scholarly journals Statistical Downscaling of Precipitation for Mahanadi Basin in India - Prediction of Future Streamflows

2021 ◽  
Author(s):  
Nayak P. C ◽  
Poonam Wagh ◽  
Venkatesh B. ◽  
Thomas T. ◽  
Satyaji Rao Y. R. ◽  
...  
Keyword(s):  
Climate Change ◽  
Statistical Downscaling ◽  
Swat Model ◽  
Mitigation Strategies ◽  
Historical Period ◽  
Future Scenarios ◽  
Flood Events ◽  
Stochastic Weather Generator ◽  
Extreme Flood ◽  
Mahanadi Basin

Abstract Climate change has long-term impacts on precipitation patterns, magnitude, and intensity, affecting regional water resources availability. Besides, understanding the interannual to decadal variations of streamflows in a river basin is paramount for watershed management, primarily extreme events such as floods and droughts. This study investigates impact of climate change in streamflows estimation for four sub-basins of the Mahanadi River, in India. The study includes three major components: (i) Historical trend analysis of hydroclimatic variables, using Mann-Kendall test; (ii) Statistical downscaling of GCM generated precipitation using change factor method and KnnCAD V4 stochastic weather generator; (iii) Dependable flow analysis of future streamflows predicted using Soil Water Assessment Tool (SWAT) model for various future GCM scenarios. It is observed that during the historical period, there is a decrease in number of rainy days and total annual precipitation in all sub-basins. However, the analysis also indicates an increase in flood intensity in two of the sub-basins. The decadal future precipitation has a marginal decrease in precipitation (up to 10%) for future scenarios; however, the precipitation events with high intensities increases. The results indicate that the magnitudes of 5% and 10% dependable flows are higher than the historically observed streamflows, for all future scenarios. This indicates a significant increase in extreme flood events in the basin. Further, only one of the sub-basins has shown an increase in water availability for agriculture and drinking water purposes (75% and 95% dependable flows) in the future. Understanding future flood events in the Mahanadi basin can help decision-makers to implement appropriate mitigation strategies.

scholarly journals Ectomycorrhiza resilience and recovery to extreme flood events in Tuber aestivum and Quercus robur

Mycorrhiza ◽  
2021 ◽  
Author(s):  
P. W. Thomas
Keyword(s):  
Climate Change ◽  
Seedling Growth ◽  
Quercus Robur ◽  
Root Systems ◽  
Fruiting Bodies ◽  
Flood Events ◽  
Tuber Aestivum ◽  
Soil Zone ◽  
Extreme Flood ◽  
The Impact

AbstractVery little is known about the impact of flooding and ground saturation on ectomycorrhizal fungi (EcM) and increasing flood events are expected with predicted climate change. To explore this, seedlings inoculated with the EcM species Tuber aestivum were exposed to a range of flood durations. Oak seedlings inoculated with T. aestivum were submerged for between 7 and 65 days. After a minimum of 114-day recovery, seedling growth measurements were recorded, and root systems were destructively sampled to measure the number of existing mycorrhizae in different zones. Number of mycorrhizae did not display correlation with seedling growth measurements. Seven days of submersion resulted in a significant reduction in mycorrhizae numbers and numbers reduced most drastically in the upper zones. Increases in duration of submersion further impacted mycorrhizae numbers in the lowest soil zone only. T. aestivum mycorrhizae can survive flood durations of at least 65 days. After flooding, mycorrhizae occur in higher numbers in the lowest soil zone, suggesting a mix of resilience and recovery. The results will aid in furthering our understanding of EcM but also may aid in conservation initiatives as well as providing insight for those whose livelihoods revolve around the collection of EcM fruiting bodies or cropping of the plant partners.

Climate change impact on legumes' water production function in the northeast of Iran

2014 ◽  
Vol 6 (2) ◽  
pp. 374-385 ◽  
Author(s):  
N. Sayari ◽  
M. Bannayan ◽  
A. Alizadeh ◽  
A. Farid ◽  
M. R. Hessami Kermani ◽  
...  
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Climate Model ◽  
Crop Yields ◽  
Global Climate Model ◽  
Mitigation Strategies ◽  
Stochastic Weather Generator ◽  
Time Periods ◽  
Northeast Iran ◽  
Far Future

Enhanced understanding of the climate impact on crops' production is necessary to cope with expected climate variability and change. This study was conducted to find any robust association between crop yield and evapotranspiration using historical data (1986–2005) and subsequently employ the acquired relationship to project crop yield under future climate conditions for two agricultural centers in northeast Iran. Three legume crops of chickpea, lentil, and bean were selected in this study. The future precipitation and temperature data were projected by downscaling outputs of global climate model HadCM3 (A2 scenario) by LARS-WG stochastic weather generator. The data were downscaled for the baseline (1961–1990) and two time periods (2011–2030 and 2080–2099) as near and far future conditions. Projected temperature under A2 scenario showed increasing trend changed from 4 to 26% during the legumes' growth period compared to baseline. In addition, projected annual precipitation change was between −14 and 10% range under different time periods in contrast to baseline. There was a nonlinear relationship between crop yields and the seasonal values of crop evapotranspiration for all crops. The results showed that seasonal evapotranspiration would increase under climate change conditions across study locations. Crop yield would also increase for chickpea but not for lentil and bean for the far future in Sabzevar location compared to baseline. In conclusion, increasing the temperature and decreasing the precipitation may have a negative effect on legumes' yield in northeast Iran, especially for far future conditions. Therefore, planning effective adaptation and mitigation strategies would be necessary for northeast Iran.

Some Pitfalls in Statistical Downscaling of Future Climate

2018 ◽  
Vol 99 (4) ◽  
pp. 791-803 ◽  
Author(s):  
John R. Lanzante ◽  
Keith W. Dixon ◽  
Mary Jo Nath ◽  
Carolyn E. Whitlock ◽  
Dennis Adams-Smith
Keyword(s):  
Climate Change ◽  
Statistical Downscaling ◽  
Large Scale ◽  
Climate Models ◽  
Climate Model ◽  
Climate Change Impacts ◽  
Future Climate ◽  
Added Value ◽  
Historical Period ◽  
Perfect Model

AbstractStatistical downscaling (SD) is commonly used to provide information for the assessment of climate change impacts. Using as input the output from large-scale dynamical climate models and observation-based data products, SD aims to provide a finer grain of detail and to mitigate systematic biases. It is generally recognized as providing added value. However, one of the key assumptions of SD is that the relationships used to train the method during a historical period are unchanged in the future, in the face of climate change. The validity of this assumption is typically quite difficult to assess in the normal course of analysis, as observations of future climate are lacking. We approach this problem using a “perfect model” experimental design in which high-resolution dynamical climate model output is used as a surrogate for both past and future observations.We find that while SD in general adds considerable value, in certain well-defined circumstances it can produce highly erroneous results. Furthermore, the breakdown of SD in these contexts could not be foreshadowed during the typical course of evaluation based on only available historical data. We diagnose and explain the reasons for these failures in terms of physical, statistical, and methodological causes. These findings highlight the need for caution in the use of statistically downscaled products and the need for further research to consider other hitherto unknown pitfalls, perhaps utilizing more advanced perfect model designs than the one we have employed.

scholarly journals Using Integrated Hydrological Models to Assess the Impacts of Climate Change on Discharges and Extreme Flood Events in the Upper Yangtze River Basin

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 299
Author(s):  
Yanjuan Wu ◽  
Gang Luo ◽  
Cai Chen ◽  
Zheng Duan ◽  
Chao Gao
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Global Climate ◽  
Yangtze River Basin ◽  
Global Climate Models ◽  
Hydrological Models ◽  
Flood Events ◽  
Temperature And Precipitation ◽  
Extreme Flood ◽  
Impacts Of Climate Change

Amongst the impacts of climate change, those arising from extreme hydrological events are expected to cause the greatest impacts. To assess the changes in temperature and precipitation and their impacts on the discharge in the upper Yangtze Basin from pre-industrial to the end of 21st century, four hydrological models were integrated with four global climate models. Results indicated that mean discharge was simulated to increase slightly for all hydrological models forced by all global climate models during 1771–1800 and 1871–1900 relative to the 1971–2000 reference period, whereas the change directions in mean discharge were not consistent among the four global climate models during 2070–2099, with increases from HadGEM2-ES and MIROC5, and decreases from GFDL-ESM2M and IPSL-CM5A-LR. Additionally, our results indicated that decreases in precipitation may always result in the decrease in mean discharge, but increases in precipitation did not always lead to increases in discharge due to high temperature rise. The changes in extreme flood events with different return intervals were also explored. These extreme events were projected to become more intense and frequent in the future, which could have potential devastating impacts on the society and ecosystem in this region.

scholarly journals Assessment of Streamflow from EURO-CORDEX Regional Climate Simulations in Semi-Arid Catchments Using the SWAT Model

2021 ◽  
Vol 13 (13) ◽  
pp. 7120
Author(s):  
Alberto Martínez-Salvador ◽  
Agustín Millares ◽  
Joris P. C. Eekhout ◽  
Carmelo Conesa-García
Keyword(s):  
Climate Change ◽  
Assessment Tool ◽  
Swat Model ◽  
Regional Climate ◽  
Future Climate Change ◽  
Historical Period ◽  
Climate Change Scenarios ◽  
Rcp 8.5 ◽  
The Impact ◽  
Semi Arid

This research studies the effect of climate change on the hydrological behavior of two semi-arid basins. For this purpose, the Soil and Water Assessment Tool (SWAT) model was used with the simulation of two future climate change scenarios, one Representative Concentration Pathway moderate (RCP 4.5) and the other extreme (RCP 8.5). Three future periods were considered: close (2019–2040), medium (2041–2070), and distant (2071–2100). In addition, several climatic projections of the EURO-CORDEX model were selected, to which different bias correction methods were applied before incorporation into the SWAT model. The statistical indices for the monthly flow simulations showed a very good fit in the calibration and validation phases in the Upper Mula stream (NS = 0.79–0.87; PBIAS = −4.00–0.70%; RSR = 0.44–0.46) and the ephemeral Algeciras stream (NS = 0.78–0.82; PBIAS = −8.10–−8.20%; RSR = 0.4–0.42). Subsequently, the impact of climate change in both basins was evaluated by comparing future flows with those of the historical period. In the RCP 4.5 and RCP 8.5 scenarios, by the end of the 2071–2100 period, the flows of the Upper Mula stream and the ephemeral Algeciras stream will have decreased by between 46.3% and 52.4% and between 46.6% and 55.8%, respectively.

scholarly journals Climate Change Impacts on Rice Cultivation: A Comparative Study of the Tonle Sap and Mekong River

2021 ◽  
Vol 13 (16) ◽  
pp. 8979
Author(s):  
Serey Sok ◽  
Nyda Chhinh ◽  
Sanara Hor ◽  
Pheakdey Nguonphan
Keyword(s):  
Climate Change ◽  
Rainfall Variability ◽  
Rice Production ◽  
Rice Cultivation ◽  
Mekong River ◽  
Flood Events ◽  
Tonle Sap ◽  
Extreme Flood ◽  
Climate Hazards ◽  
The Impact

Climate change is unequivocal. Farmers are increasingly vulnerable to floods and drought. In this article, the negative impact of climate hazards on rice cultivation in the Tonle Sap and Mekong River influenced by climatic variability between 1994 and 2018 are analyzed. A cohort of 536 households from four Cambodian districts participated in household surveys designed to consider how various vulnerability factors interacted across this time series. It was found that: (i) The major climate hazards affecting rice production between 1994 and 2018 were frequent and extreme flood and drought events cause by rainfall variability; (ii) In 2018, extreme flood and drought occurred in the same rice cultivation cycle. The impact caused by each hazard across each region were similar; (3) An empirical model was used to demonstrate that drought events tend to limit access to irrigation, impact rice production, and result in an increased prevalence of water-borne diseases. Flood events cause reduced rice production, damage to housing, and impede children from accessing education. The impact of drought events on rice production was found to be more severe than flood events; however, each climatic hazard caused physical, economic, social, and environmental vulnerabilities. It is recommended that sufficient human and financial resources are distributed to local authorities to implement adaptation measures that prepare rice farmers for flood and drought events and promote equitable access to water resources.

scholarly journals Modelling the effects of climate change on urban coastal-fluvial flooding

2020 ◽  
Vol 11 (S1) ◽  
pp. 270-288 ◽  
Author(s):  
Jennifer Isabel Munro Kirkpatrick ◽  
Agnieszka Indiana Olbert
Keyword(s):  
Climate Change ◽  
Coastal Water ◽  
Best Practice ◽  
Climate Scenario ◽  
Flood Management ◽  
Water Levels ◽  
City Centre ◽  
Flood Events ◽  
River Flows ◽  
Extreme Flood

Abstract In coastal floodplains, high river flows and high coastal water levels can result in extensive flooding. Twenty-first century climate change is expected to alter these flood mechanisms. In this study, a coastal city of Cork, Ireland is used as a case study to investigate changes in flood mechanisms, dynamics and extents due to climate change. A hydrodynamic flood model MSN_Flood was used to compute potential future inundation patterns for a range of climate scenarios based on estimates of current, medium-range and high-end projections of extreme river flows and sea levels. Results illustrate that the flood mechanism is critical in controlling patterns and extent of inundation. Peak river discharges are the primary contributor to extreme flood events under the current climate scenario, however, high-end climate change could result in coastal inundation of comparable magnitude. The most extreme flood events affect the entire city centre – occurring as a result of a combination of fluvial and coastal drivers. The interaction of extreme fluvial discharges and coastal water levels is complex and characterised through comparison of multiple scenarios. This research establishes a best practice methodology for assessment of urban coastal-fluvial flood risk under a changing climate and can be used to determine climate-resilient flood management measures.

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