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CALIPSO: Data User’s Guide - Data Product Descriptions - Lidar Level 2 Polar Stratospheric Cloud (PSC) Version 2.00 Product


CALIPSO HOMECALIPSO User’s Guide HOMEData Products Description → Lidar Level 2 Polar Stratospheric Cloud Mask V2.00 Product

Created on March 04, 2022. - Updated: March 09, 2022

Introduction

The CALIPSO Lidar Level 2 Polar Stratospheric Cloud (PSC) data product ensemble describes the spatial distribution, optical properties, and composition of PSC layers observed by the CALIPSO lidar (CALIOP). The product contains profiles of PSC presence, composition, optical properties, and meteorological information along CALIPSO orbit tracks. In the current release, PSC detection is limited to nighttime CALIOP observations because higher levels of background light during daytime significantly reduce the signal-to-noise and, hence, the PSC detection sensitivity. Each file contains data from all nighttime orbit segments from a single day reported on a 5-km horizontal by 180-m vertical grid. The PSC data ensemble is derived from nighttime only CALIPSO Lidar Level 1B data products using the V2 PSC detection and composition classification algorithm described in Pitts et al. (2018) (https://www.atmos-chem-phys.net/18/10881/2018/). The V2 algorithm includes significant improvements in PSC detection sensitivity and composition discrimination, as well as a retrieval of backscatter and extinction coefficients to enable estimates of PSC particle surface area density and volume density.

A number of Aura Microwave Limb Sounder (MLS) products are also included in the V2 PSC data product ensemble. Of particular relevance for PSC studies are the Aura MLS measurements of the primary PSC condensable vapors HNO3 and H2O. The reported products are based on the publically available Aura MLS Level 2 V4 HNO3 and H2O gas species data that are archived at the NASA Goddard Earth Sciences Data Information and Services Center (Lambert et al., 2015; Manney et al., 2015). In addition to the Aura MLS gas species data, a number of parameters from the Aura MLS V2 Derived Meteorological Products (DMPs) are also reported, including equivalent latitude, vortex edge location, and dynamic tropopause altitude. The V2 DMPs (Manney et al., 2007; 2011) are available through the Aura MLS website (https://mls.jpl.nasa.gov/dmp/). The Aura MLS HNO3 and H2O mixing ratio data and DMP parameters are interpolated to the CALIOP PSC profile locations along each orbit track using an average of values from the two nearest MLS profile locations weighted by the inverse of the relative distance of each to the CALIPSO locations.

This is a standard only produced product.

PSCs form in the cold, polar winter stratosphere when the temperatures fall below ~195 K. Over the Antarctic, the PSC season extends from May through October. Over the Arctic, the PSC season is more variable, but may extend from December through March. The PSC Mask V2 data files are therefore only produced for the months May-October (Antarctic) and December-March (Arctic).


Data Descriptions

In the text below we provide brief descriptions of the individual data fields reported in the CALIPSO Lidar Level 2 Polar Stratospheric Cloud data product ensemble. The data descriptions are grouped into several major categories, 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)
Number_Of_LIDAR_L1_File
Number_Altitudes
Number_Profiles
L1_Input_Filenames
L1_Input_Start_Times
L1_Input_End_Times
Profile_Time
Profile_UTC_Time
Latitude
Longitude
Altitude
Orbit_Index
Temperature
Potential_Temperature
Pressure
Vortex_Edge_Outer
Vortex_Edge_Center
Equivalent_Latitude
Tropopause_Altitude_MERRA2
Parallel_Attenuated_Backscatter_532_Initial
Perpendicular_Attenuated_Backscatter_532_Initial
Parallel_Attenuated_Backscatter_532
Parallel_Attenuated_Backscatter_532_Uncertainity
Perpendicular_Attenuated_Backscatter_532
Perpendicular_Attenuated_Backscatter_532_Uncertainty
Particulate_Depolarization_Ratio_532
Particulate_Depolarization_Ratio_532_Uncertainty
Total_Attenuated_Scattering_Ratio_532
Total_Attenuated_Scattering_Ratio_532_Uncertainty
Total_Attenuated_Backscatter_1064
Total_Attenuated_Backscatter_1064_Uncertainty
Molecular_Backscatter_532
Particulate_Backscatter_532
Particulate_Backscatter_532_Uncertainty
Total_Scattering_Ratio_532
Total_Scattering_Ratio_532_Uncertainty
Perpendicular_Scattering_Ratio_532
Perpendicular_Scattering_Ratio_532_Uncertainty
Perpendicular_Backscatter_532
Perpendicular_Backscatter_532_Uncertainty
Parallel_Backscatter_532
Parallel_Backscatter_532_Uncertainty
Particulate_Extinction
Particulate_Surface_Area_Density_532
Particulate_Volume_Density_532
Lidar_Ratio_532
Multiple_Scattering_Factor_532
Retrieval_QC_Flag
PSC_Feature_Mask
PSC_Composition
PSC_Composition_Confidence_Index_Non_Spherical
PSC_Composition_Confidence_Index_NAT_Ice
PSC_Composition_Confidence_Index_STS
PSC_Ice_Mixture_Boundary
Total_Scattering_Ratio_532_Threshold
Perpendicular_Attenuated_Backscatter_532_Threshold
Number_HNO3_Pressure_Levels
Number_H2O_Pressure_Levels
Pressure_HNO3
Pressure_H2O
HNO3_Mixing_Ratio
H2O_Mixing_Ratio


Time Parameters

Profile Time
Units: sec
Format: Float_64
Valid Range: 4.204E8...1.072E9
Fill Value: -9999.0
Definition: Time expressed in International Atomic Time (TAI). Units are in seconds, starting from January 1, 1993.

Profile UTC Time
Units: NoUnits
Format: Float_64
Valid Range: 60,426.0...261,231.0
Fill Value: -9999.0
Definition: Time expressed in Coordinated Universal Time (UTC), and formatted as ‘yymmdd.ffffffff”, where ‘yy” represents the last two digits of year, ‘mm” and ‘dd” represent month and day, respectively, and ‘ffffffff’ is the fractional part of the day.


Geolocation and Altitude Registration

Latitude
Units: deg
Format: Float_32
Valid Range: -90.0...90.0
Fill Value: -9999.0
Definition: Geodetic latitude, in degrees, at the center point of the horizontal along-track averaging bin (5, 15, 45, or 135 km).

Longitude
Units: deg
Format: Float_32
Valid Range: -180.0...180.0
Fill Value: -9999.0
Definition: Longitude, in degrees, at the center point of the horizontal along-track averaging bin (5, 15, 45, or 135 km).

Altitude
Units: km
Format: Float_32
Valid Range: 8.0...31.0
Fill Value: -9999.0
Definition: Altitudes at which the Level 2 PSC profile products are reported; consisting of 121 levels between approximately 8.3 and 30.1 km, with an interval of approximately 180 m. The altitudes are a subset of the standard lidar Level 1 profile altitudes. Units are in kilometers.


Meteorological Data

Meteorological data are interpolated to the CALIOP Level 1 measurement locations from the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2). MERRA-2 is the latest atmospheric reanalysis of the modern satellite era produced by NASA’s Global Modeling and Assimilation Office (GMAO). To match the PSC data product grid, the MERRA-2 data are smoothed to the 5-km horizontal resolution and interpolated to the 180-m vertical grid.

Tropopause_Altitude_MERRA2 (external)
Units: km
Format: Float_32
Valid Range: 3.0 ... 25.0
Fill Value: -9999.0
Definition: Mean tropopause height, in kilometers above local mean sea level. Tropopause height information is based on the MERRA-2 “blended” tropopause altitudes. The MERRA-2 blended tropopause is the lower (in altitude) of the temperature-based (“thermal”) tropopause and potential vorticity (PV)-based (“dynamic”) tropopause (Bosilovich et al., 2016; Ott et al., 2016).

Temperature
Units: K
Format: Float_32
Valid Range: 150.0...350.0
Fill Value: -9999.0
Definition: Temperature, in Kelvin, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. Temperature values are interpolated from the ancillary meteorological data provided by the MERRA-2.

Potential_Temperature
Units: K
Format: Float_32
Valid Range: 200.0...1,200.0
Fill Value: -9999.0
Definition: Potential temperature, in Kelvin, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. Potential temperature values are derived from the ancillary meteorological data provided by the MERRA-2.

Pressure
Units: hPa
Format: Float_32
Valid Range: 1.0...1,000.0
Fill Value: -9999.0
Definition: Atmospheric pressure, in hPa, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. Pressure values interpolated from the ancillary meteorological data provided by the MERRA-2.

Vortex_Edge_Outer
Units: deg
Format: Float_32
Valid Range: -90.0...90.0
Fill Value: -9999.0
Definition: Distance from the outer edge of vortex, in Equivalent Latitude degrees, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. Values are derived from the ancillary meteorological data provided in the Aura MLS version 2 (V2) derived meteorological products (Manney et al., 2007; 2011).

Vortex_Edge_Center
Units: deg
Format: Float_32
Valid Range: -90.0...90.0
Fill Value: -9999.0
Definition: Distance from center of the vortex edge (defined as maximum in wind speed), in Equivalent Latitude degrees, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. Values are derived from the ancillary meteorological data provided in the Aura MLS version 2 (V2) derived meteorological products (Manney et al., 2007; 2011).

Equivalent_Latitude
Units: deg
Format: Float_32
Valid Range: -90.0...90.0
Fill Value: -9999.0
Definition: Equivalent latitude is a Lagrangian coordinate. Each isoline in a map of equivalent latitude follows the flow velocity and encloses the same area as the latitude line of equivalent value, hence “equivalent latitude.” Values are derived from the ancillary meteorological data provided in the Aura MLS version 2 (V2) derived meteorological products (Manney et al., 2007; 2011).


Profile Polar Stratospheric Cloud Properties

We have derived a set of PSC feature flags that includes information on (a) PSC presence (cloud or no cloud); (b) location relative to the local tropopause, (c) the amount of horizontal averaging required for layer detection, and (d) the optical parameter used for detection. In addition, there is a composition flag which indicates our best estimate of the PSC particle composition. These flags are reported for every 5-km horizontal x 180-m vertical resolution grid point in the PSC data product. For detected PSC layers, the values are replicated over the horizontal averaging scale required for detection (5, 15, 45, or 135 km). For non-PSC elements, the profiles are replicated over the largest horizontal scale of 135 km.


PSC Feature Mask
Units: NoUnits
Format: Int_16
Valid Range: -350...350
Fill Value: -9999
Definition: The PSC Feature Mask provides information on the detected PSC layers and also the location of the PSC relative to the tropopause. The reported values are signed integers comprising three significant digits, defined as follows:
PSC_flag = N1N2N3
N1 = PSC presence flag
N1 < 0 : No cloud detected             or             N1 > 0 : Cloud detected
N1 = -1       z < zt N1 = +1       z < zt
N1 = -2       trop < z < trop + 4km N1 = +2       trop < z < trop + 4km
N1 = -3       z > trop + 4km N1 = +3       z > trop + 4km
N1 =  0       No trop reported N1 =   0       No trop reported

 
 

N2 N3 = Horizontal averaging required and parameter used for detection
N2 N3 = 01 Detected at 5-km with R (Total scattering ratio 532)
N2 N3 = 03 Detected at 15-km with R
N2 N3 = 09 Detected at 45-km with R
N2 N3 = 27 Detected at 135-km with R
N2 N3 = 02 Detected at 5-km with Β′perp (Perpendicular attenuated backscatter at 532)
N2 N3 = 04 Detected at 15-km with Β′perp
N2 N3 = 10 Detected at 45-km with Β′perp
N2 N3 = 28 Detected at 135-km with Β′perp
N1N2N3 = -9999 Missing or bad data

PSC Composition
Units: NoUnits
Format: Int_16
Valid Range: -6...6
Fill Value: -9999
Definition: PSC composition reports information on the composition of the detected PSC. The composition is determined based on the retrieved lidar optical parameters in terms of unattenuated total scattering ratio and perpendicular backscatter at 532 nm using the algorithm described by Pitts et al. (2018). The valid values for the PSC composition are:
Comp_flag = 0 No Cloud detected
Comp_flag = 1 Liquid Supercooled Ternary (sulfuric acid, water, nitric acid) Solution (STS) droplets
Comp_flag = 2 Liquid NAT Mixtures: STS + low number densities/volumes of nitric acid trihydrate (NAT) particles
Comp_flag = 4 Water ice clouds
Comp_flag = 5 Enhanced NAT Mixtures: STS + high number densities/volumes of NAT particles
Comp_flag = 6 Wave ice: Mountain wave induced water ice clouds (R > 50)
Comp_flag = -1 Composition not determinable; total backscatter < calculated molecular backscatter
Comp_flag = -4 Likely tropospheric ice clouds, but pressure level is below (in altitude) lowest valid MLS HNO3 level of 215 hPa

PSC Composition Confidence Indices

These indices provide information on the statistical confidence in the assigned composition based on a data point’s location within the optical space. Indices are reported as the distance (in number of standard deviations) between the point and the relevant boundaries of its composition class, with larger numbers indicating higher confidence in the assigned composition. The reported indices are:


PSC_Composition_Confidence_Index_Non_Spherical
Units: NoUnits
Format: Float_32
Valid Range: -20.0...130.0
Fill Value: -9999.0
Definition: Distance (in number of standard deviation) in perpendicular backscatter vs total scattering ratio optical space between the measured point and the non-spherical composition boundary defined by the Perpendicular Backscatter 532 Threshold value for this measurement point.

PSC_Composition_Confidence_Index_NAT_Ice
Units: NoUnits
Format: Float_32
Valid Range: -150.0...40.0
Fill Value: -9999.0
Definition: Distance (in number of standard deviation) in perpendicular backscatter vs total scattering ratio optical space between the measured point and NAT/ice composition boundary defined by the PSC_Ice_Mixture_Boundary value for this measurement point.

PSC_Composition_Confidence_Index_STS
Units: NoUnits
Format: Float_32
Valid Range: 0.0...30.0
Fill Value: -9999.0
Definition: Distance (in number of standard deviation) in perpendicular backscatter vs total scattering ratio optical space between the measured point and the STS composition boundary defined by the Total_Scattering_Ratio_532_Threshold for that point.

Total_Scattering_Ratio_532_Threshold
Units: NoUnits
Format: Float_32
Valid Range: 0.0...5.0
Fill Value: -9999.0
Definition: PSC detection threshold in terms of total scattering ratio at 532 nm (no units) reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. The thresholds are calculated daily in five overlapping 100 K-thick potential temperature layers from 400 to 700 K at each of the four successive horizontal averaging scales (5, 15, 45, and 135 km). See Pitts et al. (2018) for more detail.

Perpendicular_Attenuated_Backscatter_532_Threshold
Units: NoUnits
Format: Float_32
Valid Range: 0.0E0...1.0E-4
Fill Value: -9999.0
Definition: PSC detection threshold in terms of perpendicular backscatter at 532 nm (no units) reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. The thresholds are calculated daily in five overlapping 100 K-thick potential temperature layers from 400 to 700 K at each of the four successive horizontal averaging scales (5, 15, 45, and 135 km). See Pitts et al. (2018) for more detail.

PSC_Ice_Mixture_Boundary
Units: NoUnits
Format: Float_32
Valid Range: -1.0...10.0
Fill Value: -9999.0
Definition: Value of Total Scattering Ratio at 532 nm (no units) defining the boundary between NAT mixture and ice PSCs, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field.


Profile Optical Properties

We also report a number of lidar optical properties associated with each 5-km horizontal x 180-m vertical resolution grid point in the PSC data product. Most of these are derived from the CALIOP Level 1 profile backscatter products that are described in section 6 of the CALIPSO Lidar Level 1 ATBD. For detected PSC layers, the values are replicated over the horizontal averaging scale required for detection (5, 15, 45, or 135 km). For non-PSC elements, the profiles are replicated over the largest horizontal scale of 135 km. Initial values of both parallel and perpendicular attenuated backscatter are corrected for two-way attenuation due to molecular scattering and ozone absorption. The molecular backscatter values are calculated using the MERRA-2 molecular density profiles provided in the Level 1B data files and a theoretical value for the molecular scattering cross section as described in Hostetler et al. (2006) (CALIPSO Lidar Level 1 ATBD). The backscatter data are finally corrected for attenuation due to overlying particulate layers through the retrieval of 532-nm particulate backscatter as described in detail in Pitts et al. (2018).

Note that on a point-by-point basis, any derived particulate optical parameter (e.g. particulate depolarization ratio) can exhibit anomalously large, i.e. non-physical, absolute values. These have not been removed from the data products.


Parallel_Attenuated_Backscatter_532_Initial
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Parallel attenuated backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the initial values of the CALIOP Level 1 parallel component of the 532-nm total attenuated backscatter (as described in section 6 of the CALIPSO Lidar Level 1 ATBD averaged to 180-m vertical and 5-km horizontal resolution. Profiles of the parallel component of the backscatter are obtained by simple subtraction of the perpendicular component from the total.

Perpendicular_Attenuated_Backscatter_532_Initial
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.05
Fill Value: -9999.0
Definition: Perpendicular attenuated backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the initial values of the CALIOP Level 1 perpendicular component of the 532-nm total attenuated backscatter (as described in section 6 of the CALIPSO Lidar Level 1 ATBD averaged to 180-m vertical and 5-km horizontal resolution.

Parallel_Attenuated_Backscatter_532
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Parallel attenuated backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Parallel_Attenuated_Backscatter_532_Uncertainity
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Uncertainty in parallel attenuated backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Perpendicular_Attenuated_Backscatter_532
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.05
Fill Value: -9999.0
Definition: Perpendicular attenuated backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Perpendicular_Attenuated_Backscatter_532_Uncertainty
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.05
Fill Value: -9999.0
Definition: Uncertainty in perpendicular attenuated backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Particulate_Depolarization_Ratio_532
Units: NoUnits
Format: Float_32
Valid Range: 0.0...1.0
Fill Value: -9999.0
Definition: The particulate depolarization ratio, δp(z), no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. δp(z) is defined as the ratio of the perpendicular and parallel polarization components of particulate attenuated backscatter coefficient at 532 nm , calculated using the following equation:
δp(z) = (Β′perp(z)-0.00366*Β′m(z))/(Β′tot(z)-Β′perp(z)-0.99634*Β′m(z))
Here Β′perp is the perpendicular attenuated backscatter, Β′tot is the total attenuated backscatter, Β′m is the molecular attenuated backscatter derived from the MERRA-2 density profile. The values are reported at the resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution). Note that the δp(z) values are not affected by attenuation since both parallel and perpendicular backscatter components experience the same two-way attenuation in the atmosphere.

Particulate_Depolarization_Ratio_532_Uncertainty
Units: NoUnits
Format: Float_32
Valid Range: 0.0...99.0
Fill Value: -9999.0
Definition: Uncertainty in the particulate depolarization ratio, δp(z), no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field.

Total_Attenuated_Scattering_Ratio_532
Units: NoUnits
Format: Float_32
Valid Range: 0.0...1.0
Fill Value: -9999.0
Definition: Ratio of the total attenuated backscatter at 532 nm to the molecular backscatter at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. The values are reported at the resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Total_Attenuated_Scattering_Ratio_532_Uncertainty
Units: NoUnits
Format: Float_32
Valid Range: 0.0...99.0
Fill Value: -9999.0
Definition: Uncertainty in the total attenuated scattering ratio at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. The values are reported at the resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Total_Attenuated_Backscatter_1064
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Total attenuated backscatter at 1064 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Total_Attenuated_Backscatter_1064_Uncertainty
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Uncertainty in the total attenuated backscatter at 1064 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. The values are reported at the resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Molecular_Backscatter_532
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Molecular backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Particulate_Backscatter_532
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.8
Fill Value: -9999.0
Definition: Retrieved (attenuation-corrected) particulate backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Particulate_Backscatter_532_Uncertainty
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Uncertainty in particulate backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Total_Scattering_Ratio_532
Units: NoUnits
Format: Float_32
Valid Range: 0.0...1.0
Fill Value: -9999.0
Definition: Attenuation-corrected total scattering ratio at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Total_Scattering_Ratio_532_Uncertainty
Units: NoUnits
Format: Float_32
Valid Range: 0.0...1.0
Fill Value: -9999.0
Definition: Uncertainty in total scattering ratio at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Perpendicular_Scattering_Ratio_532
Units: NoUnits
Format: Float_32
Valid Range: 0.0...1.0
Fill Value: -9999.0
Definition: Perpendicular component of the total scattering ratio at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution). It is calculated as the ratio of the attenuation-corrected perpendicular backscatter at 532 nm to the perpendicular molecular backscatter at 532 nm. The perpendicular molecular backscatter is estimated as 0.0366% of the total molecular backscatter (Level 1 ATBD).

Perpendicular_Scattering_Ratio_532_Uncertainty
Units: NoUnits
Format: Float_32
Valid Range: 0.0...1.0
Fill Value: -9999.0
Definition: Uncertainty in the perpendicular component of the total scattering ratio at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Perpendicular_Backscatter_532
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.5
Fill Value: -9999.0
Definition: Perpendicular component of the total backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Perpendicular_Backscatter_532_Uncertainty
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.1
Fill Value: -9999.0
Definition: Uncertainty in the perpendicular component of the total backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Parallel_Backscatter_532
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.5
Fill Value: -9999.0
Definition: Parallel component of the total backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Parallel_Backscatter_532_Uncertainty
Units: km-1 · sr-1
Format: Float_32
Valid Range: 0.0...0.2
Fill Value: -9999.0
Definition: Uncertainty in the parallel component of the total backscatter at 532 nm, in units of km-1 sr-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Particulate_Extinction
Units: km-1
Format: Float_32
Valid Range: 0.0...10.0
Fill Value: -9999.0
Definition: Retrieved particulate extinction at 532 nm, in units of km-1, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Particulate_Surface_Area_Density_532
Units: μm2cm-3
Format: Float_32
Valid Range: 0.0...350.0
Fill Value: -9999.0
Definition: Estimated particulate surface area density, in units of μm3cm-3, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Particulate_Volume_Density_532
Units: μm3cm-3
Format: Float_32
Valid Range: 0.0...350.0
Fill Value: -9999.0
Definition: Estimated particulate surface area density, in units of μm3cm-3, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values at resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Lidar_Ratio_532
Units: sr
Format: Float_32
Valid Range: 0.0...250.0
Fill Value: -9999.0
Definition: Ratio of extinction to backscatter at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values assumed in the particulate backscatter retrieval and are reported at the resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Multiple_Scattering_Factor_532
Units: NoUnits
Format: Float_32
Valid Range: 0.5...1.0
Fill Value: -9999.0
Definition: Multiple scattering factor at 532 nm, no units, reported for each Level 2 profile at the 121 standard altitudes in the Altitude field. These are the values assumed in the particulate backscatter retrieval and are reported at the resolution of the PSC detection (180-m vertical and 5, 15, 45, or 135-km horizontal resolution).

Retrieval_QC_Flag
Units: NoUnits
Format: Float_32
Valid Range: 8.0...30.05
Fill Value: -9999.0
Definition: Provides information on success of the particulate backscatter retrieval. For a successful retrieval, the reported value is simply the altitude of the measurement (in km). Failed retrievals are reported as a value of -6666 = retrieval did not converge; -7777 = retrieval failed due to calculated molecular backscatter > attenuated backscatter; or -8888 = calculated layer transmission unrealistic. In all cases where the retrieval failed, retrieved quantities have been set to the fill value of -9999.


Aura MLS Gas Species Data

We include profiles of Aura MLS HNO3 (Manney et al., 2015) and H2O (Lambert et al., 2015) mixing ratios derived from the publically available MLS/Aura Level 2 V4 HNO3 (https://disc.gsfc.nasa.gov/datasets/ML2HNO3_004/summary) and H2O (https://disc.gsfc.nasa.gov/datasets/ML2H2O_004/summary) data products. These are reported on their standard vertical pressure grid, but have been interpolated horizontally to the CALIOP profile locations along each CALIPSO orbit track.


Number_HNO3_Pressure_Levels
Units: NoUnits
Format: Int_32
Valid Range: 0...25
Fill Value: -9999
Definition: Number of pressure levels reported for each Aura MLS HNO3 profile.

Number_H2O_Pressure_Levels
Units: NoUnits
Format: Int_32
Valid Range: 0...25
Fill Value: -9999
Definition: Number of pressure levels reported for each Aura MLS H2O profile.

Pressure_HNO3
Units: hPa
Format: Float_32
Valid Range: 1.0...500.0
Fill Value: -9999.0
Definition: Pressure levels reported for each Aura MLS HNO3 profile.

Pressure_H2O
Units: hPa
Format: Float_32
Valid Range: 1.0...500.0
Fill Value: -9999.0
Definition: Pressure levels reported for each Aura MLS H2O profile.

HNO3_Mixing_Ratio
Units: NoUnits
Format: Float_32
Valid Range: 0.0...2.0E-8
Fill Value: -9999.0
Definition: Profile of Aura MLS HNO3 mixing ratio values interpolated to the location of CALIOP profiles along each orbit track.

H2O_Mixing_Ratio
Units: NoUnits
Format: Float_32
Valid Range: 0.0...8.0E-4
Fill Value: -9999.0
Definition: Profile of Aura MLS H2O mixing ratio values interpolated to the location of CALIOP profiles along each orbit track.


Ancillary Parameters


Number_Of_LIDAR_L1_Files
Units: NoUnits
Format: Int_16
Valid Range: 1...15
Definition: Number of Lidar Level 1B nighttime orbit files that were used to produce the PSC data product.

Number_Altitudes
Units: NoUnits
Format: Int_32
Valid Range: 1...121
Definition: Number of standard altitudes in each PSC data product profile.

Number_Profiles
Units: NoUnits
Format: Int_32
Valid Range: 1...30,000
Definition: Number of CALIOP profiles in each daily PSC data product file.

L1_Input_Filenames
Units: NoUnits
Format: String
Valid Range: N/A
Definition: List of the names of the Lidar Level 1B nighttime orbit files that were used to produce the PSC data product for this day.

L1_Input_Start_Times
Units: NoUnits (UTC - yymmdd.ffffffff)
Format: Float_64
Valid Range: 60,426.0...261,231.0
Definition: Starting times of all the Level 1B nighttime orbit files that were used to produce the PSC data product for this day.

L1_Input_End_Times
Units: NoUnits (UTC - yymmdd.ffffffff)
Format: Float_64
Valid Range: 60,426.0...261,231.0
Definition: Ending times of all the Level 1B nighttime orbit files that were used to produce the PSC data product for this day.

Orbit_Index
Units: NoUnits
Format: Int_16
Valid Range: 0...15
Fill Value: -9999
Definition: Array of orbit indices that can be used to associate each profile from the given day with a discrete orbit number ordered by time. Since there are at most 15 night profiles per day, the orbit index will range between 1 and 15, with the first night orbit assigned as 1 and the last night orbit assigned as 15.


References

Bosilovich, M. G., Lucchesi, R., and Suarez, M.: MERRA-2: File Specification, GMAO Office Note No. 9 (Version 1.1), 73 p., available at: https://gmao.gsfc.nasa.gov/GMAO_products/reanalysis_products.php (last access: July 2018), 2016.

Lambert, A., Read, W. and Livesey, N. (2015), MLS/Aura Level 2 Water Vapor (H2O) Mixing Ratio V004, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [January 1, 2020], 10.5067/Aura/MLS/DATA2009.

Manney, G.L., W.H. Daffer, J.M. Zawodny, P.F. Bernath, K.W. Hoppel, K.A. Walker, B.W. Knosp, C. Boone, E.E. Remsberg, M.L. Santee, V. Lynn Harvey, S. Pawson, D.R. Jackson, L. Deaver, C.T. McElroy, C.A. McLinden, J.R. Drummond, H.C. Pumphrey, A. Lambert, M.J. Schwartz, L. Froidevaux, S. McLeod, L.L. Takacs, M.J. Suarez, C.R. Trepte, D.T. Cuddy, N.J. Livesey, R.S. Harwood, and J.W. Waters, “Solar Occultation Satellite Data and Derived Meteorological Products: Sampling Issues and Comparisons with Aura MLS”, J. Geophys. Res., 112, D24S50, doi:10.1029/2007JD008709, 2007. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007JD008709

Manney, G.L., M.I. Hegglin, W.H. Daffer, M.L. Santee, E.A. Ray, S. Pawson, M.J. Schwartz, C.D. Boone, L. Froidevaux, N.J. Livesey, W.G. Read, and K.A. Walker, “Jet characterization in the upper troposphere/lower stratosphere UTLS: applications to climatology and transport studies”, Atmos. Chem. Phys., 11, 6115-6137, doi:10.5194/acp-11-6115-2011, 2011. https://www.atmos-chem-phys.net/11/6115/2011/

Manney, G., Santee, M., Froidevaux, L., Livesey, N. and Read, W. (2015), MLS/Aura Level 2 Nitric Acid (HNO3) Mixing Ratio V004, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [January 1, 2020], 10.5067/Aura/MLS/DATA2012.

Ott, L. E., Duncan, B. N., Thompson, A. M., Diskin, G., Fasnacht, Z., Langford, A. O., Lin, M., Molod, A. M., Nielsen, J. E., Pusede, S. E., Wargan, K., Weinheimer, A. J., and Yoshida, Y., “Frequency and impact of summertime stratospheric intrusions over Maryland during DISCOVER-AQ (2011): New evidence from NASA’s GEOS-5 simulations”, J. Geophys. Res.-Atmos., 121, 3687-3706, https://doi.org/10.1002/2015JD024052, 2016.

Pitts, M. C., L. R. Poole and R. Gonzalez, 2018: “Polar stratospheric cloud climatology based on CALIPSO spaceborne lidar measurements from 2006-2017”, Atmos. Chem. Phys., 18, 10881-10913, https://doi.org/10.5194/acp-18-10881-2018.



Data Quality Statements

 

Lidar Level 2 Polar Stratospheric Cloud Ensemble Information
Daily produced file consisting of night time only data.
Release Date Version Data Date Range Maturity Level
March 04, 2022 2.00 June 13, 2006 to March 21, 2021 Standard

Summary Statement for the release of the CALIPSO Lidar Level 2 Polar Stratospheric Cloud Ensemble Product Version 2.00, March 2022

Summary Page.




NASA
Last Updated: May 09, 2022
Curator: Charles R. Trepte
NASA Official: Charles R. Trepte

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