Microclimate

Microclimate data can be collected in any location, including the school grounds. This makes it a simple fieldwork investigation to carry out.

The lists below give you an idea of some of the ways that data collected within a microclimate investigation can be used.

To investigate microclimatic data at a small scale, within a school grounds, or large scale, for example an urban transect passing from green-belt through a variety of city environments
To investigate the abiotic conditions of different parts of a particular ecosystem
To investigate diurnal or seasonal changes in the microclimate
To investigate the influence of microclimate on something, for example the distribution of a particular species of plant or vegetation cover
To compare different locations
To investigate the affect of topography on microclimates
To investigate the impact of human interference, or features of the built environment on the microclimates of different locations
To investigate the most suitable location for something
To link with and incorporate into ecosystem investigations
To link with other data, for example soil analysis, invertebrate data

The old classic - the most suitable site for...
Assessing the possible impacts of a new building on microclimates, for example the building of a new science block
Asking a question, for example why is site x so popular with sunbathers? Do the buildings at site y create wind tunnels (known as the venturi effect)?
How much does vegetation cover affect microclimatic conditions? Different types, densities or ages of vegetation communities could be investigated
How do microclimates affect people's activities or their perceptions of place? For example questionnaires to investigate how pupils view and use different areas in the school grounds
How does proximity to water affect microclimates
How large or wide an area of microclimate is affected by buildings
During a heat wave - how much more extreme are the microclimates of urban areas
Considering hedgerows as microclimates - how do they affect local conditions and what might be the ecological impact of their removal? You could link this with ecosystem data

Equipment

Methodology

A compass should be used to determine North
Wind direction ‘apparatus' can be improvised using a home made wind sock or weather vane. The weather vane should be placed in the exact location to be investigated, and the variable, for example height above ground kept constant at each site
The Beaufort scale can be used to give a crude, qualitative judgement of wind speed by observing evidence around the site. Further information about the Beaufort Scale can be found on the Met Office website and a pictorial guide on the Howtoons website
An anemometer can give a more accurate reading, and will work in very low wind conditions, but is expensive. A ventimeter is cheaper but is not as reliable or as accurate in low wind conditions
Readings should be recorded at each location

Considerations: Limitations and validity

Very high or low wind speeds can be difficult to measure
Wind strength is hard to measure at ground level
The Beaufort scale is subjective. You need to consider that the observations are likely to come from around the site, rather than at the exact location. Is it therefore an accurate method for a micro-climate assessment?
Taking several readings and finding the average can increase validity of results

Equipment

Methodology

Different instruments operate differently and the instructions should be referred to for each
The whirling hygrometer or psychrometer should be held above the head for a set period of time, for example one minute and readings are then taken from the wet and dry bulbs. It is the difference between these two readings which informs relative humidity
Digital thermometers are reliable and precise but may not be if poorly calibrated or the batteries run low (always check the batteries)
Whether using a digital or analogue thermometer, recordings should be taken at the same height above ground at each site, for example one metre
Digital light meters are again more accurate, but the same applies as for all digital equipment in terms of calibration and battery life

Considerations: Limitations and validity

A sampling method should be decided upon to ascertain the method for data collection, for example the locations to sample, the timings and frequency of recordings
Some account should be taken of the fact that recordings will inevitably be taken at different times in different locations - while cloud cover can change from one moment to the next, affecting temperature and light readings
Allow for some margin of error in using the instruments - different products vary in accuracy and performance
If using an analogue thermometer breakage is a health and safety consideration. Also, readings may be affected by direct sunlight, or hand-heat. Ground temperatures are more extreme, so readings should not be taken directly on the ground
Cloud cover at the time of taking measurements could be recorded to help explain anomalies in data. Cloud cover is estimated in Oktas which refers to how many eighths of the sky are covered by cloud, using the following scale:
- Clear sky
- 1 okta
- 2 oktas
- 3 oktas
- 4 oktas
- 5 oktas
- 6 oktas
- 7 oktas
- Overcast

Cloud type could also be recorded, as this affects light intensity.

Equipment

Methodology

Home made gauges can be used - Ensure the same ones are used to ensure a fair test
Gauges should be set up in the desired locations
Records should be kept of anything at each site which may affect readings, for example shelter from buildings or vegetation cover
Leave gauges for a predetermined period of time at each location
For remote locations, bucket-siphon rain gauges can be used to take measurements which empty themselves daily

Considerations: Limitations and validity

Consider the accessibility of the site, is it local or remote. Which is better
Time factor, checking every day
Practicality of checking all gauges at the same time
Affect of vegetation, interception of rain or buildings providing shelter, these should be noted, but may be interesting variables to investigate in their own right
Evaporation, some open gauges allow evaporation which will affect readings
Rain splash, gauges flush with the ground level may be affected by rain splash, therefore over estimating precipitation
Also, extremely heavy rain may cause excess runoff (especially from some surfaces) which may run into flush rain gauges
Rain gauges raised above ground level may underestimate precipitation as rain may be funnelled around the gauge