This document describes the format of the NewAtmosphere HDF database file format. This describes version 2 of this data model. This file contains the all of the DIRSIG standard metadata as attributes on the document root. In addition to those attributes, the following are also defined on the document root:

Name Data Type Dimensions Description

Wgs84LatLonAltOrigin

NATIVE_FLOAT

3

The WGS84 latitude, longitude and altitude of the origin of this data model.

Custom Data Types

The following custom HDF data types are defined in this data models:

AngleRanges

Type

Compound

This type represents angle ranges for zenith and azimuth angles. Units are in radians. The following fields are defined:

Name Data Type Description

zenithMin

NATIVE_DOUBLE

Minimum zenith angle

zenithMax

NATIVE_DOUBLE

Maximum zenith angle

zenithDelta

NATIVE_DOUBLE

Sampling period for zenith angle

azimuthMin

NATIVE_DOUBLE

Minimum azimuth angle

azimuthMax

NATIVE_DOUBLE

Maximum azimuth angle

azimuthDelta

NATIVE_DOUBLE

Sampling period for azimuth angle

WavelengthInfoRecord

Type

Compound

This type represents a row in the spectral state metadata table. The following fields are defined:

Name Data Type Description

numWavelengths

NATIVE_UINT

The number of wavelengths in the spectral state

referenceIndex

NATIVE_UINT

The index in the wavelength list of the reference wavelength for the state

/Altitudes

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N

Contains a list of the altitudes that are sampled in this data model. Units for the altitudes are in meters. The size of this data set will determine the first dimension of all path tables in this data model. The following attributes are defined on this dataset:

Name Data Type Dimensions Description

AltitudeDelta

NATIVE_FLOAT

1

The sampling period for altitude samples that was used to generate these samples. Units are meters.

/SkyAngleRanges

Type

Dataset

Data Type

AngleRanges

Dataspace Type

Simple

Dimensions

1

Contains the angle ranges that are used when generating sky path tables. This dataset can be used to calculate the size of the angle dimension of those tables. The number of samples in each angle can be calculated via:

floor((max - min) / delta + 1.5)

and the total number of angular samples is the product of the number of samples in each angle.

/SpectralStates

Type

Group

Contains information about the spectral states that are referenced by the combo states in this data model.

WavelengthInfoTable

Type

Dataset

Data Type

WavelengthInfoRecord

Dataspace Type

Simple

Dimensions

N

Contains metadata about each spectral state. Rows in this table correspond to the spectral state index and also the row in WavelengthSamplesTable.

WavelengthSamplesTable

Type

Dataset

Data Type

NATIVE_DOUBLE

Dataspace Type

Simple

Dimensions

N x M

Contains the wavelength samples for each spectral state. Units are in microns. The rows correspond to the spectral state index and have a corresponding row in WavelengthInfoTable. Each row has the same number of columns, however, not all columns are necessarily used. The row in WavelengthInfoTable describes how many columns are valid for each state.

/State:index

Type

Group

Contains the atmospheric data for the combo state with and index of :index. :index is a zero-based integer index with no zero-padding. The following attributes are defined on this group:

Name Data Type Dimensions Description

LunarAzimuth

NATIVE_FLOAT

1

Azimuth of the moon [degrees]

LunarPhaseAngle

NATIVE_FLOAT

1

Phase angle of the moon [degrees]

LunarPhaseFraction

NATIVE_FLOAT

1

Phase fraction of the moon

LunarZenith

NATIVE_FLOAT

1

Zenith of the moon [degrees]

SolarAzimuth

NATIVE_FLOAT

1

Azimuth of the sun [degrees]

SolarZenith

NATIVE_FLOAT

1

Zenith of the sun [degrees]

SpectralStateIndex

NATIVE_UINT

1

Index of the referenced spectral state

TemporallStateIndex

NATIVE_UINT

1

Index of the referenced temporal state

LunarIrradiance

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N

Contains the lunar exoatmospheric irradiance spectrum. Units are W / (cm^2 micron). The size of this dataset is the same as the number of wavelength samples in the spectral state.

LunarTransmission

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N_alt x N_w

Contains the lunar transmission spectrum as a function of altitude. The size of this dataset is N_alt x N_w, where N_alt is the number altitude samples and N_w is the number of wavelength samples in the spectral state.

SensorAngleRanges

Type

Dataset

Data Type

AngleRanges

Dataspace Type

Simple

Dimensions

1

Contains the angle ranges that are used when generating sensor path tables. This dataset can be used to calculate the size of the angle dimension of those tables. The number of samples in each angle can be calculated via:

floor((max - min) / delta + 1.5)

and the total number of angular samples is the product of the number of samples in each angle.

SensorExtinctions

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N_alt x N_ang,sens x N_w

This is the sensor path table for extinction. Units are 1 / m. The size of this dataset is N_alt x N_ang,sens x N_w, where N_alt is the number of altitude samples, N_ang,sens is the number of sensor angular samples, given by SensorAngleRanges, and N_w is the number of wavelength samples in the spectral state.

SensorRadiances

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N_alt x N_ang,sens x N_w

This is the sensor path table for radiance. Units are W / (cm^2 sr micron). The size of this dataset is N_alt x N_ang,sens x N_w, where N_alt is the number of altitude samples, N_ang,sens is the number of sensor angular samples, given by SensorAngleRanges, and N_w is the number of wavelength samples in the spectral state.

SensorRanges

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N_alt x N_ang,sens

This table stores the range at which the sensor path tables were calculated. It can be used to scale path radiances to the actual path length needed in the simulation. The size of this data set is N_alt x N_ang,sens, where N_alt is the number of altitude samples, N_ang,sens is the number of sensor angular samples, given by SensorAngleRanges.

SkyRadiances

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N_alt x N_ang,sky x N_w

This is the sky path table for radiances. Units are W / (cm^2 sr micron). The size of this dataset is N_alt x N_ang,sky x N_w, where N_alt is the number of altitude samples, N_ang,sky is the number of sky angular samples, given by /SkyAngleRanges, and N_w is the number of wavelength samples in the spectral state.

SkyTransmission

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N_alt x N_ang,sky x N_w

This is the sky path table for transmissions. The size of this dataset is N_alt x N_ang,sky x N_w, where N_alt is the number of altitude samples, N_ang,sky is the number of sky angular samples, given by /SkyAngleRanges, and N_w is the number of wavelength samples in the spectral state.

SolarIrradiance

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N

Contains the solar exoatmospheric irradiance spectrum. Units are W / (cm^2 micron). The size of this dataset is the same as the number of wavelength samples in the spectral state.

SolarTransmission

Type

Dataset

Data Type

NATIVE_FLOAT

Dataspace Type

Simple

Dimensions

N_alt x N_w

Contains the solar transmission spectrum as a function of altitude. The size of this dataset is N_alt x N_w, where N_alt is the number altitude samples and N_w is the number of wavelength samples in the spectral state.

/TemporalStates

Type

Dataset

Data Type

NATIVE_UINT

Dataspace Type

Simple

Dimensions

N

Contains information about the temporal states referenced by the combo states in this data model. Each element is the temporal offset from the reference data time, in units of multiples of the time delta. Both of these quantities are given as attributes on this data set:

Name Data Type Dimensions Description

ReferenceDateTime

StrType(C_S1, H5T_VARIABLE)

1

ISO-8601 string encoding the reference date/time of this data model.

TimeDelta

NATIVE_FLOAT

1

The time in seconds used to scale the temporal offsets in this data set.