Naked Science Forum
Life Sciences => The Environment => Topic started by: Ray Harp on 15/05/2008 09:21:53
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Ray Harp asked the Naked Scientists:
I was wondering if anyone out there has considered the increase in air temperatures in a local area in relation to the increase in impervious surfaces, e.g. roadways, parking lots, etc.?
What do you think?
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Hi Ray,
I guess that a large area of tarmac could lead to an increase in local temperature, but i would doubt that it would be a huge difference, just one of many factors in the urban heat island effect.
One area where you may see this playing a positive role would be if a remote weather monitoring station was located on one of your roadways or parking lots, although i am sure that this would be picked up in the raw data. If such a station was positioned in such an area it would (could/should) produce results where the temperature was higher than expected or normal for such a location, this would then be adjusted or sited elsewhere. But what do i know?
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Glider pilots enjoy the thermals from these areas but I don't know the answer. I think in big cities the temperature is always slightly higher especially on hot days but just one carpark in the middle of the countryside wouldn't do much.
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The answer is yes - as noted above, while small, these do increase the local temp slightly. Put a lot of small things like this in one area and there is an heat island formed. The difference is only a matter of degree - no pun intended.
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With the sun on a black tarmac road the thermal energy from the sun will easily outstrip all of the heat generated by heavy traffic. More to the point car finishes are more reflective than the tarmac But vehicles also release water into the atmosphere and water is a great coolant so the airborne moisture together with the particulate emissions would help to block out the energy from the sun.
So the answer may not be as strait forward as one would initially think it is.
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Temperature data has to be adjusted all the time because of the heat island effect. www.surfacestations.org keeps track of U.S. temp stations through volunteers for this exact reason. The effect is larger than you might think and is the subject of quite a bit of debate, especially considering that many of our current stations are in urban areas.
This is a well kept station
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.surfacestations.org%2Fimages%2FOrlandCA_USHCN_Site_small.jpg&hash=501a84fc33263a236fc8ac9354084a5d)
This is a not so well kept station
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.surfacestations.org%2Fimages%2FMarysvilleCA_USHCN_Site_small.jpg&hash=956b991fe99f9844582af9e7713769e3)
These two stations are less than sixty miles apart, (the first outside of Chico, CA, and the second outside of Yuba City, CA) but you can definitely see the difference in temp reading. This has presented a lot of problems.
frethack
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If you live in London you would have probably noticed that heathrow is quite often the place with the highest day time temperature. The reason is because their is a rather large airport coverered in tarmac sitting their storing and releasing heat.
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Micky. As Frethack and I have said, these figures will have been adjusted to accommodate the higher temperature caused by the tarmac. So you can bet that the temperature you are seeing on your forecast is not because there is lots of tarmac.
Seeing as the OP has not joined the forum, we will not know what he means by local. In Meteorology "weather is the state of the atmosphere as experienced at a given time in a single location..." The key there (relating to this question) is the single location, you can have more that one weather location in your back yard!
The only way to get a temperature reading in your garden (that gives a reading equivalent to met.office readings) is to have your thermometer in a stephenson screen, sited at the regulation 1.2m above the ground. Failing that, you will get a fairly good reading if your thermometer is in the shade and is not blocked from having a gentle breeze present.
Back to different readings in your garden...Site 3 thermometers in your garden. One in the shaded area at 1.2m above the ground, One above your patio and the other outside a back, upstairs, window.
You are going to get 3 different temperatures from each thermometer, the difference between them will differ depending on the time of day, the season and the actual weather.
Should you have a nice posh automatic weather station in your back yard
(http://cgi.ebay.co.uk/WIRELESS-FORECAST-WEATHER-STATION-BAROMETER-BNIB_W0QQitemZ360072079857QQcmdZViewItem?hash=item360072079857&_trksid=p3913.c0.m22) you may want to check it for ground frost, you may need to deice your car in a morning, well if you have not sited your wireless detector at the right height then you will not be recording a ground frost reading. With a thermometer you would site it horizontally at the height of the tips of closely cut grass to get your ground reading, or at 1.2m to get an air temp reading. So you can see, the siting of any meteorological instruments is well regulated and factoring is taken in to account. If you read this and make sense of it ....well done!
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Heya Paul
Any chance you can point me in the right direction for meteorological supplies and standards?
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Casella are (probibly) the leading names in met. instruments, but obviously they are quite pricey. You can quite often find good bargains on Ebay.
Is that the kind of info you are after?
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An observation over 21 years living in Paignton.
Holiday main seasons down comes the rain. It can be dry for weeks on end and as soon as the motorists arrive in their drives the rain arrives. Now it could be a coincidence but it happens too often IMO.
So what changes have occurred that might be responsible for causing it to rain?
1. Sometimes along our particular part of the coast we are privileged to be visited by some unusual clouds rolling along the coastline. They do not cross over the hot dry coastline beyond the black tarmac road. So one side is shrouded in mist, the other side is a bright sunshine day with clear air. This can last for many hours as the mist rolls around like washing in a tumble dryer and is channelled along the coast.
2. Where the trees meet the sea mist rolls inland and hugs the wooded areas but goes no further than the tree line does. Walking in the trees on these particular days the temperature is several degrees below that outside of the trees and the air is saturated with water, the trees are dripping and the ground is moistened.
3. When the mist finally vanishes it remains shrouding the trees and the trees milk the remaining water from the air over several hours more
4. Thermals rising from the hot tarmac road can be seen as you drive along it. You can see the wavy thermal pattern as the heat rises. These thermals rise high into the atmosphere and form an invisible barrier against ocean born humidity. These same thermals cause the same barrier along desert coastlines and are undoubtedly responsible for the inherent lack of rainfall in these areas.
5. Trees transpire vast amounts of water into the atmosphere and in doing so remove the thermal barrier that prevents cloud and mist from crossing onto the land. They lower the temperature and as warm moist air rises it is cooled causing a downdraught which causes warm air to rise in a density flow and indeed this can be seen happening at times when dew point has been reached.
6. The holiday traffic involves a massive increase in vehicles cruising along the hot roads. These obviously provide some shadow and while they are moving along they remain cooled by the moistened air flowing over them from the exhaust emissions of other vehicles so an overall reduction in temperatures due to traffic is offset against the heat generated by the engine and the friction from the transmission, brakes and tyres.
7. The exhaust emissions contain collectively a vast amount of warm water released into the atmosphere along with particles which rise due to the heat from combustion. These gasses quickly cool transferring the heat into the atmosphere and fall back towards the ground while the dry hot air rises again generating the same flow and return system that the trees perform.
8. This additional water from exhausts also blocks out some of the suns energy and like the trees removes the thermal barrier so moisture from the ocean can again cross onto the land and fall as rain, and rain it does with incredible regularity.
So the old adage said to holiday makers with regularity “you have brought the bad weather with you may have a lot of truth in it after all.
Andrew K Fletcher
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Casella are (probibly) the leading names in met. instruments, but obviously they are quite pricey. You can quite often find good bargains on Ebay.
Is that the kind of info you are after?
Its a good start. Thanks very much [:)] Didnt really think of ebay for met instruments.
Im working on my B.S. in Geology at UT, and paleoclimatology is my main area of interest. I would like to have a rudimentary weather station to experiment with (my interest is growing in meteorology), and a friend has offered to let me put it on his land in the outskirts of Austin. The present is the key to the past, and the past is the key to the future, right? [;D]
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Andrew,
In those 21 years did you manage to take a photograp of those "unusual clouds that vist" you?
Just back off holliday, will get round to the rest later.
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Went one better and videod them for posterity. Will find a way to digitise the tape.
Andrew,
In those 21 years did you manage to take a photograp of those "unusual clouds that vist" you?
Just back off holliday, will get round to the rest later.
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Glider pilots enjoy the thermals from these areas but I don't know the answer. I think in big cities the temperature is always slightly higher especially on hot days but just one carpark in the middle of the countryside wouldn't do much.
I'm a glider pilot. I was going to note this.
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Glider pilots enjoy the thermals from these areas but I don't know the answer. I think in big cities the temperature is always slightly higher especially on hot days but just one carpark in the middle of the countryside wouldn't do much.
I'm a glider pilot. I was going to note this.
But surely you are not out looking for carparks, airports or large area's of tarmac. Aren't you actually looking out for cumulus cloud?
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Went one better and videod them for posterity. Will find a way to digitise the tape.
Andrew,
In those 21 years did you manage to take a photograp of those "unusual clouds that vist" you?
Just back off holliday, will get round to the rest later.
Can you not just upload a few stills?
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Casella are (probibly) the leading names in met. instruments, but obviously they are quite pricey. You can quite often find good bargains on Ebay.
Is that the kind of info you are after?
Its a good start. Thanks very much [:)] Didnt really think of ebay for met instruments.
I have seen some nice barograph's, thermographs, and hygrometers on recently. Prices ranging from £50 to £350. Anyway If this is going to be educational, should we start with measuring humidity?
Humidity to most people is relative humidity, but there is so much more and you may want to record more than just rh.
Absolute Humidity
This is the maximum amount of water vapour, in grams, that can be contained in a cubic meter of the air and water vapour mixture.
Specific Humidity
The mass of water vapour ,in grams, in a kilogram of air and water vapour mixture.
The Mixing Ratio
The mass of water vapour,in grams, present in a kilogram of dry air.
Relative Humidity
The ratio, as a percentage, of the actual amount of water vapour contained in a sample of air to the amount it could contain if saturated at the dry bulb temperature.
Calculations
Absolute measures:
The wet bulb temperature forms the basis of both rh and ah, the specific humidity of air that is saturated with water vapour increases with temperature. Saturated air with a temperature of o deg. C contains 3.0 g/kg; at 10 deg.C this rises to roughly 7.0 g/kg....
Other, and more accurate formula can be found here:
http://www.gorhamschaffler.com/humidity_formulas.htm
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Heya Paul
Any chance you can point me in the right direction for meteorological supplies and standards?
Sorry for the delay:
quote:
The notes below have been written using replies to a survey in the newsgroup and using information extracted from the UK Met.Office handbooks dealing with instruments, and their siting, which in turn are based on internationally agreed standards published by the World Meteorological Organisation (WMO). The notes are only concerned with siting & exposure, not the instruments themselves, or the construction of the screen or a shield in the case of temperature measurements. For advice on these, contact a reputable supplier, or refer to the Observer's Handbook.The BBC Weather Centre web site also has some basic information regarding weather observations etc., and a visit to them would be useful.
Standards are set for a reason: data from many different sites around the world need to be compared one with another, in the knowledge that, as far as possible, the instruments used are exposed in the same way and subject to the same errors. This requirement is particularly important when trying to determine long-term trends in meteorological parameters, both using mean values, and with regard to extremes.
However, even when the WMO recommended standards cannot be met, it is natural that people will want to install weather monitoring kit to enhance their interest in the subject. This note therefore attempts to advise on what is, and what is not possible. At the end of the day it is for the individual user to determine whether the expense involved is worth the outcome. One thing must be made clear though: throwing money into expensive equipment will not improve the exposure!
Temperature
Basic requirement: For synoptic and climatological meteorology, the temperature required is a representative one of the 'free air' conditions over as wide an area surrounding the observing point as possible, with an internationally agreed height (for the thermometer bulbs, sensors etc.) of 1.25 m above local ground level. A fixed height must be specified, because vertical temperature gradients can be intense: for example on a clear, calm night or around the middle of the day with strong solar heating.
The best site for a screen, or thermometer shield for a land station is therefore over level ground, freely exposed to the sun and wind, but not sheltered by buildings, trees, bushes etc. The temperature sensor must be shielded from direct sunshine (hence a screen or shield) and precipitation (or a dry bulb becomes a wet bulb), and there must be a good circulation of air around the bulb/sensor head. If you have a garden, then the 1.25m above ground level can usually be met with ease. What it usually problematic is gaining sufficient clearance from adjacent buildings, trees etc.
The screen/shield should be positioned over grass (or less preferably, but still acceptable, loose soil), but not compacted soil, tarmac or concrete, as these media absorb and radiate solar energy strongly, and affect the readings quite significantly.
If the garden is not suitable, or you have no garden, then consideration may be given to mounting a screen on a north facing wall. There is a problem in this case with possible contamination from heat energy emitted by the building itself. A practical compromise would be to use such a wall, but carry the screen/shield away from the wall on a bracket - this would allow a free airflow around the equipment. A distance of 20-25 cm for an unshielded sensor has been suggested, and this would certainly minimise any contamination from the walls. For a shielded (or screened) sensor, then 10 cm or so has been suggested as a useful distance. Even a north wall mounting needs watching around the summer solstice, particularly at more northern latitudes, as care needs to be taken to shield the thermometers/sensors from early morning and late evening sunshine with an unobstructed horizon to the northeast or northwest.
The roof is not considered suitable. Not only is the construction of such similar to a solid surface (e.g. tarmac or concrete), and therefore subject to the errors noted above, but a roof is obviously more than 1.25 m above ground level. However, it is worth noting that many of our current crop of weather centres, with London being a notable example, have for many years mounted thermometer screens at a considerable elevation above local ground/street level. If a roof location is all you have, use it, but bear in mind the limitations.
Rainfall
Basic requirement: Rainfall amounts are quoted as a depth of water that would result in any one location on a flat surface after a fall of rain, if there were no run-off, evaporation or percolation. The depth measured in a gauge is assumed to be representative over an area around the gauge, so it is necessary to eliminate as far as possible any local sources of error.
There are many sources of error in rainfall assessment: evaporation, adhesion (sticking of the droplets to the side of the gauge), splash etc., but by far the greatest source of error is due to inadequate exposure. The 'ideal' location is one where objects which might disturb the airflow are some considerable distance away from the gauge, i.e. they are so far away that any perturbations of the wind-flow are so small as to be part of the general 'ground-effect' turbulent flow always present as air passes over the earth's surface.
The recommended standard is that the distance from surrounding objects should be not less than twice the height of such objects, and ideally at least four times. In most suburban gardens, even if the fences are low enough to just about site a gauge to these standards, surrounding trees, neighbour's bushes, and of course, the house (and adjacent buildings) usually are the largest objects, and cannot be realistically circumvented. Most hobby observers cannot meet the latter (4 times) requirement, but something approaching the twice-times-height standard is often attainable.
Official texts completely rule out mounting on a wall or roof (apex or flat), as these features cause marked eddies of wind which grossly distort the passage of falling rain across the mouth of the gauge. However, a flat roof might be a best approximation, if there are no adjacent buildings within the '2 x object height' footprint mentioned above.
The middle of a lawn is all that most of us have .. and provided that it is not grossly shaded, would present a reasonable guide, but unless the wind is very light, under-reading of rainfall (with respect to the 'standard' sites) must be expected. With time, it is usually possible to judge where in a garden is unduly sheltered, and careful note made to avoid these locations. Remember that the 'shadow' changes with wind direction. Try setting up identical collecting receptacles (e.g. the bottom half of plastic lemonade bottles) and note the variation in catch over a period of several months. Another method is to note at the start of any rainfall event which areas become wet first and which stay dry longest. Or perhaps a matrix of collectors, and take an average!
At the end of the day of course, you are measuring rainfall that is of significance to you. Indeed, in extreme rainfall events (such as notable local storms), any measurements are better than none; adjustments and allowances can be made for exposure, and even an 'official' gauge under extreme conditions has difficulty in capturing a 'true' measure of the event. The rain/snow that falls is the amount of rain (to a reasonable approximation) that has fallen in your garden, on your roof or whatever, and as such it is a meaningful record. For this reason alone, it is worth attempting such measurements - the only suggestion is that you don't spend huge amounts of money doing it!
Wind
Basic requirement: The wind speed and direction (see ** below) in the first 30 metres or so of the atmosphere varies rapidly with height, due to the varying frictional effect of the general 'surface roughness'. It is greatly affected by undulating ground, and by adjacent obstacles such as trees, bushes, buildings etc. This is a common experience - noted for example within built up areas, major shopping centres etc.
For synoptic and climatological work therefore, a 'standard' exposure is required. That standard is for the wind speed and direction over a level surface to be measured at a height of 10 m above ground level (agl). When these conditions cannot be met, it is permissible to raise the anemometer to give an effective height of 10 m, provided the obstructions are not large, and are distributed uniformly around the instrument site.
It will be immediately apparent, that in the common 'back-garden'/urban development situation, a considerable mast is needed to carry the anemometer clear of these 'ground effect' generating obstacles. For example, consider an outer-suburban garden with houses/trees of approx. height 6m in height, the recommended exposure height would be 6 m (obstruction) + 10 m (standard height)=16 metres. (That's around 50 feet!) This provides problems in maintenance of the sensor, and also there would possibly be planning and structural constraints. To be stable, such a structure would need to be well braced which will not be easy. When considering larger obstructions, such as large blocks of flats, or office blocks, then the sensors would need to be raised even more. An example: For an obstruction of some 15 m in height (a typical large building), which is about 75 m from the site of the intended anemometer site, then the wind vane/cups would need to be about 25 m above ground level.
If such conditions are beyond the scope of your pocket or what the neighbours will allow, then the best compromise would be a fitting a short height above the ridge of a house, provided always that adjacent buildings do not unduly affect the airflow at the sensor level.
[** Wind direction, when quoted in standard meteorological reports such as SYNOP and METAR, are given in terms of deviation from TRUE north (degT). This should be remembered when setting up a weather station that includes an anemometer: align the directional head such that the read-out gives degT - to do this you will need to allow for the local magnetic deviation of your compass from true north: many websites are available that will help with this subject.]
As will be appreciated from the above, the best advice we can give when 'standard' conditions cannot be met is to think seriously whether its worth the cost and effort. By all means mount a relatively inexpensive anemometer just above the roof level of your house etc., but treat this simply as a monitor of the conditions for your site. The reading you get will not be of use to compare with adjacent 'standard' instrumentation, or even with someone a few streets away with similar problems. However, it is a record at the point you have installed the anemometer head, and as such does provide interest. You will find though that the poorer the exposure, the greater the variability in wind direction.
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And finally ... it is pertinent to note that there are occasions when limitations of exposure are a positive advantage. For example, a useful field study for students is to set up a series of temperature recording devices within a stand of trees, both horizontally and vertically. Readings from such an array would obviously be used for the study of the heat/humidity budget of the wood and any need to 'standardise' as above is not a factor, apart from ensuring of course that the thermometers or other devices are correctly calibrated and 'zero-referenced' for the range of values required. And there are specialised applications where the sensor site must depart from the WMO standards: for example, temperature and wind sensors set adjacent to a major motorway route are there precisely to monitor the disturbed airflow and heat characteristics consequent upon heavy traffic flow passing a couple of metres away. For these specialised applications, advice should be sought from the manufacturers of the equipment and other relevant authorities.
Observation timing
Systematic instrumental weather recording (e.g. using thermometers, rain-gauges etc.) began in the days when the only way such data could be obtained & logged was by someone reading & noting same. For this reason, the meteorological 'day' tended to be built around the 'human-activity' day. With most observers being available 7 to 9am local time, the climatological start/end for the day has settled in many European countries (though not all), to 0900 UTC (or to 0900 local/clock-time elsewhere). For those stations only noting maxima, minima, rainfall etc. once per day, the maximum temperature read at 0900UTC is credited to the previous day, on the assumption that on the majority of occasions, the highest value would have happened during that day's afternoon. The minimum is credited to the current day, on the assumption that, again for the most part, the lowest temperature would have occurred in the hour or so around local dawn - i.e. the day of reading the thermometer. Rainfall for this 09-09 period is apportioned to the day occupying the greatest part of the 24hr, that is it is 'thrown-back' to the previous day's date. This means of course that a severe thunderstorm producing a lot of rain in the period after midnight will have it's rainfall credited to the previous day!
A better way of noting (and recording) these data is to further divide the 'climatological' day into two periods: 0900 to 2100 & 2100 to 0900 UTC. This of course means that thermometers and rain-gauges have to be read, reset/emptied at 2100UTC. However, as with the 09-09 method, anomalies will occur. For example, if a major air-mass change occurs after 2100UTC (e.g. cold to warm in winter), then the highest temperature in the 24hr period may occur overnight, yet the logged maximum will be that recorded 0900 to 2100. And rainfall will still be credited to the date at the start of each period, i.e. the 21 - 09 UTC rainfall (read at 0900UTC) is again 'thrown-back' and added to the 09-21 total.
A further complication arises from the requirement of those providing information for use in SYNOP bulletins. As there is no 'main' SYNOP at 0900UTC, in Europe the night minimum (18 to 06) is reported in the 2-group of the 333 section of the 0600 SYNOP. (Note that during the long winter nights, the actual minimum could well occur after 0600UTC.) The day maximum (06-18) is reported in the 1-group of the same section at 1800 UTC. The rainfall (or melted snowfall) at these (and other times), is recorded using the 6-group in the main SYNOP (see here).
With the advent of high-quality electronic systems, it is very easy to log data according to the 'normal' day, 00-24 UTC, and users of such find it cumbersome to comply with the above scheme(s). This FAQ makes no comment upon this debate, except to note that all methods of recording climatological data throw up anomalies, and there is a large body of historical data tied to the 09-09, or 09-21-09 standard. The important point, especially when noting extreme temperatures and notable rainfall, is to annotate your own records (and report same where possible), so that researchers in years to come can pick out the deviations from the 'assumed' diurnal cycle of temperature, or the 'noteworthy' precipitation event.
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Setting up a weather station
In addition to the hints, tips & general advice in the earlier parts of this Section (above), many of the manufacturers in the Suppliers Reference list will supply advice on the installation of equipment.
For some basic ideas of how to start-up, see the following sites (I haven't given the full urls because they keep changing and it is difficult to remain up-to-date with same):
The Met Office: (follow links for the Education Section .. some very useful ideas for the hobbyist, and also advice if you want to make observations to climatological standards.)
http://www.metoffice.gov.uk/
and direct to the section relating on advice on weather recording, reporting etc.,
http://www.metoffice.gov.uk/bookshelf/observations/index.html
The Royal Meteorological Society: (follow links for Publications: the Society encourage meteorology at all levels, and publish some leaflets on weather observing which can be obtained either free, or for a small sum.)
http://www.royal-met-soc.org.uk/
[ and don't forget that other national meteorological societies will have similar information.]
The BBC Weather Centre (follow links for 'Weatherwise' .. or use the Search engine; a useful site to help the beginner in all aspects of observing and understanding the weather.)
http://www.bbc.co.uk/weather/
Don't forget though: throwing a large amount of money at the subject won't improve your understanding. Read up on the basics, use your senses to observe the changing 'sky-scape', note the weather (rain, hail, snow etc.), and just get used to deciding from which direction the wind is coming. For all of this, you don't need fancy equipment - that can be built up later. Even then, start in a small way if your budget is limited: some thermometers and rain-gauges from garden centres are quite good, and many department stores and catalogue shops sell 'all-in-one' desk weather stations which can stimulate interest.
Equipment & services.
General suppliers of equipment & services.
Campbell Scientific Ltd
The supply of professional automatic weather stations, including configurations approved by The Met.Office. The systems use high-quality components and so are not the cheapest. However, they are accurate, rugged and reliable and can be configured according to requirements.
Casella Limited
An extensive range of Classical Meteorological Instrumentation for monitoring temperature, sunshine, airflow, humidity, pressure and rainfall. Along side the classical range, Automatic Weather Stations are available. These resilient units use new technologies with easy to use WindowsTM software and a wide range of sensors to measure meteorological variables.
Diplex Ltd
(Current status of this company is unknown: 22 Jan 2008)
Diplex have many years experience in the supply of an extensive range of quality equipment at affordable prices to both the amateur and professional/educational community. Conventional thermometers, hygrometers, barometers and rain-gauges are of course available, but rugged, easy-to-use distant-reading electronic units to monitor temperature, relative humidity and rainfall are also offered. An inexpensive instrument screen for self-assembly is available and a wide range of recording instruments in attractive mountings, including barographs, thermographs, hygrographs, thermo-hygrographs, along with complete Weather Stations (analogue & electronic/wireless): anemometers are also supplied.
Fairmount Weather Systems
Fairmount are manufacturers a wide-range of meteorological instrumentation, from traditional to the latest design. The range includes: Automatic Weather Stations, Environmental Monitoring Systems, Data Collection Platforms & satellite reception systems. Some items available (from a wide range) are: copper rain-gauges, autographic recorders, wind vanes/anemometers, tipping bucket rain-gauges & a full range of high-grade thermometers. Also available are pens, charts, spare parts etc., as well as sunshine cards for Campbell-Stokes recorders. The company also manufactures products under design & development contracts as well as precision engineering in their own workshop.
Instromet Ltd (was R & D Instromet)
Weather monitoring instrumentation with classic analogue dials and digital readouts in real wood cabinets or brass cases with optional PC Data-logging. Automatic Weather Stations with large memory,battery back-up and Windows(TM) 'family' software. Parameters measured:- Wind speed, Wind Direction, Temperature, Sunshine Duration, Rainfall, Humidity, Automatic Internet up load. Stand-alone sensors for Wind Speed and Direction, Sunshine Duration etc. Wind Speed/Direction Alarms and Actuators.
McMurdo Ltd (was ICS Electronics)
The Davis range of weather stations - high precision Weather Monitoring solutions for Home and Industry users. Sensor options include: Anemometer, pressure, rainfall, temperature and humidity. Industrial systems also offer UV, Solar radiation and Leaf wetness. A comprehensive Windows (TM) computer data logging interface and a wide range of installation options are available: see web site for more details.
MetCheck
The supply of various weather instrumentation, including raingauges, barometers, hygrometers, thermometers, complete weather stations etc. Also Stevenson-pattern screens & various electronic instruments.
Meteorologica Weather Superstore
From individual items of equipment, through 'desktop' weather monitoring displays to fully-featured weather stations (wireless & cable), this on-line source is fully featured and a wide variety of stock is available. Software & books can also be purchased and of particular interest to many in this newsgroup, a range of lightning detectors. All items can be ordered via the site, paid for using recognised credit / debit cards.
RW Munro Limited (the Meteorological Division of the Munro Group)
R W Munro supply a wide range of meteorological & hydrological equipment sales & service. Since 1892, Munro has achieved a reputation for excellence in providing instruments & systems of the highest quality to measure, monitor & record environmental phenomena. They offer a full range of equipment from 'traditional' weather observing instruments to the latest electronic equipment. Munro supply equipment to meteorological offices, water authorities & government departments world-wide.
Prodata Associates Ltd
(1) The Davis range of weather instrumentation including the new Vantage Pro range of stations; (2) Software and expertise for linking weather stations to personal computers.
Russell Scientific Instruments
A wide range of products, including 'traditional' instrumentation, digital 'distant reading' units & a variety of thermometer (or 'Stevenson') screens. The firm will also undertake restoration of such as hall barometers.
Sales and Service Company
59A, Station Road, Chingford. London. E4 7BJ (UK)
Tel: 0208 505 3280 (intl: +44 208 505 3280) Fax: 0208 559 0425 (intl: +44 208 559 0425)
Service and supply of spares, recording charts, pens, inks etc., for all types and makes of autographic instruments. Suppliers of weather instrumentation, including: barometers, rain gauges, frost predictors, thermometers, hygrometers, hand anemometers etc.
Skye Instruments Ltd.
A British company with a world-wide reputation for the design & manufacture of high quality environmental instrumentation. Skye’s MiniMet weather station is an accurate yet low-cost system, which can be customised to suit individual requirements. Meteorological parameters such as relative humidity, air/ground temperature, solar radiation, wind speed/direction, rainfall, leaf wetness & barometric pressure can all be monitored. Downloading weather records also possible, through a direct cable link for local installations or a GSM mobile telephone link for remote locations.
Skyview - The Weather Company
Skyview is based in the UK, and supplies a wide range of meteorological, hydrological and marine instruments to commercial, civil, avionic and military authorities worldwide: the equipment would also suit the keen amateur, with competitively priced units ranging from hand-held anemometers and wireless rain-gauges to complete weather monitoring systems (wireless or cable). The company offers a wide range of high technology software and equipment, along with a spares and after-sales support service for such as Oregon, Davis & Lacrosse.
Weather Front/the UK Weather Shop
A wide range of products such as books, posters, thermometers, barometers, anemometers, rain-gauges. Also the latest electronic weather monitoring and recording equipment. All from major manufacturers such as Davis Instruments, Oregon Scientific, Kestrel, BariGo, Diplex etc. See online catalogue or visit the shop. Full details and secure online purchasing available on web site.
http://weatherfaqs.org.uk/node/106
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Micky. As Frethack and I have said, these figures will have been adjusted to accommodate the higher temperature caused by the tarmac. So you can bet that the temperature you are seeing on your forecast is not because there is lots of tarmac.
when they give a temperature measurement for the local population it needs to be the actual temperature, if they adjusted it to accommodate the higher temperature caused by the tarmac then the actual air temperature would be higher without the adjustment and they would then be reporting a false local temperature with the lower adjusted measure.
That would then cause health and safety warnings to be inaccurate and potentially dangerous as the heating effect of the tarmac would not only effect the local temperature at the airport but also the temperature of the surrounding towns.
If you get what i mean.
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when they give a temperature measurement for the local population it needs to be the actual temperature, if they adjusted it to accommodate the higher temperature caused by the tarmac then the actual air temperature would be higher without the adjustment and they would then be reporting a false local temperature with the lower adjusted measure.
That would then cause health and safety warnings to be inaccurate and potentially dangerous as the heating effect of the tarmac would not only effect the local temperature at the airport but also the temperature of the surrounding towns.
If you get what i mean.
But it is the actual temperature, even when adjusted. The temperatures are adjusted for reasons (such as) to do with historical readings and to make sure that any new equiptment will be calibrated to give the same readings as would the old equiptment.
There has to be a standardised tolerence of the recording equiptment, siting height and location. Changes to a recording site are adjusted to keep within these limits. As for "...if they adjusted it to accommodate the higher temperature caused by the tarmac then the actual air temperature would be higher without the adjustmen...", this is part of the standardisation. If you place a thermometer on the wall behind your patio chair and then another out of your bathroom window (above the patio)you will get two different air tempersatures...which is the correct one?
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I was wondering if anyone out there has considered the increase in air temperatures in a local area in relation to the increase in impervious surfaces, e.g. roadways, parking lots, etc.?
I think the recent laws regarding impervious driveways are more to do with flooding than temperature, but...
The increase in temperature of built-up areas compared to nearby countryside is well-known and is called the heat island effect. I did a project on this for my GCSE geography many years ago. Long before data came on the internet, I wrote to the Met Office and they kindly provided me with very-small-print tables of daily maximum and minimum temperatures for 5 locations in the southeast of England, which I hand-copied into my computer to plot and analyse.
While the heat island effect may add a degree or two to daytime temperatures, the effect is far more pronounced in the night-time lows. Central London nighttime frequently proved to be as much as 5 degrees warmer than Gatwick Airport (a substantially rural area) for example.
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Paul, I owe you an apology.
I became so busy with school and family issues that I did not even notice (until almost two months later) that you posted a hell of a lot of great and extra information. I very much appreciate it.
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Paul, I owe you an apology.
Don't be silly, I do it for the money! MY paypal address is....
You may want to check these out:
http://www.nkhome.com/ww/wwindex.html
http://www.erh.noaa.gov/buf/bufkit/bufkit.html
http://www.wunderground.com/ - - look for the link to how you can have your own weather station data posted there. They also include guides and tutorials.
If you have the facility to have a webcam set up, then you may be able to get some nice timlapse images such as those found here:
http://mesonet.agron.iastate.edu/cool/