scholarly journals Spatiotemporal Trends and Detection of Changes in Hydrological and Climatic Variables of Modjo River Watershed, Ethiopia

Author(s):  
Kokeb Zena Besha ◽  
Tamene Adugna Demissie ◽  
Fekadu Fufa Feyessa

Abstract Understanding hydro-climatic trends in space and time is crucial for water resource planning and management, agricultural productivity and climate change mitigation of a region. This study examined the spatiotemporal variations in precipitation, reference evapotranspiration (ETo) and streamflow in a tropical watershed located in the central highlands of Ethiopia. Temporal trend implications were analyzed using the Mann-Kendall test, and Theil-Sen approach, whereas the inverse distance weighted interpolation method was applied for spatial trend variability analysis. The result showed that a significant decreasing trends in streamflow for the major rainy (Kiremt: Jun - Sept) season and annual time scales. At the same time, the annual and monthly ETo followed significantly increasing trends, but there has been a trendless time series for most of the months and annual mean precipitation series for the period 1986 - 2015. The study indicated that the spatial variability of annual and seasonal precipitation series decreased from north to south and west to east, while this was increased for ETo both for annual and seasonal time series over the study watershed. The contribution of rainfall and mean temperature to streamflow decline was insignificant. It is pointed out that river flow regime is weakly affected by climate changes, hence human activities are stronger in explaining the river flow trends of the watershed. Therefore, urgent calls on the needs for reducing human-induced impacts, and implementing appropriate watershed management, conservation measures and an efficient use of water resources.

Agronomy ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 3 ◽  
Author(s):  
Mladen Jurišić ◽  
Ivan Plaščak ◽  
Oleg Antonić ◽  
Dorijan Radočaj

Red spicy pepper is traditionally considered as the fundamental ingredient for multiple authentic products of Eastern Croatia. The objectives of this study were to: (1) evaluate the optimal interpolation method necessary for modeling of criteria layers; (2) calculate the sustainability and vulnerability of red spicy pepper cultivation using hybrid Geographic Information System (GIS)-based multicriteria analysis with the analytical hierarchy process (AHP) method; (3) determine the suitability classes for red spicy pepper cultivation using K-means unsupervised classification. The inverse distance weighted interpolation method was selected as optimal as it produced higher accuracies than ordinary kriging and natural neighbour. Sustainability and vulnerability represented the positive and negative influences on red spicy pepper production. These values served as the input in the K-means unsupervised classification of four classes. Classes were ranked by the average of mean class sustainability and vulnerability values. Top two ranked classes, highest suitability and moderate-high suitability, produced suitability values of 3.618 and 3.477 out of a possible 4.000, respectively. These classes were considered as the most suitable for red spicy pepper cultivation, covering an area of 2167.5 ha (6.9% of the total study area). A suitability map for red spicy pepper cultivation was created as a basis for the establishment of red spicy pepper plantations.


2011 ◽  
Vol 250-253 ◽  
pp. 2782-2786
Author(s):  
Jiong Zhu ◽  
Jian Cheng Kang

The relationship between sea water temperature with depth and the maximum cyclone wind speed was analyzed, the temperature was acquired before 24h of the cyclones occurred by using of data of Argo floats and cyclones in 2005, and taking advantage of inverse distance weighted interpolation method. The results showed that: (1) the Tropical Cyclone’s intensity had a strong correlation with the sea water temperature in the depth of about 42m or so. (2) Under the conditions of similar latitude, according to the energy conservation law, the maximum intensity of cyclones wind was a linear function of sea water temperature, depth, and continuous change in the overall rate, which was verified through the actual observation data.


2013 ◽  
Vol 864-867 ◽  
pp. 2171-2174
Author(s):  
Jiong Zhu ◽  
Jian Cheng Kang

There is a correlation between sea surface temperature of the upper boundary waters and the intensity of typhoon. This paper analyzes the use of Argo float data and using inverse distance weighted interpolation method to calculate its internal regional sea surface temperature, when typhoon and other data were compared and error analysis. The results showed that: the method is reliable. When you select a point closer distance calculation and spatial distribution of Argo floats as closely as possible, the weight coefficients taken 2, known buoy number is 4-6, the relative error of calculated is less than 0.4%, RMSE error is less than 1.2 in the 0-600m depth layer


2013 ◽  
Vol 45 (2) ◽  
pp. 213-225 ◽  
Author(s):  
P. Hosseinzadeh Talaee ◽  
Hossein Tabari ◽  
Hirad Abghari

It is important to identify the spatiotemporal trends of evaporation and evapotranspiration under the changing climate for use in regional water resources planning. This work aimed to investigate the trends of the Hargreaves reference evapotranspiration (ETo), pan evaporation (Epan) and pan coefficient (Kpan) series at 12 stations in the west of Iran by using the sequential Mann–Kendall, Kendall and Spearman tests after eliminating the influence of the significant lag-1 serial correlation from the time series by the pre-whitening method for the period 1982–2003. The approximate year of the beginning of the significant trends was detected by using the Mann–Kendall rank statistic. The spatial distribution of the trend magnitudes was obtained from the Inverse-Distance-Weighted (IDW) interpolation method. No significant trends were found in the ETo time series, while an upward trend of 16 mm/year was observed in the Epan series which began in 1998. Moreover, a downward trend was obtained in the Kpan series which started in 1994.


2014 ◽  
Vol 905 ◽  
pp. 533-536
Author(s):  
Yan E. Hou ◽  
Lan Xue Dang ◽  
Yun Feng Kong

GRIB code has good features: such as self-description, flexibility and extensibility, and is widely applied in the description, storage and transmission of meteorological data. Wind filed streamline demonstrates the direction and trend of wind to some extent. For visualization of wind field streamline using GRIB Meteorological data, GRIB data are firstly converted into grid data using inverse distance weighted interpolation method, and then this paper proposes an algorithm for determining and tracking the points on streamline by streamline vector value evaluation and direction detection. Finally, the chart of wind field streamline is drawn using real GRIB data. The results have proved that the designed algorithm is feasible and the chart meets the needs of users.


2014 ◽  
Vol 599-601 ◽  
pp. 1268-1271 ◽  
Author(s):  
Fu Cai Zhang ◽  
Xiao Gang Sun

The paper introduces a kind of inverse distance weighted interpolation theoretical derivation and its solving way. The basic principle of this method is that to use known information limited data were interpolated to the unknown information for point, through the obtained interpolation point value to calculate the new interpolation point value. Thus, it is solved that the problem that limited number of temperature points can not be comprehensive description of temperature field, and the method is applied in the process of solving the unknown temperature points in the two dimensional temperature field. The characteristics of this method are simple, practical, less amount of calculation.


2012 ◽  
Vol 518-523 ◽  
pp. 1367-1370 ◽  
Author(s):  
Wei He ◽  
Ren Cang Bu ◽  
Yuan Man Hu ◽  
Zai Ping Xiong ◽  
Miao Liu

Based on the temperature datasets from 1961 to 2005 at 96 meteorological stations, the spatiotemporal trends of climate change were analyzed in annual and seasonal timescales, by a linear and regression model, cumulative anomaly method, Mann-Kendall test and inverse distance weighted interpolation methods, in Northeastern China. The results showed that: (1) Both annual and seasonal mean temperature showed increasing trends, the annual mean temperature have rised by 0.07°Cwith a rate of 0.38°C/decade, and the highest increasing rates of temperature occured in the winter (0.53°C/decade) and lowest one was the in the summer (0.23°C/decade). (2) The results of Mann-Kendall test on temperature showed that the annual and seasonal mean temperature significantly increased at 95% of confidence. The climate jump of annual mean temperature took place in 1987, and the climate jumps of spring, summer, autumn and winter mean temperature occurred in 1988, 1993, 1989 and 1981, respectively, and these results were confirmed by the cumulative anomaly curve. (3) The higher the latitude, the more obvious the increasing trend, especially in winter, and therefore the temperature increased in most parts of the Northeastern China.However, the increasing trends in the northern region of the Da Hinggan Moutains and Xiao Hinggan Moutains were the most obvious.


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