Recently in Adelaide, South Australia a record heatwave occurred as reported by the Australian Bureau of Meteorology.
"An extremely hot air mass has seen Adelaide equal its record of three consecutive 40 degree days in December (most recently set in 2007), with this record to fall tomorrow if Adelaide reaches 40 for a fourth consecutive day, as forecast."
BOM recorded the temps at Kent Town and it sparked my interest so I watched the temperature climb during the day, on their website. At about 15:30 I noticed the temperature drop and thought it wasn't going to make it. However at 5:30 the temperature rose again to 40.8C. "Unusual" I thought "why would it do that?"
I checked if this was a normal trend and monitored the daily temperatures for a few days noticing the same occurrence, with temps cooling mid afternoon and rising again. For twelve days I screenshot the afternoon temperatures from 12:00 to 19:00 on the BOM website and the results are set out below.
It is common at Kent Town for temperatures to increase after cooling late into the evening I would have thought that as the sun hit its zenith the cooling would have occurred at a steady rate. Thermal response theory tells us that 'Buildings do not respond instantaneously to fluctuations in heat input,'
Urban Heat Island
In 2012 the Bureau of Meteorology completed an extensive and dedicated international peer review, that review ranked the Bureau's procedures and data analysis as amongst the best in the world in which was stated.
Whilst it did not affect their assessment as urban sites, it is interesting to note that of the four city-centre sites (Sydney, Melbourne, Adelaide, Hobart), only Adelaide showed evidence of an anomalous minimum temperature trend over the 1910-2009 period. This suggests that either any urban influence on temperatures at these locations was already fully developed by 1910 or that anomalous urban warming was manifested as step changes, possibly associated with specific buildings or other developments in the vicinity, which were successfully removed in the homogenisation process. Page 81
While considerable effort is made to keep observational practices consistent—and to keep a careful log of changes at each site—each change in methodology or technology can leave its mark on the record.
These include artificial changes in the record due to:
a shift in the location of the station (for example, from a post office to an airport);
a change in the environment around the station (for example a tree grows, a structure is built, a lawn is irrigated); or
a change in measurement method (for example, from a manual instrument to a recording electronic instrument).
Adjustments are required to correct for these non-climate-related influences—since they may create artificial ‘jumps’ in the data over time. Correcting these biases is a key requirement for compiling and then analysing long-term records of daily maximum and minimum temperatures.
The Bureau does not alter the original temperature data measured at individual stations. Rather, the Bureau creates additional long, continuous and consistent (homogeneous) records for locations across the country.
There is no mention of traffic in the, best in the world ,data analysis practices used by BOM. The daily coming's and going's of increasing numbers are not considered to temperature measurements. Could Kent Town observatory be affected by traffic.
A six-cylinder 4-stroke cycle petrol engine is to be designed to de...(b.p) at 2500 rpm the bore / stroke ratio is to be 1:1.25. producers 74948 kJ/min heat. Considering a standard thermal efficiency of a vehicle is 26% a full 74% is emitted as heat through exhaust and cooling through the radiator or 55,461 kJ/min
If 100 cars surrounded a weather station they would emit a total of 5,546,100 kJ/min 1000 cars would emit 55,461,000kj/min. Mixing may account for a lot of this but how many cars would need to surround a weather station for it to be affected? If those cars were increasing in number every year, would the temperatures recorded increase?
Kent Town observatory at 25 College road is inundated by traffic. 41,500 cars / day 34,200 cars / day 22,600 cars / day. The amount of heat generated from these numbers so close the the weather station must affect its readings.
The Britannia Intersection is located on the eastern boundary of the City of Adelaide, some 300 meters from the observatory and is the intersection of five urban roads; Dequetteville Terrace, Kensington Road, Wakefield Road and Fullarton Road (north and south). This intersection lies on the main entry / exit path into the City of Adelaide from the eastern suburbs and is on the principal inner suburb ring route around the city.
This busy intersection is identified as a Strategic Route, a primary Freight Route, a primary Commuter Route and a secondary cycle route.
It is currently the worst unsignalised intersection within South Australia when ranked against crash statistics over the past five years. Between 2007 and 2011 a total of 289 crashes were reported at this location, including 51 casualty crashes.
Sydney Observatory is located next to the busiest road in Sydney, the Western Distributor Freeway that crosses the Sydney Harbour Bridge. At the point the observatory is located 80,000 cars / day travel along the western distributor and meet another 30,000 cars / day coming from Circular Key. Although an airier location the heat generated from that many vehicles could affect the temps if I am correct.
1. No recommendation for placement of weather recording equipment in regard traffic in their guidelines.
2. ACORN-SAT list these causes for homogenization of data:
o Merge: data from two different station numbers are being merged, with overlap.
o Merge: data from two different station numbers are being merged, with overlap.
o Move: a documented site move.
o Move (n): a documented site move, together with a change of station number.
o Screen: indicates a change or repair to the Stevenson screen.
o Obs time: indicates a change in observation time (most often the 1964 change at some stations from a midnight to 9 am observation time).
o Site env: a change has occurred in the local site environment (e.g. addition/removal of building nearby, change in vegetation).
o Statistical: a change found by statistical methods without specific documentary support.
o Statistical*: indicates some kind of documentary support which may be imprecise or subject to interpretation. This is further explained in the notes
o AWS: installation of an automatic weather station; if there was an associated site move this is shown as ‘move’.
If the construction of a new building or planting of a new tree causes the data to be effected surely a constant steal wall emitting 55,461 kJ/min of heat / vehicle in ever increasing numbers should also be taken into consideration.
It is clear, from my observations that the temperature increases are occurring at 'Peak Hour' and I suggest traffic may have some affect on the temperature readings from these two stations. If that is the case, how many in Australia and worldwide. BOM documents,make it clear that no consideration is given to the increasing traffic numbers every year in the Homogenization process used and if, as quoted, using world class data collection methods this traffic pollution to readings must occur in other stations worldwide.
It is also clear that the data used for the historical reference is made up of 70 years of very little vehicle heat influence around testing stations due to the heat generated from vehicles and 40 years of vehicular affected data spread and averaged over, in some cases, 100 years.
Could this explain the hiatus as we move closer to a point where it is 50 50 as more years of Vehicle Heat Affected Data (VHAD) fills the mix. After approximately 2040 do the temperatures measured appear to be lower or stable when the number years of Vehicle Heat Effect (VHA) is greater than the years with little VHA in the average temps used in historical data
I can find no reference or study which includes VHA on readings. Many on the pollution caused by vehicles, but none on the heat emitted.
Of course this is only my observations. I would hope that in the writing of the blog and hopefully your sharing, we might be able to get the science reopened to begin a study on the effects of the generated heat from traffic on temperature readings.
I feel I have built a case and would hope that research can be done, so we can build our utopia, with a little more common sense and without the rush. Only working together can we build a better future for all.
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