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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: 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

OCO2CLD-LIDAR-AUX

Product Availability: Availalbe 2014-2016

OCO2CLD-LIDAR-AUX combines measurements from NASA’s Orbiting Carbon Observatory-2 (OCO-2) and the NASA/CNES Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. Output is stored both on the OCO-2 native footprints and collocated with CloudSat footprints following the standard CloudSat product granule structure. It reports cloud optical depth, cloud-top pressure and cloud pressure thickness, which is geometric thickness expressed in hPa. Only liquid clouds over the ocean are retrieved. Measurements are provided over the CALIPSO and OCO-2 formation flying period from 2014-09-06 to 2017-07-14, during which time the CALIPSO lidar footprint typically fell within the OCO-2 nadir view swath with a time difference of approximately 8 minutes. Additionally, OCO-2 varies its viewing mode and only nadir view orbits are processed.

These sensors complement each other as the CALIPSO lidar precisely measures cloud top (resolution ~30 m or ~3 hPa), while many boundary layer clouds are optically thick enough to attenuate the lidar so cloud optical depth or geometric thickness cannot be retrieved. OCO-2 effectively measures photon path lengths which must then be partitioned into above-cloud and within-cloud components. CALIPSO’s tight constraint on cloud top is intended to improve cloud pressure thickness retrievals by reducing uncertainty in this partitioning.

Primary Publication(s)

Richardson, M., Leinonen, J., Cronk, H. Q., McDuffie, J., Lebsock, M. D., and Stephens, G. L.: Marine liquid cloud geometric thickness retrieved from OCO-2's oxygen A-band spectrometer, Atmos. Meas. Tech., 12, 1717–1737, https://doi.org/10.5194/amt-12-1717-2019, 2019.

Richardson, M. and Stephens, G. L.: Information content of OCO-2 oxygen A-band channels for retrieving marine liquid cloud properties, Atmos. Meas. Tech., 11, 1515–1528, https://doi.org/10.5194/amt-11-1515-2018, 2018.

  • OCOCLD-LIDAR-AUX P_R05 (Current)

Process Description and Interface Control Document (PDICD)

OCO2CLD-LIDAR-AUX P_R05 PDICD (Rev. 0) (Updated November 20, 2018)

Algorithm Specifications (for latest R05)

Geolocation Fields

Field Type Dimensions Units Valid Range Missing Missing Op. Factor Offset
Latitude FLOAT32 nray degrees [-90.0, 90.0] 1.0 0.0
Longitude FLOAT32 nray degrees [-180.0, 180.0] 1.0 0.0
Profile_time FLOAT32 nray 109 [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] 0.0
DEM_elevation INT16 nray meters [-9999, 8850] -9999 == 1.0 0.0
full_swath_sounding_id FLOAT64 nbin,nray
full_swath_sounding_latitude FLOAT32 nbin,nray
full_swath_sounding_longitude FLOAT32 nbin,nray

Data Fields

Field Type Dimensions Units Valid Range Missing Missing Op. Factor Offset
full_swath_CloudSat_OCO2_matchup_distance_km FLOAT32 nbin,nray km 1.0 0.0
full_swath_Cloud_Optical_Depth FLOAT32 nbin,nray
full_swath_Cloud_Top_Pressure FLOAT32 nbin,nray
full_swath_Cloud_Pressure_Thickness FLOAT32 nbin,nray
full_swath_chi_squared FLOAT32 nbin,nray
full_swath_CALIPSO_number_of_layers INT32 nbin,nray
full_swath_CALIPSO_OCO2_matchup_distance_km FLOAT64 nbin,nray
full_swath_cloud_flag INT8 nbin,nray
full_swath_phase_prior FLOAT64 nbin,nray
full_swath_radiance_o2_continuum FLOAT32 nbin,nray
full_swath_o2_local_avg FLOAT64 nbin,nray
full_swath_o2_local_std FLOAT64 nbin,nray
full_swath_sounding_solar_zenith FLOAT32 nbin,nray
full_swath_Quality_flag INT32 nbin,nray
full_swath_radiance_wk_continuum FLOAT32 nbin,nray
full_swath_surface_pressure_ecmwf FLOAT32 nbin,nray
full_swath_2m_minus_700hPa_temperature_ecmwf FLOAT32 nbin,nray
full_swath_two_meter_temperature_ecmwf FLOAT32 nbin,nray
CALIPSO_file CHAR8 nray
L1bSc_file CHAR8 nray
ecmwf_file CHAR8 nray
Data_quality UINT8 nray -- [0, 255] 1.0 0.0
Data_status UINT16 nray -- [0, 65535] 1.0 0.0
RayStatus_validity UINT8 nray -- [0, 255] 1.0 0.0
Data_targetID UINT8 nray -- [0, 255] 1.0 0.0
Navigation_land_sea_flag UINT8 nray -- [1, 5] 1.0 0.0
CloudSat_OCO2_pixel_index_along_track INT32 nray [0, 8360] 1.0 0.0
CloudSat_OCO2_pixel_index_cross_track INT32 nray [0, 7] 1.0 0.0
CloudSat_OCO2_matchup_distance_km FLOAT32 nray km 1.0 0.0
Cloud_Optical_Depth FLOAT32 nray Optical Depths
Cloud_Pressure_Thickness FLOAT32 nray hPa
Cloud_Top_Pressure FLOAT32 nray hPa
Quality_flag INT32 nray
CALIPSO_OCO2_matchup_distance_km FLOAT64 nray
sounding_solar_zenith FLOAT32 nray Degrees

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