Vaisala IRIS - NDOP: Multiple Doppler; Figure 57 Raingage Datagram

2. Place the cursor in the display window and right-click the mouse.
IRIS checks for the nearest rain gage location, and shows a rain gage datagram with 12
hours of history.
The following example shows the hourly rainfall accumulation for the last 12 hours.
Figure 57 Raingage Datagram
You can configure the graph show just the rain accumulations from the rain gage, or
radar rain accumulations from RAIN1 products, or both.
3. If you are displaying radar rain accumulations, select which named RAIN1 product to
display from.
The selected RAIN1 product becomes the default RAIN1 used as the topmost overlaid
product. If there is no overlaid RAIN1, then its default is o.
If you change the default RAIN1, future datagrams use the new product, until all
datagrams are dismissed.
You can show up to 10 rain gage datagrams simultaneously. This allows you to compare
dierent gages, or RAIN1 products.
5.5
NDOP : Multiple Doppler
NDOP provides a mechanism for including velocity (Doppler) data from another radar site
now enabling the measurement of horizontal wind in addition to vertical wind.
A single Doppler radar measures one component of a 3D wind vector, that is, the
component of wind towards or away from the radar: the radial wind. We can think of the 3D
wind vector as being made up of the 2D horizontal wind and the vertical wind. Typically the
horizontal wind is much stronger than the vertical wind, except in local areas of strong
convection.
With a second Doppler radar, we can measure 2 components of the wind, provided that the
radar beams are crossing at some angle (not parallel). If the vertical component of the wind
is assumed to be small, then with 2 radars we can measure the horizontal wind.
Chapter 5 – Configuring and Scheduling Optional IRIS Products
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