CloudSat DPC
  • Quicklooks
  • Data Access
    New Order Cart & Past Orders SFTP Access THREDDS/OpeNDAP Access FAQs
  • Data Products
    Overview
    Level 1B
    1B-CPR
    Level 2B
    2B-CLDCLASS 2B-CLDCLASS-LIDAR 2B-CWC-RO 2B-CWC-RVOD 2B-FLXHR 2B-FLXHR-LIDAR 2B-GEOPROF 2B-GEOPROF-LIDAR 2B-TAU 2B-TB94
    Level 2C
    2C-ICE 2C-PRECIP-COLUMN 2C-RAIN-PROFILE 2C-SNOW-PROFILE
    Level 2D
    2D-CLOUDSAT-POES 2D-CLOUDSAT-TRMM
    Level AUX
    AMSR2-AUX CRYOSPHERE-AUX ECMWF-AUX MOD06-1KM-AUX MOD06-5KM-AUX MODIS-AUX OCO2CLD-LIDAR-AUX
    Level 3
    3F-RMCP / 3S-RMCP
  • Community Products
    Arctic Observation and Reanalysis Integrated System CloudSat Reflectivity Product CloudSat Tropical Cyclone Product (2D-TC) CloudSat-TRMM and CloudSat-GPM Coincidence Dataset CloudSat/CALIPSO Cloud Cover CloudSat/CALIPSO Cloud Fraction PCFLOS Product Warm Rain Rate Estimates from AMSR 89 GHz and CloudSat Year of Tropical Convection (YOTC)
  • Resources
    CloudSat/CALIPSO Distance Footprints Software Tools Orbital Elements (TLEs)
  • Publications
  • Contact
  • Questions?
    Start Here

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: 19 September 2023 (Day 262) 15:26:30

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

2B-CWC-RO

Product Availability: Full mission availability except for anomalies and maneuver data gaps

The CloudSat Radar-Only Cloud Water Content Product (2B-CWC-RO) contains retrieved estimates of cloud liquid and ice water content, effective radius, and related quantities for each radar profile measured by the Cloud Profiling Radar on CloudSat. Retrievals are performed separately for the liquid and ice phases; the two sets of results are then combined in a simple way to obtain a composite profile that is consistent with the input measurements.

Primary Publication(s)

Austin, R. T., A. J. Heymsfield, and G. L. Stephens, (2009) Retrieval of ice cloud microphysical parameters using the CloudSat millimeter-wave radar and temperature, J. Geophys. Res., 114, D00A23, doi:10.1029/2008JD010049.

  • 2B-CWC-RO P1_R05 (Current)
  • 2B-CWC-RO P_R04

Process Description and Interface Control Document (PDICD)

PDICD (Rev. 0) (Updated May 11, 2018)
E09 Data Issues (Updated January 30, 2023)

Process Description and Interface Control Document (PDICD)

Data Issues (Updated September 21, 2011)
PDICD (Updated October 21, 2007)

Algorithm Specifications (for latest R05)

Geolocation Fields

Field Type Dimensions Units Valid Range Missing Missing Op. Factor Offset
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
Latitude FLOAT32 nray degrees [-90.0, 90.0] 1.0 0.0
Longitude FLOAT32 nray degrees [-180.0, 180.0] 1.0 0.0
Height INT16 nbin,nray 109 [-5000, 30000] -9999 == 1.0 0.0
Range_to_intercept FLOAT32 nray km [600.0, 800.0] 1.0 0.0
DEM_elevation INT16 nray meters [-9999, 8850] 9999 == 1.0 0.0
Vertical_binsize FLOAT32 scalar 109 -9999.0 == 1.0 0.0
Pitch_offset FLOAT32 scalar degrees [-90.0, 90.0] 1.0 0.0
Roll_offset FLOAT32 scalar degrees [-90.0, 90.0] 1.0 0.0

Data Fields

Field Type Dimensions Units Valid Range Missing Missing Op. Factor Offset
RO_liq_effective_radius INT16 nbin,nray um [0, 10000] -3333 <= 10.0 0.0
RO_liq_effective_radius_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_ice_effective_radius INT16 nbin,nray um [0, 30000] -3333 <= 10.0 0.0
RO_ice_effective_radius_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_liq_number_conc INT16 nbin,nray cm^{-3} [0, 30000] -3333 <= 10.0 0.0
RO_liq_num_conc_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_ice_number_conc INT16 nbin,nray L^{-1} [0, 30000] -3333 <= 10.0 0.0
RO_ice_num_conc_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_liq_distrib_width_param INT16 nbin,nray -- [0, 5000] -3333 <= 1000.0 0.0
RO_liq_distrib_width_param_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_ice_distrib_width_param INT16 nbin,nray -- [0, 5000] -3333 <= 1000.0 0.0
RO_ice_distrib_width_param_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_liq_water_content FLOAT32 nbin,nray mg m^{-3} [0.0, 15000.0] -3333.0 <= 1.0 0.0
RO_liq_water_content_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_ice_water_content FLOAT32 nbin,nray mg m^{-3} [0.0, 10000.0] -3333.0 <= 1.0 0.0
RO_ice_water_content_uncertainty UINT8 nbin,nray 37 [0, 250] 253 >= 1.0 0.0
RO_ice_phase_fraction INT16 nbin,nray -- [0, 1000] -3333 <= 1000.0 0.0
RO_radar_uncertainty INT16 nbin,nray dBZ [0, 10000] -7777 <= 100.0 0.0
LO_RO_AP_geo_mean_radius INT16 nbin,nray um [0, 10000] -7777 <= 100.0 0.0
LO_RO_AP_sdev_geo_mean_radius INT16 nbin,nray um [0, 10000] -7777 <= 100.0 0.0
LO_RO_AP_number_conc INT16 nbin,nray cm^{-3} [0, 30000] -7777 <= 10.0 0.0
LO_RO_AP_sdev_num_conc INT16 nbin,nray cm^{-3} [0, 30000] -7777 <= 10.0 0.0
LO_RO_AP_distrib_width_param INT16 nbin,nray -- [0, 5000] -7777 <= 1000.0 0.0
LO_RO_AP_sdev_distrib_width_param INT16 nbin,nray -- [0, 5000] -7777 <= 1000.0 0.0
LO_RO_effective_radius INT16 nbin,nray um [0, 10000] -3333 <= 10.0 0.0
LO_RO_effective_radius_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
LO_RO_number_conc INT16 nbin,nray cm^{-3} [0, 30000] -3333 <= 10.0 0.0
LO_RO_num_conc_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
LO_RO_distrib_width_param INT16 nbin,nray -- [0, 5000] -3333 <= 1000.0 0.0
LO_RO_distrib_width_param_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
LO_RO_liquid_water_content FLOAT32 nbin,nray mg m^{-3} [0.0, 15000.0] -3333.0 <= 1.0 0.0
LO_RO_liquid_water_content_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
IO_RO_AP_log_geo_mean_diameter INT16 nbin,nray log(mm) [-3000, 1000] -7777 <= 1000.0 0.0
IO_RO_AP_sdev_log_geo_mean_diameter INT16 nbin,nray log(mm) [0, 3000] -7777 <= 1000.0 0.0
IO_RO_AP_log_number_conc INT16 nbin,nray log(L^{-1}) [-3000, 5000] -7777 <= 1000.0 0.0
IO_RO_AP_sdev_log_num_conc INT16 nbin,nray log(L^{-1}) [0, 3000] -7777 <= 1000.0 0.0
IO_RO_AP_distrib_width_param INT16 nbin,nray -- [0, 5000] -7777 <= 1000.0 0.0
IO_RO_AP_sdev_distrib_width_param INT16 nbin,nray -- [0, 5000] -7777 <= 1000.0 0.0
IO_RO_effective_radius INT16 nbin,nray um [0, 30000] -3333 <= 10.0 0.0
IO_RO_effective_radius_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
IO_RO_log_number_conc INT16 nbin,nray log(L^{-1}) [-3000, 5000] -3333 <= 1000.0 0.0
IO_RO_log_num_conc_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
IO_RO_distrib_width_param INT16 nbin,nray -- [0, 5000] -3333 <= 1000.0 0.0
IO_RO_distrib_width_param_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
IO_RO_ice_water_content FLOAT32 nbin,nray mg m^{-3} [0.0, 10000.0] -3333.0 <= 1.0 0.0
IO_RO_ice_water_content_uncertainty UINT8 nbin,nray 37 [0, -6] -3 >= 1.0 0.0
Data_quality UINT8 nray -- [0, -1] 1.0 0.0
Data_status UINT16 nray -- [0, -1] 1.0 0.0
Data_targetID UINT8 nray -- [0, -1] 1.0 0.0
RayStatus_validity UINT8 nray -- [0, -1] 1.0 0.0
Navigation_land_sea_flag UINT8 nray -- [1, 4] 1.0 0.0
RO_liq_water_path FLOAT32 nray g m^{-2} [0.0, 15000.0] -3333.0 <= 1.0 0.0
RO_liq_water_path_uncertainty UINT8 nray 37 [0, 250] 253 >= 1.0 0.0
RO_ice_water_path FLOAT32 nray g m^{-2} [0.0, 10000.0] -3333.0 <= 1.0 0.0
RO_ice_water_path_uncertainty UINT8 nray 37 [0, 250] 253 >= 1.0 0.0
RO_CWC_status INT16 nray -- [-32768, 32767] 1.0 0.0
N_cloudy_bins INT8 nray -- [0, 125] -77 <= 1.0 0.0
LO_RO_liquid_water_path FLOAT32 nray g m^{-2} [0.0, 15000.0] -3333.0 <= 1.0 0.0
LO_RO_liquid_water_path_uncertainty UINT8 nray 37 [0, -6] -3 >= 1.0 0.0
LO_RO_norm_chi_square INT16 nray -- [0, 10000] -3333 <= 100.0 0.0
LO_RO_status INT16 nray -- [-32768, 32767] 1.0 0.0
IO_RO_ice_water_path FLOAT32 nray g m^{-2} [0.0, 10000.0] -3333.0 <= 1.0 0.0
IO_RO_ice_water_path_uncertainty UINT8 nray 37 [0, -6] -3 >= 1.0 0.0
IO_RO_norm_chi_square INT16 nray -- [0, 10000] -3333 <= 100.0 0.0
IO_RO_status INT16 nray -- [-32768, 32767] 1.0 0.0
Cloud_mask_threshold INT8 scalar -- [0, 40] 99 >= 1.0 0.0
N_ray_granule INT32 scalar 1.0 0.0
LO_RO_N_solution_found INT32 scalar 1.0 0.0
LO_RO_PCT_solution_found INT8 scalar 1.0 0.0
IO_RO_N_solution_found INT32 scalar 1.0 0.0
IO_RO_PCT_solution_found INT8 scalar 1.0 0.0
LO_RO_N_not_converged INT32 scalar 1.0 0.0
LO_RO_PCT_not_converged INT8 scalar 1.0 0.0
IO_RO_N_not_converged INT32 scalar 1.0 0.0
IO_RO_PCT_not_converged INT8 scalar 1.0 0.0
LO_RO_N_negative_x INT32 scalar 1.0 0.0
LO_RO_PCT_negative_x INT8 scalar 1.0 0.0
IO_RO_N_negative_x INT32 scalar 1.0 0.0
IO_RO_PCT_negative_x INT8 scalar 1.0 0.0
N_indeterminate_scenario INT32 scalar 1.0 0.0
PCT_indeterminate_scenario INT8 scalar 1.0 0.0
N_invalid_CLDCLASS INT32 scalar 1.0 0.0
PCT_invalid_CLDCLASS INT8 scalar 1.0 0.0
N_low_confidence_CLDCLASS INT32 scalar 1.0 0.0
PCT_low_confidence_CLDCLASS INT8 scalar 1.0 0.0
N_invalid_temperature INT32 scalar 1.0 0.0
PCT_invalid_temperature INT8 scalar 1.0 0.0
N_clear_CPR INT32 scalar 1.0 0.0
PCT_clear_CPR INT8 scalar 1.0 0.0
N_unphys_missing_reflectivity INT32 scalar 1.0 0.0
PCT_unphys_missing_reflectivity INT8 scalar 1.0 0.0
LO_RO_N_large_norm_chisq INT32 scalar 1.0 0.0
LO_RO_PCT_large_norm_chisq INT8 scalar 1.0 0.0
IO_RO_N_large_norm_chisq INT32 scalar 1.0 0.0
IO_RO_PCT_large_norm_chisq INT8 scalar 1.0 0.0
N_drizzle_or_precipitation INT32 scalar 1.0 0.0
PCT_drizzle_or_precipitation INT8 scalar 1.0 0.0
Temp_min_mixph_K FLOAT32 scalar 75 [2.33e+02, 2.73e+02] 1.0 0.0
Temp_max_mixph_K FLOAT32 scalar 75 [2.33e+02, 2.73e+02] 1.0 0.0

© 2026, CloudSat DPC