On the Frequency of the Great Floods of South East Queensland

Transcription

1 On the Frequency of the Great Floods of South East Queensland D.D.Hinde PhD, B.Eng., RPEQ Key words: asset management, infrastructure, Brisbane floods, Gympie floods, Rockhampton floods, lunar cycle regression, full moon, new moon, perigee. ABSTRACT The great floods of south eastern Queensland appear to catch many people by surprise with devastating consequences. Although floods occur from time to time there currently is no scientific published information on what causes them, nor when they are likely to occur. This study has found the fundamental timing frequency of great flood events for south eastern Queensland to be based on the 56 year greater lunar cycle. A systematic method is also presented for analyzing the trend of new and full moon perigees to further enhance the understanding of flood and non flood events. Opportunities for further work lie in the ability for asset owners to confidently include flood predictions within their asset management strategies. The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 1

2 INTRODUCTION The great floods of south eastern Queensland appear to catch many people by surprise with devastating consequences. Although floods occur from time to time there currently is no scientific published information on what causes these floods, nor when they are likely to occur [1]. This work is aimed toward alleviating some of the uncertainty of what causes them and when great floods are likely to reoccur. Background The moon orbits the earth on an elliptical path on the lunar orbital plane (L1 L2 L3 L4). Relative to the stars, the elliptical path rotates eastwards taking about 8.85 years for one revolution. In addition, the lunar orbital plane rotates westwards taking about years to complete one revolution. See Figure 1. One Moon rotation = days Full moon to full moon ~ days Elliptical obit eastwards rotation = 8.85 years Lunar plane westwards rotation ~ 18.6 years 1 year ~ days Perigee when the moon is closest to the earth Perihelion when the earh is closest to the sun Figure 1. A picture showing the elliptical orbit of the Moon on the Lunar Orbital Plane. Ref [2]. The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 2

3 Analysis of flood data Gympie floods often occur with Brisbane floods and/or Rockhampton floods [3][4][5]. In this study, only the dates for the greatest floods were used. Table 1 lists these flood dates. Any minor flood coincidences were also included. The greatest floods are in bold, and the minor Table 1. Flood dates used in this study. coincidentals are shaded lighter. Brisbane Gympie Rockhampton Greatest recorded floods plus minor flood coincidences Figure 2 below shows the floods listed in Table 1 on a linear time scale. January 1974 is chosen as the reference. One easily identifiable period that can fit the flood data is the 56 year lunar plane regression cycle [6]. The 56 year cycle is made up from three year lunar plane regression cycles. The lunar plane regression causes the lunar orbit to change its declination relative to the earth 3 times in 56 years. According to general literature, the 56 years is known to be made up from years, and this was used by the ancient Chinese, the Babylonians, and the Greeks (19 Priestesses); as well as by the Celts with the circle of 56 markers at Stonehenge. Great Floods of South East Queensland Comparison with 56 yr ( )yrs Lunar Plane Regression Cycle 19 Yrs 56 Yrs 56 Yrs 37 Yrs 56 Yrs 56 Yrs 19 Yrs 56 Yrs 18 Yrs 19 Yrs Rockhampton floods:, 1863, 1864, 1875, 1896,1918,1954, 1991,, Gympie floods:, 1893, 1898,1955,1974,1992,1999, Brisbane floods:, 1841, 1844, 1864, 1890, 1893, 1974,, D.D.Hinde Figure 2. Comparison between the great flood events listed in Table 1 and the 56 year ( yrs) lunar plane regression cycle. The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 3

4 1841/4 1863/4 1896/ /5 1991/ Fitting periodic functions to the flood events Because of the 18, 19, 19 year cycle, what goes on with the moon during the 56 years is not linear. To help overcome this problem, Figure 3 shows 3 separate 56 year fundamental frequencies spaced 18, 19, and 19 years apart allowing each series to be studied independently. Included in Figure 3 are frequencies representing the 8.85 year perigee cycle (coloured green), and a 18 2 / 3 year cycle (coloured red) representing an average angular velocity of the lunar plane regression. Figure year perigee (green), 18 2 / 3 year lunar plane (red), and three 56 year cycles spaced 18, 19, and 19 years apart with the greatest flood events. The relative difference in angular velocities between the regressing lunar plane and the earth is h--w where h is the angular velocity of the earth about our sun, and w is the angular velocity of the regressing lunar plane. The difference in these angular velocities equates to a period of days which matches the flood data. Figure 4 shows this h--w day cycle summed with h a day cycle; the result reveals a beat frequency which appears to show the basic timing for the great flood events. Figure 4. Flood events and the beat frequency from (h+w) at d plus (h) at d. The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 4

5 1991 Rockhampton flood 1992 Gympie flood Brisbane and Rockhampton floods Dec 1982 Jan 1983 New and full moon perigees and the flood events The moon is closest to the earth in its elliptical orbit at perigee. At full and new moon perigees the moon and the earth are even closer together due to the alignment between the earth, moon, and the sun. The average period from full moon perigee to full moon perigee is (h-p) which equates to days (ave). During our summer, the earth is closest to the sun at perihelion which occurs about 3 rd January each year. Therefore, the moon will be at its closest point to earth during a full or new moon perigee at perihelion which is reflected in the extra height of the tides at this time. Table 2 shows the distance between the earth and the moon [7] nearest to each great flood event. Figure 5 shows the perigees leading up to and following the 1974 Brisbane and Gympie flood events. Table 2. Distances between earth and the moon at the nearestfull or new moon Perigee. Ref: [7] Year Flood Area Phase Distance [km] 1841 Brisbane Full moon Rockhampton New moon Brisbane New moon Bris/Gympie Full moon Rockhampton New moon Rockhampton Full moon No Flood Full moon Bris/Gympie Full moon No Flood Full moon Rockhampton Full moon Gympie Full moon Brisbane/Rock Full moon Figure 5. Full moon and new moon perigees leading up to and following the 1974 Brisbane and Gympie great floods. On 8 th January 1974 a full moon and perigee occurred within 1 hour (1Hr) timing. Floods followed later in January for both Gympie and Brisbane. All great flood events appear to have similar full or new moon at perigee around perihelion as pre conditions. For example, there was a full moon at perigee (2Hr) in December 1990 followed later by the 1991 Rockhampton flood, and a full moon at perigee January 2 nd 1991 (0Hr) followed later by a flood in Gympie. See Fig. 6(a) below. Figure 6(b) shows another similar trend of the distances between the earth and the full moon at perigee which was followed shortly later by the Brisbane and Rockhampton floods. [Km] [Km] [Km] No flood event Fig. 6(a) Perigees and 1991/2 flood events Fig. 6(b) Perigees and flood events Fig. 6(c) Perigees and 1982/3 Non flood events The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 5

6 Not every full and new moon perigee is followed by a great flood. Fig. 6(c) shows a typical non-flood event. Although there were two consecutive full moon perigees during the summers of 1982/3, no great flood followed. Distance between the Earth and the Moon during New and Full moon Summer Perigees Figure 7 shows the distances between the moon and the earth during full and new moon summer perigees and there appears a limit (approximately 356,900 km) for beyond which no flood event has followed, although other pre conditions were met. Figure 7. Distances between the earth and the moon during new and full moon summer perigees. The 1841 and 1844 Brisbane floods For the 1841 flood preconditions were met and a flood followed. Full moon perigees occurred for the next two years around summer then jumped to late May of The 1844 flood was in March showing that floods can occur in succession if the perigees linger around perihelion for several years. The 1999 Gympie flood The 1999 Gympie flood appears to be a special case as it has not aligned with any of the 18, 19, 19 year regression cycles, however, there was a perigee full moon at perihelion in that year and the distance between the earth and the moon was 356,614 km which is less than the maximum distance of 356,872 km at perihelion for the 1841 flood event. Figure 8 shows a result of combining the frequencies of the full moon perigees (h-p) plus the relative effect of the lunar plane regression (h+w) plus the perihelion (h) and reveals an envelope in alignment with the 1999 Gympie flood. For using only two harmonic constituents (p and w both relative to h), this result is remarkable. Figure 8. Summation of 0.15 (h-p) at days, 0.15 (h+w) at days, and 0.7 (h) at days. The envelope in Figure 8 reveals further information on the cause for the timing of floods, however, in order to estimate whether a flood is likely, the trend of the distances between the moon and the earth at new and full moon perigees still need to be checked. The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 6

7 / /2 ( ) 1841/4 1863/4 1896/ /5 1991/ Lunar H armonics and thegreat Floods of Southeast Queensland Figure year perigee (green), 18 2 / 3 year lunar plane (red), and 56 year cycles spaced 18, 19, and 19 years apart Figure 4. Beat frequency from (h+w) at d plus (h) at d. Figure 8. Summation of 0.15 (h-p) at days, 0.15 (h+w) at days, and 0.7 (h) at days. On thefrequency of thegreat Floods of South east Queensland, Presented at The Asset Management Council Meeting, Engineers Australia, Brisbane, 14 th February 2013 David H indephd, B.Eng., RPEQ December 2012 Lunar Harmonics and the Great Floods of Southeastern Queensland The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 7

8 Summary This study finds the frequency of the great flood events of south east Queensland to be coincident with the lunar plane regression frequencies within the 56 year greater lunar cycle (18, 19, plus 19 years). The other significant influencing factors include: Conclusion The alignment of full and new moon perigees with the sun around and/or following perihelion, and; The distance between the earth and the moon was less than km. Further work needs to be done to be able to more accurately predict the location and severity of each flood event. Fundamental lunar cycles provide the key to accurate trending of extreme weather and natural event statistics. References [1] data/assets/pdf_file/0015/11706/qfci-final-report-chapter-2-floodplainmanagement.pdf [2] Picture of Lunar Orbital Plane: accessed Nov [3] Brisbane flood data from: accessed Nov [4] Gympie flood data from: a golden past_part4.pdf, accessed Nov [5] Rockhampton flood data from: accessed Nov [6] Lunar Declination Cycle: accessed November [7] Perigee and Apogee Calculator: accessed Dec Biography David Hinde was born in Brisbane in He achieved a Bachelor of engineering degree in 1988 and awarded a PhD in 2008 from QUT. David Hinde was the electrical systems engineer for Wivenhoe power station from 1992 to Throughout his 40yr + career David has mainly been involved in scientific and engineering investigations including power system and vibration harmonic analysis. David lives on the Bremer river and he had developed his own tide height algorithm for the lower Bremer river based on harmonic constituents that he uses for boating and recreational activities. As a flood victim, David found it compelling to investigate the primary cause for the great flood events that appear to have caught many generations by surprise. The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 8

9 Addendum 2 Floodplain management A floodplain is an area of land adjacent to a creek, river, estuary, lake, dam or artificial channel, which is subject to inundation by floodwater.1 Most cities and towns in Queensland are located on floodplains.2 There are ample benefits associated with making use of fertile floodplain lands, but they come with an obvious drawback: by definition, floodplain land is subject to flooding. No recommendations made by this Commission, even if implemented by government, can control the forces of nature. At some time in the future, parts of Queensland will experience floods of a magnitude as great as, or greater than, those of the 2010/ wet season. Existing science cannot predict when they will happen, or how severe they will be. Contemporary society does not countenance a fatalistic approach to such inevitabilities, even if their occurrence is unpredictable. There is an expectation that government will act to protect its citizens from disaster, and that all available science should be applied so that the nature and extent of the risk is known and appropriate action taken to ameliorate it. data/assets/pdf_file/0015/11706/qfci-final-report-chapter-2-floodplainmanagement.pdf Severe Tropical Cyclone Yasi began developing as a tropical low northwest of Fiji on 29th January and started tracking on a general westward track. The system quickly intensified to a cyclone category to the north of Vanuatu and was named Yasi at 10pm on the 30th by Fiji Meteorological Service. Yasi maintained a westward track and rapidly intensified to a Category 2 by 10am on 31st January and then further to a Category 3 by 4pm on the same day. Yasi maintained Category 3 intensity for the next 24 hours before being upgraded to a Category 4 at 7pm on 1st February. During this time, Yasi started to take a more west-southwestward movement and began to accelerate towards the tropical Queensland coast. Yasi showed signs of further intensification and at 4am on 2nd February (Full moon early 3 rd Feb) and was upgraded to a marginal Category 5 system. Yasi maintained this intensity and its west-southwest movement, making landfall on the southern tropical coast near Mission Beach between midnight and 1am early on Thursday 3rd February. Being such a strong and large system, Yasi maintained a strong core with damaging winds and heavy rain, tracking westwards across northern Queensland and finally weakened to a tropical low near Mount Isa around 10pm on 3rd February. Yasi is one of the most powerful cyclones to have affected Queensland since records commenced. Previous cyclones of a comparable measured intensity include the 1899 cyclone Mahina in Princess Charlotte Bay, and the two cyclones of 1918 at Mackay (January) and Innisfail (March). accessed Dec The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 9

10 On the Frequency of the Great Floodsof South East Queensland D Hinde, AMBoK Id 1126 The great floods of south eastern Queensland appear to catch many people by surprise with devastating consequences. Although floods occur from time to time there currently is no scientific published information on what causes them, nor when they are likely to occur. This study has found the fundamental timing frequency of great flood events for south eastern Queensland to be based on the 56 year greater lunar cycle. A systematic method is also presented for analyzing the trend of new and full moon perigees to further enhance the understanding of flood and non flood events. Opportunities for further work lie in the ability for asset owners to confidently include flood predictions within their asset management strategies. (Short Paper) The Asset Journal, Issue 2, Volume 7, 2013 This is an independent paper, well written and a fascinating read. The link between this paper and physical asset management may appear tenuous, but I believe that there is a strong argument for the application of such studies in the demand analysis process for infrastructure assets and better understanding emergency response requirements Can you comment in your presentation at the conference on what implications the outcomes of this understanding of flood patterns would have on physical asset infrastructure (dams, supply networks etc.), house design in low lying areas and emergency and relief services? Asset Management Conference 2013, Melbourne, at the MCG The Asset Journal, Issue 2, Volume 7, June 2013 AMBoK Id 1126 Page 10