A framework for assessing hydrological regime sensitivity to climate change in a convective rainfall environment: a case study of two medium-sized eastern Mediterranean catchments, Israel

Abstract

Abstract.A modeling framework is formulated and applied to assess the sensitivity of the hydrological regime of two catchments in a convective rainfall environment with respect to projected climate change. The study uses likely rainfall scenarios with high spatiotemporal resolution that are dependent on projected changes in the driving regional meteorological synoptic systems. The framework was applied to a case study in two medium-sized Mediterranean catchments in Israel, affected by convective rainfall, by combining the HiReS-WG rainfall generator and the SAC-SMA hydrological model. The projected climate change impact on the hydrological regime was examined for the RCP4.5 and RCP8.5 emission scenarios, comparing the historical (beginning of the 21st century) and future (mid-21st-century) periods from three general circulation model simulations available from CMIP5. Focusing on changes in the occurrence frequency of regional synoptic systems and their impact on rainfall and streamflow patterns, we find that the mean annual rainfall over the catchments is projected to be reduced by 15 % (outer range 2-23 %) and 18 % (7-25 %) for the RCP4.5 sand RCP8.5 emission scenarios, respectively. The mean annual streamflow volumes are projected to be reduced by 45 % (10-60 %) and 47 % (16-66 %). The average events' streamflow volumes for a given event rainfall depth are projected to be lower by a factor of 1.4-2.1. Moreover, the streamflow season in these ephemeral streams is projected to be shorter by 22 % and 26-28 % for the RCP4.5 and RCP8.5, respectively. The amplification in reduction of streamflow volumes relative to rainfall amounts is related to the projected reduction in soil moisture, as a result of fewer rainfall events and longer dry spells between rainfall events during the wet season. The dominant factors for the projected reduction in rainfall amount were the reduction in occurrence of wet synoptic systems and the shortening of the wet synoptic systems durations. Changes in the occurrence frequency of the two dominant types of the regional wet synoptic systems (active Red Sea trough and Mediterranean low) were found to have a minor impact on the total rainfall.

Deciphering the expression of climate change within the Lower Colorado River basin by stochastic simulation of convective rainfall

“…Notable limitations of existing models include large input data requirements and/or reliance on GCM output to characterize climate change (e.g. [32]).…”

Simulated response of an intermittent stream to rainfall frequency patterns

“…The study of streamflow characteristics in intermittent catchments is more complicated than perennial catchments because of irregularity of rainfall events, high evapotranspiration rates, the seasonal mismatch between rainfall and evapotranspiration, poorly developed soils, and variability in vegetation cover (Niedda & Pirastru, 2014;Peleg et al, 2015;Wheater et al, 2007;Blöschl et al, 2013). Furthermore, intermittent streams are commonly poorly gauged, thereby hindering hydrological analyses (Yu et al, 2018).…”

“…Owing to the nonlinear responses of streamflow to alterations in rainfall pattern, arid and semi-arid regions are highly vulnerable (Peleg et al, 2015). Because rainfall frequency affects soil moisture content, infiltration, and streamflow characteristics (Li et al, 2011;Dunkerley, 2017;Wang et al, 2018), likely changes in rainfall patterns can amplify risks of water scarcity and increase streamflow intermittency.…”

HASIL AIR HUTAN JATI PADA DUA SUB DAERAH ALIRAN SUNGAI DENGAN LUAS BERBEDA (Water yield of Teak Forest at two different catchment sizes)

“…Tata air termasuk hasil air suatu DAS dipengaruhi oleh faktor pengelolaan lahan, dalam hal ini jenis penutupan atau penggunaan lahan yang menentukan besar dan distribusi hasil air (Krishnaswamy et al, 2013;Muñoz-Villers & McDonnell, 2013;Shamsuddin, Yusop, & Noguchi, 2014). Selain itu juga dipengaruhi oleh faktorfaktor alami seperti formasi geologi (Stoelzle, Stahl, Morhard, & Weiler, 2014;Vannier, Braud, & Anquetin, 2014), geomorfologi dan jenis tanah (Ayalew, Krajewski, & Mantilla, 2014;Geris, Tetzlaff, McDonnell, & Soulsby, 2015), dan input hujan (Dixon & Earls, 2012;Kretzschmar, Tych, & Chappell, 2014;Peleg, Shamir, Georgakakos, & Morin, 2015). Faktor alami lain yang berpengaruh terhadap hasil air ataupun limpasan adalah luas DAS (Brown, McDonnella, Burnsb, & Kendall, 1999;Zhang, Podlasly, Ren, Feger, Wang, & Schwärzel, 2012).…”