Spatio-Temporal Trend Analysis of Rainfall and Temperature Extremes in the Vea Catchment, Ghana

Larbi, Isaac; Hountondji, Fabien C. C.; Annor, Thompson; Agyare, Wilson Agyei; Gathenya, John Mwangi; Amuzu, Joshua

doi:10.3390/cli6040087

Cited by 54 publications

(34 citation statements)

References 30 publications

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“…Recent evaluations of monthly gridded CHIRPS-v2 data against gauge station observations in West Africa reported a high correlation that is similar to the results reported in this study [15], [18], [28]. The higher accuracy of CHIRPS-v2 data is because the product was generated from high resolution climatology, multiple satellite products and, the algorithm incorporated a bias correction using the gauge station data [12].…”

Section: Discussion 395supporting

confidence: 84%

“…However, these new gridded layers need rigorous evaluation against existing ground gauge observations to ascertain their accuracy and inform resource managers on which datasets could be appropriate for specific applications or locations. Several studies have attempted to validate gridded time series data for rainfall in West Africa at the catchment [15] or (sub)-national [16] and regional [17] scales. These evaluations revealed significant disparities in the skill of the satellite rainfall estimates.…”

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confidence: 99%

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Spatial-Temporal Trends of Rainfall, Maximum and Minimum Temperatures Over West Africa

Muthoni

2020

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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This study investigates the magnitude and signifi-1 cance of spatial-temporal trends of 37 years' time series of gridded data for rainfall, maximum (Tmax) and minimum (Tmin) 3 temperature for West Africa. A modified Mann-Kendall test and 4 Theil-Sen's slope estimator were utilized to test the significance 5 and the magnitude of trends, respectively. The magnitude of 6 significant trends for three variables between six agroecological 7 zones (AEZ's) was compared. Gridded climate data represented gauge data with high accuracy and, therefore, can reliably 9 complement the sparse observation network in West Africa. The 10 three variables showed significant positive and negative trends of 11 varying magnitude and spatial extent. June to September rainfall 12 showed a positive increase (0.1-5 mm month −1 year −1) that 13 mostly occurred north of 11 o latitude. October rainfall showed 14 a positive trend across the region, but the magnitude was higher 15 south of the same latitude. A widespread significant warming 16 trend was observed across all AEZ's and months. However, a 17 localized cooling in August and September over the Sahel and 18 Sudan Savanna was an exception. The cooling over the two 19 AEZ's coincided with a positive trend of rainfall. The zonal 20 analysis revealed that the magnitude of the positive trend of June, 21 September, and October rain increased following a North-South 22 gradient from the Sahel to humid forest AEZ's. Results provide 23 spatial evidence of climate change in a limited data environment 24 to guide the targeting of appropriate adaptation measures. The 25 information generated from this study helps the design of early 26 warning systems against droughts and floods. 27 Index Terms-Agro-ecological zones, CHIRPS, CHIRTSmax, 28 satellite time series, spatial temporal trends, TerraClimate 29 I. INTRODUCTION 30 Climate change and variability have significant positive or 31 negative impacts on the productivity and resilience of agroe-32 cosystems across different regions [1], [2], [3]. These impacts 33 are more severe in predominantly rain-fed agricultural systems 34 in Africa, where they confound with extreme poverty and 35 rapid population growth [4]. The fifth assessment report of the 36 United Nations Intergovernmental Panel on Climate Change 37 (IPCC) estimated increased warming and wet season rainfall 38 over Africa's landmass [5]. Trend analysis using time series 39 of coarse resolution remote sensing data over tropical Africa 40 shows an annual mean temperature increase at a rate of 0.15 41 o C per decade from 1979 to 2010 [6]. Predictions for rainfall 42 are most uncertain primarily due to limited understanding of 43 tropical rain forming processes.

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Section: Discussion 395supporting

confidence: 84%

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confidence: 99%

Spatial-Temporal Trends of Rainfall, Maximum and Minimum Temperatures Over West Africa

Muthoni

2020

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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“…It is widely used in Ethiopia for drought monitoring [38]. It is well demonstrated that CHIRPS can complement the sparse rain gauge network and provide high spatial and temporal resolution for trend analysis [48,49]. The CHIRPS data were accessed from the ftp server (ftp://ftp.chg.ucsb.edu/pub/org/chg/products/CHIRPS-2.0).…”

Section: Datasetsmentioning

confidence: 99%

Spatio–temporal Assessment of Drought in Ethiopia and the Impact of Recent Intense Droughts

Liou

Mulualem

2019

Remote Sensing

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The recent droughts that have occurred in different parts of Ethiopia are generally linked to fluctuations in atmospheric and ocean circulations. Understanding these large-scale phenomena that play a crucial role in vegetation productivity in Ethiopia is important. In view of this, several techniques and datasets were analyzed to study the spatio-temporal variability of vegetation in response to a changing climate. In this study, 18 years (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) of Moderate Resolution Imaging Spectroscopy (MODIS) Terra/Aqua, normalized difference vegetation index (NDVI), land surface temperature (LST), Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) daily precipitation, and the Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS) soil moisture datasets were processed. Pixel-based Mann-Kendall trend analysis and the Vegetation Condition Index (VCI) were used to assess the drought patterns during the cropping season. Results indicate that the central highlands and northwestern part of Ethiopia, which have land cover dominated by cropland, had experienced decreasing precipitation and NDVI trends. About 52.8% of the pixels showed a decreasing precipitation trend, of which the significant decreasing trends focused on the central and low land areas. Also, 41.67% of the pixels showed a decreasing NDVI trend, especially in major parts of the northwestern region of Ethiopia. Based on the trend test and VCI analysis, significant countrywide droughts occurred during the El Niño 2009 and 2015 years. Furthermore, the Pearson correlation coefficient analysis assures that the low NDVI was mainly attributed to the low precipitation and water availability in the soils. This study provides valuable information in identifying the locations with the potential concern of drought and planning for immediate action of relief measures. Furthermore, this paper presents the results of the first attempt to apply a recently developed index, the Normalized Difference Latent Heat Index (NDLI), to monitor drought conditions. The results show that the NDLI has a high correlation with NDVI (r = 0.96), precipitation (r = 0.81), soil moisture (r = 0.73), and LST (r = −0.67). NDLI successfully captures the historical droughts and shows a notable correlation with the climatic variables. The analysis shows that using the radiances of green, red, and short wave infrared (SWIR), a simplified crop monitoring model with satisfactory accuracy and easiness can be developed.

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“…Extreme climatic variability on rainfall and temperature variability has been quantified using coherent analytical procedures and significant warming over wider portion of the globe (Frich et al 2002;Alexander et al 2006); and the authors discussed that there was no uniform temporal and spatial rainfall pattern. Likewise, Bary et al (2018), Byakatonda et al (2018), Labri et al (2018) and Halimatou et al (2017) stated that extreme temperature indices over Africa revealed increasing warming trends. Recent studies on extreme temperature and rainfall in Ethiopia indicated that there was a significant increase in warming indicator values and decrease in cold spell indicator values (Gebrechorkos et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Trends in extreme temperature and rainfall indices in the semi-arid areas of Western Tigray, Ethiopia

et al. 2020

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Background: Africa is the most vulnerable continent in the world; which recurrent droughts, extreme temperature and rainfall affects agriculture and food security. The aim of this study was to analyze the trends in extreme temperature and rainfall in major sesame producing areas in western Tigray using RClimDex software. We selected eight temperature and nine rainfall indices from 27 extreme temperature and rainfall indices, which are recommended by joint CCL/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices (ETCCDI). A non-parametric Mann-Kendall test and Sen's slope estimates were used to test the statistical significance and trend of each of the extreme temperature and rainfall indices, respectively.Results: Number of heavy rainy days, number of very heavy rainy days, very wet days, extremely wet days, and maximum 5 days precipitation showed a negative trend, with significant (p < 0.05) decrease throughout the study area. Monthly maximum value of maximum and minimum value of maximum temperature, monthly maximum and minimum value of minimum temperature, hot days and hot nights revealed positive trend throughout the study areas. Total rainfall was decreasing significantly (p < 0.05) by 13.34 mm, 13.8 mm, 14.65 mm, 10.9 mm and 8.4 mm/year at Humera and Dansha, Adiremets, Maygaba, Maytsebri and Sheraro, and Adigoshu, respectively. Spatial analysis on extreme temperature also indicated there was relatively lower variability on minimum temperature in Humera, Dansha, Adiremets, and Adigoshu. On average, the western part of Tigray experienced a reduction in total rainfall ranging 8.45 to 14.7 mm/year; and increase in average maximum temperature of 0.04 to 0.051 °C/year since 1983 to 2016. The results also revealed an increase in warm nights and warm days ranging from 0.31 to 0.62 days, and 0.38 to 0.71 days/ year, respectively. Conclusions:Increase in temperature and decrease in amount of rainfall may have a negative impact on crop transpiration, photosynthetic rate and soil water balance; exacerbating distribution and infestation of malaria and leishmaniasis. The results in this study could have an important role in identifying possible present and future production strategies on sesame, cotton, and sorghum crops, which are essential cash crops produced by farmers and investors.

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Spatio-Temporal Trend Analysis of Rainfall and Temperature Extremes in the Vea Catchment, Ghana

Cited by 54 publications

References 30 publications

Spatial-Temporal Trends of Rainfall, Maximum and Minimum Temperatures Over West Africa

Spatial-Temporal Trends of Rainfall, Maximum and Minimum Temperatures Over West Africa

Spatio–temporal Assessment of Drought in Ethiopia and the Impact of Recent Intense Droughts

Trends in extreme temperature and rainfall indices in the semi-arid areas of Western Tigray, Ethiopia

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