@article{BenNsirJomaaYildirimetal.2022, author = {Ben Nsir, Siwar and Jomaa, Seifeddine and Yildirim, Umit and Zhou, Xiangqian and D'Oria, Marco and Rode, Michael and Khlifi, Slaheddine}, title = {Assessment of climate change impact on discharge of the lakhmass catchment (Northwest Tunisia)}, series = {Water}, volume = {14}, journal = {Water}, number = {14}, publisher = {MDPI}, address = {Basel}, issn = {2073-4441}, doi = {10.3390/w14142242}, pages = {17}, year = {2022}, abstract = {The Mediterranean region is increasingly recognized as a climate change hotspot but is highly underrepresented in hydrological climate change studies. This study aims to investigate the climate change effects on the hydrology of Lakhmass catchment in Tunisia. Lakhmass catchment is a part of the Medium Valley of Medjerda in northwestern Tunisia that drains an area of 126 km(2). First, the Hydrologiska Byrans Vattenbalansavdelning light (HBV-light) model was calibrated and validated successfully at a daily time step to simulate discharge during the 1981-1986 period. The Nash Sutcliffe Efficiency and Percent bias (NSE, PBIAS) were (0.80, +2.0\%) and (0.53, -9.5\%) for calibration (September 1982-August 1984) and validation (September 1984-August 1986) periods, respectively. Second, HBV-light model was considered as a predictive tool to simulate discharge in a baseline period (1981-2009) and future projections using data (precipitation and temperature) from thirteen combinations of General Circulation Models (GCMs) and Regional Climatic Models (RCMs). We used two trajectories of Representative Concentration Pathways, RCP4.5 and RCP8.5, suggested by the Intergovernmental Panel on Climate Change (IPCC). Each RCP is divided into three projection periods: near-term (2010-2039), mid-term (2040-2069) and long-term (2070-2099). For both scenarios, a decrease in precipitation and discharge will be expected with an increase in air temperature and a reduction in precipitation with almost 5\% for every +1 degrees C of global warming. By long-term (2070-2099) projection period, results suggested an increase in temperature with about 2.7 degrees C and 4 degrees C, and a decrease in precipitation of approximately 7.5\% and 15\% under RCP4.5 and RCP8.5, respectively. This will likely result in a reduction of discharge of 12.5\% and 36.6\% under RCP4.5 and RCP8.5, respectively. This situation calls for early climate change adaptation measures under a participatory approach, including multiple stakeholders and water users.}, language = {en} } @article{DuethmannBolchFarinottietal.2015, author = {Duethmann, Doris and Bolch, Tobias and Farinotti, Daniel and Kriegel, David and Vorogushyn, Sergiy and Merz, Bruno and Pieczonka, Tino and Jiang, Tong and Su, Buda and G{\"u}ntner, Andreas}, title = {Attribution of streamflow trends in snow and glacier melt-dominated catchments of the Tarim River, Central Asia}, series = {Water resources research}, volume = {51}, journal = {Water resources research}, number = {6}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0043-1397}, doi = {10.1002/2014WR016716}, pages = {4727 -- 4750}, year = {2015}, abstract = {Observed streamflow of headwater catchments of the Tarim River (Central Asia) increased by about 30\% over the period 1957-2004. This study aims at assessing to which extent these streamflow trends can be attributed to changes in air temperature or precipitation. The analysis includes a data-based approach using multiple linear regression and a simulation-based approach using a hydrological model. The hydrological model considers changes in both glacier area and surface elevation. It was calibrated using a multiobjective optimization algorithm with calibration criteria based on glacier mass balance and daily and interannual variations of discharge. The individual contributions to the overall streamflow trends from changes in glacier geometry, temperature, and precipitation were assessed using simulation experiments with a constant glacier geometry and with detrended temperature and precipitation time series. The results showed that the observed changes in streamflow were consistent with the changes in temperature and precipitation. In the Sari-Djaz catchment, increasing temperatures and related increase of glacier melt were identified as the dominant driver, while in the Kakshaal catchment, both increasing temperatures and increasing precipitation played a major role. Comparing the two approaches, an advantage of the simulation-based approach is the fact that it is based on process-based relationships implemented in the hydrological model instead of statistical links in the regression model. However, data-based approaches are less affected by model parameter and structural uncertainties and typically fast to apply. A complementary application of both approaches is recommended.}, language = {en} }