Analysis of Historical Temperature Data of Victoria
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Analysis of historical temperature data of Victoria J.D. Vlok University of Tasmania School of Engineering 2017/04/13 Last update: 2017/07/25 http://eprints.utas.edu.au/23461/ [email protected] © 2017 UTAS Abstract Raw temperature data collected and made available online by the Australian Bureau of Meteorology are analysed in this report. The monthly mean maximum and minimum temperature series available for the state of Victoria are studied and historical temperature patterns from 1910 { 2016 are presented. It is shown that a high degree of synchrony exists between the temperature measurements across the state, including both the maximum and minimum temperature series. An average temperature trend for Victoria is also calculated by simply combining all the available raw measurements, and comparisons are made with other temperature series, including the ACORN-SAT record. This report forms part of a larger study where the aim is to reconstruct historical temperature trends for any given area where sufficient raw temperature data are available. Contents Abbreviations7 1 Introduction8 2 Methodology 10 3 Monthly mean temperature series 12 3.1 Mean maximum temperature series...................... 12 3.2 Mean minimum temperature series...................... 15 4 Comparison between different datasets 17 4.1 Comparison between ACORN-SAT and two CDO datasets......... 18 4.2 Comparison between ACORN-SAT and CDO Tmax records......... 20 4.3 Comparison between raw and anomaly CDO Tmax record.......... 24 5 Discussion 26 5.1 Limitations of raw mean method....................... 27 A Victorian CDO vs ACORN data 28 A.1 Mean temperature trends............................ 29 A.2 Cape Otway Lighthouse............................ 30 A.3 Gabo Island Lighthouse............................ 31 A.4 Kerang...................................... 32 A.5 Laverton RAAF................................. 33 A.6 Melbourne Regional Office........................... 34 A.7 Mildura..................................... 36 A.8 Nhill....................................... 38 A.9 Orbost...................................... 39 A.10 Rutherglen.................................... 40 A.11 Sale....................................... 41 A.12 Wilsons Promontory.............................. 43 B Statistical values for annual trends 44 B.1 BOM-published anomaly values........................ 46 B.2 Raw average of daily ACORN-SAT data records............... 47 B.3 Raw average of CDO records used in ACORN-SAT............. 48 B.4 Raw average of all available CDO records in Victoria............ 49 B.5 Rutherglen ACORN-SAT record........................ 50 3 B.6 Rutherglen CDO record............................ 51 C Victorian CDO station ranking 52 List of Figures 1 CDO weather stations in Victoria, with ACORN-SAT station names indi- cated.......................................9 2 Probability density function of Victorian mean maximum temperature dur- ing 1910 { 2016. The red lines indicate the mean of each of the 11 ACORN- SAT weather stations..............................9 3 Monthly mean data with twelve-month moving average for the Rutherglen Research station................................. 11 4 Moving average of all VIC CDO mean maximum temperature records.... 12 5 Moving average of all VIC CDO mean maximum temperature records (1910{1945).................................... 13 6 Moving average of all VIC CDO mean maximum temperature records (1945{1980).................................... 13 7 Moving average of all VIC CDO mean maximum temperature records (1980{2016).................................... 14 8 Moving average of all VIC CDO mean minimum temperature records.... 15 9 Moving average of all VIC CDO mean minimum temperature records (1910{ 1945)....................................... 16 10 Moving average of all VIC CDO mean minimum temperature records (1945{ 1980)....................................... 16 11 Moving average of all VIC CDO mean minimum temperature records (1980{ 2016)....................................... 16 12 Comparison of Victoria and South-East Australia annual temperature trends. 17 13 Victoria ACORN-SAT and CDO annual temperature trends for different CDO datasets................................... 19 14 Moving average of 16 VIC CDO mean maximum temperature records.... 22 15 Moving average of 11 VIC ACORN mean maximum temperature records.. 23 16 Comparison of Victoria annual temperature trends and CDO anomaly... 24 17 Mean trends of CDO and ACORN recordings of ACORN weather stations in Victoria.................................... 29 18 CDO vs ACORN-SAT data record comparison for Cape Otway (90015). Each year value indicated on the x-axis corresponds to January of that year. 30 4 19 CDO vs ACORN-SAT data record comparison for Gabo Island (84016)... 31 20 CDO vs ACORN-SAT data record comparison for Kerang (80023)..... 32 21 CDO vs ACORN-SAT data record comparison for Laverton (87031)..... 33 22 CDO vs ACORN-SAT data record comparison for Melbourne (86071).... 34 23 CDO vs ACORN-SAT data record comparison for Mildura (76031)..... 36 24 CDO vs ACORN-SAT data record comparison for Nhill (78015)....... 38 25 CDO vs ACORN-SAT data record comparison for Orbost (84145)...... 39 26 CDO vs ACORN-SAT data record comparison for Rutherglen (82039)... 40 27 CDO vs ACORN-SAT data record comparison for Sale (85072)....... 41 28 CDO vs ACORN-SAT data record comparison for Wilsons Promontory (85096)...................................... 43 29 BOM-published ACORN-SAT annual temperature trends for Victoria... 46 30 ACORN-SAT 11-record raw mean annual temperature trends for Victoria. 47 31 CDO 16-record raw mean annual temperature trends for Victoria...... 48 32 CDO raw mean annual temperature trends for Victoria............ 49 33 ACORN-SAT annual temperature trends for Rutherglen........... 50 34 CDO annual temperature trends for Rutherglen................ 51 List of Tables 1 Victorian weather stations that contribute data to the ACORN-SAT network 28 2 Temperature data record lengths associated with Cape Otway Lighthouse (90015)...................................... 30 3 Temperature data record lengths associated with Gabo Island Lighthouse (84016)...................................... 31 4 Temperature data record lengths associated with Kerang (80023)...... 32 5 Temperature data record lengths associated with Laverton Raaf (87031).. 33 6 Temperature data record lengths associated with Melbourne Regional Of- fice (86071).................................... 34 7 Temperature data record lengths associated with Mildura Airport (76031). 36 8 Temperature data record lengths associated with Nhill Aerodrome (78015). 38 9 Temperature data record lengths associated with Orbost (84145)...... 39 10 Temperature data record lengths associated with Rutherglen Research (82039). 40 11 Temperature data record lengths associated with East Sale Airport (85072). 41 12 Temperature data record lengths associated with Wilsons Promontory Light- house (85096)................................... 43 13 Statistical values for annual mean temperature trends............ 45 5 14 Statistical values for Victoria annual mean temperature (ACORN-SAT BOM values).................................. 46 15 Statistical values for Victoria annual mean temperature (ACORN-SAT 11- record raw average)............................... 47 16 Statistical values for Victoria annual mean temperature (16 CDO datasets) 48 17 Statistical values for Victoria annual mean temperature (all CDO datasets) 49 18 Statistical values for Rutherglen ACORN-SAT annual mean temperature. 50 19 Statistical values for Rutherglen CDO annual mean temperature...... 51 20 VIC station ranking (1 - 50)........................... 53 21 VIC station ranking (51 - 100)......................... 54 22 VIC station ranking (101 - 150)......................... 55 23 VIC station ranking (151 - 200)......................... 56 24 VIC station ranking (201 - 250)......................... 57 25 VIC station ranking (240 - 289)......................... 58 6 Acronyms ACORN-SAT Australian climate observations reference network - surface air temperature BOM bureau of meteorology CDO climate data online LS least squares MA moving average PDF probability density function SE South-East 7 1 Introduction The Australian bureau of meteorology (BOM) employs a vast network of sensors across the continent to measure a number of weather parameters. Over the last 160 years, a to- tal of nearly 1900 weather stations have contributed to the historical Australian weather record which is publicly available at the online BOM archive [1]. The weather station network has however continuously changed over its history as old stations were closed or moved and new ones were opened. Human activity has also influenced measurements as landscapes have changed, cities expanded, and measuring equipment and standards were updated. Different approaches are followed to reconstruct historical weather records in an attempt to understand climate patterns, to evaluate the effect of human activity, and to make pre- dictions. The study presented here focuses on the raw BOM climate data online (CDO) temperature record for the state of Victoria. Monthly mean temperature records available from the online archive are used here to analyse trends and patterns without perform- ing any interpolation or changes to the raw data. Some comparison to other records, including the Australian climate observations reference network - surface air temperature (ACORN-SAT) dataset are also made. CDO temperature records originating