scholarly journals Water resources of the Desna river basin under future climate

2021 ◽  
Author(s):  
Osypov Valeriy ◽  
Speka Oleh ◽  
Chyhareva Anastasiia ◽  
Osadcha Nataliia ◽  
Krakovska Svitlana ◽  
...  
Keyword(s):  
Water Resources ◽  
River Basin ◽  
General Circulation ◽  
Large Scale ◽  
Climate Models ◽  
Assessment Tool ◽  
General Circulation Models ◽  
Future Climate ◽  
Moderate Increase ◽  
Water Balance Components

Abstract Climate change impact on water resources has been observing in Ukraine since the end of the 20th century. For now, only large-scale climate impact studies cover Ukraine territory, having low credibility for a specific catchment. This study aims to calculate future changes in river discharge, water flow components, and soil water within the Desna basin and evaluate vulnerability trends on this basis. The framework assembles the process-based SWAT (Soil and Water Assessment Tool) model and eight high-resolution regional climate models (RCMs) driven by RCP4.5 and RCP8.5 emission scenarios. The climate models are provided by the Euro-CORDEX initiative and based on three RCMs (RCA4, HIRHAM5, and RACMO22E) forced by five general circulation models (CNRM-CM5, EC-EARTH, IPSL-CM5A-MR, HadGEM2-ES, and MPI-ESM-LR). The results preferably show a moderate increase in the annual discharge till the end of the 21st century. The intra-annual changes of water balance components negatively affect the vegetation period because of higher dryness and temperature stress but reduce flood risk, diffuse pollution, and water erosion in the far future. In the river basin management plan, the highest attention should be paid to adaptive strategies in agriculture because of possible water deficit in the vegetation season under future climate scenarios.

Polar meteorology: a review of some recent research

Polar Record ◽  
1974 ◽  
Vol 17 (108) ◽  
pp. 277-294 ◽  
Author(s):  
Gunter Weller
Keyword(s):  
Heat Source ◽  
General Circulation ◽  
Large Scale ◽  
Climate Models ◽  
General Circulation Models ◽  
Cloud Formation ◽  
Driving Mechanism ◽  
Polar Regions ◽  
International Geophysical Year ◽  
Polar Meteorology

The general large-scale circulation of the global atmosphere has its basic driving mechanism in the equator-poleward temperature gradients in both hemispheres. It has become increasingly obvious over the last few decades that to understand and predict the behaviour of the atmosphere at any point, it is essential to understand the behaviour of the total global fluid system. The Global Atmospheric Research Project (GARP) is an outcome of this recognition. Studies of the heat sinks (the polar regions) are therefore just as important as studies of the heat source (the equatorial regions) to understand the meteorology of the planet. Interest in polar meteorology has undergone many cyclic fluctuations, peaking during the various international polar years and, more recently, during the International Geophysical Year, 1957–58. At the present, the focus of GARP's first objective (improved extended weather forecasts) is on the tropical heat source, where convection and cloud formation and dissipation are still relatively little understood processes. However, the second GARP objective (better understanding of the physical basis of climate) requires more attention to be devoted to the cryosphere, its long-term interaction with oceans and atmosphere, and its role as an indicator of climatic change. The idea of a polar experiment (POLEX) was initially introduced by Treshnikov and others (1968) and by Borisenkov and Treshnikov (1971). A summary of the early history of POLEX was recently given by Weller and Bierly (1973). The two closely related objectives of POLEX that most directly pertain to GARP may be restated in their simplest terms as (1) a better understanding of energy transfer processes and the heat budgets of the polar regions for the purpose of parameterizing them properly in general circulation models and climate models, and (2) provision of adequate data from the polar regions during the First GARP Global Experiment (FGGE) in 1978.

scholarly journals SimCloud version 1.0: a simple diagnostic cloud scheme for idealized climate models

2021 ◽  
Vol 14 (5) ◽  
pp. 2801-2826
Author(s):  
Qun Liu ◽  
Matthew Collins ◽  
Penelope Maher ◽  
Stephen I. Thomson ◽  
Geoffrey K. Vallis
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Climate Models ◽  
General Circulation Models ◽  
Cloud Fraction ◽  
Specific Humidity ◽  
Polar Regions ◽  
Modeling Framework ◽  
Tropical Regions ◽  
Subtropical Oceans

Abstract. A simple diagnostic cloud scheme (SimCloud) for general circulation models (GCMs), which has a modest level of complexity and is transparent in describing its dependence on tunable parameters, is proposed in this study. The large-scale clouds, which form the core of the scheme, are diagnosed from relative humidity. In addition, the marine low stratus clouds, typically found off the west coast of continents over subtropical oceans, are determined largely as a function of inversion strength. A “freeze-dry” adjustment based on a simple function of specific humidity is also available to reduce an excessive cloud bias in polar regions. Other cloud properties, such as the effective radius of cloud droplet and cloud liquid water content, are specified as simple functions of temperature. All of these features are user-configurable. The cloud scheme is implemented in Isca, a modeling framework designed to enable the construction of GCMs at varying levels of complexity, but could readily be adapted to other GCMs. Simulations using the scheme with realistic continents generally capture the observed structure of cloud fraction and cloud radiative effect (CRE), as well as its seasonal variation. Specifically, the explicit low-cloud scheme improves the simulation of shortwave CREs over the eastern subtropical oceans by increasing the cloud fraction and cloud water path. The freeze-dry adjustment alleviates the longwave CRE biases in polar regions, especially in winter. However, the longwave CRE in tropical regions and shortwave CRE over the extratropics are both still too strong compared to observations. Nevertheless, this simple cloud scheme provides a suitable basis for examining the impacts of clouds on climate in idealized modeling frameworks.

SWAT modeling for assessing future scenarios of soil erosion in West Rapti River Basin of Nepal

2020 ◽  
Author(s):  
Rocky Talchabhadel ◽  
Hajime Nakagawa ◽  
Kenji Kawaike ◽  
Kazuki Yamanoi ◽  
Anil Aryal ◽  
...  
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Climate Models ◽  
Assessment Tool ◽  
Watershed Modeling ◽  
Fine Tuning ◽  
Moderate Increase ◽  
Future Scenarios ◽  
Sediment Discharge ◽  
Rcp 8.5

<p>This study uses Soil Water Assessment Tool (SWAT) for watershed modeling in West Rapti River Basin (WRRB) of Nepal for assessing future scenarios of soil erosion till the end of 2100. Firstly, the river discharge was calibrated for the period (2003–2009) and validated for the period (2010-2013). We used three discharge stations (namely Mari at upstream, Bagasoti at mid-stream and Jalkundi at downstream). Secondly, sediment discharge was calibrated and validated at two sediment monitoring stations (namely Mari at upstream and Jalkundi at downstream). A Sequential Uncertainty Fitting (SUFI-2) technique was employed for the fine-tuning of sensitive hydrological parameters. The model achieved a good performance in both the calibration and validation periods. R<sup>2</sup>, NSE, PBIAS, and RSR were taken as performance indicators.  Finally, the developed model was then used to assess future scenarios of sediment yield in the WRRB. This study used five regional climate models (RCMs) for precipitation and temperature, and their ensemble under two representative concentration pathways (RCPs 4.5 and 8.5). This study analyses future scenarios for three time-frames namely, near future (NF: 2025-2049), mid future (MF: 2050-2074), and far future (FF: 2075-2099) with respect to the baseline (2003-2013). We found a significant increase in temperature in the future with annual average temperature anticipated to change from +0.76<sup> o</sup>C to +5.8 <sup>o</sup>C and a moderate increase in precipitation with annual precipitation projected to change from -1.9% to 19.3% under different scenarios. In general, the MME shows slightly increasing precipitation (higher under RCP 4.5 than RCP 8.5), significantly increasing temperature (higher under RCP 8.5 than RCP 4.5) and moderately increasing sediment discharge. Our findings are useful for water resources and sediment management in WRRB under changing climate.</p>

scholarly journals Impact of Climate Change on Water Balance Components and Droughts in the Guajoyo River Basin (El Salvador)

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2360 ◽  
Author(s):  
Pablo Blanco-Gómez ◽  
Patricia Jimeno-Sáez ◽  
Javier Senent-Aparicio ◽  
Julio Pérez-Sánchez
Keyword(s):  
Climate Change ◽  
El Salvador ◽  
River Basin ◽  
General Circulation ◽  
Goodness Of Fit ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Historical Series

This study assessed how changes in terms of temperature and precipitation might translate into changes in water availability and droughts in an area in a developing country with environmental interest. The hydrological model Soil and Water Assessment Tool (SWAT) was applied to analyze the impacts of climate change on water resources of the Guajoyo River Basin in El Salvador. El Salvador is in one of the most vulnerable regions in Latin America to the effects of climate change. The predicted future climate change by two climate change scenarios (RCP 4.5 and RCP 8.5) and five general circulation models (GCMs) were considered. A statistical analysis was performed to identify which GCM was better in terms of goodness of fit to variation in means and standard deviations of the historical series. A significant decreasing trend in precipitation and a significant increase in annual average temperatures were projected by the middle and the end of the twenty–first century. The results indicated a decreasing trend of the amount of water available and more severe droughts for future climate scenarios with respect to the base period (1975–2004). These findings will provide local water management authorities useful information in the face of climate change to help decision making.

scholarly journals Climatology and Forcing of the Quasi-Biennial Oscillation in the MAECHAM5 Model

2006 ◽  
Vol 19 (16) ◽  
pp. 3882-3901 ◽  
Author(s):  
M. A. Giorgetta ◽  
E. Manzini ◽  
E. Roeckner ◽  
M. Esch ◽  
L. Bengtsson
Keyword(s):  
Gravity Wave ◽  
Zonal Wind ◽  
General Circulation ◽  
Large Scale ◽  
Climate Models ◽  
Middle Atmosphere ◽  
General Circulation Models ◽  
Wave Drag ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation

Abstract The quasi-biennial oscillation (QBO) in the equatorial zonal wind is an outstanding phenomenon of the atmosphere. The QBO is driven by a broad spectrum of waves excited in the tropical troposphere and modulates transport and mixing of chemical compounds in the whole middle atmosphere. Therefore, the simulation of the QBO in general circulation models and chemistry climate models is an important issue. Here, aspects of the climatology and forcing of a spontaneously occurring QBO in a middle-atmosphere model are evaluated, and its influence on the climate and variability of the tropical middle atmosphere is investigated. Westerly and easterly phases are considered separately, and 40-yr ECMWF Re-Analysis (ERA-40) data are used as a reference where appropriate. It is found that the simulated QBO is realistic in many details. Resolved large-scale waves are particularly important for the westerly phase, while parameterized gravity wave drag is more important for the easterly phase. Advective zonal wind tendencies are important for asymmetries between westerly and easterly phases, as found for the suppression of the easterly phase downward propagation. The simulation of the QBO improves the tropical upwelling and the atmospheric tape recorder compared to a model without a QBO. The semiannual oscillation is simulated realistically only if the QBO is represented. In sensitivity tests, it is found that the simulated QBO is strongly sensitive to changes in the gravity wave sources. The sensitivity to the tested range of horizontal resolutions is small. The stratospheric vertical resolution must be better than 1 km to simulate a realistic QBO.

scholarly journals Potential Climate Change Impacts on Water Resources in Egypt

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1715
Author(s):  
Soha M. Mostafa ◽  
Osama Wahed ◽  
Walaa Y. El-Nashar ◽  
Samia M. El-Marsafawy ◽  
Martina Zeleňáková ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Irrigation Water ◽  
General Circulation ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Impact Of Climate Change ◽  
Water Demands ◽  
The Impact

This paper presents a comprehensive study to assess the impact of climate change on Egypt’s water resources, focusing on irrigation water for agricultural crops, considering that the agriculture sector is the largest consumer of water in Egypt. The study aims to estimate future climate conditions using general circulation models (GCMs), to assess the impact of climate change and temperature increase on water demands for irrigation using the CROPWAT 8 model, and to determine the suitable irrigation type to adapt with future climate change. A case study was selected in the Middle part of Egypt. The study area includes Giza, Bani-Sweif, Al-Fayoum, and Minya governorates. The irrigation water requirements for major crops under current weather conditions and future climatic changes were estimated. Under the conditions of the four selected models CCSM-30, GFDLCM20, GFDLCM21, and GISS-EH, as well as the chosen scenario of A1BAIM, climate model (MAGICC/ScenGen) was applied in 2050 and 2100 to estimate the potential rise in the annual mean temperature in Middle Egypt. The results of the MAGICC/SceGen model indicated that the potential rise in temperature in the study area will be 2.12 °C in 2050, and 3.96 °C in 2100. The percentage of increase in irrigation water demands for winter crops under study ranged from 6.1 to 7.3% in 2050, and from 11.7 to 13.2% in 2100. At the same time, the increase in irrigation water demands for summer crops ranged from 4.9 to 5.8% in 2050, and from 9.3 to 10.9% in 2100. For Nili crops, the increase ranged from 5.0 to 5.1% in 2050, and from 9.6 to 9.9% in 2100. The increase in water demands due to climate change will affect the water security in Egypt, as the available water resources are limited, and population growth is another challenge which requires a proper management of water resources.

scholarly journals HYDROLOGIC BEHAVIOUR OF HIGHLAND CATCHMENT IN HUMID TROPICAL REGION USING QSWAT MODEL

2020 ◽  
Vol 9 (6) ◽  
pp. 95-103
Keyword(s):  
Water Resources ◽  
Water Balance ◽  
River Basin ◽  
Assessment Tool ◽  
Annual Rainfall ◽  
Tropical Region ◽  
Water Balance Components ◽  
Monthly Streamflow ◽  
Average Annual Rainfall ◽  
Tropical Watersheds

Water resources planning and management of a region requires an understanding of the water balance in the region. The Soil and Water Assessment Tool (SWAT) with QGIS interface (QSWAT) has been used here to arrive at the water balance components in the Palapuzha watershed of Valapattanam river basin in Kerala. Valapattanam river drains an area of 1867 sq.km. with 456 sq.km. area in Karnataka State. The river basin receives an average annual rainfall of 3600 mm. The Palapuzha watershed drains an area of 237.25 sq.km with an average annual rainfall of 4562 mm. The QSWAT model has been calibrated and validated using data for a period of eight years (2000-2007) for which both rainfall and streamflow data are available. The model was successful in simulating monthly streamflow during the calibration and validation periods with Nash Sutcliffe efficiency and correlation co-efficient greater than 0.75 and percent bias less than 10%, showing that the model is very good for predicting streamflow in Valapattanam river basin. This calibrated model was used to arrive at the different water balance components in the Palapuzha watershed. The results obtained will be useful for the sustainable development and planning of the water resources system in the highland humid tropical watersheds

scholarly journals Reducing the basin vulnerability by land management practices under past and future climate: a case study of the Nam Ou River Basin, Lao PDR

2014 ◽  
Vol 11 (8) ◽  
pp. 9863-9905
Author(s):  
M. Maharjan ◽  
M. S. Babel ◽  
S. Maskey
Keyword(s):  
River Basin ◽  
Land Management ◽  
Sediment Yield ◽  
General Circulation ◽  
Management Practices ◽  
Greenhouse Gas Emission ◽  
General Circulation Models ◽  
Future Climate ◽  
Projection Data ◽  
Research Station

Abstract. This research evaluates different land management practices for the Nam Ou River Basin in Northern Laos for reducing vulnerability of the basin due to erosion and sediment yield under existing and future climate conditions. We use climate projection data (precipitation and temperature) from three general circulation models (GCMs) for three greenhouse gas emission scenarios (GHGES), namely B1, A1B and A2 and three future periods, namely 2011–2030, 2046–2065 and 2080–2099. These large resolution GCM data are downscaled using the Long Ashton Research Station-Weather Generator (LARS-WG). The Soil and Water Assessment Tool (SWAT), which is a process based hydrological model, is used to simulate discharge and sediment yield and a threshold value of annual sediment yield is applied to identify vulnerable sub-basins. Results show that the change in the annual precipitation is expected to be between −7.60 to 2.64% in 2011–2030, −8.98 to 11.85% in 2046–2065, and −11.04 to 25.84% in 2080–2099. In the meantime, the changes in mean monthly temperature vary from 0.3 to 1.3 °C in the 2011–2030, 1.3 to 2.9 °C in the 2046–2065 and 1.9 to 4.9 °C in the 2080–2099. Five sub-basins are identified vulnerable (critical) under the current climate. Our results show that terracing is the most effective land management practice to reduce sediment yield in these sub-basins followed by strip-cropping and filter strip. Appropriate land management practices applied under future climate scenarios show significant reduction in sediment yield (i.e. up to the tolerance limit) except for some sub-basins. In these exceptional sub-basins, designing an optimum combination of management practices is essential to reduce the vulnerability of the basin.

4. Modelling future climate

2021 ◽  
pp. 44-63
Author(s):  
Mark Maslin
Keyword(s):  
Global Economy ◽  
General Circulation ◽  
Climate Models ◽  
Driving Forces ◽  
Global Climate ◽  
Three Dimensional ◽  
Ghg Emissions ◽  
General Circulation Models ◽  
Future Climate ◽  
Box Models

‘Modelling future climate’ examines the modelling of future global climate. There is a whole hierarchy of climate models, from relatively simple box models to extremely complex three-dimensional general circulation models (GCMs). Each has a role in examining and furthering the understanding of the global climate system. At the heart of the climate models is the carbon cycle, central to estimating what happens to anthropogenic carbon dioxide and methane emissions. The biggest unknown in the models is the estimation of future human global GHG emissions. It is worth noting here the shared socioeconomic pathways (SSPs) and representative concentration pathways (RCPs), a set of narratives and driving forces that model the possible shape of the global economy and global emissions in the future. The latest IPCC projections on future global temperature, precipitation, and sea level based on the different SSPs make for interesting reading.

scholarly journals Application of a technique for scenario prediction of climate change impact on the water balance components of northern river basins

2014 ◽  
Vol 62 (3) ◽  
pp. 197-208 ◽  
Author(s):  
Yeugeniy M. Gusev ◽  
Olga N. Nasonova
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Water Balance ◽  
River Basin ◽  
General Circulation ◽  
General Circulation Models ◽  
River Basins ◽  
Surface Model ◽  
Water Balance Components ◽  
Northern River

Abstract The scenario forecasting technique for assessing changes of water balance components of the northern river basins due to possible climate change was developed. Three IPCC global emission scenarios corresponding to different possible scenarios for economic, technological, political and demographic development of the human civilization in the 21st century were chosen for generating climate change projections by an ensemble of 16 General Circulation Models with a high spatial resolution. The projections representing increments of monthly values of meteorological characteristics were used for creating 3-hour meteorological time series up to 2063 for the Northern Dvina River basin, which belongs to the pan-Arctic basin and locates at the north of the European part of Russia. The obtained time series were applied as forcing data to drive the land surface model SWAP to simulate possible changes in the water balance components due to different scenarios of climate change for the Northern Dvina River basin

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