scholarly journals Will the arid and semi-arid regions of Northwest China become warmer and wetter based on CMIP6 models?

2021 ◽  
Author(s):  
Liu Yang ◽  
Jiaxi Tian ◽  
Yuanhai Fu ◽  
Bin Zhu ◽  
Xu He ◽  
...  
Keyword(s):  
Simulated Data ◽  
Northwest China ◽  
Index Method ◽  
Temperature And Precipitation ◽  
The Future ◽  
Wet Climate ◽  
Eastern Inner Mongolia ◽  
Climate Transition ◽  
Precipitation Changes ◽  
Emissions Scenario

Abstract Whether there is a transition underway, from a warm-dry climate to a warm-wet climate in Northwest China remains a controversial and scientifically significant issue. Will this trend continue in the future? Another hot issue is whether the climate in Northwest China will continue to be warm and humid over the next few decades. In this paper, eight CMIP6 models were employed to investigate temperature and precipitation changes under five principal Shared Socioeconomic Pathway (SSP) scenarios (from 2015 to 2099) to project the future warming and humidification in Northwest China using the SPEI (standardized precipitation evapotranspiration index) method. The results revealed that (1) the simulated temperature and precipitation of eight CMIP6 models were consistent with that of observed data during 1961–2014, which showed an increase of approximately 28.2 mm, while simulated data revealed an increase of approximately 9.4 mm. The annual precipitation gradually decreased from Eastern Inner Mongolia and the Southern Northwest Mongolia region (>700 mm) to the Central Northwest Mongolia region (<100 mm) from 1961 to 2014; (2) the MME significantly overestimated the temperature and slightly underestimated the precipitation in Northwest Mongolia. The temperature difference between the simulated and observed data was approximately 0.4 °C. The observed data showed an increase of approximately 0.9 °C from 1961 to 2014, whereas the simulated data revealed an increase of approximately 0.7 °C; (3) in the SSP5-8.5 scenario, the percentage of precipitation anomalies at 1.5, 2, 3, and 4 °C were 166.64, 190.58, 226.44, and 274.56%, respectively; thus, alleviating the drought situation while facilitating the warm-dry to warm-wet climate transition; (4) the water balance between rising temperatures and increased evapotranspiration resulting from increased precipitation suggested that not all sites will be wet in the future. There was still a drying trend in some areas, where drought was more severe under the high emissions scenario than the low emissions scenario.

Temperature and precipitation changes in different environments in the arid region of northwest China

2012 ◽  
Vol 112 (3-4) ◽  
pp. 589-596 ◽  
Author(s):  
Baofu Li ◽  
Yaning Chen ◽  
Xun Shi ◽  
Zhongsheng Chen ◽  
Weihong Li
Keyword(s):  
Arid Region ◽  
Northwest China ◽  
Temperature And Precipitation ◽  
Precipitation Changes

scholarly journals Validation of SWAT simulated streamflow in the Eastern Nile and sensitivity to climate change

2011 ◽  
Vol 8 (5) ◽  
pp. 9005-9062 ◽  
Author(s):  
D. T. Mengistu ◽  
A. Sorteberg
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Annual Rainfall ◽  
Annual Streamflow ◽  
Blue Nile ◽  
Temperature And Precipitation ◽  
Monthly Streamflow ◽  
The Future ◽  
Precipitation Changes ◽  
Precipitation And Temperature

Abstract. The hydrological model SWAT was calibrated with daily station based precipitation and temperature data for the whole Eastern Nile basin including the three subbasins: the Blue Nile, Baro Akobo and Tekeze. The daily and monthly streamflow was calibrated and validated at six outlets in the three different subbasins. The model performed very well in simulating the monthly variability of the Eastern Nile streamflow while comparison to daily data revealed a more diverse performance for the extreme events. Of the Eastern Nile average annual rainfall it was estimated that around 60% is lost through evaporation and estimated runoff coefficients were 0.24, 0.30 and 0.18 for Blue Nile, Baro Akobo and Tekeze subbasins, respectively. About half to two-thirds of the runoff could be attributed to surface runoff while the remaining contributions were from groundwater. The annual streamflow sensitivity to changes in precipitation and temperature differed among the basins and the dependence of the response on the strength of the changes was not linear. On average the annual streamflow responses to a change in precipitation with no temperature change was 19%, 17%, and 26% per 10% change in precipitation while the average annual streamflow responses to a change in temperature and no precipitation change was −4.4% K−1, −6.4% K−1, and −1.3% K−1 for Blue Nile, Baro Akobo and Tekeze river basin, respectively. While we show the Eastern Nile to be very sensitive to precipitation changes, using 47 temperature and precipitation scenarios from 19 AOGCMs participating in IPCC AR4 we estimated the future change in streamflow to be strongly dependent on the choice of climate model as the climate models disagree on both the strength and the direction of future precipitation changes. Thus, no clear conclusions can be made about the future changes in Eastern Nile streamflow.

scholarly journals Climate Transition from Warm-Dry to Warm-Wet in Eastern Northwest China

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 548
Author(s):  
Jinhu Yang ◽  
Qiang Zhang ◽  
Guoyang Lu ◽  
Xiaoyun Liu ◽  
Youheng Wang ◽  
...  
Keyword(s):  
Temperature Change ◽  
Water Resource Management ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
Coupled Model ◽  
Research Programme ◽  
Northwest China ◽  
Humid Climate ◽  
Synergistic Enhancement ◽  
Climate Transition

During the second half of the 20th century, eastern Northwest China experienced a warming and drying climate change. To determine whether this trend has continued or changed during the present century, this study systematically analyzes the characteristics of warming and dry–wet changes in eastern Northwest China based on the latest observational data and World Climate Research Programme (WCRP) Coupled Model Intercomparison Project Phase 6 (CMIP6) collection data. The results show that eastern Northwest China has warmed continuously during the past 60 years with a sudden temperature change occurring in the late 1990s. However, the temperature in the 2000s decreased slowly, and that in the 2010s showed a warming trend. The amount of precipitation began to increase in the late 1990s, which indicates a contemporary climate transition from warm-dry to warm-wet in eastern Northwest China. The contribution of precipitation to humidity is significantly more than that of temperature. Long-term and interannual variations dominate the temperature change, with the contribution of the former much stronger than that of the latter. However, interannual variation dominates the precipitation change. The warming accelerates from period to period, and the temperature spatial consistently increased during the three most recent climatic periods. The precipitation decreased from 1961–1990 to 1981–2010, whereas its spatial consistency increased from 1981–2010 to 1991–2019. The significant warming and humidification which began in the late 1990s and is expected to continue until the end of the 21st century in the medium emission scenario. However, the current sub-humid climate will not easily be changed. The warming could cause a climate transition from warm temperate to subtropical by 2040. The dry-to-wet climate transition in eastern Northwest China could be related to a synergistic enhancement of the East Asian summer monsoon and the westerly circulation. This research provides a scientific decision-making basis for implementing western development strategies, ecological protection, and high-quality development of the Yellow River Basin Area as well as that for ecological construction planning and water resource management of eastern Northwest China.

Quantification of temperature and precipitation changes in northern China during the “5000-year” Chinese History

2021 ◽  
Vol 255 ◽  
pp. 106819 ◽  
Author(s):  
Can Zhang ◽  
Cheng Zhao ◽  
Aifeng Zhou ◽  
Haixia Zhang ◽  
Weiguo Liu ◽  
...  
Keyword(s):  
Northern China ◽  
Chinese History ◽  
Temperature And Precipitation ◽  
Precipitation Changes

Future Extreme Climates Projection over Huang-Huai-Hai Region of China

2014 ◽  
Vol 955-959 ◽  
pp. 3887-3892 ◽  
Author(s):  
Huang He Gu ◽  
Zhong Bo Yu ◽  
Ji Gan Wang
Keyword(s):  
Climate Changes ◽  
Climate Model ◽  
Regional Climate ◽  
Surface Air Temperature ◽  
Daily Rainfall ◽  
Heavy Rain ◽  
Near Surface ◽  
Temperature And Precipitation ◽  
Huai River ◽  
The Future

This study projects the future extreme climate changes over Huang-Huai-Hai (3H) region in China using a regional climate model (RegCM4). The RegCM4 performs well in “current” climate (1970-1999) simulations by compared with the available surface station data, focusing on near-surface air temperature and precipitation. Future climate changes are evaluated based on experiments driven by European-Hamburg general climate model (ECHAM5) in A1B future scenario (2070-2099). The results show that the annual temperature increase about 3.4 °C-4.2 °C and the annual precipitation increase about 5-15% in most of 3H region at the end of 21st century. The model predicts a generally less frost days, longer growing season, more hot days, no obvious change in heat wave duration index, larger maximum five-day rainfall, more heavy rain days, and larger daily rainfall intensity. The results indicate a higher risk of floods in the future warmer climate. In addition, the consecutive dry days in Huai River Basin will increase, indicating more serve drought and floods conditions in this region.

scholarly journals Benchmarking homogenization algorithms for monthly data

2012 ◽  
Vol 8 (1) ◽  
pp. 89-115 ◽  
Author(s):  
V. K. C. Venema ◽  
O. Mestre ◽  
E. Aguilar ◽  
I. Auer ◽  
J. A. Guijarro ◽  
...  
Keyword(s):  
Time Series ◽  
Performance Metrics ◽  
Linear Trend ◽  
Simulated Data ◽  
Integrated Approach ◽  
Global Network ◽  
Temperature And Precipitation ◽  
Skill Scores ◽  
Simulated Network ◽  
The Individual

Abstract. The COST (European Cooperation in Science and Technology) Action ES0601: advances in homogenization methods of climate series: an integrated approach (HOME) has executed a blind intercomparison and validation study for monthly homogenization algorithms. Time series of monthly temperature and precipitation were evaluated because of their importance for climate studies and because they represent two important types of statistics (additive and multiplicative). The algorithms were validated against a realistic benchmark dataset. The benchmark contains real inhomogeneous data as well as simulated data with inserted inhomogeneities. Random independent break-type inhomogeneities with normally distributed breakpoint sizes were added to the simulated datasets. To approximate real world conditions, breaks were introduced that occur simultaneously in multiple station series within a simulated network of station data. The simulated time series also contained outliers, missing data periods and local station trends. Further, a stochastic nonlinear global (network-wide) trend was added. Participants provided 25 separate homogenized contributions as part of the blind study. After the deadline at which details of the imposed inhomogeneities were revealed, 22 additional solutions were submitted. These homogenized datasets were assessed by a number of performance metrics including (i) the centered root mean square error relative to the true homogeneous value at various averaging scales, (ii) the error in linear trend estimates and (iii) traditional contingency skill scores. The metrics were computed both using the individual station series as well as the network average regional series. The performance of the contributions depends significantly on the error metric considered. Contingency scores by themselves are not very informative. Although relative homogenization algorithms typically improve the homogeneity of temperature data, only the best ones improve precipitation data. Training the users on homogenization software was found to be very important. Moreover, state-of-the-art relative homogenization algorithms developed to work with an inhomogeneous reference are shown to perform best. The study showed that automatic algorithms can perform as well as manual ones.

scholarly journals Regional climate change scenarios for Greece: future temperature and precipitation projections form ensembles of RCMs

2013 ◽  
Vol 14 (4) ◽  
pp. 407-421 ◽  
Keyword(s):  
Regional Climate ◽  
Regional Climate Change ◽  
Summer Temperature ◽  
Climate Change Scenarios ◽  
Emission Scenarios ◽  
Temperature And Precipitation ◽  
The Future ◽  
Future Emission ◽  
Spatial Grid ◽  
Of Greece

The potential regional future changes in seasonal (winter and summer) temperature and precipitation are assessed for the greater area of Greece over the 21st century, under A2, A1B and B2 future emission scenarios of IPCC. Totally twenty-two simulations from various regional climate models (RCMs) were assessed; fourteen of them with a spatial grid resolution of 50km for the period 2071-2100 under A2 (9 simulations) and B2 (5 simulations) scenarios and eight of them with an even finer resolution of 25km under A1B scenario for both 2021-2050 and 2071-2100 time periods. The future changes in temperature and precipitation were calculated with respect to the control period (1961-1990). All the models estimated warmer and dryer conditions over the study area. The warming is more intense during the summer months, with the changes being larger in the continental than in the marine area of Greece. In terms of precipitation, the simulations of the RCMs estimate a decrease up to -60% (A2 scenario). Finally it is shown that the changes in the atmospheric circulation over Europe play a key role in the changes of the future precipitation and temperature characteristics over the domain of study in a consistent way for the different emission scenarios.

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