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CALIPSO - Data User's Guide - IIR / Lidar Level 2 Track Product

Version 3 release (V3.01 and V3.02)
CALIPSO HOME → CALIPSO User’s Guide → HOME → IIR/Lidar Level 2 Track Product

Introduction

This document provides a description and preliminary quality assessment of the Level 2 IIR/Lidar track product DP2.2A, as described in Section 2.8 of the CALIPSO CALIPSO Data Products Catalog (Version 3.5) (PDF).

The primary geophysical variables reported in the IIR/Lidar track product are the brightness temperatures under the lidar track for the three IIR channels (8.65, 10.60 and 12.05 μm) directly derived from the Level 1 radiances, a scene classification derived from the CALIOP Level 2 5-km Cloud and Aerosols Layer products possibly also involving additional CALIOP constraints, effective emissivity of the selected cloud or aerosols layers and ice cloud microphysical properties for the selected layers (effective diameter of particles and ice water path). A mineral aerosols index is also provided. It is important that quality flags (see QA section) are read and used before conclusions are drawn from any data analysis.

Don't forget to check out the detailed data quality summary for this data product. (At the end of page).

The main data quality summaries page may be found in this link: https://www-calipso.larc.nasa.gov/products/inventory.php.

Input data summary:

  • CALIPSO IIR Level 1B product DP1.2, version V1.10 until 19 Aug 08 and V1.11 afterwards
  • CALIPSO Lidar Level 2, 5-km Cloud and Aerosols layer product DP2.1A, version V3.01.
  • GMAO GEOS 5 Met data: version 5.10 or 5.20 since August 2008, depending on availability.
  • IGBP surface type and NSIDC snow/ice index (1/6° resolution, same as in CALIOP products).

Output summary:

IIR/Lidar track product, version V3.01, named after the CALIPSO Lidar Level 2 product.



Other documentations and references

IIR Level 2 Algorithm Theoretical Basis Document (ref PC-SCI-204), revised version in preparation.

Related Publications:

  • Chiriaco, M., H. Chepfer, P. Minnis, M. Haeffelin, S. Platnick, D. Baumgardner, P. Dubuisson, M. McGill, V. Noel, J. Pelon, D. Spangenberg, S. Sun-Mack, and G. Wind, 2007: "Comparison of CALIPSO-Like, LaRC, and MODIS Retrievals of Ice-Cloud Properties over SIRTA in France and Florida during CRYSTAL-FACE", J. Appl. Meteor. Climatol., 46, 249-272.
  • Chiriaco, M, H. Chepfer, V. Noel, A. Delaval, M. Haeffelin, P. Dubuisson, and P. Yang, 2004: "Improving Retrievals of Cirrus Cloud Particle Size Coupling Lidar and Three-Channel Radiometric Techniques", Mon. Wea. Rev., 132, 1684-1700.
  • Chomette, O., A. Garnier, J. Pelon, A. Lifermann, T. Bret-Dibat, S. Ackerman, H. Chepfer, P. Dubuisson, V. Giraud, Y. Hu, D. Kratz, V. Noel, C. M. R. Platt, F. Sirou, and C. Stubenrauch, 2003: "Retrieval of cloud emissivity and particle size frame of the CALIPSO mission", IEEE International Geoscience and Remote Sensing Symposium, Toulouse, France.
  • Dubuisson, P., V. Giraud, J. Pelon, B. Cadet, and P. Yang, 2008: "Sensitivity of Thermal Infrared Radiation at the Top of the Atmosphere and the Surface to Ice Cloud Microphysics", J. Appl. Meteor. Climatol., 47, 2545-2560.
  • Dubuisson P., V. Giraud, O. Chomette, H. Chepfer, J. Pelon, 2005: "Fast radiative transfer modeling for infrared imaging radiometry", J. Quant. Spectr. Rad. Tr.,Volume 95, 2, 201-220.
  • Garnier, A. J. Pelon, P. Dubuisson, M. Faivre, O. Chomette, N. Pascal, D. P. Kratz, 2012: &"Retrieval of cloud properties using CALIPSO Imaging Infrared Radiometer. Part I: effective emissivity and optical depth", accepted at J. Appl. Meteor. Climatol..
  • Josset, D., J. Pelon, A. Garnier, Y. Hu, M. Vaughan, P.-W. Zhai, R. Kuehn, and P. Lucker, 2012: "Cirrus optical depth and lidar ratio retrieval from combined CALIPSO-CloudSat observations using ocean surface echo", J. Geophys. Res., 117, D05207, doi:10.1029/2011/D016959.
  • Liu, Z., Liu, D., Huang, J., Vaughan, M., Uno, I., Sugimoto, N., Kittaka, C., Trepte, C., Wang, Z., Hostetler, C., and Winker, D., 2008: "Airborne dust distributions over the Tibetan Plateau and surrounding areas derived from the first year of CALIPSO lidar observations", Atmos. Chem. Phys., 8, 5045-5060.
  • Parol F., J. C. Buriez, G. Brogniez and Y. Fouquart, 1991: "Information content of AVHRR channels 4 and 5 with respect to the effective radius of cirrus cloud particles", J. Appl. Meteor., 30, pp. 973-984.
  • Scott, N., 2009: "Assessing Calipso IIR radiances accuracy via stand-alone validation and a GEO/LEO inter-calibration approach using MODIS/Aqua and SEVIRI/MSG", GSICS Quaterly, vol 3, n°3.
  • Sourdeval, O., G. Brogniez, J. Pelon, L. C.-Labonnote, P. Dubuisson, F. Parol, D. Josset, A. Garnier, M. Faivre, A. Minikin, 2012: "Validation of IIR/Calipso level 1 measurements by comparison with collocated airborne observations during ‘Circle-2’ and ‘Biscay 08’ campaigns", J. Atmos. Oceanic Technol., doi:10.1175/JTECH-D-11-00143.1, (in press).
  • Wilber, A.C., D.P. Kratz, S.K. Gupta, 1999: "Surface Emissivity Maps for Use of Satellite Retrievals of Longwave Radiation", NASA Tech. Pub., TP-99-209362, [Available at Wilber, et al 1999 (PDF)].
  • Yang P., H. Wei., H. L. Huang, B. A. Baum, Y. X. Hu, G. W. Kattawar, M. I. Mishchenko, and Q. Fu, 2005: "Scattering and absorption property database for nonspherical ice particles in the near-through far-infrared spectral region", Appl. Opt., 44, pp. 5512-5523.

Standard and Expedited Data Set Definitions

Standard Data Sets:

Standard data processing begins immediately upon delivery of all required ancillary data sets. The ancillary data sets used in standard processing (e.g., GMAO meteorological data from the National Snow and Ice Data Center) must be spatially and temporally matched to the CALIPSO data acquisition times, and thus the time lag latency between data onboard acquisition and the start of standard processing can be on the order of several days. The data in each data set are global, but are produced in files by half orbit, with the day portion of an orbit in one file and the night portion of the orbit in another.

Expedited Data Sets:

Expedited data are processed as soon as possible after following downlink from the satellite and delivery to Langley Research Center (LaRC). Latency between onboard acquisition and analysis expedited processing is typically on the order or 6 to 28 hours. Expedited processing uses the most recently current available set of ancillary data (e.g., GMAO meteorological profiles) and calibration coefficients available, which may lag the CALIPSO data acquisition time/date by several days.

Expedited data files contain at the most, 90 minutes of data. Therefore, each file may contain both day and night data.

NOTE: Users are strongly cautioned against using Expedited data products as the basis for research findings or journal publications. Standard data sets only should be used for these purposes.

The differences between expedited processing and standard processing are explained in more detail in Adapting CALIPSO Climate Measurements for Near Real Time Analyses and Forecasting (PDF).


Data Descriptions

In the text below we provide brief descriptions of individual data fields reported in the CALIPSO IIR/Lidar Level 2 Track products. Where appropriate, we also provide an assessment of the quality and accuracy of the data in the current release. The data descriptions are as follows:

Additionally all the science data sets (SDSs) are listed in the table to the right, click on the SDS name to go directly to the description.

Science Data Set (SDS) Data Maturity Product
Profile_ID NA All
Latitude NA All
Longitude NA All
LIDAR_Shot_Time NA All
IIR_Image_Time_12_05 NA All
Brightness_Temperature_08_65, Brightness_Temperature_12_05, Brightness_Temperature_10_60 Beta All
Effective_Emissivity_08_65, Effective_Emissivity_12_05, Effective_Emissivity_10_60 Beta All
Effective_Emissivity_Uncertainty_08_65, Effective_Emissivity_Uncertainty_12_05, Effective_Emissivity_Uncertainty_10_60 Beta All
Emissivity_08_65, Emissivity_12_05, Emissivity_10_60 Beta All
Emissivity_Uncertainty_08_65, Emissivity_Uncertainty_12_05, Emissivity_Uncertainty_10_60 Beta All
Particle_Shape_Index Beta All
Particle_Shape_Index_Confidence Beta All
Effective_Particle_Size Beta All
Effective_Particle_Size_Uncertainty Beta All
Reference_Brightness_Temperature Beta All
Blackbody_Brightness_Temperature Beta All
Computed_Brightness_Temperature_Surface Beta All
Optical_Depth_12_05 Beta All
Optical_Depth_12_05_Uncertainty Beta All
Ice_Water_Path Beta All
Ice_Water_Path_Confidence Beta All
Optical_Depth_0532_Upper_Level Beta All
Depolarization_Upper_Level Beta All
Integrated_Backscatter_Upper_Level Beta All
Layer_Top_Height_Upper_Level Beta All
Centroid_IAB_0532_Upper_Level Beta All
Layer_Bottom_Height_Upper_Level Beta All
Layer_Top_Temperature_Upper_Level Beta All
Temperature_Centroid_IAB_0532_Upper_Level Beta All
Optical_Depth_0532_Lower_Level Beta All
Depolarization_Lower_Level Beta All
Integrated_Backscatter_Lower_Level Beta All
Layer_Top_Height_Lower_Level Beta All
Centroid_IAB_0532_Lower_Level Beta All
Layer_Bottom_Height_Lower_Level Beta All
Layer_Top_Temperature_Lower_Level Beta All
Temperature_Centroid_IAB_0532_Lower_Level Beta All
Surface_Emissivity_08_65, Surface_Emissivity_10_60, Surface_Emissivity_12_05 Beta All
IIR_Data_Quality_Flag Beta All
LIDAR_Data_Quality_Flag Beta All
Type_of_Scene Beta All
Surrounding_Obs_Quality_Flag Beta All
High_Cloud_vs_Background_Flag Beta All
Computed_vs_Observed_Background_Flag Beta All
Regional_Background_Std_Dev_Flag Beta All
Multi_Layer_Cloud_Flag Beta All
Microphysics Beta All

Science Data Parameters

Latitude
This parameter is a replicate of the parameter “Latitude” in Level 1B IIR product. It gives the geodetic latitude at the center of the pixel.

Longitude
This parameter is a replicate of the parameter “Longitude” in Level 1B IIR product. It gives the geodetic longitude at the center of the pixel.

LIDAR_Shot_Time
This parameter is a replicate of the parameter “Lidar_Shot_Time” in Level 1B IIR product.
Time expressed in International Atomic Time (Temps Atomique International, TAI). Units are in seconds, starting from January 1, 1993.

IIR_Image_Time_12_05
This parameter is a replicate of the parameter “Image_Time_12.05” in Level 1B IIR product.
Time expressed in International Atomic Time (Temps Atomique International, TAI). Units are in seconds, starting from January 1, 1993.

Brightness_Temperature_08_65, Brightness_Temperature_12_05, Brightness_Temperature_10_60
These parameter give the brightness temperature expressed in Kelvin of IIR channel 1 centered on 8.65 μm, IIR channel 3 centered on 12.05 μm and IIR channel 2 centered on 10.6 μm respectively. It is calculated from the corresponding IIR Level 1 calibrated radiance (Calibrated_Radiances_8.65, Calibrated_Radiances_12.05 and Calibrated_Radiances_10.60 ), expressed in W.m-2.sr-1.μm-1 assuming spectral blackbody radiances centered respectively on 8.65 μm, 12.05 μm and 10.60 μm.

Effective_Emissivity_08_65, Effective_Emissivity_12_05, Effective_Emissivity_10_60
These parameters give the effective emissivity at 8.65 μm, 12.05 μm and 10.60 μm of the single or upper cloud or aerosols layer(s), defined as the upper level of the scene selected according to the Level 2 Cloud and Aerosols Layer Product.

Scene classification and description are given in “Type_of_scene”.

For each spectral channel k, centered on the wavelength λk, the track effective emissivity, εeff, k of the selected upper level, located at the equivalent altitude Zc, is defined according to the ATBD as

εeff, k =[Rk - Rk,BG]/[Bk(T,Zc) - Rk,BG]
where:

- Rk is the IIR Level 1 calibrated radiance measured in channel k,
- Rk,BG or background radiance is the outgoing top of the atmosphere background radiance which would be observed in the absence of the upper level. It is either derived from measurements in suitable neighboring pixels (distance < 100 km) or from calculations using the fast radiative transfer model FASRAD (Dubuisson et al, 2005) if no measured reference can be found (see High_Cloud_vs_Background). This model is not accounting for cloud scattering. For this release (V3), the Rk,BG values are provided in Reference_Brightness_Temperature after conversion to the equivalent brightness temperatures.
- Bk(T,Zc) is the radiance of a black-body source located at the equivalent altitude Zc defined from lidar observations, corresponding to a temperature T(Zc) retrieved from ancillary meteorological data (GMAO GEOS 5). It is computed using the FASRAD model (Dubuisson et al., 2005). For this release (V3), the Bk(T,Zc) values are provided in Blackbody_Brightness_Temperature after conversion to the equivalent brightness temperatures.
- Effective_Emissivity is set to invalid if found outside the physical [0. , 1.] range. Further analysis can be done by inter-comparing the observed, reference and blackbody brightness temperatures used for the retrievals which are provided even if the retrieved effective emissivity is found invalid. For instance, when the upper level is very low, or very close to the background reference layer, the retrievals are more difficult, and non-physical or invalid results may be found. This also corresponds to larger values of the uncertainties when physical values are obtained.


Effective_Emissivity_Uncertainty_08_65, Effective_Emissivity_Uncertainty_12_05, Effective_Emissivity_Uncertainty_10_60
These parameters give the uncertainty Δε on the effective emissivity, ε, at 08.65 μm, 12.05 μm and 10.60 μm.

According to the ATBD, the effective emissivity uncertainty, Δεeff, k for each spectral channel k, centered on the wavelength λk is composed of 3 terms which can be written as

Δε1eff, k = ΔRk x 1/ (Rk,BG - Bk(T,Zc)) due to the uncertainty on the radiance measurement,

Δε2eff, k = (1 -εeff,k ) x ΔRk,BG x 1/ [ Rk,BG - Bk(T,Zc) ] due to the uncertainty on the background reference,

Δε3eff, k= εeff,k x Δ Bk(T,Zc) x 1/ [ Rk,BG - Bk(T,Zc) ] due to the uncertainty on the equivalent black-body source radiance.

For each channel, the Effective_Emissivity_Uncertainty, Δεeff, k is the overall uncertainty derived from the 3 independent terms listed above considered as random errors so that:

Δεeff, k= [Rk,BG - Bk(T,Zc)]-1 x [(ΔRk)2 + (1 -εeff,k )2 x (ΔRk,BG)2 + εeff,k 2x (ΔBk(T,Zc))2 ] 1/2

It is inversely proportional to the radiative difference between the background reference and the upper level of thermodynamic temperature T(Zc).

The effective emissivity uncertainty is set to invalid if found outside the [0. , 1.] range (V3). If the effective emissivity is invalid, the corresponding uncertainty is invalid too.

Reported emissivity uncertainties are less than 0.03 for most of the high (>7 km) semi-transparent clouds. They are computed assuming a 1 K equivalent error in measured and calculated radiances, which is a realistic/conservative value for the IIR measurements.

The background reference is preferably measured in neighboring pixels (distance < 100km) and its representativeness evaluated through its mean distance from the current pixel (cf High_Cloud_vs_Background_Flag which gives also the type of reference used). Otherwise, the background reference is computed using the FASRAD model.

When a measured background reference is used, Computed_vs_Observed_Background_Flag gives the mean relative difference between this observation and the computed radiance derived from the FASRAD model. The standard deviation associated to this parameter is given in Regional_Background_Std_Dev.

Statistical analyses show that the brightness temperature differences between clear sky observations and computations (available in Computed_Brightness_Temperature_Surface in V3) are most of the time smaller than 1K over ocean for each IIR channel even though GMAO moisture and temperature profiles are expected to be less accurate than over land due to fewer sounding stations available for the analysis. Over land, significant differences are observed (up to several K) due to errors in surface emissivities and temperatures. Large differences (up to 10 K) are observed in a limited number of cases.

Statistical analyses show that brightness temperature differences between low opaque cloud observations and computations (available in Blackbody_Brightness_Temperature in V3) are typically within 3 K for each IIR channel. Larger differences can be observed on sporadic points.

The uncertainty on the black-body radiance is driven by the uncertainty on the equivalent radiative altitude and the corresponding temperature derived from GMAO. In case of thick features or vertically stretched multi-layer upper levels (cf Multi_Layer_Cloud_Flag added in V3), the equivalent black-body radiance is not as accurate as for thin mono-layer systems, due to the expected error on the equivalent altitude chosen to retrieve the thermodynamic temperature.


Emissivity_08_65, Emissivity_12_05, Emissivity_10_60
Not computed for this release.

Emissivity_Uncertainty_08_65, Emissivity_Uncertainty_12_05, Emissivity_Uncertainty_10_60
Not computed for this release.

Particle_Shape_Index
Ice cloud microphysical properties are derived from two microphysical indices, defined as the ratio of the effective infrared optical depths in the pairs of IIR channels 12.05-8.65 and 12.05-10.60 μm (Parol et al, 1991) derived from the respective effective emissivities (see Effective_Emissivity_08_65, Effective_Emissivity_10_60, Effective_Emissivity_12_05).

Look-up tables allow deriving cirrus ice crystals effective size and shape. These tables are built using the FASDOM radiative transfer model (Dubuisson et al, 2008). This model calculations are taking into account cloud scattering, theoretical optical properties of several complex rystals (Yang et al, 2005), and various atmospheric and surface parameters.

This parameter is the optimal shape leading to the best agreement between the effective particle diameters D(12.05,8.65) and D(12.05, 10.60) derived from each microphysical index. If the microphysical indices are not within the range of values expected from the look-up tables, Particle_Shape_Index cannot be retrieved and is set to invalid.

Value Interpretation
7 Aggregates
8 Plates
9 Solid columns

The full set of effective diameters obtained for each shape is provided in Microphysics.


Particle_Shape_Index_Confidence
The particle shape index confidence reflects the relative difference between the effective particle diameters D(12.05,8.65) and D(12.05, 10.60) associated to each microphysical index. Confidence is considered as good (1) when both diameters agree within 30% and medium (2) otherwise. It is set to invalid when Particle_Shape_Index could not be retrieved.

Value Interpretation
1 Good confidence
2 Medium confidence

Effective_Particle_Size
In nominal conditions, i.e. when the microphysical indices derived from the 3 IIR effective emissivities are within the range of values expected from the look-up tables, this parameter is the mean of the effective diameters D(12.05,8.65) and D(12.05, 10.60) retrieved from the microphysical indices and the model identified in Particle_Shape_Index. In nominal conditions, both the Effective_Particle_Size and the Particle_Shape_Index are retrieved and Particle_Size_Uncertainty is half of the difference between D(12.05,8.65) and D(12.05, 10.60). These parameters characterize the layer(s) for which effective emissivities are retrieved, i.e. the scene’s upper layer(s) (cf Type of Scene).

However, numerous other conditions are encountered where the microphysical indices are not within the range of values expected from the look-up tables. It can be due to the absence of the adapted look-up table (for instance in case of aerosols or liquid clouds) or to a wrong value of at least one microphysical index. If only one microphysical index is within the expected range, or if the microphysical indices slightly deviate from the closest possible value (with a 15% tolerance), the algorithm attempts to provide an Effective_Particle_Size estimate. These degraded configurations are flagged in Effective_Particle_Size_Uncertainty. Otherwise, Effective_Particle_Size is set to invalid.

It is very important that the users refer to Effective_Particle_Size_Uncertainty to find out if the Effective_Particle_Size has been retrieved in a nominal or a degraded configuration.


Effective_Particle_Size_Uncertainty
In the nominal configuration, the effective particle size is derived from the pair of microphysical indices and the model identified in Particle_Shape_Index. Effective_Particle_Size_Uncertainty is defined as half of the difference between both effective particle diameters (in microns). In the nominal configuration, Effective_Particle_Size_Uncertainty is always strictly smaller than 100 as an absolute value (and can be negative due to its definition).

Effective_Particle_Size_Uncertainty values of 100 or more are used to flag specific degraded configurations when one (or both) microphysical indices is (are) outside the value range expected from the look-up tables (see Effective_Particle_Size). For these a priori medium to very low confidence cases, the algorithm cannot provide the Particle_Shape_Index but still attempts to provide some piece of information about the size.

Value Interpretation Confidence Shape index provided
< 100. = 0.5 x [Size from (12.05; 8.65) + Size from (12.05; 10.60] (microns) Good/Medium Yes
100. Particle_Size from (12.05; 8.65) only Medium No
200. Particle_Size from (12.05;10.60) only Medium No
300. size < Particle_size from (12.05;10.6) and (12.05;8.65) Low No
310. size < Particle_Size (12.05;10.60) questionable Very low No
320. size < Particle_Size (12.05; 8.65) questionable Very low No
400. size > Particle_Size from (12.05;10.6) and (12.05;8.65) Low No
410. size > Particle_Size (12.05;10.60) questionable Very low No
420. size > Particle_Size (12.05; 8.65) questionable Very low No

Reference_Brightness_Temperature
This parameter is the brightness temperature (in Kelvin) derived from the background (surface or dense cloud) reference radiance used to compute the effective emissivity of the selected upper layer(s). The three elements are for the IIR channels 08.65 μm, 10.60 μm and 12.05 μm respectively. This parameter constitutes a more general information than the parameters Clear_Sky_Radiance_08_65, Clear_Sky_Radiance_10_60, Clear_Sky_Radiance_12_05 (W.m-2.sr-1.μm-1) previously available in version V2 which were limited to clear sky background reference only.

The background reference radiance is preferably measured in neighboring pixels. Criteria for deciding to use a measured reference are:

  • the distance between the measured background radiance and the upper level must be smaller than 100 km and both must be of the same IGBP type (new condition added in V3);
  • if the reference is an opaque layer, the permitted altitude difference is +/- 100 m corresponding to +/- 1 K radiative difference (worst case).

If the background radiance cannot be derived from measurements, it is computed using the FASRAD model:

  • assuming clear sky if the reference is clear sky or a low altitude (<7 km) non -depolarizing aerosols layer,
  • and assuming a blackbody located at the altitude "Centroid_IAB_0532_Lower_Level" for opaque layers.

FASRAD uses temperature, water vapor and ozone profiles from the GMAO GEOS 5 model. For clear sky simulations, it uses also surface emissivities derived from the IGBP geotype (see Surface_emissivities) and GMAO GEOS 5 surface temperatures.

The conditions selected by the algorithm to compute the background radiance are given in High_Cloud_vs_Background. When a measured reference is used, Computed_vs_Observed_Background_Flag gives the mean relative difference between this observation and the computed radiance derived from the FASRAD model. The standard deviation associated to this parameter is given in Regional_Background_Std_Dev.


Blackbody_Brightness_Temperature
This parameter is the brightness temperature (in Kelvin) derived from the blackbody radiance computed using the FASRAD model and GMAO GEOS 5 profiles to retrieve the effective emissivity of the selected upper layer(s). The three elements are for the IIR channels 08.65 μm, 10.60 μm and 12.05 μm respectively.

Computed_Brightness_Temperature_Surface
This parameter is the brightness temperature (in Kelvin) derived from the surface radiance computed using the FASRAD model assuming a clear sky atmosphere for types of scenes identified as clear sky (10), or containing semi-transparent aerosols (52, 53 and 54, see Type_of_Scene). FASRAD uses temperature, water vapor and ozone profiles and surface temperatures from the GMAO GEOS 5 model, and surface emissivities derived from the IGBP geotype (see Surface_Emissivities). The three elements are for the IIR channels 08.65 μm, 10.60 μm and 12.05 μm respectively.

Optical_Depth_12_05
This parameter is the effective absorption optical depth at 12.05 μm derived from the effective emissivity at 12.05 μm as:

Optical_Depth_12_05 = - ln (1 - Effective_Emissivity_12_05)

Optical_Depth_12_05 is set to invalid if found outside the [0. , 10.] range (V3) and if Effective_Emissivity_12_05 is invalid.


Optical_Depth_12_05_Uncertainty
This parameter is the Optical_Depth_12_05 uncertainty derived from Effective_Emissivity_Uncertainty_12_05.

Optical_Depth_12_05_Uncertainty is set to invalid if found outside the [0. , 10.] range (V3) and if Optical_Depth_12_05 is invalid.


Ice_Water_Path
This parameter is an estimate for the upper level ice water path (in g.m-2) derived from the effective particle size and the optical depth at 12.05 μm as:

IWP (g.m-2) = 0.307 x Effective_Particle_Size (μm) x (2 x Optical_Depth_12_05).


Ice_Water_Path_Confidence
As Ice_Water_Path provided in this release is an estimate, this parameter is not computed. However, the users should refer to Effective_Particle_Size_Uncertainty and Optical_Depth_12_05_Uncertainty.

Optical_Depth_0532_Upper_Level
This parameter is the summation of the layers’ Feature_Optical_Depth_532 provided in the CALIOP lidar Level 2 Cloud or Aerosols layers products for the layers included in the upper level (V3). In V2, this parameter reported the optical depth of the uppermost layer.

This parameter is set to invalid if no feature is selected (clear sky) or if the type of scene is undetermined.


Depolarization_Upper_Level
This parameter is the layers’ average Integrated_Volume_Depolarization_Ratio from CALIOP lidar Level 2 Cloud or Aerosols layers products weighted with the individual mean attenuated backscatter for the layers included in the upper level (V3). It is different from the parameter reported in V2, which was the depolarization ratio of the uppermost layer.

This parameter is set to invalid if no feature has been detected (clear sky) or if the type of scene is undetermined.


Integrated_Backscatter_Upper_Level
This parameter is the summation of the layers’ Integrated_Attenuated_Backscatter_532 from CALIOP lidar Level 2 Cloud or Aerosols layers products for the layers included in the upper level. In V2, this parameter reported the integrated attenuated backscatter of the uppermost layer.

This parameter is set to invalid if no feature has been detected (clear sky) or if the type of scene is undetermined.


Layer_Top_Height_Upper_Level
This parameter is a replicate of the Layer_Top_Altitude parameter from CALIOP lidar Level 2 Cloud or Aerosols layers product for the uppermost layer in the upper level. As the algorithm only keeps features detected with 5 or 20 km horizontal averaging, the uppermost layer reported here can be lower than in the CALIOP product.

This parameter is set to invalid if no feature has been detected (clear sky) or if the type of scene is undetermined.


Centroid_IAB_0532_Upper_Level
This parameter is the upper level centroid altitude Zc used to compute the radiance of the equivalent blackbody B(T, Zc).

For single-layer systems (cf Multi_Layer_Cloud_Flag), this parameter is a replicate of the centroid altitude provided in Attenuated_Backscatter_Statistics_532 in CALIOP lidar Level 2 Cloud or Aerosols layers product.

In case of a multi-layer scenes (N layers), this parameter is the mean of the centroid altitudes z(i) of each layer, i, weighted with the mean attenuated backscatter beta_mean (i) in each layer:

Centroid_IAB_0532_Upper_Level = som[1,N : z(i).beta_mean(i)]/N.som[1,N : beta_mean(i)]

This parameter is set to invalid if no feature has been detected (clear sky) or if the type of scene is undetermined.


Layer_Bottom_Height_Upper_Level
This parameter is a replicate of the Layer_Base_Altitude parameter from CALIOP lidar Level 2 Cloud or Aerosols layers products for the lowermost layer in the upper level.

This parameter is set to invalid only if no feature has been detected (clear sky) or if the type of scene is undetermined.


Layer_Top_Temperature_Upper_Level
Not computed for this release.

Temperature_Centroid_IAB_0532_Upper_Level
This parameter is the upper level centroid temperature derived from Centroid_IAB_0532_Upper_Level and GMAO temperature profiles.

This parameter is set to invalid if no feature has been detected (clear sky) or if the type of scene is undetermined.


Optical_Depth_0532_Lower_Level
Not provided for this release.

Depolarization_Lower_Level
This parameter is a replicate of the parameter Integrated_Volume_Depolarization_Ratio from CALIOP lidar Level 2 Cloud or Aerosols layers products for the opaque reference level, if any, according to "Type_of_Scene". Otherwise, this parameter is set to invalid.

Integrated_Backscatter_Lower_Level
=This parameter is a replicate of the parameter "Integrated_Attenuated_Backscatter_532" from CALIOP lidar Level 2 Cloud or Aerosols layers products for the opaque reference level, if any, according to "Type_of_Scene". Otherwise, this parameter is set to invalid.

Layer_Top_Height_Lower_Level
This parameter is a replicate of the parameter "Layer_Top_Altitude" from CALIOP lidar Level 2 Cloud or Aerosols layers products for the opaque reference level, if any, according to "Type_of_Scene". Otherwise, this parameter is set to invalid.

Centroid_IAB_0532_Lower_Level
This parameter is the centroid altitude of the opaque reference level, if any, according to "Type_of_Scene". Otherwise, this parameter is set to invalid.

It is a replicate of the centroid altitude provided in Attenuated_Backscatter_Statistics_532 in CALIOP lidar Level 2 Cloud or Aerosols layers products.


Layer_Bottom_Height_Lower_Level
This parameter is a replicate of the parameter "Layer_Base_Altitude" from CALIOP lidar Level 2 Cloud or Aerosols layers products for the opaque reference level, if any, according to "Type_of_Scene". Otherwise, this parameter is set to invalid.

Layer_Top_Temperature_Lower_Level
Not computed for this release.

Temperature_Centroid_IAB_0532_Lower_Level
This parameter is the centroid temperature of the opaque reference level if any, according to "Type_of_Scene" Otherwise, this parameter is set to invalid.

It is derived from the Centroid_IAB_0532_Lower_Level altitude and GMAO temperature profile (V3, was a replicate of the CALIOP parameter "Mid_Layer_Temperature" in V2).


Surface_Emissivity_08_65, Surface_Emissivity_10_60, Surface_Emissivity_12_05
These parameters are the surface emissivities for channels centered on 08.65, 12.05 and 10.60 μm respectively.

They are derived from IGBP surface type and NSIDC snow/ice indices (1/6° resolution, same as in CALIOP products). For NSDIC indices between 10 and 103, geotype index takes the IGBP snow/ice index (15).

Surface emissivities are computed accounting for the IIR spectral response functions (D. P. Kratz, NASA Langley, CERES team, see also Wilbert et al, 1999). The following values are used:

IIR Ch. 1
8.2 - 9.2 μm
IIR Ch. 2
10.35 - 10.95 μm
IIR Ch. 3
11.50 - 12.50 μm
IGBP surface
0.9904 0.9888 0.9909 (1) evergreen needleleaf
0.9904 0.9888 0.9909 (2) evergreen broadleaf
0.9775 0.9738 0.9733 (3) deciduous needleleaf
0.9775 0.9738 0.9733 (4) deciduous broadleaf
0.9839 0.9813 0.9821 (5) mixed forests
0.9478 0.9653 0.9685 (6) closed shrublands
0.8754 0.9332 0.9411 (7) open shrublands
0.9801 0.9812 0.9886 (8) woody savannas
0.9801 0.9812 0.9886 (9) savannas
0.9801 0.9812 0.9886 (10) grasslands
0.9819 0.9857 0.9871 (11) permanent wetlands
0.9801 0.9812 0.9886 (12) croplands
1.0000 1.0000 1.0000 (13) urban
0.9820 0.9812 0.9854 (14) mosaic
0.9951 0.9967 0.9854 (15) snow/ice
0.8392 0.9171 0.9275 (16) barren/sparsely vegetated
0.9838 0.9903 0.9857 (17) water
0.9753 0.9936 0.9909 (18) tundra

IIR_Data_Quality_Flag
This parameter is an indicator of the IIR calibrated radiance quality and is extracted from the "Pixel_Quality_Index" parameter of the IIR Level 1 product.

If not zero, corresponding to nominal quality:

  • either one channel has poor quality or is missing, or
  • the radiances in the 3 channels are not all part of the same image measurement sequences (information added in V3) which, for scenes with high broken clouds, could lead to some errors at the edge of the images for geometrical reasons.

Bit Bit value Interpretation
1 0 IIR calibrated radiances in the 3 channels are of nominal quality
1 At least one of the channels has poor quality or is missing
2 0 Channels 08.65 and 10.60 derived from the same sequence of acquisition
1 Channels 08.65 and 10.60 not derived from the same sequence of acquisition
3 0 Channels 08.65 and 12.05 derived from the same sequence of acquisition
1 Channels 08.65 and 12.05 not derived from the same sequence of acquisition
4 0 Channels 10.60 and 12.05 derived from the same sequence of acquisition
1 Channels 10.60 and 12.05 not derived from the same sequence of acquisition
5-8 0 N/A

LIDAR_Data_Quality_Flag
This flag is the Feature Type QA derived from the parameter "Feature_Classification_Flag" in the CALIOP lidar Level 2 Cloud and Aerosols layers product for the uppermost layer in the upper level.
Value Interpretation : Feature QA from Feature_Classification_Flag
0 none
1 low
1 medium
2 high

Type_of_Scene
This parameter is the scene classification derived from the CALIOP lidar Level 2 Cloud and Aerosols layers products, designed to select the scenes to be further analyzed in term of effective emissivity and in the meantime to be possibly compared with existing well established clouds classifications.

Only layers identified with a 5 or 20-km horizontal resolution are used in the analysis. Those obtained at a horizontal averaging of 80km are systematically rejected as they are not expected to impact the thermal IR signals.

The scenes are first organized according to the background reference scene (4th column in the table below), which can be either the surface (scenes identified as clear sky or possibly containing low semi-transparent depolarizing aerosol layers) or an opaque layer.

For each category, one to several semi-transparent (ST) layers can be considered as the upper level to compute the effective emissivity (3rd column in the table). Layers are high when their centroid altitude is above 7 km, and are low otherwise.

Low altitude aerosols layers are classified according to their mean volume depolarization ratio, with a threshold of 6%. Type 53 contains the depolarizing features (>6%), typically corresponding to desert dust aerosols (Liu et al, 2008). Type 52 are the non-depolarizing features. The threshold was set to 7% in V2.

Low level (Type 20 and 70) and high level (Type 40 and 80) opaque clouds are classified in V3 according to the maximum volume depolarization ratio in the layer, with a threshold of 40% (there was no distinction in V2).

A low altitude ST cloud layer (Type 24) is re-classified to Type 59 if the maximum attenuated backscatter and the maximum volume depolarization ratio in the layer are smaller than 0.02 sr-1 and 7% respectively, as a possible indicator of the presence of aerosols (V3).

Besides the changes described above, the classification has been updated with the addition of some complex types of scenes. Several types involving high ST aerosols layers have been added (Types 64, 65, 66) to better account for stratospheric clouds, classified as "aerosols" in the CALIOP product. The remaining scenes which do not match the classification are reported as #99.

In V2, scenes composed of 1, 2 or 3 high ST clouds (types 21, 22, 26) were re-classified as type 40 (opaque cloud) when the retrieved effective emissivity was greater than 0.6. It is not the case anymore for this release (V3) where the classification relies only on the CALIOP product.

The types of scenes are listed in the table below. Ice cirrus clouds fall in the scenes containing 1 to 5 high semi-transparent cloud layers overlying either the surface or a dense opaque layer, or in the scenes containing 1 high opaque cloud (Types 40, 80, 21, 22, 26, 31, 32, 41, 42, 30, 37). Overall, the changes with respect to version V2 are significant, due to changes in the IIR classification as described above, corrections of bugs and also due to the changes in the Version 3 CALIOP Level 2 layer products (for instance cloud/aerosols discrimination, opacity flags). Comparing IIR Level 2 V2 and V3 classifications is therefore not straightforward.

Value Description Number of layers in upper level Reference Type of scene Version 3 vs Version 2
CLEAR SKY      
10 Clear sky (no aerosols detected by lidar) n/a n/a Same
AEROSOLS      
51 1 to 4 high ST aerosol 1 to 4 10 Different
52 1 to 4 low ST aerosols, vol_depolarization_ratio_mean < 6% 1 to 4 10 Different
53 1 to 4 low ST aerosols, vol_depolarization_ratio_mean > 6% 1 to 4 10 Different
54 1 to 4 high ST aerosols and 1 low ST aerosol 2 to 5 10 Different
55 1 high opaque aerosols 1 10 Same
56 1 low opaque aerosol 1 10 Same
64 1 to 4 high ST aerosols/ 1 low opaque aerosols 1 to 4 56 New
57 Any other aerosols only 3 to 8 10 Different
CLOUDS      
20 Low opaque cloud, vol_depol_ratio_max >40% 1 10 (or 52 backup) Different
70 Low opaque cloud, vol_depol_ratio_max < 40% 1 10 (or 52 backup) New
40 High opaque cloud, vol_depol_ratio_max >40% 1 10 (or 52 backup) Different
80 High opaque cloud, vol_depol_ratio_max < 40% 1 10 (or 52 backup) New
21 1 high ST cloud only (no aerosol) 1 10 (or 52 backup) Different
22 2 high ST clouds 2 10 (or 52 backup) Different
23 1 high ST cloud and 1 low ST cloud 2 10 (or 52 backup) Same
24 1 low ST cloud, attenuated_backscatter_max > 0.02 sr-1 or vol_depol_ratio_max > 7%. 1 10 (or 52 backup) Different
59 1 low ST cloud, attenuated_backscatter_max < 0.02 sr-1 and vol_depol_ratio_max < 7%. 1 10 (or 52 backup) New
25 2 low ST clouds only (no aerosols) 2 10 (or 52 backup) Same
26 3 high ST clouds 3 10 (or 52 backup) Same
27 2 high ST clouds and 1 low ST cloud 3 10 (or 52 backup) Different
67 3-4 high ST clouds and 1 low ST cloud 4 or 5 10 (or 52 backup) New
28 1 high ST cloud and 2 low ST clouds 3 10 (or 52 backup) Different
68 2-3 high ST clouds and 2 low ST clouds or 3 high ST clouds and 3 low ST clouds 4 to 6 10 (or 52 backup) New
29 3 low ST clouds only (no aerosols) 3 10 (or 52 backup) Same
31 1 high ST cloud / 1 low opaque cloud 1 20 Same
32 2 to 5 high ST cloud/ 1 opaque cloud 2 to 5 20 Different
62 3 to 6 ST cloud (at least 1 low ST)/ 1 opaque cloud 3 to 6 20 New
33 1 high ST cloud and 1 low ST cloud/ 1 opaque cloud 2 20 Same
34 1 low ST cloud/ 1 opaque cloud 1 20 Same
39 2 to 4 low ST clouds/ 1 low opaque cloud 2 to 4 20 Same
41 1 high ST cloud/ 1 high opaque cloud 1 40 Different
42 2 high ST cloud/ 1 high opaque cloud 2 40 Different
MIXED AEROSOLS/CLOUDS      
30 1 high ST cloud / 1 low ST aerosol 1 52 Same
66 1 high ST aerosols / 1 high ST cloud and 1 low ST cloud 3 10 (or 52 backup) New
63 1 to 4 low aerosols and 1 low ST cloud 2 to 5 10 (or 52 backup) New
35 1 high ST aerosols/ 1 low opaque cloud 1 20 Same
36 1 low ST aerosols/ 1 low opaque cloud 1 20 Same
37 1 high ST cloud/ 1 low opaque aerosols 1 56 Same
38 1 low ST cloud/ 1 low opaque aerosols 1 56 Same
65 1 high ST aerosols / 1 high opaque cloud 1 40 New
OTHERS      
99 OTHERS Not processed Not processed Different

Surrounding_Obs_Quality_Flag
This flag is a composite of 3 different pieces of information:
  • the units digit indicates if the studied pixel is isolated or part of a structure with consecutive IIR pixels of same "Type_of_scene" (same as in V2).
  • the tens digit is a mineral aerosols index based on IIR inter-channels brightness temperature differences (BTD). Mineral aerosols layers are identified (tens digit=1) when the 08_65 minus 12_05 BTD is < -2K and the 10_60 minus 12_05 BTD is < -0.5 K (added in V3).
  • the hundreds digit is an index describing the difference between observed and computed brightness temperatures for specific types of scenes: scenes identified as clear sky (10) or containing low aerosols (52, 53) and scenes containing opaque clouds (20, 40). This index is designed to identify the pixels exhibiting large differences and which may require further analysis (added in V3).

Digit Digit value Digit Interpretation
Units 0 3 or more consecutive pixels with the same Type_of_Scene
1 2 consecutive pixels with the same Type_of_Scene
2 Not computed
Tens
IIR aerosols index
0 No mineral aerosols detected
1 Mineral aerosols detected
Hundres
Obs-Computed BTs
0 Not computed or satisfactory for computed cases:
Mean (Observed - Computed) Brightness Temperatures between -2K and +2K
1 Low
Mean (Observed - Computed) Brightness Temperatures between -5K and -2K
2 High
Mean (Observed - Computed) Brightness Temperatures between +2K and +5K
3 Very low
Mean (Observed - Computed) Brightness Temperatures < -5K
4 Very high
Mean (Observed - Computed) Brightness Temperatures > 5K

High_Cloud_vs_Background_Flag
This flag is to give the main characteristics of the background radiance used to retrieve the effective emissivity of the current pixel.

If the background radiance is derived from reference measurements in the vicinity of the pixel, the unit digit gives an indication of the mean distance from the current pixel. If it is derived from the FASRAD model, the unit digit is set to zero.

Depending on Type_of_Scene, the reference can be clear sky (10) or possibly low ST non depolarizing aerosols (52), a low opaque cloud (20), a high opaque cloud (40), or a low opaque aerosols layer (56). This information is provided in the hundreds digit (added in V3). When the reference is a cloud or aerosol layer selected among nearby observations (i.e. not computed), the tens digit (added in V3) indicates the range of values of its effective emissivity. Otherwise, it is set to 0 (computed reference) or -9 (clear sky).

Digit Digit value Digit interpretation
Units 0 Background reference computed
1 Background reference measured at a distance <= 10 km
2 Background reference measured, 10 km < distance <= 50 km
3 Background reference measured, 50 km < distance <= 100 km
Tens 0 Background reference computed
1 Measured background reference effective emissivity between -0.1 and 1.1
2 Measured background reference effective emissivity < -0.1
3 Measured background reference effective emissivity > 1.1
-9 Measured background reference is clear sky
Hundreds 0 Background reference: clear sky (10)
1 Background reference: low opaque cloud (20)
2 Background reference: high opaque cloud (40)
3 Background reference: low semi-transparent non depolarizing aerosols (52)
4 Background reference: low opaque aerosols (56)

Computed_vs_Observed_Background_Flag
This parameter is to assess the impact of computed versus measured background reference radiances in the retrieved effective emissivities. If the background reference is derived from a series of neighboring pixels (cf High_Cloud_vs_Background_Flag), this parameter gives the mean relative difference between those measurements and the computed radiances (not used to retrieve the effective emissivities). Otherwise, the parameter is set to invalid. The three elements are for the IIR channels 08.65 μm, 10.60 μm and 12.05 μm respectively.

Value Interpretation
0 Computed_vs_Observed_Background standard deviation <= 0.15
1 Computed_vs_Observed_Background standard deviation > 0.15

Regional_Background_Std_Dev_Flag
This parameter is the standard deviation associated to the previous parameter. (in W.m-2.sr-1.μm-1)
Regional_Background_Std_Dev_Flag Interpretation
0 Standard deviation <= 0.15
1 Standard deviation > 0.15

Multi_Layer_Cloud_Flag
This flag is to give some information about the upper level whose effective emissivity is provided especially when composed of several layers (ten thousands and thousands digits). The difference between the bottom altitude of the uppermost layer and the top altitude of the lowermost layer (tens-units-decimals digits) is an indicator of the confidence in the retrieved effective emissivity in case of multi-layer upper levels.

Digits Interpretation
Tens-Units-Decimals Difference between the bottom altitude of the uppermost layer and the top altitude of the lowermost layer within the s-called upper level. Multi_Layer_Cloud_Flag takes the sign of this quantity. This quantity is set to zero for mono-layer cases.
Hundreds 0
Ten thousands-and thousands Number of layers composing the upper level.

Microphysics
Ice cloud microphysical properties are derived from two microphysical indices, defined as the ratio of the effective infrared optical depths in the pairs of channels 12.05-8.65 and 12.05-10.60 μm (Parol et al, 1991). Look-up tables allow deriving the effective size of the cirrus ice crystals and their shape.

The model leading to the best agreement between both microphysical indices is the one selected by the algorithm (see Particle_Shape_Index) to retrieve Effective_Particle_Size.

Microphysics gives the whole set of effective sizes retrieved from each the pair of channels for each model considered in the algorithm, allowing the user to evaluate the robustness of the model selection. The first three elements are for aggregates, plates and solid column models respectively (Yang et al, 2005).

Digits Interpretation
Units Shape_index: 7 (aggregates, record #1) ; 8 (plates, record #2), 9(solid column, record #3)
Thousands-Hundreds-Tens Effective diameter in microns derived from the (12.05 ; 8.65) pair
Millions- Hundred and ten thousands Effective diameter in microns derived from the (12.05 ;10.60) pair

Metadata Parameters

Product_ID
An 80-byte (max) character string specifying the data product name. For the IIR Level 2 track products, the value of this string is "CAL_IIR_L2_Track".

Date_Time_at_Granule_Start
A 27-byte character string that reports the date and time at the start of the file orbit segment (i.e., granule). The format is yyyy-mm-ddThh:mm:ss.ffffffZ.

Date_Time_at_Granule_End
A 27-byte character string that reports the date and time at the end of the file orbit segment (i.e., granule). The format is yyyy-mm-ddThh:mm:ss.ffffffZ.

Date_Time_at_Granule_Production
This is a 27-byte character string that defines the date at granule production. The format is yyyy-mm-ddThh:mm:ss.ffffffZ.

Initial_IIR_Scan_Center_Latitude
This field reports the first subsatellite latitude of the granule.

Initial_IIR_Scan_Center_Longitude
This field reports the first subsatellite longitude of the granule.

Ending_IIR_Scan_Center_Latitude
This field reports the last subsatellite latitude of the granule.

Ending_IIR_Scan_Center_Longitude
This field reports the last subsatellite longitude of the granule.

Orbit_Number_at_Granule_Start
This field reports the orbit number at the granule start time.

Orbit_Number_at_Granule_End
This field reports the orbit number at the granule stop time.

Orbit_Number_Change_Time
This field reports the time at which the orbit number changes in the granule.

Path_Number_at_Granule_Start
This field reports the path number at the start time.

Path_Number_at_Granule_End
This field reports the path number at the granule stop time.

Path_Number_Change_Time
This field reports the time at which the path number changes in the granule.

Number_of_IIR_Records_in_File
This field reports the number of IIR records in the file.

Number_of_Valid_08_65_Pixels
This field reports the number of IIR pixels in the file with valid and good quality radiance in channel 08_65.

Number_of_Valid_12_05_Pixels
This field reports the number of IIR pixels in the file with valid and good quality radiance in channel 12_05.

Number_of_Valid_10_60_Pixels
This field reports the number of IIR pixels in the file with valid and good quality radiance in channel 10_60.

Number_of_Invalid_08_65_Pixels
This field reports the number of IIR pixels in the file with invalid or poor quality radiance in channel 08_65.

Number_of_Invalid_12_05_Pixels
This field reports the number of IIR pixels in the file with invalid or poor quality radiance in channel 12_05.

Number_of_Invalid_10_60_Pixels
This field reports the number of IIR pixels in the file with invalid or poor quality radiance in channel 10_60.

Number_of_Rejected_08_65_Pixels
This field reports the number of IIR pixels in the file in channel 08_65 rejected by the algorithm.

Number_of_Rejected_12_05_Pixels
This field reports the number of IIR pixels in the file in channel 12_05 rejected by the algorithm.

Number_of_Rejected_10_60_Pixels
This field reports the number of IIR pixels in the file in channel 10_60 rejected by the algorithm.

Number_of_Rejected_08_65_Pixels_Location
This field reports the number of IIR pixels in the file in channel 08_65 rejected by the algorithm due to co-location.

Number_of_Rejected_12_05_Pixels_Location
This field reports the number of IIR pixels in the file in channel 12_05 rejected by the algorithm due to co-location.

Number_of_Rejected_10_60_Pixels_Location
This field reports the number of IIR pixels in the file in channel 10_60 rejected by the algorithm due to co-location.

Number_of_Rejected_08_65_Pixels_Radiance
This field is set to 0.

Number_of_Rejected_12_05_Pixels_Radiance
This field is set to 0.

Number_of_Rejected_10_60_Pixels_Radiance
This field is set to 0.

Mean_08_65_Radiance_All
This field reports the mean radiance (in W.m-2.sr-1. μm-1) in the file in channel 08_65.

Mean_12_05_Radiance_All
This field reports the mean radiance (in W.m-2.sr-1. μm-1) in the file in channel 12_05.

Mean_10_60_Radiance_All
This field reports the mean radiance (in W.m-2.sr-1. μm-1) in the file in channel 10_60.

Mean_08_65_Radiance_Selected_Cases
This field reports the mean radiance (in W.m-2.sr-1. μm-1) in the file in channel 08_65 for cloudy and aerosols pixels selected by the algorithm (low opaque features excluded)

Mean_12_05_Radiance_Selected_Cases
This field reports the mean radiance (in W.m-2.sr-1. μm-1) in the file in channel 12_05 for cloudy and aerosols pixels selected by the algorithm (low opaque features excluded).

Mean_10_60_Radiance_Selected_Cases
This field reports the mean radiance (in W.m-2.sr-1. μm-1) in the file in channel 10_60 for cloudy and aerosols pixels selected by the algorithm (low opaque features excluded).

Mean_08_65_Brightness_Temp_All
This field reports the mean brightness temperature (in Kelvin) in the file in channel 08_65.

Mean_12_05_Brightness_Temp_All
This field reports the mean brightness temperature (in Kelvin) in the file in channel 12_05.

Mean_10_60_Brightness_Temp_All
This field reports the mean brightness temperature (in Kelvin) in the file in channel 10_60.

Mean_08_65_Brightness_Temp_Selected_Cases
This field reports the mean brightness temperature (in Kelvin) in the file in channel 08_65 for cloudy and aerosols pixels selected by the algorithm (low opaque features excluded).

Mean_12_05_Brightness_Temp_Selected_Cases
This field reports the mean brightness temperature (in Kelvin) in the file in channel 12_05 for cloudy and aerosols pixels selected by the algorithm (low opaque features excluded).

Mean_10_60_Brightness_Temp_Selected_Cases
This field reports the mean brightness temperature (in Kelvin) in the file in channel 10_60 for cloudy and aerosols pixels selected by the algorithm (low opaque features excluded).

Number_of_Valid_LIDAR_Pixels
This field reports the number records in the lidar input product available at IIR pixel resolution.

Number_of_Invalid_LIDAR_Pixels
This field is set to 0.

Number_of_Rejected_LIDAR_Pixels
This field is set to 0.

Number_of_Identified_Pixels_Upper_Level
This field reports the number of cloudy and aerosols pixels in the file (low opaque clouds excluded).

Percent_of_Identified_Pixels_Upper_Level
This field reports the percentage of cloudy and aerosols pixels in the file (low opaque features excluded).

Number_of_Identified_Pixels_Lower_Level
This field reports the number of pixels in the file with a low level opaque cloud.

Percent_of_Identified_Pixels_Lower_Level
This field reports the percentage of pixels in the file with a low level opaque cloud.

Number_of_Identified_Pixels_Clear_Sky
This field reports the number of "clear sky" pixels in the file (i. e no clouds and no aerosols).

Percent_of_Identified_Pixels_Clear_Sky
This field reports the percentage of "clear sky" pixels in the file (i. e no clouds and no aerosols).

Mean_Altitude_Upper_Level
This field reports the mean altitude (in km) of the scattering features selected by the algorithm (low opaque features excluded).

GEOS_Version
This is a 64-byte character that reports the version of the GEOS data product provided by the GMAO.


Data Release Versions

IIR Level 2 Track
Half orbit (Night and Day) emissivity and cloud particle data related to pixels that have been co-located to the Lidar track
Release Date Version Data Date Range Maturity Level
December 2011 3.02 November 1, 2011 to present Beta
May 2011 3.01 June 13, 2006 to October 31, 2011 Beta

Data Quality Statement for the release of the CALIPSO IIR Level 2 Track Product Version 3.02, December 2011

The CALIPSO Team is releasing Version 3.02 which represents a transition of the Lidar, IIR, WFC processing and browse code to a new cluster computing system. No algorithm changes were introduced and very minor changes were observed between V 3.01 an dV 3.02 as a result of the compiler and computer architecture differences. Version 3.02 is being released in a forward processing mode beginning November 1, 2011.


Data Quality Statement for the release of the CALIPSO IIR Level 2 Track Product Version 3.01, May 2011

Version 3.01 includes cloud microphysics parameters (effective particle size and uncertainty, particle shape and confidence, and ice-water path) and an IR mineral aerosols index. Various radiances computed with the fast real-time radiative transfer code FASRAD are added (Reference and blackbody brightness temperatures, computed surface brightness temperature). In addition, a number of QA flags were revisited to better assess the uncertainties of the derived optical and microphysical parameters.

The Version 3.01 IIR scene classification algorithm has been updated with respect to Version 2. Also, Version 3.01 IIR products use Version 3.01 CALIOP Level 2 products (instead of Version 2 for the previous release). Overall, changes in the IIR scene classification are significant in Version 3.01 compared to Version 2.




NASA
Last Updated: November 22, 2021
Curator: Charles R. Trepte
NASA Official: Charles R. Trepte

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