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 |
|---|---|---|---|
|
|
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 |
|---|---|---|
|
|
Minimum zenith angle |
|
|
Maximum zenith angle |
|
|
Sampling period for zenith angle |
|
|
Minimum azimuth angle |
|
|
Maximum azimuth angle |
|
|
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 |
|---|---|---|
|
|
The number of wavelengths in the spectral state |
|
|
The index in the wavelength list of the reference wavelength for the state |
/Altitudes
Type |
Dataset |
Data Type |
|
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 |
|---|---|---|---|
|
|
1 |
The sampling period for altitude samples that was used to generate these samples. Units are meters. |
/SkyAngleRanges
Type |
Dataset |
Data Type |
|
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 |
|
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 |
|
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 |
|---|---|---|---|
|
|
1 |
Azimuth of the moon [degrees] |
|
|
1 |
Phase angle of the moon [degrees] |
|
|
1 |
Phase fraction of the moon |
|
|
1 |
Zenith of the moon [degrees] |
|
|
1 |
Azimuth of the sun [degrees] |
|
|
1 |
Zenith of the sun [degrees] |
|
|
1 |
Index of the referenced spectral state |
|
|
1 |
Index of the referenced temporal state |
LunarIrradiance
Type |
Dataset |
Data Type |
|
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 |
|
Dataspace Type |
Simple |
Dimensions |
|
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 |
|
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 |
|
Dataspace Type |
Simple |
Dimensions |
|
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 |
|
Dataspace Type |
Simple |
Dimensions |
|
This is the sensor path table for radiance.
Units are W / (cm^2 sr micron) / 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.
SensorRanges
Type |
Dataset |
Data Type |
|
Dataspace Type |
Simple |
Dimensions |
|
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 |
|
Dataspace Type |
Simple |
Dimensions |
|
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 |
|
Dataspace Type |
Simple |
Dimensions |
|
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 |
|
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 |
|
Dataspace Type |
Simple |
Dimensions |
|
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 |
|
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 |
|---|---|---|---|
|
|
1 |
ISO-8601 string encoding the reference date/time of this data model. |
|
|
1 |
The time in seconds used to scale the temporal offsets in this data set. |