- Title
- Precipitation and evaporative aspects of the terrestrial water balance in Central Victoria and their relationship to large-scale climate drivers during the growing season
- Creator
- Marshall, Adam
- Date
- 2016
- Type
- Text; Thesis; Masters
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/102915
- Identifier
- vital:10828
- Abstract
- Terrestrial Water Balance (TWB) incorporates the combined effects of precipitation and evaporation, and is an important factor influencing agricultural and hydrological processes and management. This study analyses the TWB components at five stations in central Victoria from 1972 - 2013, a region which spans a range of agricultural and hydrological regimes. These stations represent distinct climatic and geographic locations including the dry inland plains, the Great Dividing Range and the southern coastal area. This research focuses on the „Growing Season‟ from March - November; a period where increased availability of moisture is critical for commencing, maintaining and ceasing a variety of agricultural practices. Moisture surplus is known as „Effective Precipitation‟ and is represented by a Precipitation/Evaporation (P-E) ratio >1. Whilst the combined P-E ratio is significant, an emphasis is placed upon examining individual meteorological components which determine the TWB. Hence rainfall and pan evaporation characteristics are analysed on both monthly and seasonal timescales within the 'Growing Season'. Trends in rainfall are fairly consistent across all stations with ongoing declines generally observed in all months except November, most notable in April, May and October. Pan evaporation displays much more variation between stations with both strong positive and negative trends evident throughout the station network in each season. The varying trends in pan evaporation between the stations suggest that the same large scale conditions can result in vastly different effects locally, owing to topographic and geographic factors. The influence of El Niño - Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) on pan evaporation is widespread and statistically significant during Winter and Spring. The Southern Annular Mode (SAM) displays marked intra-seasonal influence which appears to be highly location dependent. Consistent with the literature, rainfall shows increasing correlations with ENSO and IOD through Winter before peaking in Spring at all stations. Interestingly, despite changes in teleconnection strength over time, these tropical climate drivers display a stronger relationship with pan evaporation than rainfall over the full analysis period. Therefore an opportunity may exist to use such relationships to develop seasonal forecasts of evaporation, similar to what is currently employed for seasonal rainfall forecasting. This is important as Effective Precipitation is significantly influenced by the evaporative component of the TWB. Critically, this study shows that variations in such elements need to be considered on a regional basis, bearing in mind differences in geographic and topographic location, as well as intra-seasonal regimes within the overall Growing Season.; Master of Applied Science
- Publisher
- Federation University Australia
- Rights
- Copyright Adam Marshall
- Rights
- Open Access
- Rights
- This metadata is freely available under a CCO license
- Subject
- Terrestrial Water Balance (TWB); Precipitation; Evaporation; Central Victoria; Climate drivers; Growing season
- Full Text
- Thesis Supervisor
- Gell, Peter
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