IHAZE

Aerosol model

Attributes

integer | discrete | dynamic | unit-less | basic

Description

The variable IHAZE selects one of the predefined aerosol model or coupled with OPAC aerosol database, thus defining the aerosol optical properties (i.e., extinction, absorption and scattering) used for the boundary-layer (0-2 km). The available options are shown in the Table below:

Value(s)Description

0

No aerosols/clouds

1

Rural * Default value

4

Maritime *

5

Urban *

6

Tropospheric *

10

Desert

31-39

Navy maritime
This option allows users to input the Navy Aerosol Maritime (NAM) model with different Air Mass values for different proportions of its intrinsic components that model from Open Ocean (31) to Strong Land Influence (39). The NAM model also depends on the current and 24 hours average wind conditions, which in ALG are set to their default values for each atmospheric MODEL type. Read (Gathman, 1983) for further information.

≥ 11

User-defined
This option allows users to input stored aerosol optical properties from an user-defined model created using the Aerosol Toolkit.

≤ -1

Opac
This option allows users to input OPAC aerosol optical properties from default (between -1 and -10) or user-input (≤ -11) aerosol types. Read AERTYPE for further information.

* Parameters and refractive indices based on (Shettle et al., 1979).

The relative humidity dependence of the boundary-layer aerosol extinction coefficients is based on the water vapor content of the model atmosphere selected by MODEL and its only applied for Rural, Maritime, Urban, Tropospheric and OPAC aerosol models. The seasonal dependence of their vertical profiles for both the tropospheric (2-10 km) and stratospheric (10-30 km) aerosols is automatically selected through the model atmosphere selected by MODEL.

This variable, therefore, has an impact on the simulation of the absorption-scattering processes caused by suspended particles in the sun-target-sensor optical path.

The amount of suspended particles is specified separately from the Aerosol Optical Thickness (VIS) key input variable.

References