scholarly journals Characteristics and cause analysis of flue-cured tobacco's water requirements during growth periods in low latitude plateau area, China

2018 ◽  
Vol 11 (2) ◽  
pp. 402-419
Author(s):  
Na Fu ◽  
Xiaoyu Song ◽  
Lu Xia ◽  
Lanjun Li ◽  
Xiaogang Liu
Keyword(s):  
21St Century ◽  
Yunnan Province ◽  
Principal Component ◽  
Growth Period ◽  
Irrigation Requirement ◽  
Water Requirements ◽  
Intergovernmental Panel ◽  
Plateau Area ◽  
The Future ◽  
Late 21St Century

Abstract This study aimed to identify the future changes in water requirements (ETc) of flue-cured tobacco by comparing estimated ETc values in the future with previous usage. This will provide a basis for estimating irrigation requirements, and help improve agricultural water use efficiency in the future. The Penman–Monteith equation and the single-crop efficient method were used to calculate the flue-cured tobacco ETc, net irrigation requirement (IR) and net irrigation requirement index (IDI) for the period 1956–2015, and the four Intergovernmental Panel on Climate Change (IPCC) AR5 emission scenarios were used to estimate ETc for two future periods (2046–2065 and 2081–2100) in the central Yunnan Province, China. The results showed that the IDI gradually decreased, along with the growth of flue-cured tobacco. The ETc, IR and IDI values increased with latitude in central Yunnan Province. Furthermore, the variations in the ETc over the whole growth period in the mid-21st century and late-21st century also tended to increase with latitude. In addition, based on the influence of climate variation on the ETc as assessed by a principal component analysis, precipitation was the main factor affecting flue-cured tobacco growth. This study contributes to the establishment of suitable irrigation systems for flue-cured tobacco at every growth stage in central Yunnan Province.

scholarly journals Influence mechanism of climate change over crop growth and water demands for wheat-rice system of Punjab, Pakistan

2020 ◽  
Author(s):  
Mirza Junaid Ahmad ◽  
Gun-Ho Cho ◽  
Sang-Hyun Kim ◽  
Seulgi Lee ◽  
Bashir Adelodun ◽  
...  
Keyword(s):  
Climate Change ◽  
Temperature Rise ◽  
Growth Period ◽  
Crop Growth ◽  
Crop Failure ◽  
Water Requirements ◽  
Security Issues ◽  
Agriculture Sector ◽  
Water Demands ◽  
The Future

Abstract Conceptualizing the climate change perspective of crop growth and evapotranspiration (ETc) rates and subsequent irrigation water requirements (IWR) is necessary for sustaining the agriculture sector and tackling food security issues in Pakistan. This article projects the future growth periods and water demands for the wheat-rice system of Punjab. Intense and hotter transitions in the future thermal regimes and erratic monsoon rainfall increments were envisaged. The crop growth rates were accelerated by the probable temperature rise resulting in shortened growth periods. The temperature rise increased the reference evapotranspiration rates; however, the future ETc declined due to reduced growth period and net radiation. Highly unpredictable, but mostly increasing, cumulative seasonal and annual rainfalls were indicative of more effective rainfalls during the future crop seasons. Reduced ETc and increments in seasonal effective rainfalls gave rise to the declining IWR for both crops. The study findings seemingly undermined the harmful climate change influences on the water requirements of the wheat-rice system of Punjab but alarmingly shortening of growth periods indicates a higher crop failure tendency under the projected future thermal regime.

scholarly journals Ensemble Projection of Extreme Precipitation Over China Based on Three Dynamical Downscaling Simulations

2021 ◽  
Vol 9 ◽  
Author(s):  
Guangtao Dong ◽  
Ye Xie ◽  
Ya Wang ◽  
Dongli Fan ◽  
Zhan Tian
Keyword(s):  
21St Century ◽  
Extreme Precipitation ◽  
North China ◽  
Climate Models ◽  
Climate Model ◽  
Dynamical Downscaling ◽  
Global Climate Models ◽  
Vapor Flux ◽  
The Future ◽  
Late 21St Century

Based on the outputs of the global climate models (GCMs) HadGEM2-ES, NorESM1-M and MPI-ESM-LR from Coupled Model Intercomparison Project Phase 5 (CMIP5) and the downscaling results with the regional climate model (RCM) REMO, the ability of the climate models to reproduce the extreme precipitation in China during the current period (1986–2005) is evaluated. Then, the future extreme precipitation in the mid (2036–2065) and the late 21st century (2066–2095) is projected under the RCP8.5 scenario. The results show that the RCM simulations have great improvements compared with the GCMs, and the ensemble mean of the RCM results (ensR) outperforms each single RCM simulation. The annual precipitation of the RCM simulations is more consistent with the observation than that of the GCMs, with the overestimation of the peak precipitation reduced, and the ensR further reduces the bias. For the extreme precipitation, the RCM simulations significantly decrease the underestimation of intensity in the GCMs. The RCM simulations and the ensR can greatly improve the simulations of Rx5day and CWD compared with the GCMs, decreasing the wet bias in North China and Northwest China. In the future, the consecutive dry days (CDD) will decrease in the northern arid regions, especially in North China and Northeast China. However, the southern regions will experience longer dry period. Both the amount and the intensity of precipitation will increase in various regions of China. The number of wet days will decrease in the south and increase in the north area. The significantly greater Rx5day and R95t indicate more intensive extreme precipitation in the future, and the intensity in the late 21st century will be stronger than that in the middle. Attribution analysis indicates that the extreme precipitation indices especially the R95t have significant positive temporal and spatial correlations with the water vapor flux.

Underestimation of the projected 21st century increase in drought duration, according to emergent constraint: consistent result in CMIP5 and CMIP6 models

2021 ◽  
Author(s):  
Irina Y. Petrova ◽  
Diego G. Miralles ◽  
Florent Brient ◽  
Markus Donat
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Climate Models ◽  
Model Errors ◽  
Drought Duration ◽  
Intergovernmental Panel ◽  
Uncertainty Range ◽  
The Future ◽  
Emergent Constraint ◽  
Global Mean

<p>Droughts are defined as one of the most devastating natural disasters of modern times and a key challenge faced under climate change. The complexity of interacting physical processes that underlie the shortage of rainfall in climate models hampers accurate representation of present-day droughts, and leads to differences in their responses to increased greenhouse gas (GHG) concentrations in the future. As a result, the confidence in drought projections is currently defined as ‘medium to low' by the Intergovernmental Panel on Climate Change (IPCC), and reducing this uncertainty remains one of the main goals in coming years, with significant benefits for human and natural systems. </p><p>In this study we explore a relationship between biases in simulated present-day values of longest annual drought (LAD) and future projections of LAD in an ensemble of CMIP5 and CMIP6 models. We find that present-day model bias explains almost 95 % of the future uncertainty in LAD by the end of the 21st century, attributed to the well-known precipitation simulation errors: “drier” models with longer annual droughts at present tend to predict larger LAD values worldwide in the future, as well as a stronger response to GHG forcing in LAD, which is significant in more than 40 % of the global land area.</p><p>Substituting observational LAD estimates from satellite data into this model-revealed “present–future relationlarship” suggests that the 21st century global mean increase in duration of annual meteorological droughts could be significantly larger than predicted by the CMIP5 and CMIP6 model ensembles. This emergent constraint reduces global mean uncertainty range in future LAD estimates from 45–100 to 75–90 days, a level more typical of the prediction range of “drier” models. The findings reveal world regions where climate change may cause stronger meteorological drought aggravation than expected, and emphasise the importance of reducing model errors, which are presently largely owed to rain biases, to increase confidence in future predictions.</p>

PREDICTION OF PADDY IRRIGATION REQUIREMENTS BY USING STATISTICAL DOWNSCALING AND CROPWAT MODELS: A CASE STUDY FROM THE KERIAN IRRIGATION SCHEME IN MALAYSIA

2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Nuramidah Hamidon ◽  
Sobri Harun ◽  
M. A Malek ◽  
Tarmizi Ismail ◽  
Noraliani Alias
Keyword(s):  
Global Warming ◽  
Irrigation Water ◽  
Production Systems ◽  
Climate Trends ◽  
Irrigation Requirement ◽  
Irrigation Scheme ◽  
Water Requirements ◽  
Local Climate ◽  
Paddy Irrigation ◽  
The Future

With an average rainfall of 2500mm per year, Malaysia has abundant water resources but climate change coupled with drought, urbanisation and pollution sometimes causes water stress. Global warming has changed the local climate, threatening agricultural activities with particular impact on paddy production systems. To ensure availability of sufficient irrigation water for growing crops, there is a need to estimate future irrigation water requirements in the face of the complex dynamic resulting from global warming. The current study was therefore carried out to estimate paddy irrigation water requirements based on future climate trends by using SDSM and CROPWAT Models at the Kerian Irrigation Scheme, Perak, Malaysia. The application of the SDSM model revealed that both temperature and rainfall will increase in the future. Meanwhile the CROPWAT model predicted that the annual irrigation requirement will slightly decrease for period between 2010-2069 and increase for years 2070-2099 even though crop evapotranspiration (ETcrop) is predicted to increase in future for rise in temperature for year 2010 to 2099. This integration of SDSM and CROPWAT models produced better simulations of crop water requirement and irrigation requirement. Therefore, it can assist the reservoir’s operating management team in giving effective and proficient response to climate changes in the future.

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