Recent climatic trends and linkages to river discharge in Central Vietnam

Abstract

In this study, change in rainfall, temperature and river discharge are analysed over the last three decades in Central Vietnam. Trends and rainfall indices are evaluated using non‐parametric tests at different temporal levels. To overcome the sparse locally available network, the high resolution APHRODITE gridded dataset is used in addition to the existing rain gauges. Finally, existing linkages between discharge changes and trends in rainfall and temperature are explored. Results are indicative of an intensification of rainfall (+15%/decade), with more extreme and longer events. A significant increase in winter rainfall and a decrease in consecutive dry days provides strong evidence for a lengthening wet season in Central Vietnam. In addition, trends based on APHRODITE suggest a strong orographic signal in winter and annual trends. These results underline the local variability in the impacts of climatic change at the global scale. Consequently, it is important that change detection investigations are conducted at the local scale. A very weak signal is detected in the trend of minimum temperature (+0.2°C/decade). River discharge trends show an increase in mean discharge (31 to 35%/decade) over the last decades. Between 54 and 74% of this increase is explained by the increase in precipitation. The maximum discharge also responds significantly to precipitation changes leading to a lengthened wet season and an increase in extreme rainfall events. Such trends can be linked with a likely increase in floods in Central Vietnam, which is important for future adaptation planning and management and flood preparedness in the region. Copyright © 2012 John Wiley & Sons, Ltd.

Quantifying human impacts on hydrological drought using a combined modelling approach in a tropical river basin in central Vietnam

“…The patterns of timing and magnitude of streamflow essentially depend on climatic variables such as precipitation (Zhang et al, 2007;Min et al, 2011;Souvignet et al, 2013;Ahn and Merwade, 2014), temperature, and the resulting altered evapotranspiration rates (Vörösmarty et al, 2000;Santer et al, 2011;Trenberth, 2011;Ahn and Merwade, 2014), as well as on the modification of the hydrological systems by humans introducing water infrastructure such as reservoirs and damming, interbasin water transfers, and construction of weirs.…”

“…The climate in the VGTB basin is characterized by a strong wet season with typhoons lasting from September to December and an extended dry season (Souvignet et al, 2013). Next to the two major seasons -which we here term the "dry" and "wet" seasons -there are four minor seasons observed in this region and referred to in this study as summer -June, July, August (JJA); autumn -September, October, November (SON); winter -December, January, February (DJF); and spring -March, April, May (MAM) (Souvignet et al, 2013).…”

“…Next to the two major seasons -which we here term the "dry" and "wet" seasons -there are four minor seasons observed in this region and referred to in this study as summer -June, July, August (JJA); autumn -September, October, November (SON); winter -December, January, February (DJF); and spring -March, April, May (MAM) (Souvignet et al, 2013). Rainfall during the wet season accounts for 65-80 % of the total annual rainfall, with 40-50 % of the annual rainfall occurring in October and November, and this high rainfall regularly causes severe floods (Souvignet et al, 2013). The long dry season lasts from January to August and is frequently accompanied by droughts (e.g.…”

Assessment of climate variations in temperature and precipitation extreme events over Iran

“…Similar results were produced by Manton et al (2001) in a study over Southeast Asia and the South Pacific islands including Australia and New Zealand. Souvignet et al (2014) studied the recent climatic trends and their linkages to river discharge in Central Vietnam. They found an intensification of rainfall (+15 %/decade), with more extreme and longer events.…”

Managing Water and Soils to Achieve Adaptation and Reduce Methane Emissions and Arsenic Contamination in Asian Rice Production

“…The 2011 Southeast Asian flood caused water levels in Cambodia's Tonle Sap Lake to rise above normal for more than one month, destroying 12% of the area planted in rice in Battambang Province, with notable implications for livelihoods and food security in the region [16]. The frequency of such flooding is expected to increase with climate change [17][18][19]). In sum, rice production is susceptible to yield impairment due to several aspects of climate change, including changes in rainfall patterns, higher temperatures, and an increase in the frequency and severity of flooding events.…”