Basic Weather Station BWS-200
4
about twice the height of the structure. Ideally, therefore, the weather station
should be located outside this zone of influence in order to obtain representative
values for the region (see Figure 1).
Figure 1 Effect of Structure on Air Flow
2.3 Siting on Roofs
Weather stations are commonly located on roof surfaces and interrogated from a
room below. There are several inherent problems with this. The urban environment
can generate its own climate and even smaller scale microclimates are possible,
depending on the building materials and design. High air temperatures caused by
heat convected or conducted from the surface of the building are the most obvious
source of error. Also, the physical and radiative properties of the building fabric
are important, for example, in determining heat loading.
2.4 The Effects of an Urban Environment
The impervious nature of an urban surface compared to surrounding rural areas,
together with the efficient channelling of water as surface run-off, leads to a
generally drier environment. However, the ponding of water that occurs, for
example, on flat roofs, can also lead to local areas of high relative humidity.
Wind speeds are generally lower in urban areas compared to more exposed rural
locations. However, aspects of city design and building geometry can combine to
create areas of high or low wind speeds because of the funnelling of air.
3. What You Get with Your Basic Weather Station
3.1 Standard Equipment
Fibreglass Enclosure with integral, rechargeable, lead-acid battery power
supply unit (to supply power to the datalogger).
SOP5 Solar Panel, mounted on the door of the enclosure, for charging the
battery.
CR200X Series Datalogger.
Wind Speed and Direction Sensors (R M Young’s Wind Sentry
Anemometer and Vane) complete with junction box.
Weather station
Safe location of weather station
Drawing not to scale
