# POLDER 2 - List of Parameters in POLDER "ERB, WV & CLOUDS"

### List of Parameters in POLDER "ERB, WV & CLOUDS" level 2 products

The following geophysical parameters are computed from the level 1 product for each superpixel (3x3 pixels), by orbit segment.

For details about the calculation of these parameters, see POLDER2 advanced algorithms.

**(a) Level 2 non-directional parameters**

t | GMT time (h mn) |

Ni | Total number of viewing directions (7 ? Ni ? 14) |

Nr Np | Number of viewing directions used for the Rayleigh pressure derivation (0 ? Nr ? 14) Number of elementary pixels (5 ? Np ? 12) |

Min_{Glitter}, Max_{Glitter} | No of the first / last viewing direction within the expected region of solar specular reflection |

µ_{s} | Cosine of solar zenith angle (defined for the central elementary pixel) |

A_{vis} | Mean albedo at 670 nm over land and 865 nm over ocean, result from an averaging over pixels and a weighting over directions |

RSD(A_{vis}) | Relative Spatial standard Deviation of the albedos derived by pixel and by direction at 670/865 nm |

RAD(A_{vis}) | Relative Angular standard Deviation of the albedos derived by pixel and by direction at 670/865 nm |

QA_{vis} | Quality index related to the ratio between the relative angular deviation RAD(A_{vis}) and that derived under the Lambertian hypothesis (the lower the better with a 0 ideal case) |

A*_{vis} | Mean of the albedos calculated under the assumption of an homogeneous scene at 670/865 nm |

RAD(A*_{vis}) | Relative Angular standard Deviation of the albedos at 670/865 nm calculated under the assumption of an homogeneous scene |

[A_{model}(_{c}=0)]_{vis} | Modeled clear-sky albedo at 670/865 nm, that is independent of POLDER measurements |

A_{SW} | Shortwave albedo derived from the 443, 670 and 865 nm albedos |

[A_{model}(_{c}=0)]_{SW} | Modeled clear-sky shortwave albedo, that is independent of POLDER measurements |

CC | Cloud Cover, defined as the number of cloudy pixels divided by the total number of pixels. |

CC+/- | Uncertainty on cloud cover related to re-classification, i.e. number of pixels firstly classified as indeterminate and finally classified as clear (+) /cloudy (-) divided by the total number of pixels |

QCC | Quality index related to cloud detection (the lower the better with a 0 ideal case) |

U_{H2O} | Total column precipitable water vapor of the clear part of the superpixel |

QU_{H2O} | Quality index related to total column precipitable water vapor (the lower the better with a 0 ideal case) |

P_{oxy} | Mean cloud Oxygen pressure. It is expected to be close to the cloud middle pressure |

AD(P_{oxy}) | Angular standard Deviation of the cloud Oxygen pressure derived by direction |

P_{ray} | Mean cloud Rayleigh pressure. It is expected to be close to the cloud top pressure |

AD(P_{ray}) | Angular standard Deviation of the cloud Rayleigh pressure derived by direction |

_{c} | Linear mean cloud optical thickness at 670 nm over land and 865 nm over ocean, result from an averaging over cloudy pixels and a weighting over directions |

RSD(_{c}) | Relative Spatial standard Deviation of the cloud optical thickness at 670/865 nm |

Indicator of the radiative variability of the cloud optical thickness distribution. It is defined by = 1 - _{c}* / (CC x _{c}) where _{c}* and CC x _{c} are respectively the radiative and the linear mean cloud optical thickness of the whole superpixel. It is equal to 0 for a homogeneous distribution and increases towards 1 as the variability increases. | |

S_{c} | Mean cloud spherical albedo (defined over black surface with no atmosphere) at 670/865 nm, result from an averaging over cloudy pixels and a weighting over directions |

Phase | Cloud thermodynamic phase |

Micro-index | Microphysical index calculated only for ice clouds. It is expected to be indicative of the ice crystal type |

_{strato-aer} | Stratospheric aerosol optical thickness (exogeneous data) |

U_{O3} | Total column ozone (exogeneous data) |

V_{wind} | Meteorological surface wind intensity (in m/s) (exogeneous data) |

_{wind} | Meteorological surface wind bearing (in degrees) (exogeneous data) |

P_{surface} | Meteorological surface pressure (exogeneous data) |

T(k), k=1,10 | Meteorological temperature profile (exogeneous data) |

U(k), k=1,10 | Meteorological integrated water vapor profile (exogeneous data) |

**(b) Level 2 directional parameters**

_{v}(i) | Viewing zenith angle (defined for the central elementary pixel) in the given direction (i) |

(i) | Relative azimutal angle (defined for the central elementary pixel) in the given direction (i) |

R_{vis}(i) | Mean of the reflectances corrected from gaseous absorption at 670 nm over land and 865 nm over ocean, result from an averaging over cloudy pixels in the given direction (i) |

A_{vis}(i) | Mean "directional" albedo at 670/865 nm, result from an averaging over cloudy pixels in the given direction (i) |

R_{SW}(i) | Mean shortwave reflectance estimated from narrowband reflectances |

A_{SW}(i) | Mean shortwave "directional" albedo estimated from narrowband "directional" albedos |

LPSMOD_{865}(i) | Modified polarized radiance at 865 nm |

N_{cloud}(i), N(i) | Relative number of cloudy / clear pixels (from 0 to 1 by steps of 1/9), i.e. the number of cloudy /clear pixels divided by the total number of pixels. Their sum is less than unity when some pixels are unclassified in the given direction |

CC(i) | Cloud Cover, defined as the number of cloudy (including "unclassified" relabeled as cloudy) pixels divided by the total number of pixels |

S_{c}(i) | Mean cloud spherical albedo (defined over black surface with no atmosphere) at 670/865 nm, result from an averaging over cloudy pixels in the given direction (i) |

### List of Parameters in POLDER "ERB, WV & CLOUDS" level 3 products

The following geophysical parameters are computed from the level 2 product for each superpixel (3x3 pixels), by orbit segment.

For details about the calculation of these parameters, see POLDER2 advanced algorithms.

Ndays | Number of days for which POLDER data are available |

Norb | Number of orbits for which POLDER data are available |

Norb-snow | Number of orbits with no snow/ice risk |

Norb-clear | Number of orbits without cloud |

Norb-cloudy | Number of orbits with clouds |

Norb-A | Number of orbits for which albedo is calculated |

Norb-Poxy | Number of orbits for which cloud Oxygen pressure is calculated |

Norb-Pray | Number of orbits for which cloud Rayleigh pressure is calculated |

Norb-Phase | Number of orbits for which cloud phase is calculated |

Norb-U_{H2O} | Number of orbits for which total column precipitable water vapor is calculated |

M(µ_{s}) | Monthly mean of the cosine of solar zenith angle |

M(A_{vis}) | Monthly mean of the instantaneous albedo at 670 nm over land and 865 nm over ocean |

TD(A_{vis}) | Temporal standard Deviation of the instantaneous albedo at 670/865 nm |

M(A_{vis})_{clear} | Monthly mean of the instantaneous albedo at 670/865 nm when the superpixel is declared clear |

TD(A_{vis})_{clear} | Temporal standard Deviation of the instantaneous albedo at 670/865 nm when the superpixel is declared clear |

M(A_{model}(_{c}=0)_{vis}) | Monthly mean of the modeled clear-sky albedo at 670/865 nm, that is independent of POLDER measurements and must not be confused with M(A_{vis})_{clear} |

M(A_{SW}) | Monthly mean of the instantaneous shortwave albedos |

TD(A_{SW}) | Temporal standard Deviation of the instantaneous shortwave albedo |

M(A_{SW})_{clear} | Monthly mean of the instantaneous shortwave albedo when the superpixel is declared clear |

TD(A_{SW})_{clear} | Temporal standard Deviation of the instantaneous shortwave albedo when the superpixel is declared clear |

M(A_{model}(_{c}=0)_{SW}) | Monthly mean of the modeled clear-sky shortwave albedo, that is independent of POLDER measurements and must not be confused with M(A_{vis})_{SW} |

M(F_{inc}) | Monthly average shortwave incident flux density (expressed in W/m^{2}) |

M(F_{refl}) | Monthly average shortwave reflected flux density (expressed in W/m^{2}) ; it must not be confused with the mean of the instantaneous fluxes M(F_{inc}) x M(A_{SW}) |

M(F_{refl})_{clear} | Monthly average clear-sky shortwave reflected flux density (expressed in W/m^{2}) ; it must not be confused with the mean of the instantaneous fluxes M(F_{inc}) x (A_{SW})_{clear} nor even less with the mean of the modeled clear-sky flux M(F_{inc}) x M(A_{model}(_{c}=0)_{SW}) |

M(CC) | Monthly mean of the cloud cover |

TD(CC) | Temporal standard Deviation of the cloud cover |

M(CC+/-) | Monthly mean of the uncertainty on cloud cover related to re-classification |

M(U_{H2O}) | Monthly mean of the total column precipitable water vapor |

TD(U_{H2O}) | Temporal standard Deviation of the total column precipitable water vapor |

M(P_{oxy}) | Monthly mean of the cloud Oxygen pressure |

TD(P_{oxy}) | Temporal standard Deviation of the cloud Oxygen pressure |

M(P_{ray}) | Monthly mean of the cloud Rayleigh pressure |

TD(P_{ray}) | Temporal standard Deviation of the cloud Rayleigh pressure |

M(_{c}) | Monthly mean of the cloud optical thickness at 670 nm over land and 865 nm over ocean |

RTD(_{c}) | Relative Temporal standard Deviation of the cloud optical thickness at 670/865 nm |

M(_{c})_{liquid} | Monthly mean of the liquid water cloud optical thickness at 670/865 nm |

M(_{c})_{ice} | Monthly mean of the ice cloud optical thickness at 670/865 nm |

M(_{c})_{mixed} | Monthly mean of the mixed-phase cloud optical thickness at 670/865 nm |

M(S_{c}) | Monthly mean of the cloud spherical albedo at 670/865 nm |

TD(S_{c}) | Temporal standard Deviation of the cloud spherical albedo at 670/865 nm |

FREPHASE | Frequency of occurrence of cloud phase in 4 classes (1: liquid, 2: ice, 3: mixed, 4: undetermined) expressed in percent (%) |

FRECRYSTAL | Frequency of occurrence of ice crystal type in 7 classes (1: undetermined, 2-5: different classes of a priori randomly oriented crystals, 6-7: absolute and relative percentage of horizontally oriented crystals) |

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