Australia: The Land Where Time Began

A biography of the Australian continent 

Range Increase of Precipitation Between the Wet and Dry Season

As the global temperatures have risen during the past few decades the atmospheric water vapour content has also risen, and the global hydrological cycle has strengthened (Knutso @ Manabe, 1995; Held & Soden, 2006; Wentz et al., 2007; Allan et al., 2010). This has led to a strengthening of the regional pre-existing climatic conditions, with wet regions getting wetter and dry regions getting drier (Knutso @ Manabe, 1995; Held & Soden, 2006; Wentz et al., 2007; Allan et al., 2010; John, Allan & Soden, 2009; Li et al., 2011). It has been suggested by climate model simulations that existing patterns may also apply to the rainfall seasonal cycle (Chou & Lan, 2012). The authors¹ have analysed trends, regional and global, in seasonal extremes of precipitation for the period of the last 3 decades by the use of a number of global and land-only observational datasets. Their results have demonstrated that there has been an increase in the annual precipitation range, largely as a result of wet seasons becoming wetter. As a result of the limitations inherent in the datasets used, the sign of the tendency is robust, though the magnitude of the shift is uncertain. Their study shows that the tendency, on a regional scale, for wet regions to get wetter occurs in regions that are already rainier. In dry regions there is a tendency for these regions to get drier. The enhancement of the seasonal precipitation cycle could, as suggested by the authors¹, have marked consequences for the frequency of droughts and floods, even if the total amount of rainfall does not change significantly.

Sources & Further reading

Chou, Chia, John C. H. Chiang, Chia-Wei Lan, Chia-Hui Chung, Yi-Chun Liao, and Chia-Jung Lee. "Increase in the Range between Wet and Dry Season Precipitation." Nature Geosci 6, no. 4 (04//print 2013): 263-67.