Melbourne Urban Heat Island Contamination of Temperature Trend Maps in Victoria, Australia

Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia

1; Albert Parker activities, and the thermal inertia is also increased by the presence of industrial materials such as roads and buildings 1 RMIT University, PO Box 71 Bundoora VIC 3083, Mel- (the heat island effect). bourne, Australia

Abstract. The paper presents a regression analysis of the temperature data measured by the Australian Bureau of Me- teorology in their historical measuring stations in Victoria. All the downloaded data was free of quality issues and re- ferred to speciﬁc geographical locations, with only minor gaps in the recorded data. Temperatures at stations located in regional Victoria show no growth in the long, medium and short term. Temperatures in the greater Melbourne area show growth biased by the establishment of a metropolitan heat island. Corrected for the heat island effect, the temperature changes are minimal.

Keywords. pattern recognition, temperature records, heat island effect, Victoria, Australia.

1 Trend maps and local temperature results The population of Australia is estimated to be more than 22.5 million over an area of 7,617,930 km2. The population is concentrated mainly in urban areas, with Melbourne and Sydney accounting for about 4 million each. Victoria is the second most populous state in Australia and geographically the smallest mainland state, with a population estimated to be more than 5.5 million over an area of 237,629 km2. Aus- tralia has an extensive network of meteorological measuring stations many of which have been operational for more Figure 1. Australian Government Bureau of Meteorol- than a century; some measuring stations have started oper- ogy. Australian climate variability & change Trend maps ation very recently, and others have been discontinued [1- (from [1]). 4]. Most of the newly established stations are located in fast growing areas, while most of the stations with longer The Australian Government Bureau of Meteorology [1] records disconnected were located in remote country areas. presents trend maps of generalized warming for Australia The relative weight of measuring stations in fast growing as presented in Figure 1. The maps are available for periods urban areas vs. stations in country areas has been dramati- 1910-present to 1970-present every 10 years. cally increased recently. It has been shown already [23] that for the speciﬁc loca- In measuring stations located in fast growing urban ar- tion of the Northern Territory these trend maps show strong eas, an increasing amount of thermal energy is being re- warming especially in the central Australian desert, where leased because of the increasing population and productive Alice Springs is the only established measuring station, a conclusion that is not supported by the actual thermometer Corresponding author: measurements. There is a similar lack of experimental evi- Albert Parker, E-mail: [email protected]. dence for the warming depicted on these summary maps in Received: 18 March 2013. Accepted: 4 June 2013. Victoria also, as shown in this paper. 40 A. Parker

Heat island build-up is a well-known bias that occurs in region has a growing population now in excess of 4 million recorded temperatures of urban areas [5-18]. The urban people and with a long-term population growth projected at heat island (UHI) of Melbourne is analyzed in details in 1.3 per cent a year. When the Melbourne regional office [16-17]. The analysis of [17] concludes “it appears to be station commenced operation in 1908, the thermal inertia very difficult to make allowances for any UHI effects when of the area surrounding the measurement location as well analyzing temperatures and therefore difficult to dismiss the as the amount of energy being released about the measure- possibility that UHI effects are creating a false impression ment location, were definitively negligible by comparison of global warming.” Small towns in regional Victoria also with today, and this heat build-up will certainly have af- display an UHI [18], even if obviously less significant. At fected the reading of the thermometer. the same time that temperatures recorded in the greater Mel- bourne metropolitan area show a warming, the temperatures recorded in regional Victoria show no long term warming 2 Local temperature regression analyses with various trend. time windows This statement is supported by the temperature database of historical measuring stations used by the Australian Bu- To better understand the warming trends it is therefore nec- reau of Meteorology [5] in their synthetic statistical and essary to consider individually all the stations with a sig- yearly averaged temperatures. The data available in this nificant number of years of operation, and correct the data compilation are the historical highest and lowest and 2010 for all possible biasing factors, first and foremost of which values, plus the yearly averaged maximum and minimum is the heat island effect. Of all 14 high quality historical mean temperatures. These data are described in the sup- measuring stations with longer records of Victoria [3] con- porting material. The stations considered in detail in this sidered, ECHUCA, BALLARAT, MELBOURNE, CAPE paper are listed in Table 1. OTWAY and WILSON PROMONTORY are selected here For most of the locations considered the mean maximum analysis in order to provide a more accurate regional tem- and minimum temperatures lie near the mean values over perature record. Each station is first analysed individually all the years [5], and the time series of yearly averaged tem- in order to understand the individual trends at stations with peratures do not show any warming. The heat island effect little heat island effect. appears to be significant especially in the downtown Mel- From the list of Australian meteorology stations open bourne location, where the temperatures are always above for more than 50 years [3] those still operational in Vic- the mean local values over all the years. toria are used to serve as a good basis for estimating the From the synthetic statistical and yearly averaged tem- average trend for temperature across in the whole state. peratures proposed by the Australian Bureau of Meteorol- To show the influence of the heat island build up on the ogy [5], the temperature changes at specific station loca- measured temperature and also to assess better the current tions over the available times of record are as follows: MIL- trends for temperature in Victoria, the raw data of monthly DURA is marginally warming in the mean maximum and mean maximum and minimum temperatures have therefore almost unchanged in the mean minimum. HORSHAM and been downloaded from the Australian Bureau of Meteorol- RUTHERGLEN are slightly cooling in both temperatures. ogy [4] and analyzed with different statistics. ORBOST is slightly warming in both mean temperatures. WILSONS PROMONTORY is warming in the mean min- 2.1 Long term (100-150 years) statistic imum and steady in the mean maximum. MELBOURNE is warming significantly especially in the mean minimum The last 100-150 years raw monthly mean maximum temperature. BALLARAT is cooling in the mean minimum and minimum temperatures for the Ballarat Aerodrome, and unchanged in the mean maximum. CAPE OTWAY Cape Otway Lighthouse, Melbourne regional office, Wilson is cooling in the mean maximum and unchanged in the Promontory Lighthouse and Echuca Aerodrome measuring mean minimum. CASTERTON is marginally warming in stations are presented in Figure 2. The 12 months moving the mean maximum and unchanged in the mean minimum. average is also superimposed to the raw data to understand LAVERTON (within the greater Melbourne metropolitan the trends. Linear (solid black line) and second order poly- area) is warming. SALE is marginally warming in the mean nomial (dotted line) fittings are also applied. These results maximum and unchanged in the mean minimum. OUYEN show clearly that temperatures are not increasing at Bal- is unchanged in both mean temperatures. GABO ISLAND larat, Cape Otway, Wilson Promontory and Echuca, while is unchanged in both mean temperatures. ECHUCA is in Melbourne the temperatures, especially the mean mini- slightly cooling in the mean minimum and unchanged in mum temperature, are slightly higher now than in the past. the mean maximum. The long term linear statistics tell us that:

The null hypothesis for the warming shown at Mel- In Ballarat the maximum temperature is slightly in- bourne is that it results from the build-up of an urban heat creasing (0.00778°C/year) but the minimum temper- island around the measurement location. The Melbourne ature is slightly decreasing ( 0:0050°C/year); Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 41

(a) BALLARAT AERODROME. Commenced: 1908; Latitude: 37.51ı S; Longitude: 143.79ı E; Elevation: 435 m.

(b) CAPE OTWAY LIGHTHOUSE. Commenced: 1861; Latitude 38.86ı S; Longitude: 143.51ı E; Elevation: 82 m.

(d) WILSONS PROMONTORY LIGHTHOUSE. Commenced: 1872; Latitude: 39.13ı S; Longitude: 146.42ı E; Eleva- tion: 95 m.

(e) ECHUCA AERODROME. Commenced: 1859; Latitude: 36.16ı S; Longitude: 144.76ı E; Elevation: 96 m. Figure 2. Last 100-150 years raw data for monthly mean maximum and minimum temperatures for selected historical measuring stations in Victoria, Australia. 12 months moving averages and linear and second order polynomial trend lines applied to the monthly average data. 42 A. Parker

Table 1. List of stations considered.

Measuring location Site Year Latitude Longitude Elevation No. Commenced (S) (E) (m) MILDURA AIRPORT 76031 1946 34.24° 142.09° 50 HORSHAM POLKEMMET RD 79023 1873 36.66° 142.07° 128 RUTHERGLEN RESEARCH 82039 1913 36.10° 146.51° 175 ORBOST COMPARISON 84030 1883 37.69° 148.46° 41 WILSONS PROMONTORY LIGHTHOUSE 85096 1872 39.13° 146.42° 95 MELBOURNE REGIONAL OFFICE 86071 1908 37.81° 144.97° 31 BALLARAT AERODROME 89002 1908 37.51° 143.79° 435 CAPE OTWAY LIGHTHOUSE 90015 1861 38.86° 143.51° 82 CASTERTON SHOWGROUNDS 90135 1956 37.59° 141.41° 71 LAVERTON RAAF 87031 1941 37.86° 144.76° 20 EAST SALE AIRPORT 85072 1943 38.12° 147.13° 5 OUYEN POST OFFICE 76047 1911 35.07° 142.32° 50 GABO ISLAND LIGHTHOUSE 84016 1859 37.57° 149.92° 15 ECHUCA AERODROME 80015 1859 36.16° 144.76° 96

At Cape Otway the maximum temperature is signifi- thermal inertia sometimes plays an opposite role to the al- cantly decreasing ( 0:0165°C/year) and the minimum ways warming heat release. (In keeping with this, the tem- temperature is slightly increasing (0.0057°C/year); perature in a desert oscillates about a lower minimum and a higher maximum than do temperatures in a city or along At Wilson Promontory, the maximum tempera- the coast [25]). ture is slightly decreasing ( 0:0032°C/year) but The presence of a warming trend in Melbourne in con- the minimum temperature is significantly increasing trast with the flat temperature profiles for country locations (0.0104°C/year); around Melbourne reflects the perturbed conditions of the

In Echuca the maximum temperature is slightly de- Melbourne measuring location due to the build-up of the creasing ( 0:0008°C/year) and the minimum temper- urban thermal heat bubble [5-18]. The data indicate that ature is also decreasing slightly ( 0:0073°C/year). the strongly varied thermal energy release and storage close to the measuring location in Melbourne downtown com- The same long term linear statistic for Melbourne menced well before 1990. shows that the maximum temperature is slightly in- We may therefore reasonably conclude that: no warming creasing (0.0061°C/year) and the minimum tempera- has occurred at Ballarat, Cape Otway, Wilson Promontory ture is significantly increasing (0.0143°C/year). and Echuca; that the temperatures of Wilson Promontory At all the locations in regional Victoria, small heat islands are biased upwards by some specific local effect; and that may also be present and biasing readings. The thermometer the warming temperatures of Melbourne are induced by a sites are usually located close to buildings, and there may large heat island. also always be an additional bias due to the modified land Considering that similar results have been obtained by use, the increased thermal capacity of roads and buildings, analyzing other long term [3] measuring station in Victo- the heat released by air conditioning systems or other pro- ria, I conclude no warming is represented in the full set of cesses and activities. A characteristic of the UHI is that the recorded data for Victoria except that due to small or large minimum temperatures increase much more than the max- urban heat islands. imum temperatures as observed at several of the stations analysed. 2.2 Medium term (40 years) statistic The heat island build-up effect exercises more influence on minimum rather than maximum temperatures. The in- The last 41 years of data, from October 1970 to October creased heat release and thermal inertia produce a more 2010, have been used to compute the linear trends in tem- pronounced increase of the minimum temperature whereas peratures and rainfall for Melbourne, Ballarat, Cape Otway, the maximum temperature increases much less because the Wilson Promontory and Echuca (Figure 3). Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 43

(a) BALLARAT AERODROME. Commenced: 1908; Latitude: 37.51ı S; Longitude: 143.79ı E; Elevation: 435 m.

(b) CAPE OTWAY LIGHTHOUSE. Commenced: 1861; Latitude 38.86ı S; Longitude: 143.51ı E; Elevation: 82 m.

(d) WILSONS PROMONTORY LIGHTHOUSE. Commenced: 1872; Latitude: 39.13ı S; Longitude: 146.42ı E; Eleva- tion: 95 m.

(e) ECHUCA AERODROME. Commenced: 1859; Latitude: 36.16ı S; Longitude: 144.76ı E; Elevation: 96 m. Figure 3. Last four decades raw data for monthly mean maximum and minimum temperatures for selected historical measuring stations in Victoria, Australia. 44 A. Parker

In Melbourne the maximum temperature is increas- At Wilson Promontory the maximum temperature is ing ( 0.0339°C/year and the minimum temperature is decreasing ( 0:0313°C/ year) and the minimum tem- alsoC increasing ( 0.0203°C/year). perature is also decreasing ( 0:0493°C/year). C In Echuca the maximum temperature is decreasing In Cape Otway the maximum temperature is slightly decreasing ( 0:00005°C/year) but the minimum tem- ( 0:0914°C/year) and the minimum temperature is perature is also increasing ( 0.0103°C/year). also decreasing ( 0:0458°C/year). C

In Ballarat the maximum temperature is increasing It is very well known that longer temperature records of- ( 0.0305°C/year) but the minimum temperature is de- ten display inter annual and decadal variability. However, if creasingC ( 0:0272°C/year). there is meaning into discussing the reality of global warming from a trend of only ten years when this trend is of In Wilson Promontory the maximum temperature is in- warming, then a ten year period may also be used when the creasing ( 0.0157°C/year) and the minimum temper- trend is a cooling one. Of interest also is the comparison of ature is alsoC increasing ( 0.0177°C/year). C the short term trends of Figure 4 with the long term trends of Figure 2 as well as with the medium trend of Figure 3 all In Echuca the maximum temperature is increasing ( 0.0210°C/ year) but the minimum temperature is of which demonstrate a cooling trend. decreasingC ( 0:0229°C/year). The small and large heat island build up considerations first described over a longer time scale (Figure 2) are also appar- 3 Temperatures for Ballarat and Melbourne ent over the medium time scale (Figure 3). Additionally, it Figure 5 finally presents the average monthly maximum and should be noted that the shorter time window magnifies the minimum temperature anomalies vs. 1908 values for Mel- inter-annual and multi decadal oscillations of temperatures bourne and Ballarat. Distance in between Melbourne and about a longer term trend. Ballarat is 100 km. Ballarat is also a heat island, even if Clearly 1970 is close to a valley of the peak and valley a weaker one than Melbourne, being a small regional city of these inter-annual and multi decadal oscillations of tem- of about 100,000 peoples vs. a capital city of 4,000,000 peratures about a longer term trend. Picking up the starting peoples. Anomalies are significant only in the minimum year that followed either a peak or valley in the inter-annual temperature for Melbourne, the one more closely related to and multi- decadal oscillations would clearly greatly influ- the heat island build up effect. It is noteworthy that smaller ence the resultant trend line. oscillations for maximum temperature occur in Melbourne, which supports the argument that an UHI effect has pro- duced the 1.43 C increase over the last century in Mel- 2.3 Short term (10 years) statistic bourne. In order to correct Melbourne and Wilson promontory data of the heat island effect, the last 10 years of data, from October 2000 to October 2010, are now used to compute the linear trends in temperatures for Melbourne, Ballarat, 4 Discussion Cape Otway, Wilson Promontory and Echuca. In the last 10 Separation of background (non-urban) and urban tem- years, it can be expected that the heat island effect around perature trends is important for global warming moni- the Melbourne downtown and the Wilson Promontory mea- toring. All the Victorian sites analysed here show no suring sites has not greatly changed. The last 10 years of warming once corrected for the UHI effect. This is raw monthly averaged maximum and minimum tempera- true for all of the stations depicted in Figures 2 to tures are presented in Figure 4. 5 - ECHUCA AERODROME, WILSONS PROMON- TORY LIGHTHOUSE, MELBOURNE REGIONAL OF- In Melbourne the maximum temperature is decreas- FICE, BALLARAT AERODROME and CAPE OTWAY ing ( 0:0252°C/year) and the minimum temperature LIGHTHOUSE – as well as for the most part of the stations is also decreasing ( 0:0521°C/year). with data proposed in supporting material that are included in the HIGH-QUALITY AUSTRALIAN ANNUAL TEM- At Cape Otway the maximum temperature is decreasing ( 0:0361°C/year) and the minimum temperature PERATURE DATASET [22] (see supporting material). is also decreasing ( 0:0690°C/year). The statistical reliability of the analysed trends is therefore expected to be good, and the large variability of trends

In Ballarat the maximum temperature is decreasing (- among stations is consistent too with the lack of a com- 0.0650 °C/year) and the minimum temperature is also mon long term warming trend. The linear trends pro- decreasing ( 0:0298 °C/year). duce pretty much the same rate of rise of temperatures vs. Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 45

(a) BALLARAT AERODROME. Commenced: 1908; Latitude: 37.51ı S; Longitude: 143.79ı E; Elevation: 435 m.

(b) CAPE OTWAY LIGHTHOUSE. Commenced: 1861; Latitude 38.86ı S; Longitude: 143.51ı E; Elevation: 82 m.

(d) WILSONS PROMONTORY LIGHTHOUSE. Commenced: 1872; Latitude: 39.13ı S; Longitude: 146.42ı E; Eleva- tion: 95 m.

(e) ECHUCA AERODROME. Commenced: 1859; Latitude: 36.16ı S; Longitude: 144.76ı E; Elevation: 96 m. Figure 4. Last decade raw data for monthly mean maximum and minimum temperatures for selected historical measuring stations in Victoria, Australia. 46 A. Parker

(a) MELBOURNE REGIONAL OFFICE

(b) BALLARAT AERODROME

Figure 5. Average monthly maximum and minimum temperature anomalies vs. 1908 values for Melbourne and Ballarat. time for ECHUCA AERODROME, BALLARAT AERO- Regarding the Melbourne regional office, a basic site DROME and CAPE OTWAY LIGHTHOUSE. The only summary is available in [32]. This includes a graphical exception to this rule is MELBOURNE REGIONAL OF- summary of the climate data available for the site and an FICE, where the heat island effect is responsible for a differ- operational summary, as well as the instrument location ent trend, and to a minor extent also WILSONS PROMON- and the recent detailed surrounding features and skyline TORY LIGHTHOUSE. It is noteworthy that these results diagram. The thermometer is located in the city centre hold irrespective of whether stations in the data base [3] are at the corner of Latrobe and Victoria Street. The trends included that lie within or outside the greater Melbourne changes in minimum temperatures starting in 1960 is ex- metropolitan area [3]. plainable by UHI which have a greater effect on mini- As suggested in [26], the theoretical model based claims mum and post 1970s by Pacific decadal Oscillation (PDO) of global warming are supported by surface thermometer decadal changes, but the sudden discontinuity in maximum measurements pointed out that the surface is warming by temperatures starting in the latter 1990s suggests a local about 0.18 C/decade [27]. However, this claim of strong land use change. surface warming in the last 25 years is not that supported Figure 6 presents a picture of the Melbourne regional of- by a strong signal in the proxy measurements of tempera- fice thermometer location (from [33]). This is a clear ex- ture, the tree ring data, the ice core data, or the Mg/Ca iso- ample of sub-standards location for measuring temperature tope data. Furthermore, the poor locations of thermometers accurately. The main Australian historic site is only 2 me- [28], poor geographical coverage of thermometers with less ters from a sidewalk, and a couple of meters more from a than 30% of the globe having sensors [29], urban heat is- major street intersection and voluminous traffic. Hardly to land contamination [30], land use changes [31], all bias the be defended as the best place to measure temperatures free result of thermometer reading to overestimate global warm- of any bias. This picture demonstrates the growing trend ing. of climate monitoring stations that have been gradually sur- Regarding the warming due to UHI, [30] demonstrates rounded by increasingly closer urban influences [33]. the relationship existing between the size of a village, town or city as measured by its population, and the magnitude of the UHI it produces by analysing data gathered by au- tomobile traverses in 10 settlements on the St. Lawrence 5 Conclusions Lowland, whose populations range from 1000 to 2 million It is argued that the increased release of thermal energy in inhabitants. areas of increased urban population, coupled to the thermal Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 47

In this equation, y0 and a are constants to compute the average temperature rise over the period of observation. The least squares method is used to calculate a straight line that best ﬁts the data. The dependent y-values are the monthly average temperatures, a function of the indepen- dent x-values the time in years. The calculations for a, the temperature gradient, and y0 are based on the formulas:

k P .x x0/ .y y0/ i j D a k D P 2 : .x x0/ i j D y0 y a x D 0 0

In these equations x0 and y0 are the sample means and j and k are the indices of the ﬁrst and last record of the measured distribution considered for the estimation of the temperature gradient. The monthly minimum and maximum temperatures are used rather than the monthly mean temperature because the monthly minimum better evidence the presence of a heat island.

Figure 6. Melbourne regional office temperature measure- Note ment (from [33]). The supporting data have been downloaded from the Aus- tralian Government Bureau of Meteorology on December inertia of buildings and roads, is a major factor that biases 12, 2010 and all the data are provided as supporting ma- the temperature readings for Victoria, Australia. terial. Climate data passes through a number of stages in Individual analysis of temperature measured in stations quality control which occurs over a period of time. Data with records longer than more than a century, and not af- included in this study satisfied either one or other of the fected by heat island build up, shows that temperatures in following criteria: there is, as a minimum requirement, a 2010 fall within the norm of what has happened since the medium degree of certainty that the data have no errors or beginning of the last century. no significant errors have yet been detected, although this The analysis in this paper supports similar findings re- conclusion might change during a later stage of the quality cently published for nearby New Zealand [19-20], where control process. Historically, if an observational site moved temperatures have not increased over the last century, and a relatively short distance (within about 1 to 2 km) it may where warmings are localized in space and time. have continued to use the same station number. The data Rates of rise of temperature of 0.4°C/decade supporting proposed are for a single station number in a given loca- a four degrees and beyond potential for a global temperature tion. Changes may have occurred in instrumentation and/or increase by 2100 [24] are not substantiated. Once the UHI observing practices over the period included in a dataset, effect is taken into consideration there is no warming. which may have an effect on the long-term record. In re- Smaller warmings have however been measured over cent years many stations have had observers replaced by short time windows, and in other specific locations when automatic weather stations, either completely or at certain and where a heat island has been established. times of the day. Very few stations have a complete unbro- When corrected for the urban heat island effect, the tem- ken record of climate information, but the stations selected perature changes for Victoria over the last century have here have minimal gaps. These gaps have been closed by been minimal. interpolation between neighboring months.

6 Methods References The classic approach to analyze temperature data is to use a [1] Australian Government Bureau of Meteorology, Australian linear ﬁt: climate variability & change - Trend maps. www.bom. gov.au/cgi-_bin/climate/change/trendmaps.cgi y y0 a x: (retrieved December 12, 2010) D C 48 A. Parker

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Figure 7. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. MILDURA AIRPORT. Site no.: 76031, Commenced: 1946, Latitude: 34.24ı S, Longitude: 142.09ı E, Elevation: 50 m 50 A. Parker

Figure 8. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. HORSHAM POLKEMMET RD. Site no.: 79023 Commenced: 1873 Latitude: 36.66ı S Longitude: 142.07ı E Eleva- tion: 128 m Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 51

Figure 9. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. RUTHERGLEN RESEARCH. Site no.: 82039 Commenced: 1913 Latitude: 36.10ı S Longitude: 146.51ı E Elevation: 175 m 52 A. Parker

Figure 10. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. ORBOST (COMPARISON). Site no.: 84030 Commenced: 1883 Latitude: 37.69ı S Longitude: 148.46ı E Elevation: 41 m Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 53

Figure 11. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. WILSONS PROMONTORY LIGHTHOUSE. Site no.: 85096 Commenced: 1872 Latitude: 39.13ı S Longitude: 146.42ı E Elevation: 95 m 54 A. Parker

Figure 12. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. MELBOURNE REGIONAL OFFICE.Site no.: 86071 Commenced: 1908 Latitude: 37.81ı S Longitude: 144.97ı E Ele- vation: 31 m Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 55

Figure 13. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. BALLARAT AERODROME. Site no.: 89002 Commenced: 1908 Latitude: 37.51ı S Longitude: 143.79ı E Elevation: 435 m 56 A. Parker

Figure 14. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. CAPE OTWAY LIGHTHOUSE. Site no.: 90015 Commenced: 1861 Latitude: 38.86ı S Longitude: 143.51ı E Elevation: 82 m Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 57

Figure 15. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. CASTERTON SHOWGROUNDS. Site no.: 90135 Commenced: 1956 Latitude: 37.59ı S Longitude: 141.41ı E Eleva- tion: 71 m 58 A. Parker

Figure 16. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. LAVERTON RAAF. Site no.: 87031 Commenced: 1941 Latitude: 37.86ı S Longitude: 144.76ı E Elevation: 20 m Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 59

Figure 17. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. EAST SALE AIRPORT.Site no.: 85072 Commenced: 1943 Latitude: 38.12ı S Longitude: 147.13ı E Elevation: 5 m 60 A. Parker

Figure 18. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. OUYEN (POST OFFICE). Site no.: 76047 Commenced: 1911 Latitude: 35.07ı S Longitude: 142.32ı E Elevation: 50 m Melbourne urban heat island contamination of temperature trend maps in Victoria, Australia 61

Figure 19. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. GABO ISLAND LIGHTHOUSE. Site no.: 84016 Commenced: 1859 Latitude: 37.57ı S Longitude: 149.92ı E Eleva- tion: 15 m 62 A. Parker

Figure 20. Australian Government Bureau of Meteorology temperature graphs for historical locations in Victoria, Aus- tralia. ECHUCA AERODROME. Site no.: 80015 Commenced: 1859 Latitude: 36.16ı S Longitude: 144.76ı E Elevation: 96 m