scholarly journals Numerical Simulation of the Effects of Grassland Degradation on the Surface Climate in Overgrazing Area of Northwest China

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yanfei Li ◽  
Zhaohua Li ◽  
Zhihui Li ◽  
Xiaoli Geng ◽  
Xiangzheng Deng
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
Wrf Model ◽  
Northwest China ◽  
Grassland Degradation ◽  
Climatic Effects ◽  
Barren Land ◽  
Surface Climate ◽  
The Impact

The climatic effects of LUCC have been a focus of current researches on global climate change. The objective of this study is to investigate climatic effects of grassland degradation in Northwest China. Based on the stimulation of the conversion from grassland to other land use types during the next 30 years, the potential effects of grassland degradation on regional climate in the overgrazing area of Northwest China from 2010 to 2040 have been explored with Weather Research and Forecasting model (WRF). The analysis results show that grassland will mainly convert into barren land, croplands, and urban land, which accounts for 42%, 48%, and 10% of the total converted grassland area, respectively. The simulation results indicate that the WRF model is appropriate for the simulation of the impact of grassland degradation on climate change. The grassland degradation during the next 30 years will result in the decrease of latent heat flux, which will further lead to the increase of temperature in summer, with an increment of 0.4–1.2°C, and the decrease of temperature in winter, with a decrement of 0.2°C. In addition, grassland degradation will cause the decrease of precipitation in both summer and winter, with a decrement of 4–20 mm.

scholarly journals Possible Influence of the Cultivated Land Reclamation on Surface Climate in India: A WRF Model Based Simulation

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Yi Qu ◽  
Feng Wu ◽  
Haiming Yan ◽  
Bangrong Shu ◽  
Xiangzheng Deng
Keyword(s):  
Climate Change ◽  
Heat Flux ◽  
Simulation Analysis ◽  
Land Reclamation ◽  
Global Climate ◽  
Regional Climate ◽  
Sensible Heat Flux ◽  
Wrf Model ◽  
Cultivated Land ◽  
The Impact

Land use/cover change (LUCC) has become one of the most important factors for the global climate change. As one of the major types of LUCC, cultivated land reclamation also has impacts on regional climate change. Most of the previous studies focused on the correlation and simulation analysis of historical LUCC and climate change, with few explorations for the impacts of future LUCC on regional climate, especially impacts of the cultivated land reclamation. This study used the Weather Research and Forecasting (WRF) model to forecast the changes of energy flux and temperature based on the future cultivated land reclamation in India and then analyzed the impacts of cultivated land reclamation on climate change. The results show that cultivated land reclamation will lead to a large amount of land conversions, which will overall result in the increase in latent heat flux of regional surface as well as the decrease in sensible heat flux and further lead to changes of regional average temperature. Furthermore, the impact on climate change is seasonally different. The cultivated land reclamation mainly leads to a temperature decrease in the summer, while it leads to a temperature increase in the winter.

scholarly journals An ensemble approach to assess hydrological models' contribution to uncertainties in the analysis of climate change impact on water resources

2013 ◽  
Vol 17 (2) ◽  
pp. 565-578 ◽  
Author(s):  
J. A. Velázquez ◽  
J. Schmid ◽  
S. Ricard ◽  
M. J. Muerth ◽  
B. Gauvin St-Denis ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Climate Models ◽  
Hydrological Model ◽  
Global Climate ◽  
Regional Climate ◽  
Structural Complexity ◽  
Global Climate Models ◽  
Hydrological Models ◽  
The Impact

Abstract. Over the recent years, several research efforts investigated the impact of climate change on water resources for different regions of the world. The projection of future river flows is affected by different sources of uncertainty in the hydro-climatic modelling chain. One of the aims of the QBic3 project (Québec-Bavarian International Collaboration on Climate Change) is to assess the contribution to uncertainty of hydrological models by using an ensemble of hydrological models presenting a diversity of structural complexity (i.e., lumped, semi distributed and distributed models). The study investigates two humid, mid-latitude catchments with natural flow conditions; one located in Southern Québec (Canada) and one in Southern Bavaria (Germany). Daily flow is simulated with four different hydrological models, forced by outputs from regional climate models driven by global climate models over a reference (1971–2000) and a future (2041–2070) period. The results show that, for our hydrological model ensemble, the choice of model strongly affects the climate change response of selected hydrological indicators, especially those related to low flows. Indicators related to high flows seem less sensitive on the choice of the hydrological model.

scholarly journals The Impact of Incongruous Lake Temperatures on Regional Climate Extremes Downscaled from the CMIP5 Archive Using the WRF Model

2016 ◽  
Vol 29 (2) ◽  
pp. 839-853 ◽  
Author(s):  
Tanya L. Spero ◽  
Christopher G. Nolte ◽  
Jared H. Bowden ◽  
Megan S. Mallard ◽  
Jerold A. Herwehe
Keyword(s):  
Global Climate ◽  
Regional Climate ◽  
Wrf Model ◽  
Climate Extremes ◽  
Daily Maximum ◽  
Sea Level Pressure ◽  
Thermally Induced ◽  
Monthly Average ◽  
Southern Florida ◽  
The Impact

Abstract The impact of incongruous lake temperatures is demonstrated using the Weather Research and Forecasting (WRF) Model to downscale global climate fields. Unrealistic lake temperatures prescribed by the default WRF configuration cause obvious biases near the lakes and also affect predicted extremes hundreds of kilometers from the lakes, especially during winter. Using these default temperatures for the Great Lakes in winter creates a thermally induced wave in the modeled monthly average sea level pressure field, which reaches southern Florida. Differences of more than 0.5 K in monthly average daily maximum 2-m temperature occur along that wave during winter. Noteworthy changes to temperature variability, precipitation, and mesoscale circulation also occur when the default method is used for downscaling. Consequently, improperly setting lake temperatures for downscaling could result in misinterpreting changes in regional climate and adversely affect applications reliant on downscaled data, even in areas remote from the lakes.

scholarly journals Impacts of Future Grassland Changes on Surface Climate in Mongolia

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Fan Zhang ◽  
Xing Li ◽  
Weimin Wang ◽  
Xinli Ke ◽  
Qingling Shi
Keyword(s):  
Climate Change ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Forecast Model ◽  
Underlying Surface ◽  
Grassland Degradation ◽  
Annual Average ◽  
Surface Data ◽  
Surface Climate ◽  
Plan Making

Climate change caused by land use/cover change (LUCC) is becoming a hot topic in current global change, especially the changes caused by the grassland degradation. In this paper, based on the baseline underlying surface data of 1993, the predicted underlying surface data which can be derived through overlaying the grassland degradation information to the map of baseline underlying surface, and the atmospheric forcing data of RCP 6.0 from CMIP5, climatological changes caused by future grassland changes for the years 2010–2020 and 2040–2050 with the Weather Research Forecast model (WRF) are simulated. The model-based analysis shows that future grassland degradation will significantly result in regional climate change. The grassland degradation in future could lead to an increasing trend of temperature in most areas and corresponding change range of the annual average temperature of −0.1°C–0.4°C, and it will cause a decreasing trend of precipitation and corresponding change range of the annual average precipitation of 10 mm–50 mm. This study identifies lines of evidence for effects of future grassland degradation on regional climate in Mongolia which provides meaningful decision-making information for the development and strategy plan making in Mongolia.

The impact of global climate change on the characteristics of seasons in the Carpathian Basin

2021 ◽  
Author(s):  
Csenge Dian ◽  
Rita Pongrácz ◽  
Judit Bartholy ◽  
Attila Talamon
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Heat Waves ◽  
Global Climate ◽  
Regional Climate ◽  
Weather Conditions ◽  
Carpathian Basin ◽  
Data Series ◽  
Heating And Cooling ◽  
The Impact

<p>Similarly to many other regions, warming and extreme weather conditions (e.g. related to temperature and precipitation) are expected to increase due to the effects of climate change in the Carpathian Basin during the 21st century. Consequently, as a result of the clearly detectable warming, the number of frost days in winter decreases and the summer heat waves become more frequent. The transition between winter and summer tends to become shorter and the inter-annual variability is likely to increase. The precise definition of the transition periods between the two extremes of the annual temperature course is very important for several disciplines, e.g. building energy design, where outdoor temperature is a key input to determine the beginning and end of heating and cooling periods. The aim of this research is to examine the possible transformation of the four seasons characteristics of the Carpathian Basin in details using various specific climate indexes (e.g. monthly percentiles, daily temperature fluctuation time series) based on the data of regional climate model simulations taking into account different future scenarios. For this purpose, RCP4.5 and RCP8.5 scenarios are compared to historical runs, and simulated temperature data series are analyzed for the middle and end of the century.</p>

Balanced subsampling of future regional climate ensembles of opportunity

2020 ◽  
Author(s):  
Jesús Fernández ◽  
María Dolores Frías
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
National Level ◽  
Future Climate Change ◽  
Climate Projections ◽  
Climate Modelling ◽  
Model Intercomparison ◽  
Climate Change Projections ◽  
The Impact

<p>International model intercomparison initiatives, such as CORDEX or CMIP5, along with several relatively recent projects at international and national level, provide a wealth of model simulations of future regional climate. In a recent work, Fernandez et al (2019) collected 196 different future climate change projections over Spain, considering data from ENSEMBLES, ESCENA, EURO- and Med-CORDEX, along with their driving global climate projections from CMIP3 and CMIP5. This ensemble mixed different multi-model initiatives in an ensemble of opportunity, in the sense that it does not respond to any scientific design beyond the exploration of multi-model uncertainty. This ensemble of opportunity is not only the result of the mixture of different initiatives, but also responds to the lack of a balanced experimental design within most of the initiatives. Many of the initiatives -especially those unfunded, such as CORDEX- are carried out on a voluntary basis, with no strong constraint in the global climate models (GCMs) used as boundary conditions or in the number of contributing members per regional climate model (RCM).</p><p>Fernandez et al (2019) found in this ensemble a strong influence of the driving GCM on the regional climate change signal, along with favored GCMs, selected by many regional climate modelling groups to the detriment of GCMs publishing their output later or not at all. In this work, we quantitatively assess the impact of unbalanced GCM-RCM ensembles. For this purpose, we subsampled the ensemble of opportunity to obtain balanced sets of members according to different “what-if” situations: What if all RCMs had contributed a single member to the ensemble? What if each GCM had been dynamically downscaled only once? What if a given GCM/RCM had not contributed to the ensemble? For each hypothesis, there are a number of alternative sub-ensembles, which are used to evaluate uncertainty.</p><p><strong>Acknowledgement:</strong></p><p>This work is partially funded by the Spanish government through MINECO/FEDER co-funded projects INSIGNIA (CGL2016-79210-R) and MULTI-SDM (CGL2015-66583-R). </p><p><strong>References:</strong></p><p>Fernández, J., et al. (2019) Consistency of climate change projections from multiple global and regional model intercomparison projects. Clim Dyn 52:1139. https://doi.org/10.1007/s00382-018-4181-8</p>

scholarly journals Regional Climate Effects of Conversion from Grassland to Forestland in Southeastern China

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Rui Yu ◽  
Xinsheng Wang ◽  
Zhe Yan ◽  
Haiming Yan ◽  
Qunou Jiang
Keyword(s):  
Land Cover ◽  
Global Climate ◽  
Regional Climate ◽  
Wrf Model ◽  
Climatic Effects ◽  
Annual Average ◽  
Climate Effects ◽  
Global Climate Changes ◽  
Land System ◽  
Mutual Conversion

The land-use and land-cover change (LUCC) is the synthetic result of natural processes and human activities; it largely depends on the surface vegetation conditions, and the mutual conversion among land cover types can accelerate or alleviate the regional and global climate changes. Aiming at analyzing the regional climatic effects of the conversion from grassland to forestland, especially in the long term perspective, we carried out the comparison simulation using the Weather Research and Forecasting (WRF) Model in Fujian province, results indicated that this conversion had a significant influence on the regional climate; the annual average temperature decreased by 0.11°C and the annual average precipitation increased by 46 mm after 11.2% of the grassland was converted into the forestland in the study area from 2000 to 2008. In the future (form 2010 to 2050), the conversion from grassland to forestland is significant under two representative concentration pathways (RCPs) (RCP6 and RCP8.5); the spatial pattern of this conversion under the two scenarios is simulated by dynamic of land system (DLS); then, the regional climate effects of the conversion are simulated using WRF model.

Convection-Permitting Regional Climate Simulations over North America

2020 ◽  
Author(s):  
Changhai Liu ◽  
Kyoko Ikeda ◽  
Roy Rasmussen
Keyword(s):  
Climate Change ◽  
North America ◽  
Water Cycle ◽  
Regional Climate ◽  
Water System ◽  
Wrf Model ◽  
Future Climate ◽  
Convective Precipitation ◽  
Historical Simulation ◽  
The Impact

<p>The NCAR Water System Program has been striving to improve the representation of the water cycle and its future changes in both regional and global models during the past decade. One of our efforts is conducting continental-scale convection-permitting simulations of the current and future climate of North America using the WRF model based atmospheric-hydrological coupling system. The major science objectives of these simulations are: 1) to evaluate the capability of convection-permitting WRF model in capturing orographic precipitation and snow mass balance over the western mountains of North America and convective precipitation in the eastern part of the continent; 2) to assess future changes in seasonal snowfall and snowpack and associated surface hydrological cycles under the CMIP5-projected global warming; 3) to investigate water cycle changes in response to climate warming, including the summertime convective precipitation and associated mesoscale convective storm tracks; and 4) to examine the impact of climate change on severe weather over North America. As such, two phases of convection-permitting climate modeling have been undertaken using 4-km horizontal grid spacing covering most of North America.</p><p>The phase-one effort involves two 13-year simulations as reported in Liu et al. (2017): 1) a historical simulation with initial and boundary conditions from ERA-interim, and 2) a future climate sensitivity simulation, called pseudo-global warming (PGW), with modified reanalysis-derived initial and boundary conditions by adding the CMIP5 ensemble-mean projected climate change. These WRF-downscaled climate change simulations provide a unique high-resolution dataset to the community for studying one possible scenario of regional climate changes and impacts.</p><p>Recognizing that only the thermodynamic future climate impacts can be adequately addressed in the PGW approach, the NCAR Water System team has started conducting a second set (phase II) of current and future simulations at 4-km grid spacing over North America. In these simulations, the WRF model is forced using the weather perturbations derived from the NCAR CESM model 6-hourly output plus the reanalysis-based bias-corrected CMIP5 ensemble mean climate as detailed in Dai et al. (2017). The model domain is also expanded northward to include Canada and the Canadian Arctic. Because storm track changes are permitted, these simulations complement the previous PGW simulations, allowing us to address the impact of dynamic changes in the future warmer climate. We will present some preliminary analysis results of these simulations, with focus on the evaluation of the historical simulation and the added value of convection-permitting resolution and mean climate bias corrections.</p>

scholarly journals The impact of climate change on hydrological patterns in Czech headwater catchments

2010 ◽  
Vol 7 (1) ◽  
pp. 1245-1278 ◽  
Author(s):  
A. Benčoková ◽  
P. Krám ◽  
J. Hruška
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Climate Model ◽  
Global Climate ◽  
Regional Climate ◽  
General Circulation Models ◽  
Annual Runoff ◽  
Mean Flow ◽  
Forested Catchments ◽  
The Impact

Abstract. The aim of this study was to estimate the impacts of anticipated global climate change on runoff and evapotranspiration in small-forested catchments. The investigated Lysina and Pluhův Bor catchments are situated in the Slavkov Forest in the western part of the Czech Republic. To forecast hydrological patterns for the period 2071–2100, outputs from two general circulation models, HadAM3H and ECHAM4/OPYC3, were downscaled by an RCAO (regional climate model) which ran the SRES emission scenarios A2 and B2 for each model. Bias-corrected RCAO daily outputs were used in combination with the hydrological model Brook90. Annual runoff is predicted to decline by 6–45%, and impacts on the distribution of monthly flow are predicted to be significant, with summer-autumn decreases of 29–96%, and winter increases of up to ~48% compared to mean flow from 1967–1990. Mean daily flows are estimated to decrease by 63–94% from August to November. These changes would have serious ecological consequences, since streams could regularly dry-up for short periods of time.

scholarly journals Quantifying the potential impacts of land-use and climate change on hydropower reliability of Muzizi hydropower plant, Uganda

2021 ◽  
Author(s):  
Hilary Keneth Bahati ◽  
Abraham Ogenrwoth ◽  
Jotham Ivan Sempewo
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Regional Climate ◽  
Hydropower Plant ◽  
Exceedance Probability ◽  
Climate Change Scenarios ◽  
Lulc Change ◽  
Barren Land ◽  
The Impact

Abstract Ugandan rivers are being tapped as a resource for the generation of hydropower in addition to other uses. Studies on the reliability of these hydropower plants due to climate and land-use/land cover changes on the hydrology of these rivers are scanty. Therefore, this study aimed to model the impact of the changing climate and land use/cover on hydropower reliability to aid proper planning and management. The hydropower reliability of River Muzizi catchment was determined from its past (1998–2010) and midcentury (2042–2070) discharge at 75 and 90% exceedance probability under Representative Concentration Pathways (RCPs) of 4.5 and 8.5, respectively. The past and projected hydropower were compared to determine how future climate and land-use changes will impact the discharge and hydropower reliability of River Muzizi catchment. Six LULC scenarios (deforestation, 31–20%; grassland, 19–3%; cropland, 50–77%; water bodies, 0.02–0.01%; settlement, 0.23–0.37%, and Barren land 0.055–0.046% between 2014 and 2060) and three downscaled Regional Climate Model (REMO and RCA4 for precipitation and RACMO22T for temperature from pool of four CORDEX (Coordinated Regional Climate Downscaling Experiment) Africa RCMs) were examined. A calibrated SWAT simulation model was applied for the midcentury (2041–2060) period, and a potential change in hydropower energy in reference to mean daily flow (designflow ≥ 30% exceedance probability), firm flow (flow ≥ 95% exceedance probability), and mean annual flow was evaluated under the condition of altered runoff under RCP4.5 and RCP8.5 climate change scenarios for an average of REMO and RCA4 RCM. The future land use (2048) was projected using the MOLUSCE (Module for Land Use Change Evaluation) plugin in QGIS using CA-ANN. Three scenarios have been described in this study, including LULC change, climate change, and combined (climate and LULC change). The results suggest that there will be a significant increase in hydropower generation capacity (from 386.27 and 488.1 GWh to 867.82 and 862.53 GWh under RCP4.5 and RCP8.5, respectively, for the combined future effect of climate and land-use/cover changes. Energy utilities need to put in place mechanisms to effectively manage, operate, and maintain the hydropower plant amidst climate and land-use change impacts, to ensure reliability at all times.

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