Spring Snowmelt Flood Estimate in the Upper Heihe River under Climate Change Scenarios

Author(s):  
Guangxi Zhu

<p>With the climate warming, high mountainous areas, including cryosphere, show more frequent and early outbreaks trend in flood hazard, cursing more losses to downstream areas. Based on meteorological, hydrological and MODIS snow cover data, using the snowmelt runoff model (SRM) to simulate and verify the spring runoff result during the snowmelt period from 1990 to 2012 in the upper Heihe River. SRM model simulates results shows it has a high accuracy (NSE = 0.7229), which can be used to predict the future flood intensity changes in studying area. In order to predict the trends of Heihe River Basin in flood return periods under the different future climate change scenarios, analyze used the temperature and precipitation forecast data. By the end of this century, the result of flood runoff shows differently according to climate change scenarios compared with the basic period. In RCP 2.6, due to the small changes of the temperature and precipitation, flood intensity will change slightly around 10% in all return periods; in RCP 4.5, it will increase about 20%; in RCP 8.5, return periods may be rise over 30%.</p>

2013 ◽  
Vol 4 (3) ◽  
pp. 265-286 ◽  
Author(s):  
Jan Kyselý ◽  
Ladislav Gaál ◽  
Jan Picek ◽  
Martin Schindler

The study deals with estimates of return periods associated with the August 2010 heavy precipitation in northern Bohemia (Czech Republic), which resulted in flooding with enormous material damage and loss of lives, in the present climate and under climate change scenarios. We focus on the record-breaking 1-day and 2-day amounts at lower-elevation stations, exceeding 150 and 250 mm, respectively. The estimates of return periods are based on two methods of regional frequency analysis and they are compared with local (at-site) estimation. The regional methods consistently suggest that the August 2010 event was exceptional in view of past records, but the return levels decline substantially – by a factor of 2–4 – if parameters of the generalized extreme value distribution are allowed to vary in accordance with scenarios based on an ensemble of regional climate model projections for 2070–99. In spite of large uncertainty associated with future climate change scenarios, increased recurrence probability of such heavy precipitation events in the 21st century should be taken into account when designing and implementing flood risk prevention and mitigation measures.


2016 ◽  
Vol 3 (2) ◽  
pp. 99-120
Author(s):  
S. Reza Alvankar ◽  
Farzane nazari ◽  
Ebrahim Fattahi ◽  
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2020 ◽  
Vol 6 (9) ◽  
pp. 1715-1725 ◽  
Author(s):  
Safieh Javadinejad ◽  
Rebwar Dara ◽  
Forough Jafary

Climate change is an important environmental issue, as progression of melting glaciers and snow cover is sensitive to climate alteration. The aim of this research was to model climate alterations forecasts, and to assess potential changes in snow cover and snow-melt runoff under the different climate change scenarios in the case study of the Zayandeh-rud River Basin. Three cluster models for climate change (NorESM1-M, IPSL-CM5A-LR and CSIRO-MK3.6.0) were applied under RCP 8.5, 4.5 and 2.6 scenarios, to examine climate influences on precipitation and temperature in the basin. Temperature and precipitation were determined for all three scenarios for four periods of 2021-2030, 2031-2040, 2041-2050 and 2051-2060. MODIS (MOD10A1) was also applied to examine snow cover using temperature and precipitation data. The relationship between snow-covered area, temperature and precipitation was used to forecast future snow cover. For modeling future snow melt runoff, a hydrologic model of SRM was used including input data of precipitation, temperature and snow cover. The results indicated that all three RCP scenarios lead to an increase in temperature, and reduction in precipitation and snow cover. Investigation in snowmelt runoff throughout the observation period (November 1970 to May 2006) showed that most of annual runoff is derived from snow melting. Maximum snowmelt runoff is generated in winter. The share of melt water in the autumn and spring runoff is estimated at 35 and 53%, respectively. The results of this study can assist water manager in making better decisions for future water supply.


1998 ◽  
Vol 22 (3) ◽  
pp. 350-374 ◽  
Author(s):  
Great Britain ◽  
D. Conway

This article reviews recent climatically extreme periods in Great Britain and presents results from the latest general circulation model (GCM) experiments showing the possible spatial patterns and magnitude of future climate change for this region. During the last decade the British Isles has seen record-breaking periods of above-average temperatures, alongside periods with above and below-average precipitation, combined with an increase in winter precipitation and a decrease in summer precipitation. The impacts of these anomalies, coupled with the possibility that future climate change may increase their frequency and/or severity, have prompted the UK Department of the Environment, Transport and Regions and other organizations involved in environmental management, such as the Environment Agency, to commission a number of studies into their impacts. These have highlighted wide-ranging impacts on the natural environment of Great Britain and on human ativities to the extent of affecting the national economy. The use of GCMs for the development of future climate change scenarios is reviewed. Results from recent ensemble GCM experiments with and without the effects of sulphate aerosols are presented. These show broadly similar changes in temperature and precipitation to previous climate change scenarios prepared for Great Britain. In summary, the scenarios suggest the following: a warming of about 3 8C (3.5 8C) over the region by 2100 with (without) the effects of sulphate aerosols; slight increases in annual precipitation over northern England and Scotland, more pronounced increases over the whole of the region in winter; and slight decreases in precipitation over Wales and central England in summer. These changes are synchronous with decreases in the number of wet-days and increases in the intensity of precipitation on wet-days. The high level of uncertainty associated with regional scenarios of temperature and precipitation is discussed and emphasized


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Nabaz R. Khwarahm

Abstract Background The oak tree (Quercus aegilops) comprises ~ 70% of the oak forests in the Kurdistan Region of Iraq (KRI). Besides its ecological importance as the residence for various endemic and migratory species, Q. aegilops forest also has socio-economic values—for example, as fodder for livestock, building material, medicine, charcoal, and firewood. In the KRI, Q. aegilops has been degrading due to anthropogenic threats (e.g., shifting cultivation, land use/land cover changes, civil war, and inadequate forest management policy) and these threats could increase as climate changes. In the KRI and Iraq as a whole, information on current and potential future geographical distributions of Q. aegilops is minimal or not existent. The objectives of this study were to (i) predict the current and future habitat suitability distributions of the species in relation to environmental variables and future climate change scenarios (Representative Concentration Pathway (RCP) 2.6 2070 and RCP8.5 2070); and (ii) determine the most important environmental variables controlling the distribution of the species in the KRI. The objectives were achieved by using the MaxEnt (maximum entropy) algorithm, available records of Q. aegilops, and environmental variables. Results The model demonstrated that, under the RCP2.6 2070 and RCP8.5 2070 climate change scenarios, the distribution ranges of Q. aegilops would be reduced by 3.6% (1849.7 km2) and 3.16% (1627.1 km2), respectively. By contrast, the species ranges would expand by 1.5% (777.0 km2) and 1.7% (848.0 km2), respectively. The distribution of the species was mainly controlled by annual precipitation. Under future climate change scenarios, the centroid of the distribution would shift toward higher altitudes. Conclusions The results suggest (i) a significant suitable habitat range of the species will be lost in the KRI due to climate change by 2070 and (ii) the preference of the species for cooler areas (high altitude) with high annual precipitation. Conservation actions should focus on the mountainous areas (e.g., by establishment of national parks and protected areas) of the KRI as climate changes. These findings provide useful benchmarking guidance for the future investigation of the ecology of the oak forest, and the categorical current and potential habitat suitability maps can effectively be used to improve biodiversity conservation plans and management actions in the KRI and Iraq as a whole.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2101
Author(s):  
Christian Charron ◽  
André St-Hilaire ◽  
Taha B.M.J. Ouarda ◽  
Michael R. van den Heuvel

Simulation of surface water flow and temperature under a non-stationary, anthropogenically impacted climate is critical for water resource decision makers, especially in the context of environmental flow determination. Two climate change scenarios were employed to predict streamflow and temperature: RCP 8.5, the most pessimistic with regards to climate change, and RCP 4.5, a more optimistic scenario where greenhouse gas emissions peak in 2040. Two periods, 2018–2050 and 2051–2100, were also evaluated. In Canada, a number of modelling studies have shown that many regions will likely be faced with higher winter flow and lower summer flows. The CEQUEAU hydrological and water temperature model was calibrated and validated for the Wilmot River, Canada, using historic data for flow and temperature. Total annual precipitation in the region was found to remain stable under RCP 4.5 and increase over time under RCP 8.5. Median stream flow was expected to increase over present levels in the low flow months of August and September. However, increased climate variability led to higher numbers of periodic extreme low flow events and little change to the frequency of extreme high flow events. The effective increase in water temperature was four-fold greater in winter with an approximate mean difference of 4 °C, while the change was only 1 °C in summer. Overall implications for native coldwater fishes and water abstraction are not severe, except for the potential for more variability, and hence periodic extreme low flow/high temperature events.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hector Lobeto ◽  
Melisa Menendez ◽  
Iñigo J. Losada

AbstractExtreme waves will undergo changes in the future when exposed to different climate change scenarios. These changes are evaluated through the analysis of significant wave height (Hs) return values and are also compared with annual mean Hs projections. Hourly time series are analyzed through a seven-member ensemble of wave climate simulations and changes are estimated in Hs for return periods from 5 to 100 years by the end of the century under RCP4.5 and RCP8.5 scenarios. Despite the underlying uncertainty that characterizes extremes, we obtain robust changes in extreme Hs over more than approximately 25% of the ocean surface. The results obtained conclude that increases cover wider areas and are larger in magnitude than decreases for higher return periods. The Southern Ocean is the region where the most robust increase in extreme Hs is projected, showing local increases of over 2 m regardless the analyzed return period under RCP8.5 scenario. On the contrary, the tropical north Pacific shows the most robust decrease in extreme Hs, with local decreases of over 1.5 m. Relevant divergences are found in several ocean regions between the projected behavior of mean and extreme wave conditions. For example, an increase in Hs return values and a decrease in annual mean Hs is found in the SE Indian, NW Atlantic and NE Pacific. Therefore, an extrapolation of the expected change in mean wave conditions to extremes in regions presenting such divergences should be adopted with caution, since it may lead to misinterpretation when used for the design of marine structures or in the evaluation of coastal flooding and erosion.


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 119
Author(s):  
Antonio Fidel Santos-Hernández ◽  
Alejandro Ismael Monterroso-Rivas ◽  
Diódoro Granados-Sánchez ◽  
Antonio Villanueva-Morales ◽  
Malinali Santacruz-Carrillo

The tropical rainforest is one of the lushest and most important plant communities in Mexico’s tropical regions, yet its potential distribution has not been studied in current and future climate conditions. The aim of this paper was to propose priority areas for conservation based on ecological niche and species distribution modeling of 22 species with the greatest ecological importance at the climax stage. Geographic records were correlated with bioclimatic temperature and precipitation variables using Maxent and Kuenm software for each species. The best Maxent models were chosen based on statistical significance, complexity and predictive power, and current potential distributions were obtained from these models. Future potential distributions were projected with two climate change scenarios: HADGEM2_ES and GFDL_CM3 models and RCP 8.5 W/m2 by 2075–2099. All potential distributions for each scenario were then assembled for further analysis. We found that 14 tropical rainforest species have the potential for distribution in 97.4% of the landscape currently occupied by climax vegetation (0.6% of the country). Both climate change scenarios showed a 3.5% reduction in their potential distribution and possible displacement to higher elevation regions. Areas are proposed for tropical rainforest conservation where suitable bioclimatic conditions are expected to prevail.


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