Site Selection
Guidance for choosing a deployment site with representative exposure, safe access, and minimal measurement interference.
Selecting an appropriate location is one of the most important factors in producing reliable weather observations. Even well-calibrated sensors can produce biased or misleading data if they are installed in locations affected by nearby structures, artificial surfaces, or poor exposure.
The goal of site selection is to place the station where measurements best represent the surrounding environment while minimizing local disturbances. Careful siting improves data quality, allows meaningful comparison with nearby stations, and supports long-term environmental monitoring.
Many of the principles used for 3D-PAWS deployments follow international meteorological guidance described in the World Meteorological Organization (WMO) Guide to Instruments and Methods of Observation (WMO-No. 8).
General Siting Principles
In most deployments, the station should be installed in an open, level area that represents the surrounding landscape.
When selecting a site, aim to:
avoid nearby buildings, trees, or large structures
avoid artificial surfaces such as pavement, rooftops, or parking areas
avoid local heat sources such as vents, machinery, or reflective walls
select terrain that is representative of the surrounding environment
maintain open exposure to prevailing winds
ensure rainfall collection is unobstructed
Natural surfaces such as grass or soil generally provide the most representative conditions for temperature and humidity measurements.
Instrument Exposure Considerations
Different sensors respond differently to environmental conditions. When selecting a location, consider how surrounding features may influence each measurement.
Temperature and Humidity
Temperature sensors should be placed above natural ground surfaces and away from artificial heat sources or reflective materials. Nearby obstacles may create shading or altered airflow that can bias measurements.
Wind
Wind measurements are particularly sensitive to nearby obstacles. Buildings, trees, and terrain features can block or redirect airflow, causing wind speeds to appear lower than they actually are. Open exposure to the prevailing wind direction is therefore important.
Precipitation
Rain gauges should be installed in locations free of overhead obstructions. Nearby objects can block precipitation or create turbulence that alters how rainfall enters the gauge.
Because each instrument has slightly different siting requirements, perfect conditions for every measurement are rarely possible. The goal is to minimize the most significant sources of interference.
Accessibility and Security
Stations should be located where they can be safely accessed for installation, inspection, and maintenance.
Consider the following practical factors:
safe access for technicians and equipment
visibility and security to reduce vandalism risk
permission from landowners or site managers
protection from vehicles, animals, or public disturbance
In many cases, installations within fenced facilities, research sites, or monitored areas provide a good balance between access and protection.
Mounting and Physical Stability
The station should be mounted on a stable structure capable of supporting the sensors and resisting environmental forces such as wind, rain, and snow.
Typical installations include:
steel or aluminum masts
PVC or modular station frames
poles set securely in concrete foundations
A stable mount helps maintain proper sensor alignment and reduces movement that could affect measurements.
Documenting the Site
Even when the ideal site cannot be achieved, careful documentation allows data users to understand potential influences on the observations.
Important information to record includes:
nearby obstacles and their distance from the station
ground surface type and vegetation
terrain slope and surrounding topography
horizon obstructions or shading
changes to the environment over time
These details should be recorded during installation and stored as part of the station's site metadata.
Instruction Slides for Site Selection
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