Load melting layer specification (MLSPEC)

RVP10 allows you to get melting layer-specific information, including the melting layer height and the uncertainties, from the latest melting layer product created in IRIS.

The melting layer specifications are set as a function of range, azimuth, and elevation based on the information coming from the configuration of the task and either the melting layer product parameters used in the latest melting product created or the melting layer product default parameters.

RVP10 can use spatially variable melting layer (ML) altitudes, which may be preloaded for each interval of data processing (PROC). The ML altitudes are referenced to the Mean Sea Level (MSL), and estimate the top of ML.

The input data are the maps of melting layer altitudes projected into sweep cones of the data sweeps, to be carried out by the PROC command.

The command is an extended OpCommand and is defined as follows:

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|               | 0   0   0   1    0   0   0   1   1   1   1   1 |  Command 
|---------------|------------------------|---|-------------------|

The lowest 5 bits correspond to the default 0X1F for extended opcode commands and the 7 middle bits are the value for the XOP_MLSPEC command (0X10).

The application software provides input data by, for example, converting the IRIS standard cartesian MLHGT products to the curved Earth coordinates of the sweeps configured for the radar task. Typically, a map for a collection of sweeps (a volume) is uploaded.

The application software adjusts the spatial resolution of the map by down scaling of gates so that it fits in the buffer managed in RDA:

DPOLAPP_MAX_ML_SWEEPS*DPOLAPP_MAX_ML_RAYS*DPO LAPP_MAX_ML_BINS

The command also checks the maximum number of sweeps and rays (DPOLAPP_MAX_ML_SWEEPS = 30 and DPOLAPP_MAX_ML_RAYS=90). If the buffer does not exist or exceeds its limits, it is flushed.

RVP10 supports a command that provides a way to feedback the melting layer information from IRIS to the RDA. The melting layer altitude information is specified for each antenna angle and range. This way, the melting layer height can be used in different live data processing applications such as HydroClass.

RVP10 maintains an internal array of up to 1024 different filter versus- range tables, each of which is keyed to a particular angle (EL, for PPIs and AZ for RHIs). Each XOP_MLSPEC command uploads the complete sweep. Then, for each live bin in every processed ray processed, RVP10 obtains the melting layer at the midpoint AZ/EL of the ray.

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|            Scan Type (Unsigned 16-bit integer)                 |  XARG 1 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|         Number of sweeps (Unsigned 16-bit integer)             |  XARG 2 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|            Number of rays (Unsigned 16-bit integer)            |  XARG 3 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|          Number of bins (Unsigned 16-bit integer)              |  XARG 4 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|         Angular resolution  (Unsigned 16-bit integer)          |  XARG 5 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|        Bin staring in m  (Unsigned 16-bit integer)             |  XARG 6 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|        Bin spacing in cm  (Unsigned 16-bit integer)            |  XARG 7 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|    Melting layer thickness (Unsigned 16-bit integer)           |  XARG 8 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|               Status (Unsigned 16-bit integer)                 |  XARG 9 
|----------------------------------------------------------------|

The XARGS statements allow flexibility for backward compatibility. They include the current task and the product configuration settings. The command uploads the melting layer height and thickness for every volume.

Scan type: The melting layer information can be uploaded to the RDA for both RHI and PPI scans.
Number of sweeps: The minimum between the number of sweep of the running task and the DPOLAPP_MAX_ML_SWEEPS.
Number of rays: The number of rays is calculated as $# r a y s = \frac{360000}{i r e s}$
where iRES is the desired angular resolution expressed as an integer number of thousands of degrees.
Number of bins: The number of output bins.
Angular resolution: The binary angle of the corresponding angle in degrees, $θ = \frac{360}{n M L r a y s}$
Bin starting: Range of the first bin in centimeters.
Bin Spacing: The product of the number of output bins by the step divided by the number of bins.
Melting layer thickness: The user setting of the melting layer thickness in the product configuration.
Status: Indicates the status of the DSP features.

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|        Static elevation angle (16-bit binary angle)            |  Input 1 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|                 Ray angle (16-bit binary angle)                |  Input 2 
|----------------------------------------------------------------|

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|   |   |   |   |   |   |   |   |    |   |   |   |   |   |   |   |
|    Melting layer altitude #1  |    Melting layer altitude #2   |  Input 3 
|-------------------------------|--------------------------------| 

                                :
                                :
                                :
                        Number of Mlbins/2