# Presentation: 941742

## Short Course on the Fundamentals of Boundary Layer Wind and Temperature Profiling using Radar and Acoustic TechniquesFebruary 8-9, 2003

-          Profiler Siting Considerations, Interference Sources,                                                             		Installation and Maintenance – Radar
- 				      Clark W. King
- 				        NOAA/ETL
- 				       Boulder, CO

## Overview

- Siting considerations for wind profilers and RASS
- Clutter/RFI
- Electrical power
- Communications
- Equipment shelters
- Site monitoring and maintenance

## Profiler Siting Considerations

- Questions to answer prior to choosing a site:
- Are there minimal clutter sources?
- Is reliable power and phone service available?
- Does the location meet the project goals?
- Is the landowner amenable to a long-term lease?
- Is there sufficient security?
- Will the operation of RASS disturb anyone?

## Best Locations for a Profiler Site

- Small to medium sized airports
- Minimal clutter
- Good security
- Availability of power and phone
- Low leasing costs
- RASS is not a problem
- FAA clearance is usually not a problem (FAA Form 7460-Notice of proposed construction or alteration)
- Other good sites:
-      Wastewater treatment plants
-      Government or university research labs

## Difficult locations for a profiler site

- Urban Areas
- Clutter
- RFI
- Security issues
- RASS noise
- Environmentally sensitive areas (National Parks, wildlife refuges, open space)
- Visual impact
- RASS noise
- Permitting
- Power Plants
- Clutter
- Access
- Space availability

## Clutter Targets

- As a general guideline use the 5 degree rule:  Clutter targets should not extend more than 5 degrees above the horizon.

## Examples of Clutter Sources

- Roads that are heavily traveled or elevated highways and overpasses
- Trees either close in or on hillsides
- Constant air traffic
- Birds
- Ocean waves
- Power lines
- Transmission towers
-      When clutter cannot be avoided:
-      Orient the clutter sources off the corners of the radar antenna.
-      Switch operation from 5-beam to 3-beam.

## Interference Sources

- RFI
- Cell phone towers
- Cell phones
-    Once a potential site has been selected it is always a good idea to use a radio frequency scanner to identify sources near the profiler frequency.  Scan the 902-928 MHz range.  Although the scanner is not as sensitive as the radar, it may help to identify potential interference sources within the profiler’s bandwidth.

## Radio Acoustic Sounding System(RASS)

-         RASS greatly complicates profiler siting!

## RASS Siting

- Atmospheric conditions determine the distance the sound can be heard
- In flat terrain try to allow at least 1 km distance between the RASS source and any business or residence
- In hilly or mountainous terrain sound can travel a long distance because of reflections and sound ducting – if houses are within 2 km and located at an elevation greater than the RASS sources, the sound will be a problem, at least during the nighttime hours.
-     Solution - Consequence:
- Turn down the amplifier volume – lose height coverage
- Set the timer so RASS operates during selected hours – lose RASS information at times when it may be most valuable.

## Electrical Power

-     Type of installation depends on whether the profiler site is temporary or semi-permanent

- Semi permanent site:
- Permits (County, City)
- Request for service from power provider
- Establish account
- Installation of transformer, poles, wire, and meter
- Private contractor to install meter socket and  disconnect, and to connect electrical to equipment shelter.
- Final inspections
-     Total costs will depend on distance to power source but can run from $7.5 K to $20 K plus monthly electrical usage charges
- Temporary site:
- Connect to existing source and compensate owner for usage
-      Cost for electrician to connect from existing source to equipment shelter usually $1 K to $2.5 K.  Compensate at ~ $0.1 K per month for      usage.
-      Typical power requirement is 120/240 V 40 amp service

## Communications

- Phone (land line)
-      Usually available
-      Low cost (installation ~$200 + $50 per month usage)
- Cell phone
-      Alternative if a land line is unavailable, can be expensive if used frequently
- Satellite phone
-      Expensive ( $3 K for hardware + $1 - $1.50 per minute airtime)
- GOES
-      Initial cost is $3 K for hardware but airtime is free.  You must demonstrate a need and a transmit window needs to be available.  The new system will transmit at 9600 baud (currently 100 – 300 baud)

## Equipment Shelters

- Semi-permanent sites:
- Use Vaisala guidelines
- Temporary sites:
- Mobile office trailers (8’ x 20’), cost is ~ $200 per month plus ~ $1000 for delivery, setup, and tie downs.
- Equipment trailers (6’ x 10’) with AC, heat, lights, receptacles, and insulation costs ~ $5 K.

## NOAA/ETL Installation at San Nicolas Island, California

## Winter Profiler/RASS Operations

- Placing canvas covers, supported by 2 X4’s, over antennas prevents most snow from collecting on the antennas.
- The only solution for RASS is to either cover the antennas during snowstorms or dig the snow out of the antennas

- Concord, New Hampshire

## Site Maintenance

- Monitor data daily using NOAA/ETL Web display
- Site visits at 4 – 6 week intervals
- Site checklist

## Keep an eye on your data!

- Observing the data daily allows you to identify a problem as simple as a blown fuse in the radar electronics.  This allows you to repair the problem quickly with a minimal loss of data.

## Accounting for  changes in the meteorological

- conditions, a sudden
- change in the height
- of RASS coverage may
- indicate either a blown
- voice coil or water, snow, or debris collecting in the
- RASS dishes

- In this case the relative humidity sensor goes bad at 2100 UTC.  Again, by keeping an eye on the data, repairs can be made quickly.

-     When the winds gust over 30 m/s and the data stops coming in, you know you have big problems

## A site checklist provides

- documentation of your
- site visit.  It is always
- important to follow a
- regular procedure on
- each visit to document
- any problems or changes.

## NOAA/ETL uses calibrated

- standards for comparison
- with their meteorological
- instrumentation.

## Always add comments to the 

- Always add comments to the
- checklist.  They may seem
- unimportant at the time but often
- come in handy when post-
- processing the data or answering
- an auditors inquiries.

## Summary

-     Usually, no site is perfect, but for successful measurements you will need to have answered “yes” to   most of the following questions:
- Are there minimal clutter sources?
- Is reliable power and phone service available?
- Does the location meet the project goals?
- Is the landowner amenable to a long-term lease?
- Is there sufficient security?
- Will the operation of RASS disturb anyone?