Vaisala IRIS, User Manual

Page: 67 / 394

1. Select Type > RHI .
2. In Data : Display , select any data type defined in your RHI task.
Also, if you measure V you can select SHEAR or output data type for radial shear. Radial
shear is the difference between the velocity of successive bins in range.
SHEAR is allowed as an output data type to the RHI , but not to other similar
products like PPI .
3. In Max Range , enter up to 2 values in format of xx.x kilometers.
If you enter only one value, the first one is assumed to be 0.
The first limit is the beginning of your display.
Zero means the image starts from the radar site.
If you enter negative values, data is picked from another azimuth on the other side of
the radar site in the same task, or if your task is scanning over-the-top.
You can also enter positive values, especially if you do not use high elevations and you
want to avoid the flat corner of a triangular-shaped image.
4. In Azimuth Angle , specify an azimuth angle:
If you do not know this value in advance, IRIS selects the closest angle at run time, so
you are always assured of getting a display.
If the associated task has only one azimuth angle sweep, that angle is used for the
RHI
product.
If you enter * to the field, the product is made for every azimuth in the associated task.
5. In Max Height , XZ Smoother , and Range filter , specify the Max Height field in
XX.X km.
Because you specify both the maximum range and height, you can make an RHI at any
horizontal-to-vertical aspect ratio.
Note that the final display is from 0 to the
Max Height above the reference height.
The radar is located on the left edge, above the corner if the radar is above the
reference. Negative elevation angles are included in that case. Rays are inserted
straight, and the grid of constant height lines is curved to show earth curvature.
You can type the
X-Z (height) Smoother values in km.
If you have SHEAR as an output data type, it is somewhat noisy, and must be smoothed
with a range filter. This number is unused for data types other than SHEAR .
6. In Resolution , select Low (288 × 136), Medium (600 × 290), High (840 × 530), or
XHigh (1060 × 750) resolution or type a resolution in the field.
RHI products look best with a rectangular resolution.
More information
‣
Display Parameters (page 27)
‣
Product Parameters (page 23)
‣
Associating Products with Tasks (page 17)
‣ XSECT: Cross Section (page 110)
‣
SHEAR: Wind Shear (page 176)
‣
Should I Use RHI or XSECT? (page 67)
Chapter 3 – Configuring IRIS Products
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