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.

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.

The influence of global climate changes on Western Siberia climate in the first half of XXI century

2018 ◽  
Author(s):  
А.А. Лагутин ◽  
Н.В. Волков ◽  
Е.Ю. Мордвин
Keyword(s):  
Radiative Forcing ◽  
Climate Changes ◽  
Western Siberia ◽  
Climate Model ◽  
Global Climate ◽  
Regional Climate ◽  
First Century ◽  
Global Climate Changes ◽  
Rcp 8.5

Представлены результаты исследований влияния глобальных климатических изменений системы Земля на климат Западной Сибири. Для установления зон региона, в которых к середине XXI в. прогнозируются изменения, использовались модельные данные региональной климатической модели RegCM4 и принятые в этом классе задач стандартизованные евклидовы расстояния между характеристиками климата для двух состояний климатической системы — современного и будущего. Установлены зоны Западной Сибири, в которых в рамках сценариев RCP 4.5 и RCP 8.5 возможной эволюции глобальной системы к 2050 г. прогнозируются изменения климата. Purpose. An analysis of the influence of a global climate changes on the climate of Western Siberia, determination of zones of the region where changes are expected in the middle of the twenty-first century. Methodology. Results obtained using the model data of the regional climate model RegCM4 and the standardized Euclidean distances between climate characteristics. Findings, originality. Simulations of the climate characteristics for the two states of the climate system — contemporary and future — have been carried out. The zones of Western Siberia region, in which climate change is expected in the framework of RCP 4.5 and RCP 8.5 radiative forcing scenarios by the 2050, have been determined.

scholarly journals Assessing the impact of global climate changes on irrigated wheat yields and water requirements in a semi-arid environment of Morocco

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Elhoussaine Bouras ◽  
Lionel Jarlan ◽  
Said Khabba ◽  
Salah Er-Raki ◽  
Alain Dezetter ◽  
...  
Keyword(s):  
Global Climate ◽  
Regional Climate ◽  
Arid Environment ◽  
Water Requirements ◽  
Global Climate Changes ◽  
Development Cycle ◽  
Aquacrop Model ◽  
Irrigated Wheat ◽  
Fertilizing Effect ◽  
The Impact

AbstractThe present work aims to quantify the impact of climate change (CC) on the grain yields of irrigated cereals and their water requirements in the Tensift region of Morocco. The Med-CORDEX (MEDiterranean COordinated Regional Climate Downscaling EXperiment) ensemble runs under scenarios RCP4.5 (Representative Concentration Pathway) and RCP8.5 are first evaluated and disaggregated using the quantile-quantile approach. The impact of CC on the duration of the main wheat phenological stages based on the degree-day approach is then analyzed. The results show that the rise in air temperature causes a shortening of the development cycle of up to 50 days. The impacts of rising temperature and changes in precipitation on wheat yields are next evaluated, based on the AquaCrop model, both with and without taking into account the fertilizing effect of CO2. As expected, optimal wheat yields will decrease on the order of 7 to 30% if CO2 concentration rise is not considered. The fertilizing effect of CO2 can counterbalance yield losses, since optimal yields could increase by 7% and 13% respectively at mid-century for the RCP4.5 and RCP8.5 scenarios. Finally, water requirements are expected to decrease by 13 to 42%, mainly in response to the shortening of the cycle. This decrease is associated with a change in temporal patterns, with the requirement peak coming two months earlier than under current conditions.

scholarly journals Variations of Near Surface Energy Balance Caused by Land Cover Changes in the Semiarid Grassland Area of China

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Qun’ou Jiang ◽  
Chengcai Tang ◽  
Enjun Ma ◽  
Yongwei Yuan ◽  
Wei Zhang
Keyword(s):  
Land Cover ◽  
Energy Flux ◽  
Land Use Planning ◽  
Environmental Sustainability ◽  
Wrf Model ◽  
Near Surface ◽  
Semiarid Grassland ◽  
Land System ◽  
Rapid Economic Growth ◽  
Rate Of Increase

This study applies the Dynamics of Land System (DLS) model to simulating the land cover under the designed scenarios and then analyzes the effects of land cover conversion on energy flux in the semiarid grassland area of China with the Weather Research and Forecasting (WRF) model. The results indicate that the grassland will show a steadily upgrowing trend under the coordinated environmental sustainability (CES) scenario. Compared to the CES scenario, the rate of increase in grassland cover is lower, while the rate of increase in urban land cover will be higher under the rapid economic growth (REG) scenario. Although the conversion from cropland to grassland will reduce the energy flux, the expansion of urban area and decreasing of forestry area will bring about more energy flux. As a whole, the energy flux of near surface will obviously not change under the CES scenario, and the climate therefore will not be possible to be influenced greatly by land cover change. The energy flux under the REG scenario is higher than that under the CES scenario. Those research conclusions can offer valuable information for the land use planning and climate change adaptation in the semiarid grassland area of China.

scholarly journals Technical challenges and solutions in representing lakes when using WRF in downscaling applications

2014 ◽  
Vol 7 (5) ◽  
pp. 7121-7150 ◽  
Author(s):  
M. S. Mallard ◽  
C. G. Nolte ◽  
T. L. Spero ◽  
O. R. Bullock ◽  
K. Alapaty ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Wrf Model ◽  
Ice Cover ◽  
Alternative Methods ◽  
Weather Research And Forecasting ◽  
Inland Lakes ◽  
Air Temperatures

Abstract. The Weather Research and Forecasting (WRF) model is commonly used to make high resolution future projections of regional climate by downscaling global climate model (GCM) outputs. Because the GCM fields are typically at a much coarser spatial resolution than the target regional downscaled fields, inland lakes are often poorly resolved in the driving global fields, if they are resolved at all. In such an application, using WRF's default interpolation methods can result in unrealistic lake temperatures and ice cover at inland water points. Prior studies have shown that lake temperatures and ice cover impact the simulation of other surface variables, such as air temperatures and precipitation, two fields that are often used in regional climate applications to understand the impacts of climate change on human health and the environment. Here, alternative methods for setting lake surface variables in WRF for downscaling simulations are presented and contrasted.

scholarly journals The role of land cover in the climate of glacial Europe

2021 ◽  
Vol 17 (3) ◽  
pp. 1161-1180
Author(s):  
Patricio Velasquez ◽  
Jed O. Kaplan ◽  
Martina Messmer ◽  
Patrick Ludwig ◽  
Christoph C. Raible
Keyword(s):  
Land Cover ◽  
Regional Climate Model ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Quasi Equilibrium ◽  
Earth System ◽  
Vegetation Model ◽  
The Alps

Abstract. Earth system models show wide disagreement when simulating the climate of the continents at the Last Glacial Maximum (LGM). This disagreement may be related to a variety of factors, including model resolution and an incomplete representation of Earth system processes. To assess the importance of resolution and land–atmosphere feedbacks on the climate of Europe, we performed an iterative asynchronously coupled land–atmosphere modelling experiment that combined a global climate model, a regional climate model, and a dynamic vegetation model. The regional climate and land cover models were run at high (18 km) resolution over a domain covering the ice-free regions of Europe. Asynchronous coupling between the regional climate model and the vegetation model showed that the land–atmosphere coupling achieves quasi-equilibrium after four iterations. Modelled climate and land cover agree reasonably well with independent reconstructions based on pollen and other paleoenvironmental proxies. To assess the importance of land cover on the LGM climate of Europe, we performed a sensitivity simulation where we used LGM climate but present-day (PD) land cover. Using LGM climate and land cover leads to colder and drier summer conditions around the Alps and warmer and drier climate in southeastern Europe compared to LGM climate determined by PD land cover. This finding demonstrates that LGM land cover plays an important role in regulating the regional climate. Therefore, realistic glacial land cover estimates are needed to accurately simulate regional glacial climate states in areas with interplays between complex topography, large ice sheets, and diverse land cover, as observed in Europe.

scholarly journals Differences between downscaling with spectral and grid nudging using WRF

2012 ◽  
Vol 12 (8) ◽  
pp. 3601-3610 ◽  
Author(s):  
P. Liu ◽  
A. P. Tsimpidi ◽  
Y. Hu ◽  
B. Stone ◽  
A. G. Russell ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Dynamical Downscaling ◽  
Global Climate ◽  
Regional Climate ◽  
Wrf Model ◽  
Global Climate Models ◽  
Small Scale ◽  
Data Set ◽  
Spectral Nudging

Abstract. Dynamical downscaling has been extensively used to study regional climate forced by large-scale global climate models. During the downscaling process, however, the simulation of regional climate models (RCMs) tends to drift away from the driving fields. Developing a solution that addresses this issue, by retaining the large scale features (from the large-scale fields) and the small-scale features (from the RCMs) has led to the development of "nudging" techniques. Here, we examine the performance of two nudging techniques, grid and spectral nudging, in the downscaling of NCEP/NCAR data with the Weather Research and Forecasting (WRF) Model. The simulations are compared against the results with North America Regional Reanalysis (NARR) data set at different scales of interest using the concept of similarity. We show that with the appropriate choice of wave numbers, spectral nudging outperforms grid nudging in the capacity of balancing the performance of simulation at the large and small scales.

scholarly journals Technical challenges and solutions in representing lakes when using WRF in downscaling applications

2015 ◽  
Vol 8 (4) ◽  
pp. 1085-1096 ◽  
Author(s):  
M. S. Mallard ◽  
C. G. Nolte ◽  
T. L. Spero ◽  
O. R. Bullock ◽  
K. Alapaty ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Wrf Model ◽  
Ice Cover ◽  
Alternative Methods ◽  
Weather Research And Forecasting ◽  
Air Temperatures ◽  
Impacts Of Climate Change

Abstract. The Weather Research and Forecasting (WRF) model is commonly used to make high-resolution future projections of regional climate by downscaling global climate model (GCM) outputs. Because the GCM fields are typically at a much coarser spatial resolution than the target regional downscaled fields, lakes are often poorly resolved in the driving global fields, if they are resolved at all. In such an application, using WRF's default interpolation methods can result in unrealistic lake temperatures and ice cover at inland water points. Prior studies have shown that lake temperatures and ice cover impact the simulation of other surface variables, such as air temperatures and precipitation, two fields that are often used in regional climate applications to understand the impacts of climate change on human health and the environment. Here, alternative methods for setting lake surface variables in WRF for downscaling simulations are presented and contrasted.

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 Projected Impacts of Bioenergy-Demand-Induced Land Use and Cover Changes on Regional Climate in Central Europe

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Fang Yin ◽  
Yihui Xiong ◽  
Li Jiang ◽  
Zhiguo Pang
Keyword(s):  
Land Use ◽  
Central Europe ◽  
Regional Climate ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Bioenergy Production ◽  
Land System ◽  
Land Use Structure ◽  
Climatic Impacts ◽  
Main Input

Energy shortfalls are becoming more and more serious all over the world, and worldwide governments have tried to promote the development of biofuels in order to mitigate the climatic impacts of massive fossil fuel consumption. Since the land is the main input factor of the bioenergy production, the development of biofuels will inevitably lead to change of the land use structure and allocation and thereby affect the climate system. With Central Europe as the study area, this study explored the impacts of land use/land cover change (LUCC) on climate under the influence of demand of bioenergy production for land resources. First, the land use structure from 2010 to 2050 is simulated with the Agriculture and Land Use model in MiniCam. The result indicates that the main conversion will be mainly from grassland and forest to cropland and from cropland to grassland. Then the Dynamics of Land System model was used to spatially simulate the LUCC in the future. The impacts of LUCC on the climate were analyzed on the basis of simulation with the Weather Research and Forecasting (WRF) model. The climate change will be characterized by the increase of latent heat flux and temperature and the decrease of precipitation.

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