EWB climate analysis
•Download as PPTX, PDF•
1 like•303 views
Growing season rainfall in the eastern wheatbelt of Western Australia has decreased by 43.8mm (19%) since 1900, primarily due to losses in May and June rainfall. Summer rainfall, particularly in January, has increased by 32.5mm (60%), but the temperature increases of 0.7°C for maximum and 0.26°C for minimum temperatures reduce the value of this summer rainfall for plants. The observed changes in rainfall and temperatures are consistent with projections for mid-century climate change in the literature.
Recommended
More Related Content
Similar to EWB climate analysis
Similar to EWB climate analysis (7)
EWB climate analysis
- 1. Climate Impacts on the Eastern Wheatbelt Tim Scanlon Supporting your success
- 2. Contents • Nothing surprising in the analysis • Looked at two zones so far • 16 sites in Westonia and Yilgarn • 69 sites in Mt Marshall to Narembeen • Major changes in January and May-July rainfall • Significant changes in temperatures Supporting your success
- 3. WA Rainfall Change Isohyets Equivalent of moving 50 km
- 4. Something happening since 2000? England, Ummenhoffer and Santosa, 2006
- 5. Something happening since 2000?
- 7. EWB Rainfall
- 8. Decadal Trends Since 1900
- 11. EWB Site Rainfall Ranges
- 12. EWB Temperature
- 14. EWB Change in Temperature
- 17. Yields?
- 18. Summary Summary Growing season rainfall has decreased 43.8mm (19%). Mostly a loss in May and June rainfall. Gains in summer rainfall, particularly January, of 32.5mm (60%). Annual rainfall only declined 10.5mm as a result (3.5%). Summer rainfall highly variable, one in three years. The annual average temperature increases of 0.7 (maxima) and 0.26 (minima). These are in line with current analyses and predictions from the literature. Early (April-June) and late (Oct) season much hotter. Mid season overnight colder (June-Sept). Temperature increases and winter season dominance mean the summer gains of little value to plants. The rainfall changes are the changes expected by mid-century. Mid-century figures will need a rethink. Supporting your success
- 19. Projected rainfall changes for end of century Supporting your success IOCI3 Technical Report, 2012
- 20. WA Rainfall Change Isohyets
- 21. Summary Summary Growing season rainfall has decreased between 20 and 45mm. Mostly a loss in May and June rainfall. Gains in summer rainfall, particularly January, offset the annual rainfall figures. Temperature increases and season winter season dominance mean the summer gains of little value to plants. The temperature changes are in line with current analyses and predictions from the literature. The rainfall changes are the changes expected by mid-century. Mid-century figures will need a rethink. Supporting your success
- 22. 2000 - 2013 Yields from ABARES, and estimated from GIWA for 2013/14. WA Wheat Production and Seasonal Rainfall Supporting your success Seasonal rainfall and production Year MAM JJA ASO May-Oct Production 2000 B B B B 5.8 2001 B B N-A B 7.8 2002 B B B B 4.0 2003 A N-A A N-A 11.1 2004 B N-B N-A N-B 8.6 2005 A N-B A A 9.1 2006 B B N-B B 5.1 2007 B B N-B B 5.8 2008 N B N-A B 8.3 2009 B N-A N N-B 8.1 2010 B B B B 5.0 2011 B A A N-A 11.0 2012 B B B B 6.6 2013 A B A N-B 15.2
- 23. Indian Ocean Climate Initiative Key findings include: ❖ Winter rainfall has decreased sharply and suddenly in the region since the mid 70s. ❖ The decline was not gradual but more of a switching to an alternative rainfall regime. ❖ The rainfall decrease accompanied and was apparently associated with, documented change in large scale atmospheric circulation at the time. ❖ The decrease in rainfall, and associated circulation changes, bear some resemblance to model projections for an enhanced greenhouse effect (EGE) but are not sufficiently similar to indicate, beyond doubt, that the EGE is responsible. ❖ Most likely both natural variability and the EGE have contributed to the rainfall decrease. 1975 and 2000 “special dates” 2000 thought to be because of post 1998 El Nino ENSO phase with a greater proportion of heat being accumulated in the oceans. Climate changes for post 2000
- 24. Pre versus Post 2000?
- 25. Something happening since 2000
- 26. Scan statistic for 5 year window by Karyn Reeves and Mario D’Antuono. Scan statistic for pre versus post 2000
- 27. Thank you Visit agric.wa.gov.au Supporting your success
Editor's Notes
- Schematic diagram showing the connection between Indian Ocean climate variability and (a) dry, (b) wet years over southwest Western Australia. Sea surface temperature anomalies are shown as actual observed composite fields (color shaded in °C). Wind anomalies are shown as bold arrows, pressure anomalies by H (high) and L (low), and rainfall anomalies by sun/cloud symbols.
- Warming periods post 1975 and 2000 for Sea Surface Temperature Anomalies. 1975 and 2000 “special dates” 2000 because post 1998 El Nino ENSO phase a greater proportion of heat being accumulated in the oceans. Warming periods post 1975 and 2000 for Sea Surface Temperature Anomalies. From IOCI Report 2 Report 3 includes future projections: https://data.csiro.au/dap/landingpage?execution=e1s2&_eventId=viewDescription http://www.ioci.org.au/publications/ioci-stage-3/cat_view/17-ioci-stage-3/23-reports.html From Andrew Glikson: That the average rate of warming of the atmosphere has decreased since 2000 relative to the 1975-1998 rate is a consequence in part of rising sulphur aerosol emissions (particularly in China), a low in the 11th years sun spot cycle and strong La Nina events. However, the oceans continued to warm at a high rate, measured at a depth of 0-100 meters as about +0.4 degrees C and at up to 700 meters at a rate of +15 10^22 Joules during 1950-2012 http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/ http://www.nodc.noaa.gov/ OC5/3M_HEAT_CONTENT/index3.html Hansen et al. (2012) estimate the current Earth radiative imbalance, namely of heat trapped in the Earth surface, atmosphere and oceans, as about 0.6 Watt/m2, mostly due to greenhouse gases due to the release of more than 500 billion tons of carbon since 1750. http://theconversation.com/what-climate-tipping-points-should-we-be-looking-out-for-27108
- 556 sites throughout the agricultural zone, not including DAFWA sites. Red is Zone 12 – 16 sites (Westonia and Yilgarn) Blue is Zone 10 – 69 sites 4 sites on the border of each, so just went with their allocated demarcations. Blue and red sites make up the Merredin advisory district of: Bruce Rock, Kellerberrin, Koorda, Merredin, Mount Marshall, Mukinbudin, Narembeen, Nungarin, Trayning, Westonia, Yilgarn.
- Annual rainfall for the EWB sites has declined 10.5mm, from an adjusted figure of 297 to 286mm. Summer/Out of season rainfall has increased 32.5mm, whilst growing season (April to Oct) has decreased 43.8mm. GSR 230 to 186mm. All months had changes in rainfall except March and August. Although most changes were only small, less than 3 mm. Main changes were in January, adjusted increase of 9.6mm, and the loss of 36.9mm in the May-July period. This was predominately June losses. NB: Figures quoted are not raw figures but back transformed averages from the analysis. This is especially important to note for January, which has a large shift in the raw data, but 9.6mm shift in the transformed data (because not an annual change, more like one big wet summer every three years).
- 20-30mm diff between deciles <1999 Now 2mm diff to 20mm Deciles <1999 >2000 Change 1 166.4 137.6 28.8 2 195.3 139.2 56.2 3 210.3 159.4 50.9 4 219.3 175.8 43.5 5 238.0 193.1 44.9 6 248.3 208.5 39.8 7 269.1 232.1 37.1 8 283.0 252.1 30.9 9 309.3 262.7 46.6
- Percentages hard to follow, present as number of years. Decile GSR Summer 1 166.4 23.5 2 195.3 31.5 3 210.3 40.7 4 219.3 48.2 5 238.0 59.3 6 248.3 68.8 7 269.1 85.8 8 283.0 103.4 9 309.3 139.4
- Annual temperatures have increased for maximum temperatures is 0.7 degrees. Biggest changes have been to April-June and October, with May and October having 1.3 and 1.22 degree increases. Annual minimum temperatures have increased 0.26 degrees. Most months have increased between 0.3 and 0.5 degrees, with October and November increasing 0.59 and 0.86. June to September have actually decreased in minimum temperatures by 0.2 of a degree.
- Implications for smaller rainfall events and drying of soil surface, but also means potentially better growing early. Possible increased frost risk in June to September. The increase in frost risk
- Annual rainfall for Westonia and Yilgarn sites increased 14.1mm, from an adjusted figure of 285 to 299mm. Summer/Out of season rainfall has increased 42.5mm, whilst growing season (April to Oct) has decreased 22.5mm. GSR 210 to 188mm. All months had changes in rainfall except April, August and October. Although most changes were only small, less than 5mm. Main changes were in January, adjusted increase of 10.9mm, and the loss of 27.3mm in the May-July period. This was predominately June losses. NB: Figures quoted are not raw figures but back transformed averages from the analysis. This is especially important to note for January, which has a large shift in the raw data, but 10.9mm shift in the transformed data (because not an annual change, more like one big wet summer every three years).
- Annual temperatures have increased for maximum temperatures is 0.6 degrees. Biggest changes have been to April-August and October-November, with April, May and October having >1.0 degree increases. Annual minimum temperatures have increased 0.3 degrees. January to May increased in night time temperatures, as did October to December. Decreases were seen in June to September. Decreases were generally less than 0.4 degrees, whilst increases were roughly half a degree, except November with a 0.95 degree increase.
- Other work in this space looking at rainfall isohyets. General rule of thumb is moving south west with isohyets.
- Analysis from Ian Foster and Fiona Evans looking at season types and resulting production statewide for wheat. Wet finishes determine the big years (A). Below average lead in to the season never results in anything better than average. Couple of main patterns exist.
- From IOCI Report 2 Report 3 includes future projections: https://data.csiro.au/dap/landingpage?execution=e1s2&_eventId=viewDescription http://www.ioci.org.au/publications/ioci-stage-3/cat_view/17-ioci-stage-3/23-reports.html From Andrew Glikson: That the average rate of warming of the atmosphere has decreased since 2000 relative to the 1975-1998 rate is a consequence in part of rising sulphur aerosol emissions (particularly in China), a low in the 11th years sun spot cycle and strong La Nina events. However, the oceans continued to warm at a high rate, measured at a depth of 0-100 meters as about +0.4 degrees C and at up to 700 meters at a rate of +15 10^22 Joules during 1950-2012 http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/ http://www.nodc.noaa.gov/ OC5/3M_HEAT_CONTENT/index3.html Hansen et al. (2012) estimate the current Earth radiative imbalance, namely of heat trapped in the Earth surface, atmosphere and oceans, as about 0.6 Watt/m2, mostly due to greenhouse gases due to the release of more than 500 billion tons of carbon since 1750. http://theconversation.com/what-climate-tipping-points-should-we-be-looking-out-for-27108
- Why look at before and after 2000? What is so special, is it justified? Already some evidence: Figure from GRDC report by David Stephens showing moisture stress since 2000 (except Qld which has had more tropical moisture).
- Second figure from David Stephens GRDC report showing yield declines since 2000 (except Qld)
- Confirmed whether is was appropriate to look at pre versus post 2000. Mario and Karyn did 5 and 14 year scan statistic windows. 5 year windows only really confirm that weather is highly variable, although Karyn noted a possible decrease in rainfall and increase in variance post 2000 in comparison to 1980-1999. But when compared to the entire range of years this did not appear to be the case. Using a 14 year window to compare how likely the 2000-2013 period was in comparison to any other 14 year window in the data changed this, showing a 20mm difference that wasn’t elsewhere in the data.