Impacts of climate change on irrigation water requirements for rice–wheat cultivation in Bagmati River Basin, Nepal

2013 ◽  
Vol 4 (4) ◽  
pp. 422-439 ◽  
Author(s):  
S. Shrestha ◽  
B. Gyawali ◽  
U. Bhattarai
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Irrigation Water ◽  
General Circulation ◽  
Large Scale ◽  
Circulation Model ◽  
Growth Stages ◽  
Water Requirements ◽  
Bagmati River ◽  
Impacts Of Climate Change

This study highlights the spatial and temporal impacts of climate change on rice–wheat cropping systems, focusing on irrigation water requirement (IWR) in the Bagmati River Basin of Nepal. The outputs from a general circulation model (HadCM3) for two selected scenarios (A2 and B2) of IPCC and for three time periods (2020s, 2050s, and 2080s) have been downscaled and compared to a baseline climatology. CROPWAT 8.0 model is used to estimate the water requirements. IWRs show different trends in different physiographic regions and different growth stages of rice and wheat. A decreasing trend of IWRs in the Mid Hills and the High Hills indicates that farmer-based small irrigation schemes are sufficient to meet the requirements. However, in the Terai region, where there is an increasing trend in IWRs, the deficit volume of water needs to be supplied from potential large-scale irrigation schemes.

Climate change impacts on irrigation water requirements in the Guadalquivir river basin in Spain

2007 ◽  
Vol 7 (3) ◽  
pp. 149-159 ◽  
Author(s):  
J. A. Rodríguez Díaz ◽  
E. K. Weatherhead ◽  
J. W. Knox ◽  
E. Camacho
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Irrigation Water ◽  
Climate Change Impacts ◽  
Water Requirements ◽  
Guadalquivir River

scholarly journals Development of a SWAT Hydropower Operation Routine and Its Application to Assessing Hydrological Alterations in the Mekong

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2193
Author(s):  
Jayandra P. Shrestha ◽  
Markus Pahlow ◽  
Thomas A. Cochrane
Keyword(s):  
Climate Change ◽  
Reservoir Operation ◽  
General Circulation ◽  
Hydrological Model ◽  
Circulation Model ◽  
Climate Change Scenarios ◽  
Reservoir Operations ◽  
Reservoir Systems ◽  
Hydropower Operation ◽  
Impacts Of Climate Change

Reservoir operations and climate change can alter natural river flow regimes. To assess impacts of climate and hydropower operations on downstream flows and energy generation, an integrated hydropower operations and catchment hydrological model is needed. The widely used hydrological model Soil and Water Assessment Tool (SWAT) is ideal for catchment hydrology, but provides only limited reservoir operation functions. A hydropower reservoir operation routine (HydROR) was thus developed for SWAT to analyze complex reservoir systems under different policies. The Hydrologic Engineering Center’s Reservoir System Simulation (HEC-ResSim) model, a well-established reservoir simulation model, was used to indirectly evaluate functionality of the HydROR. A comparison between HydROR and HEC-ResSim under a range of operation rule curves resulted in R2 values exceeding 0.99. The HydROR was then applied to assess hydrological alterations due to combined impacts of climate change and reservoir operations of 38 hydropower dams in the 3S basin of the Mekong River. Hydropower production under climate change varied from −1.6% to 2.3%, depending on the general circulation model chosen. Changing the hydropower operation policy from maximizing energy production to maintaining ecological flows resulted in a production change of 13%. The calculation of hydrological alteration indices at the outlet of the 3S basin revealed that over 113% alteration in the natural river outflow regime occurred from the combined impacts of climate change and reservoir operations. Furthermore, seasonal flows and extreme water conditions changed by 154% and 104%, respectively. Alterations were also significant within the basin, and, as expected, were larger for high-head and small-river reservoirs. These alterations will adversely affect ecological dynamics, in particular, habitat availability. HydROR proved to be a valuable addition to SWAT for the analyses of complex reservoir systems under different policies and climate change scenarios.

An Examination of Climate Change on Extreme Heat Events and Climate–Mortality Relationships in Large U.S. Cities

2011 ◽  
Vol 3 (4) ◽  
pp. 281-292 ◽  
Author(s):  
Scott Greene ◽  
Laurence S. Kalkstein ◽  
David M. Mills ◽  
Jason Samenow
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Large Scale ◽  
Circulation Model ◽  
The United States ◽  
Attributable Mortality ◽  
Climate Projections ◽  
Synoptic Classification ◽  
The Impact ◽  
Related Mortality

Abstract This study examines the impact of a changing climate on heat-related mortality in 40 large cities in the United States. A synoptic climatological procedure, the spatial synoptic classification, is used to evaluate present climate–mortality relationships and project how potential climate changes might affect these values. Specifically, the synoptic classification is combined with downscaled future climate projections for the decadal periods of 2020–29, 2045–55, and 2090–99 from a coupled atmospheric–oceanic general circulation model. The results show an increase in excessive heat event (EHE) days and increased heat-attributable mortality across the study cities with the most pronounced increases projected to occur in the Southeast and Northeast. This increase becomes more dramatic toward the end of the twenty-first century as the anticipated impact of climate change intensifies. The health impact associated with different emissions scenarios is also examined. These results suggest that a “business as usual” approach to greenhouse gas emissions mitigation could result in twice as many heat-related deaths by the end of the century than a lower emissions scenario. Finally, a comparison of future estimates of heat-related mortality during EHEs is presented using algorithms developed during two different, although overlapping, time periods, one that includes some recent large-scale significant EHE intervention strategies (1975–2004), and one without (1975–95). The results suggest these public health responses can significantly decrease heat-related mortality.

scholarly journals Assessing the climate change impact on hydrological response in the Gorganrood River Basin, Iran

2017 ◽  
Vol 9 (3) ◽  
pp. 421-433 ◽  
Author(s):  
Hamed Rouhani ◽  
Marayam Sadat Jafarzadeh
Keyword(s):  
Climate Change ◽  
River Basin ◽  
General Circulation ◽  
Assessment Tool ◽  
Circulation Model ◽  
Low Flow ◽  
Future Climate Change ◽  
Monthly Precipitation ◽  
Climate Change Scenarios ◽  
Annual Scale

Abstract A general circulation model (GCM) and hydrological model SWAT (Soil and Water Assessment Tool) under forcing from A1B, B1, and A2 emission scenarios by 2030 were used to assess the implications of climate change on water balance of the Gorganrood River Basin (GRB). The results of MPEH5C models and multi-scenarios indicated that monthly precipitation generally decreases while temperature increases in various parts of the basin with the magnitude of the changes in terms of different stations and scenarios. Accordingly, seasonal ET will decrease throughout the GRB over the 2020s in all seasons except in summer, where a slight increase is projected for A1B and A2 scenarios. At annual scale, average quick flow and average low flow under the B1, A1B, and A2 scenarios are projected to decrease by 7.3 to 12.0% from the historical levels. Over the ensembles of climate change scenarios, the simulations project average autumn total flow declines of ∼10% and an overall range of 6.9 to 13.2%. In summer, the components of flow at the studied basin are expected to increase under A2 and A1B scenarios but will slightly decrease under B1 scenario. The study result addresses a likelihood of inevitable future climate change.

scholarly journals Storm Track Shifts under Climate Change: What Can Be Learned from Large-Scale Dry Dynamics

2013 ◽  
Vol 26 (24) ◽  
pp. 9923-9930 ◽  
Author(s):  
Cheikh Mbengue ◽  
Tapio Schneider
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Large Scale ◽  
Storm Track ◽  
Circulation Model ◽  
Hadley Circulation ◽  
Phase Changes ◽  
Storm Tracks ◽  
Convective Stability ◽  
Poleward Shift

Abstract Earth’s storm tracks are instrumental for transporting heat, momentum, and moisture and thus strongly influence the surface climate. Climate models, supported by a growing body of observational data, have demonstrated that storm tracks shift poleward as the climate warms. But the dynamical mechanisms responsible for this shift remain unclear. To isolate what portion of the storm track shift may be accounted for by large-scale dry dynamics alone, disregarding the latent heat released in phase changes of water, this study investigates the storm track shift under various kinds of climate change in an idealized dry general circulation model (GCM) with an adjustable but constant convective stability. It is found that increasing the mean surface temperature or the convective stability leads to poleward shifts of storm tracks, even if the convective stability is increased only in a narrow band around the equator. Under warming and convective stability changes roughly corresponding to a doubling of CO2 concentrations from a present-day Earthlike climate, storm tracks shift about 0.8° poleward, somewhat less than but in qualitative agreement with studies using moist GCMs. About 63% (0.5°) of the poleward shift is shown to be caused by tropical convective stability variations. This demonstrates that tropical processes alone (the increased dry static stability of a warmer moist adiabat) can account for part of the poleward shift of storm tracks under global warming. This poleward shift generally occurs in tandem with a poleward expansion of the Hadley circulation; however, the Hadley circulation expansion does not always parallel the storm track shift.

scholarly journals Assessment of hydrological response in Subarnarekha river basin under anticipated climate change scenarios

2020 ◽  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
General Circulation ◽  
Circulation Model ◽  
Climate Modelling ◽  
Climate Change Scenarios ◽  
Hydrological Response ◽  
Study Region ◽  
Subarnarekha River ◽  
Subarnarekha River Basin

<p>Two hydrological climate modelling techniques, general circulation model (GCM) and hypothetical climate change scenarios, were used to analyse the hydrological response to the anticipated climate change scenarios in the Subarnarekha river basin in Eastern India. Both models verified individually for the same river basin and a comparative performance of the models was evaluated to relate the two models for the near (2014-2040) period climate. The hydrological response under the anticipated climate change in the Subarnarekha river basin is well assessed by GCM under the RCP 8.5 scenarios compared to the RCPs 4.5. Results indicate GCM best suited over the hypothetical climate change scenarios as GCM has demonstrated their potential in accurately reproducing the past observed climatic changes. The strong performance of the hypothetical climate change scenarios model, particularly for warming climate scenarios, suggests that it may have distinct advantages for the analysis of water balance components in the river basin. The monthly streamflows of Subarnarekha river basin was simulated using a total of 14 years (2000-2013) daily observed streamflow data in the ArcSWAT model integrated with model calibration and uncertainty analysis by means of SUFI-2 algorithm. The results indicate during the calibration the coefficient of determination (R2) and Nash-Sutcliff Efficiency (NSE) were reported as 0.98 and 0.97, respectively, while during the validation the R2 and NSE were obtained as 0.94 and 0.94, respectively, confirms the hydrological model performance was very good both in calibration and validation. The obtained climate change water impact index (ICCWI) values reveal the Subarnarekha river basin is more responsive to climate change. The reduction in precipitation along with the significant warming under the projected future climate is likely to reduce availability of water substantially in the study region. This work would be useful for the effective management of water resources for sustainable agriculture and in mitigating natural hazards such as droughts and floods in the study region.</p>

scholarly journals Impacts of Climate Change on Rainfall Trends Under RCP Scenarios in Johor, Malaysia

2021 ◽  
Author(s):  
Siti Nazahiyah Rahmat ◽  
Aainaa Hatin Ahmad Tarmizi ◽  
Nurul Nadrah Aqilah Tukimat
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Historical Data ◽  
Rainfall Variability ◽  
Daily Rainfall ◽  
Circulation Model ◽  
Upward Trend ◽  
Rcp Scenarios ◽  
Rainfall Trends ◽  
Impacts Of Climate Change

Abstract Changes in the spatial and temporal rainfall pattern affected by the climate change need to be investigated as its significant characteristics are often used for managing water resources. In this study, the impacts of climate change on rainfall variability in Johor was investigated by using General Circulation Model (GCM) on the availability of daily simulation for three representative concentration pathways (RCP) scenarios, RCP2.6, RCP4.5 and RCP8.5 for interval year of Δ2030, Δ2050 and Δ2080. In addition, the annual future rainfall trend for the first interval year of Δ2030 was also made. Daily rainfall series from eight (8) stations in Johor, Malaysia capturing 30 years period (1988-2017) with less than 10% missing data were chosen. The annual mean rainfall for RCP 2.6, 4.5 and 8.5 was predicted increase by 17.5%, 18.1% and 18.3%, respectively as compared to historical data. Moreover, the Mann-Kendall (MK) test was used to detect the trend and resulted in no trend for RCP2.6. Even so, RCP4.5 showed a significant upward trend in Muar and Kota Tinggi, and for RCP8.5, all regions were detected to have an upwards trend except for Pontian and Kluang. In general, the concentration of greenhouse gases from RCP8.5 gave the highest rainfall in future.

scholarly journals Estimating monthly rainfall in rural river basins under climate change: an improved bias-correcting statistical downscaling approach

2013 ◽  
Vol 10 (6) ◽  
pp. 6847-6896
Author(s):  
D. L. Jayasekera ◽  
J. J. Kaluarachchi
Keyword(s):  
Climate Change ◽  
General Circulation Model ◽  
River Basin ◽  
Bias Correction ◽  
General Circulation ◽  
Circulation Model ◽  
Correction Method ◽  
Annual Rainfall ◽  
Bias Correction Method ◽  
Time Space

Abstract. This study extended the work of Kim et al. (2008) to generate future rainfall under climate change using a discrete-time/space Markov chain based on historical conditional probabilities. A bias-correction method is proposed by fitting suitable statistical distributions to transform rainfall from the general circulation model (GCM) scale to watershed scale. The demonstration example used the Nam Ngum River Basin (NNRB) in Laos which is a rural river basin with high potential for hydropower generation and significant rain-fed agriculture supporting rural livelihoods. This work generated weekly rainfall for a 100 yr period using historical rainfall data from 1961 to 2000 for ten selected weather stations. The bias-correction method showed the ability to reduce bias of the mean values of GCMs when compared to the observed mean amount at each station. The simulated rainfall series is perturbed using the delta change estimated at each station to project future rainfall for the Special Report on Emission Scenarios (SRES) A2. GCMs consisting of third generation coupled general circulation model (CGCM3.1 T63) and European center Hamburg model (ECHAM5) projected an increasing trend of mean annual rainfall in the NNRB. Seasonal rainfall percent changes showed an increase in the wet and dry seasons with the highest increase in the dry season mean rainfall of about 31% from 2051 to 2090. While the GCM projections showed good results with appropriate bias corrections, the Providing REgional Climates for Impacts Studies (PRECIS) regional climate model significantly underestimated historical behavior and produced higher mean absolute errors compared to the corresponding GCM predictions.

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