.0 eq
EV_1KM_RefSB_rad_offsets FLOAT32 nbin,nray -999.0 eq
EV_1KM_RefSB_rad_scales FLOAT32 nbin,nray -999.0 eq
EV_1KM_RefSB_Uncert_Indexes UINT8 scalar [0, 15] -1 eq
EV_1KM_RefSB_scaling_factor FLOAT32 nbin,nray -999.0 eq
EV_1KM_RefSB_spec_uncert FLOAT32 nbin,nray -999.0 eq
EV_1KM_Emissive UINT16 scalar [0, 32767] -32768 ge
EV_1KM_Emissive_rad_offsets FLOAT32 nbin,nray -999.0 eq
EV_1KM_Emissive_rad_scales FLOAT32 nbin,nray -999.0 eq
EV_1KM_Emissive_Uncert_Indexes UINT8 scalar [0, 15] -1 ge
EV_1KM_Emissive_scaling_factor FLOAT32 nbin,nray -999.0 eq
EV_1KM_Emissive_spec_uncert FLOAT32 nbin,nray -999.0 eq
EV_250_RefSB UINT16 scalar [0, 32767] -32768 ge
EV_250_RefSB_ref_offsets FLOAT32 nbin,nray -999.0 eq
EV_250_RefSB_ref_scales FLOAT32 nbin,nray -999.0 eq
EV_250_RefSB_rad_offsets FLOAT32 nbin,nray -999.0 eq
EV_250_RefSB_rad_scales FLOAT32 nbin,nray -999.0 eq
EV_250_RefSB_Uncert_Indexes UINT8 scalar [0, 15] -1 eq
EV_250_RefSB_scaling_factor FLOAT32 nbin,nray -999.0 eq
EV_250_RefSB_spec_uncert FLOAT32 nbin,nray -999.0 eq
EV_500_RefSB UINT16 scalar [0, 32767] -32768 ge
EV_500_RefSB_ref_offsets FLOAT32 nbin,nray -999.0 eq
EV_500_RefSB_ref_scales FLOAT32 nbin,nray -999.0 eq
EV_500_RefSB_rad_offsets FLOAT32 nbin,nray -999.0 eq
EV_500_RefSB_rad_scales FLOAT32 nbin,nray -999.0 eq
EV_500_RefSB_Uncert_Indexes UINT8 scalar [0, 15] -1 eq
EV_500_RefSB_scaling_factor FLOAT32 nbin,nray -999.0 eq
EV_500_RefSB_spec_uncert FLOAT32 nbin,nray -999.0 eq

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