scholarly journals Climate change and its implications for rainfed agriculture in Ethiopia

2020 ◽  
Author(s):  
Desalew Meseret Moges ◽  
H. Gangadhara Bhat
Keyword(s):  
Coupled Model ◽  
Daily Rainfall ◽  
Kendall Test ◽  
Future Climate ◽  
Rainfed Agriculture ◽  
Rcp Scenarios ◽  
Precipitation Concentration Index ◽  
Spatio Temporal ◽  
Temperature Records ◽  
Climate Analysis

Abstract This study aims to investigate the spatio-temporal variability and trends in climate and its implications for rainfed agriculture in the Rib watershed, north-western highland Ethiopia from 1986 to 2050. The daily rainfall and temperature records for the period 1986–2017 were used to detect the variability and trends of the current climate using the coefficient of variation, precipitation concentration index, Mann–Kendall test, and Sen's slope estimator. On the other hand, future climate changes (2018–2050) were analyzed based on the Coupled Model Intercomparison Project version 5 (CMIP5) model outputs under under two representative concentration pathway (RCP) scenarios, RCP 4.5 and 8.5. The results showed high inter-seasonal and inter-annual variability of rainfall and temperature in the studied watershed over the last four decades. The annual and Kiremt (June–September) rainfall showed a generally increasing trend, while the Belg (March–May) rainfall exhibited a decreasing trend between 1986 and 2017. Conversely, the minimum, maximum and mean temperature demonstrated increasing trends over the study period although most of the detected trends were statistically insignificant at 5 and 10% level of significance. Future climate analysis results showed an increase in future temperature and annual and Kiremt rainfall while Belg rainfall declined.

scholarly journals PLASIM-ENTSem: a spatio-temporal emulator of future climate change for impacts assessment

2013 ◽  
Vol 6 (2) ◽  
pp. 3349-3380 ◽  
Author(s):  
P. B. Holden ◽  
N. R. Edwards ◽  
P. H. Garthwaite ◽  
K. Fraedrich ◽  
F. Lunkeit ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
General Circulation ◽  
Coupled Model ◽  
Co2 Concentration ◽  
General Circulation Models ◽  
Climate Impacts ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Data ◽  
Spatio Temporal

Abstract. Many applications in the evaluation of climate impacts and environmental policy require detailed spatio-temporal projections of future climate. To capture feedbacks from impacted natural or socio-economic systems requires interactive two-way coupling but this is generally computationally infeasible with even moderately complex general circulation models (GCMs). Dimension reduction using emulation is one solution to this problem, demonstrated here with the GCM PLASIM-ENTS. Our approach generates temporally evolving spatial patterns of climate variables, considering multiple modes of variability in order to capture non-linear feedbacks. The emulator provides a 188-member ensemble of decadally and spatially resolved (~ 5° resolution) seasonal climate data in response to an arbitrary future CO2 concentration and radiative forcing scenario. We present the PLASIM-ENTS coupled model, the construction of its emulator from an ensemble of transient future simulations, an application of the emulator methodology to produce heating and cooling degree-day projections, and the validation of the results against empirical data and higher-complexity models. We also demonstrate the application to estimates of sea-level rise and associated uncertainty.

scholarly journals PLASIM-ENTSem v1.0: a spatio-temporal emulator of future climate change for impacts assessment

2014 ◽  
Vol 7 (1) ◽  
pp. 433-451 ◽  
Author(s):  
P. B. Holden ◽  
N. R. Edwards ◽  
P. H. Garthwaite ◽  
K. Fraedrich ◽  
F. Lunkeit ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
General Circulation ◽  
Coupled Model ◽  
Co2 Concentration ◽  
General Circulation Models ◽  
Climate Impacts ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Data ◽  
Spatio Temporal

Abstract. Many applications in the evaluation of climate impacts and environmental policy require detailed spatio-temporal projections of future climate. To capture feedbacks from impacted natural or socio-economic systems requires interactive two-way coupling, but this is generally computationally infeasible with even moderately complex general circulation models (GCMs). Dimension reduction using emulation is one solution to this problem, demonstrated here with the GCM PLASIM-ENTS (Planet Simulator coupled with the efficient numerical terrestrial scheme). Our approach generates temporally evolving spatial patterns of climate variables, considering multiple modes of variability in order to capture non-linear feedbacks. The emulator provides a 188-member ensemble of decadally and spatially resolved (~ 5° resolution) seasonal climate data in response to an arbitrary future CO2 concentration and non-CO2 radiative forcing scenario. We present the PLASIM-ENTS coupled model, the construction of its emulator from an ensemble of transient future simulations, an application of the emulator methodology to produce heating and cooling degree-day projections, the validation of the simulator (with respect to empirical data) and the validation of the emulator (with respect to high-complexity models). We also demonstrate the application to estimates of sea-level rise and associated uncertainty.

scholarly journals Long–term spatio–temporal warming tendency in the Vietnamese Mekong Delta based on observed and high–resolution gridded datasets

2019 ◽  
pp. 01-16
Author(s):  
Dang Nguyen Dong Phuong ◽  
Dang Kien Cuong ◽  
Duong Ton Dam ◽  
Nguyen Kim Loi
Keyword(s):  
High Resolution ◽  
Statistical Tests ◽  
Mekong Delta ◽  
Kendall Test ◽  
Trend Detection ◽  
Homogeneity Test ◽  
Spatio Temporal ◽  
Temperature Records ◽  
Slope Estimator ◽  
Increasing Trends

The Vietnamese Mekong Delta is among the most vulnerable deltas to climate–related hazards across the globe. In this study, the annual mean and extreme temperatures from 11 meteorological stations over the Vietnamese Mekong Delta were subjected to normality, homogeneity and trend analysis by employing a number of powerful statistical tests (i.e. Shapiro–Wilk, Buishand Range test, classical/modified Mann–Kendall test and Sen’s slope estimator). As for spatio–temporal assessment, the well–known (0.5° × 0.5°) high–resolution gridded dataset (i.e. CRU TS4.02) was also utilized to examine trend possibilities for three different time periods (i.e. 1901–2017, 1951–2017 and 1981–2017) by integrating spatial interpolation algorithms (i.e. IDW and Ordinary Kriging) with statistical trend tests. Comparing the calculated test–statistics to their critical values (a = 0.05), it is evident that most of the temperature records can be considered to be normal and non–homogeneous with respect to normality and homogeneity test respectively. As for temporal trend detection, the outcomes show high domination of significantly increasing trends. Additionally, the results of trend estimation indicate that the magnitude of increase in minimum temperature was mostly greater than mean and maximum ones and the recent period (1981–2017) also revealed greater increasing rates compared to the entire analyzed period and second half of the 20th century. In general, these findings yield various evident indications of warming tendency in the Vietnamese Mekong Delta over the last three decades.

 Spatio-temporal characterization of rainfall using an innovative trend and discrete wavelet transformation approaches in Bhakra catchment, India

2021 ◽  
Author(s):  
Neha Gupta ◽  
Sagar Chavan
Keyword(s):  
Extreme Rainfall ◽  
Kendall Test ◽  
Mitigation Measures ◽  
Discrete Wavelet ◽  
Precipitation Concentration Index ◽  
Seasonal Time Series ◽  
Seasonal Basis ◽  
Spatio Temporal ◽  
Water Resources Projects ◽  
Slope Estimator

<p>Using a high-resolution daily gridded rainfall data of 0.25° from the Indian Meteorological Department (IMD), the present study investigates the detailed characteristics of rainfall in the Bhakra Catchment from 1901 to 2019. The long term spatial and temporal rainfall variations in Bhakra Catchment are not well explored. The spatial pattern of rainfall regimes in this catchment is identified by estimating index like the precipitation concentration index (PCI) and seasonality index (SI). Extreme rainfall trends on annual and seasonal basis are examined using the innovative trend analysis (ITA) method. Reliability of ITA was assessed by comparing them with widely applied Mann–Kendall (MK) or modified Mann–Kendall (mMK) test results. Furthermore, the change in two halves of rainfall series is estimated using percent bias technique for estimating changes in rainfall. Changes in slopes are estimated by using Sen’s slope estimator (Q). Discrete wavelet transform (DWT) in conjunction with Sequential Mann–Kendall test (SQMK) is employed to find out the dominant periodicity in rainfall patterns. The effectiveness of the graphical method in qualitative analysis can be seen, while DWT is found efficient in identifying periodicity. Both positive and negative trends are detected in annual and seasonal time series over the study area. The outcomes of this study may be helpful in the planning and management of water resources projects in the catchment along with the planning of mitigation measures to alleviate the effects of climate change under extreme rainfall conditions.</p>

scholarly journals Daily precipitation concentration across Europe 1971–2010

2012 ◽  
Vol 12 (9) ◽  
pp. 2799-2810 ◽  
Author(s):  
N. Cortesi ◽  
J. C. Gonzalez-Hidalgo ◽  
M. Brunetti ◽  
J. Martin-Vide
Keyword(s):  
Temporal Trend ◽  
Daily Precipitation ◽  
Daily Rainfall ◽  
Kendall Test ◽  
Western Mediterranean ◽  
Statistical Structure ◽  
Precipitation Concentration Index ◽  
North West ◽  
Precipitation Concentration ◽  
Western Mediterranean Basin

Abstract. Daily Precipitation Concentration Index (CI) was used in this paper to investigate the statistical structure of daily precipitation across Europe based on 530 daily rainfall series for the period 1971–2010. Annual CI shows a North-West to South-East gradient (excluding Turkey and Greece). The same gradient is also observed in winter, spring and autumn, while in summer the gradient is North-South. Highest annual and seasonal daily concentrations of rainfall were detected in the western Mediterranean basin, mainly along Spanish and French coastlands. Latitude and distance from the sea seems to play a major role on spatial CI distribution; at subregional scale also relief plays an important role. The Mann–Kendall test did not identify uniform significant pattern in temporal trend across Europe for 1971–2010 period. The only broad areas with increasing annual and seasonal CI values are located in northern and south-western France and northern coastlands of the Iberian Peninsula. This findings suggest that daily precipitation distribution has not significantly changed during the 1971–2010 over Europe.

scholarly journals Simulating Potential Impacts of Future Climate Change on Post-Rainy Season Sorghum Yields in India

2021 ◽  
Vol 14 (1) ◽  
pp. 334
Author(s):  
Keerthi Chadalavada ◽  
Sridhar Gummadi ◽  
Koteswara Rao Kundeti ◽  
Dakshina Murthy Kadiyala ◽  
Kumara Charyulu Deevi ◽  
...  
Keyword(s):  
Climate Change ◽  
Rainy Season ◽  
Climate Model ◽  
Crop Yields ◽  
Coupled Model ◽  
Daily Rainfall ◽  
Future Climate ◽  
Future Climate Change ◽  
Air Temperatures ◽  
Rcp 8.5

Given the wide use of the multi-climate model mean (MMM) for impact assessment studies, this work examines the fidelity of Coupled Model Intercomparison Project Phase 5 (CMIP5) in simulating the features of Indian summer monsoons as well as the post-rainy seasons for assessing the possible impacts of climate change on post-rainy season sorghum crop yields across India. The MMM simulations captured the spatial patterns and annual cycles of rainfall and surface air temperatures. However, bias was observed in the precipitation amounts and daily rainfall intensity. The trends in the simulations of MMM for both precipitation and temperatures were less satisfactory than the observed climate means. The Crop Environment Resource Synthesis (CERES)-sorghum model was used to estimate the potential impacts of future climate change on post-rainy season sorghum yield values. On average, post-rainy season sorghum yields are projected to vary between −4% and +40% as well as +10% and +59% in the near future (2040–2069) for RCP 4.5 and RCP 8.5, respectively, and between +20% and +70% (RCP 4.5) as well as +38% and +89% (RCP 8.5) in the far future (2070–2099). Even though surface air temperatures are increasing in future climate change projections, the findings suggest that an increase in the post-rainy season sorghum yields was due to an increase in the rainfall amounts up to 23% and an increase in the atmospheric CO2 levels by the end of the 21st century. The results suggest that the projected climate change during the post-rainy season over India is an opportunity for smallholders to capitalize on the increase in rainfall amounts and further increase sorghum yields with appropriate crop management strategies.

scholarly journals Precipitation trends and a daily precipitation concentration index for the mid-Eastern Atlantic (Canary Islands, Spain)

2017 ◽  
Vol 43 (1) ◽  
pp. 255 ◽  
Author(s):  
P. Máyer ◽  
M.V. Marzol ◽  
J.M. Parreño
Keyword(s):  
Time Series ◽  
Canary Islands ◽  
Concentration Index ◽  
Daily Precipitation ◽  
Daily Rainfall ◽  
Kendall Test ◽  
High Concentration ◽  
Precipitation Concentration Index ◽  
Precipitation Concentration ◽  
The North

This paper pursues two objectives: first, to determine the trends of seasonal and annual precipitation in the Canary Islands and, second, to identify trends in the daily precipitation concentration index (CI). For the first objective, we used data from 1970-2013 of 23 rainfall stations located on different islands, after verifying the homogeneity of their series. For the second, the sample was reduced to eleven series since deficiencies in data records of less than 1 mm of daily precipitation were appreciated. We used the nonparametric Mann-Kendall test to determine whether the series showed linear trends in annual and seasonal precipitation and in the values of CI. The seasonal results showed negative trends in spring and winter in almost all the time series considered, especially in the north of Gran Canaria and Tenerife. Conversely, 78% of the series in autumn recorded an increase in the precipitation. The annual balance indicated a decline of rainfall in most of the locations, because of the high concentration of precipitation in winter. Finally, the majority of the time series exhibited a trend toward a greater concentration of daily rainfall, in particular those series located in areas where the main towns are settled, which is an important issue to consider because of severe flooding and other geomorphological processes.

scholarly journals How a typical West African day in the future-climate compares with current-climate conditions in a convection-permitting and parameterised convection climate model

2020 ◽  
Vol 163 (1) ◽  
pp. 267-296
Author(s):  
Rory G. J. Fitzpatrick ◽  
Douglas J. Parker ◽  
John H. Marsham ◽  
David P. Rowell ◽  
Lawrence S. Jackson ◽  
...  
Keyword(s):  
West Africa ◽  
Climate Model ◽  
Coupled Model ◽  
Daily Rainfall ◽  
Future Climate ◽  
Decision Makers ◽  
Precipitation Event ◽  
Climate Conditions ◽  
Current Climate ◽  
The Future

AbstractCurrent-climate precipitation and temperature extremes have been identified by decision makers in West Africa as among the more impactful weather events causing lasting socioeconomic damage. In this article, we use a plausible future-climate scenario (RCP8.5) for the end of the twenty-first century to explore the relative commonness of such extremes under global warming. The analysis presented considers what a typical day in the future climate will feel like relative to current extrema. Across much of West Africa, we see that the typical future-climate day has maximum and minimum temperatures greater than 99.5% of currently experienced values. This finding exists for most months but is particularly pronounced during the Boreal spring and summer. The typical future precipitation event has a daily rainfall rate greater than 95% of current storms. These findings exist in both a future scenario model run with and without parameterised convection, and for many of the Coupled Model Inter-comparison Project version 5 ensemble members. Additionally, agronomic monsoon onset is projected to occur later and have greater inter-annual variability in the future. Our findings suggest far more extreme conditions in future climate over West Africa. The projected changes in temperature and precipitation could have serious socioeconomic implications, stressing the need for effective mitigation given the potential lack of adaptation pathways available to decision makers.

scholarly journals Assessing Impact of Climate Variability in Southwest Coastal Bangladesh Using Livelihood Vulnerability Index

Climate ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 107
Author(s):  
Sabrina Mehzabin ◽  
M. Shahjahan Mondal
Keyword(s):  
Climate Variability ◽  
Linear Regression Analysis ◽  
Kendall Test ◽  
Vulnerability Index ◽  
Precipitation Anomaly ◽  
Primary Data ◽  
Precipitation Concentration Index ◽  
Coastal Bangladesh ◽  
Present Decade ◽  
The Impact

This study analyzed the variability of rainfall and temperature in southwest coastal Bangladesh and assessed the impact of such variability on local livelihood in the last two decades. The variability analysis involved the use of coefficient of variation (CV), standardized precipitation anomaly (Z), and precipitation concentration index (PCI). Linear regression analysis was conducted to assess the trends, and a Mann–Kendall test was performed to detect the significance of the trends. The impact of climate variability was assessed by using a livelihood vulnerability index (LVI), which consisted of six livelihood components with several sub-components under each component. Primary data to construct the LVIs were collected through a semi-structed questionnaire survey of 132 households in a coastal polder. The survey data were triangulated and supplemented with qualitative data from focused group discussions and key informant interviews. The results showed significant rises in temperature in southwest coastal Bangladesh. Though there were no discernable trends in annual and seasonal rainfalls, the anomalies increased in the dry season. The annual PCI and Z were found to capture the climate variability better than the currently used mean monthly standard deviation. The comparison of the LVIs of the present decade with the past indicated that the livelihood vulnerability, particularly in the water component, had increased in the coastal polder due to the increases in natural hazards and climate variability. The index-based vulnerability analysis conducted in this study can be adapted for livelihood vulnerability assessment in deltaic coastal areas of Asia and Africa.

scholarly journals Historical drought patterns over Canada and their teleconnections with large-scale climate signals

2018 ◽  
Vol 22 (6) ◽  
pp. 3105-3124 ◽  
Author(s):  
Zilefac Elvis Asong ◽  
Howard Simon Wheater ◽  
Barrie Bonsal ◽  
Saman Razavi ◽  
Sopan Kurkute
Keyword(s):  
Large Scale ◽  
Southern Oscillation ◽  
Low Frequency ◽  
Kendall Test ◽  
Wavelet Coherence ◽  
Climate Indices ◽  
Data Sets ◽  
Canadian Prairies ◽  
Agriculture Industry ◽  
Spatio Temporal

Abstract. Drought is a recurring extreme climate event and among the most costly natural disasters in the world. This is particularly true over Canada, where drought is both a frequent and damaging phenomenon with impacts on regional water resources, agriculture, industry, aquatic ecosystems, and health. However, nationwide drought assessments are currently lacking and impacted by limited ground-based observations. This study provides a comprehensive analysis of historical droughts over the whole of Canada, including the role of large-scale teleconnections. Drought events are characterized by the Standardized Precipitation Evapotranspiration Index (SPEI) over various temporal scales (1, 3, 6, and 12 consecutive months, 6 months from April to September, and 12 months from October to September) applied to different gridded monthly data sets for the period 1950–2013. The Mann–Kendall test, rotated empirical orthogonal function, continuous wavelet transform, and wavelet coherence analyses are used, respectively, to investigate the trend, spatio-temporal patterns, periodicity, and teleconnectivity of drought events. Results indicate that southern (northern) parts of the country experienced significant trends towards drier (wetter) conditions although substantial variability exists. Two spatially well-defined regions with different temporal evolution of droughts were identified – the Canadian Prairies and northern central Canada. The analyses also revealed the presence of a dominant periodicity of between 8 and 32 months in the Prairie region and between 8 and 40 months in the northern central region. These cycles of low-frequency variability are found to be associated principally with the Pacific–North American (PNA) and Multivariate El Niño/Southern Oscillation Index (MEI) relative to other considered large-scale climate indices. This study is the first of its kind to identify dominant periodicities in drought variability over the whole of Canada in terms of when the drought events occur, their duration, and how often they occur.

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