Variable Rainfall Patterns Research Articles

Evaluation of harvesting urban water resources for sustainable water management: Case study in Filton Airfield, UK

Filton Airfield in the UK is a new community under development aiming to become self-sufficient in its water supply toward a circular economy. Urban water management strategies, water demand minimization, urban resource reuse, and wastewater discharge minimization, can improve the urban circular economy. Understanding the practical impacts of those strategies is crucial for a new development area like Filton. As a site investigation, the physiochemical and microbial characteristics of raw rainwater showed acceptable for irrigation and drinking water, indicating no significant risk of using rainwater collected within Filton, but still requiring a treatment process depending on chosen applications. This study further conducted stochastic water demand profiles and urban water cycle simulations at a block scale, taking possible rainwater harvesting (RWH) and greywater recycling (GWR) options for non-potable purposes to quantitatively assess the impact of urban water management strategies on urban harvesting potential indicators (0–100%). When the RWH was implemented, the water demand minimization potential varied from 62% to 71%. Meanwhile, the combined use of RWH and GWR yielded even better results in terms of water demand minimization, peaking at 78% due to the additional supply from GWR. The combination also reduced wastewater production potential from 100% to 54% and consequently improves self-sustainability potential from 0 with no recycling, to 44% with only GWR, and to 100% with the combined use of RWH and GWR. The sensitivity analysis revealed that wastewater discharge is the most sensitive to variations in rainfall patterns (wet and dry conditions) and urban density (water demand patterns), indicating that both need to be balanced for better implementation of urban water harvesting strategies. This study can provide insights into the applicability of urban water resource harvesting and its assessment approaches in existing and new development areas.

Centennial Annual Rainfall Pattern Changes Show an Increasing Trend with Higher Variation over Northern Australia

Abstract Global warming and anthropogenic activities have imposed noticeable impacts on rainfall pattern changes at both spatial and temporal scales in recent decades. Systematic diagnosis of rainfall pattern changes is urgently needed at spatiotemporal scales for a deeper understanding of how climate change produces variations in rainfall patterns. The objective of this study was to identify rainfall pattern changes systematically under climate change at a subcontinental scale along a rainfall gradient ranging from 1800 to 200 mm yr−1 by analyzing centennial rainfall data covering 230 sites from 1910 to 2017 in the Northern Territory of Australia. Rainfall pattern changes were characterized by considering aspects of trends and periodicity of annual rainfall, abrupt changes, rainfall distribution, and extreme rainfall events. Our results illustrated that rainfall patterns in northern Australia have changed significantly compared with the early period of the twentieth century. Specifically, 1) a significant increasing trend in annual precipitation associated with greater variation in recent decades was observed over the entire study area, 2) temporal variations represented a mean rainfall periodicity of 27 years over wet to dry regions, 3) an abrupt change of annual rainfall amount occurred consistently in both humid and arid regions during the 1966–75 period, and 4) partitioned long-term time series of rainfall demonstrated a wetter rainfall distribution trend across coastal to inland areas that was associated with more frequent extreme rainfall events in recent decades. The findings of this study could facilitate further studies on the mechanisms of climate change that influence rainfall pattern changes. Significance Statement Characterizing long-term rainfall pattern changes under different rainfall conditions is important to understand the impacts of climate change. We conducted diagnosis of centennial rainfall pattern changes across wet to dry regions in northern Australia and found that rainfall patterns have noticeably changed in recent decades. The entire region has a consistent increasing trend of annual rainfall with higher variation. Meanwhile, the main shifting period of rainfall pattern was during 1966–75. Although annual rainfall seems to become wetter with an increasing trend, more frequent extreme rainfall events should also be noticed for assessing the impacts of climate changes. The findings support further study to understand long-term rainfall pattern changes under climate change.

Analysis of changes in extreme rainfall characteristics over Ambica river basin, India

ABSTRACT Significant variations are detected in extreme rainfall characteristics over Ambica river basin, Gujarat. The frequent flooding in Ambica basin has become a persistent phenomenon over last decade. Based on new knowledge and understanding in Extreme Value Theory (EVT), the discrepancies in extreme rainfall characteristics over entire basin are analyzed considering the daily rainfall series of 25 rain gauge stations for period of 1961–2017. At each station, the threshold value was selected as 90th percentile rainfall for computing the excesses of Peak over Threshold (POT) series. To examine the variations in rainfall pattern, basic rainfall indices viz. total annual rainfall (PRCPTOT), rainy days (RD) and simple daily intensity index (SDII) are calculated. To assess the non-uniformity of extreme rainfall, coefficient of variation (Cv) has been found. Non-parametric tests like Modified Mann-Kendall (MMK) test and Sen’s slope test were used for evaluating the trend. The western parts of the basin show a declining trend in PRCPTOT and SDII, wherein stationarity has been observed for RD. The stations in the central region show a significantly declining trend in total annual rainfall. The SDII and RD are found to be higher and lower respectively for the stations situated in eastern parts of the basin. It has been found that 20 %, 4 % and 17 % of stations exhibit significant decreasing trends in PRCPTOT, RD and SDII respectively. The western basin has lesser values of coefficient of variation (Cv) as compared to stations in eastern part. At the majority of stations, extreme rainfall duration and frequency were found to be stationary, whereas intensity of extreme rainfall is found to be non-stationary. Also, it has been found that 16 % of stations exhibit significant decreasing trends in extreme rainfall intensity and duration, which demonstrates the consequences to water availability in near future.

Characterisation of rainfall events in northern Tunisia using self-organising maps

Study regionThe study is carried out for northern Tunisia. Study focusPrecipitations are often analysed via intensity or accumulation for a specified timescale (e.g., annual, seasonal, etc). We propose in this study to analyse regional rainfall variability by adopting a variable time step through the rain event concept. This event-based approach, ensures the integration of information related to rain intermittency, which is one of the fundamental properties of precipitations. This study focuses essentially on wet spells characteristics derived from the aggregation of daily winter dataset over a 50 years period (1960–2009). The multivariate analysis, based on the combination of two clustering approaches, i.e., self-organizing map and hierarchical clustering, allows the identification of different rainfall regimes. This study helps to understand rainfall variability patterns and to address rainfall regionalization and water use management issues. New hydrological insights for the regionThe winter precipitations of northern Tunisia are classified into 4 typical situations: Extremely dry seasons with a few short and weak rainfall events, dry seasons, with high frequency of weak events, intermediate seasons with medium amount of rain and intermittent events and rainiest seasons with long and intense events. The regionalization yields two geographical regions: northern sector characterized by rainy seasons, whereas the stations of the southern sector are mostly dry. The temporal variability analysis shows that the dry season classes dominate extending over three consecutive decades from 1970 to 2000.

Land Use and Climate Change Impacts on Streamflow Using SWAT Model, Middle Awash Sub Basin, Ethiopia

Assessing the impact of land use and climate change on streamflow is important for watershed management. This study aims to examine the possible impacts of land use and climate change on the streamflow of the Jewaha catchment. The Soil and Water Assessment Tool (SWAT) model is used to simulate streamflow by integrating complex interactions between climate and land use/cover. The past land-use changes were determined by classifying the Landsat images from 1990, 2000, and 2018 with Earth Resource Development System (ERDAS) Imagine 2015. The potential of climate change impact was examined under Representative Concentration Pathway (RCP) 2.6 and RCP 8.5 emission scenarios for 2041–2070 time horizon with the baseline 1971–2000. Climate change scenarios over the catchment indicated an increasing trend in temperature, in both RCP 2.6 and RCP 8.5, and variability in rainfall patterns in the catchment. The average annual temperature will increase by 0.1 °C and 0.15 °C for the RCP 2.6 and RCP 8.5 scenarios, respectively. Generally, the result indicated that in the future summer streamflow highly increases due to climate and land-use change and a decrease in the dry season because of the changes in the climate variables.

Assessment of Prioritized Climate Smart Agricultural Practices and Technologies of Household Farmers in Southeast, Nigeria

The study assessed prioritized climate smart agricultural (CSA) practices and technologies of household farmers in Southeast, Nigeria. A multi-stage sampling technique was used to isolate 326 household farmers who participated on the study. Data collection was done using research instrument (questionnaire). Both descriptive and inferential statistics were employed for data analysis. Results indicated that majority of the respondents were females, had secondary education, and had household size of 9 persons with a mean age of 48 years and 19 years of farming experience. Temperature variation (3.85), increase in number of sunny days (3.50), increase in amount of rainfall (3.10), variation in rainfall pattern (3.56), decrease in total rainfall (3.21), increase in frequency of heavy rains (2.85), etc were seriously perceived as climate change effects in the area. Again, various prioritized CSA practices and technologies such as growing a single crop, using a mixture of appropriately chosen genotypes of a given species (46.6%), use of quality seeds and planting materials of well-adapted crops and varieties (77.9%), crop rotation and diversity (41.1%) integrated pest management (47.5%), improved water use and management (26.4%), etc. were adopted by the farmers in mitigating climate change effects. Climate threats identified in the area include, decrease in overall productivity due to increased extreme weather events (0.97), decrease in crop production due to changes in average rainfall (0.94), decrease crop production due to increase in temperatures and rainfall variability (0.79), rapid migration of some pests and diseases (0.72), etc. Lack of access to up to-date information (2.88), access to micro-finance and insurance (2.57), access to agricultural input and output markets (2.14), etc. constrained the adoption of CSA practices. Age, education, occupation, years in farming experience further influenced the adoption of CSA practices and technologies. Policy motions in propagating climate change awareness through the mass media were recommended.

Adoption of Conservation Agricultural Practices Among Maize Farmers: An Alternative Livelihood to Mitigate Climate Change Impact in Bawku Municipality, Ghana

<i>Background and Objective</i>: The plight of farmers are worsening by the impact of climate change. This is evident in all agro-ecological zones in Ghana. Warming and variability in rainfall pattern is causing floods and long dry spells of drought with resultant effects of reduced food crop and livestock production. Conservation Agricultural (CA) practices was therefore introduced to address the challeges of conventional tillage. CA has therefore been identified as a substitute to conventional agriculture for sustainable agricultural productivity. The objective of the study was to assess the rate of adoption of CA practices in the Bawku Municipality in the Upper East region of Ghana. <i>Methodology</i>: The study was conducted in the Bawku Municipal area of Ghana. The research design used for the study was the mixed methods. The purposive sampling technique was used to select the Bawku Municipality as the major area where agricultural conservation practices occurs in the Upper East region. The simple random sampling technique was used to select ten (10) communities in the Municipality, whilst the systematic random sampling was used to select forty (40) respondents from each community for the study. The target population for the study was maize farmers in the Bawku Municipality. In all, a total of 358 respondents were interviewed for the study. Data was taken on socio-cultural and socio-economic characteristics of respondents. Data analysis was done using the Statistical Package for Social Sciences (SPSS). Descriptive statistics, such as frequencies, percentages, and means were computed. Cross tabulations of variables were also computed and the chi-square tests used to establish relationships. <i>Results</i>: The study revealed that age, sex, level of education, religion, household size, government policy, access to credit, source of income, farm size, and access to extension services were found to have significantly influenced adoption of CA practices. The results of the study indicated that majority of farmers were aware and had knowledge about CA practices. “No-tillage with cover crops, minimum tillage with cover crops, and crop rotation with cover crops” were the main practices of conservation agriculture in the study area. The study further revealed that majority of the farmers indicated that the practices of conservation agriculture reduces soil erosion, increases soil fertility, increases soil organic matter and improves agricultural productivity. <i>Conclusion</i>: Majority of farmers adopted CA practices in full. It is recommended that the Ghanaian government should boost CA practices by instituting an annual national award scheme to award hardworking CA practioners in Ghana.

Influência do regime de chuvas do bioma Cerrado na manutenção das armadilhas de larvas e na morfologia dos adultos de Myrmeleon brasiliensis (Navás) (Neuroptera: Myrmeleontidae)

ABSTRACT Seasonality in the Cerrado biome of Brazil is characterized by a dry season and a rainy season, affecting the availability of water and generating nutritional limitations. Thus, plants and animals have developed adaptive mechanisms in order to survive in this environment. Insects known as antlions (Neuroptera: Myrmeleontidae) occur in areas of the Cerrado and build traps in dry soil to capture prey items. In the rainy season, these insects are unable to forage due to the waterlogged soil. The aim of this study was to investigate the influence of the rainfall regime in the Cerrado on aspects of trap-building behavior, larval development and morphological characteristics of adult antlions. Larvae of the antlion Myrmeleon brasiliensis (Návas, 1914) were observed and collected in an area of the Cerrado biome in the municipality of Aquidauana (MS), Brazil. Observations were performed in the rainy and dry seasons to determine the abundance of traps built by M. brasiliensis larvae. In the laboratory, experiments were performed involving the manipulation of the frequency of simulated rain on the traps. The results revealed that variations in rainfall due to seasonality in the Cerrado affect M. brasiliensis larvae, with greater foraging observed in the dry season. The laboratory experiments demonstrated that differences in the frequency of rains affect the mortality of the larvae, larval development time and the size of the adults. Thus, variations in rainfall patterns can lead to variations in the characteristics of the population structure of M. brasiliensis in areas of the Cerrado biome in Brazil.

Understanding traditional agro-ecosystem dynamics in response to systematic transition processes and rainfall variability patterns at watershed-scale in Southern Ethiopia

Multi-temporal analysis of land cover dynamics using remote sensing can enable the determination of the spatial extent and average rate of land cover change. With the application of an appropriate change analysis method, it is also possible to distinguish whether a land cover change has occurred by the effect of a random or a systematic process. In connection with this, characterizing rainfall variability and historical meteorological drought events can allow understanding of their effects on agro-ecosystems and vegetation cover dynamics. Therefore, this study has evaluated multi-temporal land cover change in response to the possible impacts of population pressure and rainfall variability on agro-ecosystem dynamics. This was conducted on a traditional agroforestry-dominated landscape in Southern Ethiopia. Using Landsat images acquired in 1985, 2000, and 2018, a post-classification land cover change analysis approach was employed to distinguish between a systematic and random process of inter-category transitions. Assessment of drought events and rainfall variability dynamics were performed using standardized precipitation index (SPI) and rainfall coefficient of variation (CV), respectively. Mann–Kendall test was also applied for the detection of a monotonic rainfall trend. A bias-corrected Climate Hazards group Infrared Precipitation with Stations (CHIRPS) over 1981–2017 was used to calculate the SPI, CV and Mann–Kendall trend test. The analysis showed that above 41% of the landscape has experienced land cover transitions between 1985 and 2018. This has primarily resulted by a systematic and rapid expansion of agriculture, urban areas, and eucalyptus plantations, at the expense of natural vegetation ecosystems. Consequently, over the last 33 years (1985–2018), natural forest, grassland, and wetland have declined by 74.8%, 83.3%, and 78.4%, respectively. Another major land cover change identified in this study was the replacement of open-field crops by agroforestry, mainly in the western part of the catchment. Such expansion of agroforestry has appeared to be spatially correlated with a lower amount of long-term average and more variable rainfall. Perhaps, this could indicate farmers’ response to rainfall variability by diversifying agricultural production options (i.e. agroforestry system), by replacing the more risk-prone mono-cropping culture. The observed persistence and further expansion of traditional agroforestry (a combination of perennial crops and scattered trees) have implications in terms of enhancing biodiversity conservation and environmental protection. Overall, the land cover transitions that occurred over the last three decades suggest future conservation priorities for improved landscape management, with more emphasis on the most exposed natural vegetation ecosystems.

Assessment of spatiotemporal trend of precipitation indices and meteorological drought characteristics in the Mahi River basin, India

Understanding the trend and variability in hydroclimatic extremes as well as drought characteristics in the context of changing climate is of paramount importance in the management of watershed and rain-fed farming systems. This study focuses on understanding the variations in rainfall patterns & drought types with 3 regions of the agro-climatic zone, in the Mahi River basin, India. The basin is surrounded by three states i.e. Rajasthan, Madhya Pradesh, and Gujarat which is known for its substantial drought occurrences. Very limited studies have been carried out using agroclimatic indices. A 50 years of daily rainfall data (gridded, 0.25°×0.25° spatial resolution) from 1970 to 2019 has been taken from India Meteorological Department (IMD) to compute extreme precipitation indices using ClimPACT2 package and time series trend was tested by Mann-Kendall. Further, 51 grid points are divided into three regions (region 1, region 2, and region 3) as per the agro-climatic zones over the Mahi River basin. The region-wise agroclimatic rainfall variability has been analyzed using monthly standard deviation and anomaly index. The run theory was applied for the characterization of drought assessment. Standardized precipitation index (SPI) was performed for 3, 6, 12, and 24-months. The result found a Consecutive dry day (CDD) with increasing trend significantly and Consecutive wet days (CWD) with decreasing trend may cause a possible impact on agriculture. Findings revealed that region 2 recorded consequent frequent and maximum droughts events over the basin. Hence, the regional topography and moisture availability perform a major role in regional precipitation variability. The output of the current study would be utilized in a better understanding of the drought condition and give a better climate change indication at a regional-basin level. This finding may be valuable for researchers to find out the crucial agro-climatic regions in the basin for preparedness for effective management and planning of water resources.

The impact of land use and land cover change on hydrological processes in Brantas watershed, East Java, Indonesia

Assessing the impact of land use and land cover change (LULCC) on hydrology is essential for water resource management. The Brantas watershed contributes about 30% of the water supply of the East Java region. The present rapid pace of land occupation for agriculture and settlements is expected to continue to alter flow processes within the watershed. This study aims to simulate LULCC and its impact on the hydrological processes of the watershed. The long-term impact of LULCC is evaluated using the Soil &amp; Water Assessment Tool (SWAT). The analysis model is calibrated using monthly data series from 1996 to 2005 and then validated using data series from 2006 to 2015. Two editions of maps (2001 and 2015) are then used to calculate the LULCC that took place across this time period. The impacts of LULCC on hydrological processes at the sub-basin level are also evaluated. The results show that the variability of rainfall patterns from 2001 to 2015 strongly affected flow variability. The LULCC from agricultural land to other uses (irrigated rice fields, settlements and forests/plantations) is most evident in three sub-basins (sub-basins 2, 9 and 17). However, each sub-basin may respond differently with respect to the LULCC taking place. The increase in area occupied by each class of land use and cover use (LULC) is not always linear to the observed flow, and widely differing LULC classes may display similar flow responses while classes with similar characteristics may have differing impacts on flows within a sub-basin. In other words, the hydrological processes taking place are too complex to be simplified at the sub-basin level.

Adoption of Conservation Agricultural Practices among Maize Farmers: An Alternative Livelihood to Mitigate Climate Change Impact in Bawku Municipality, Ghana

The plight of farmers are worsening by the impact of climate change. This is evident in all agro-ecological zones in Ghana. Warming and variability in rainfall pattern is causing floods and long dry spells of drought with resultant effects of reduced food crop and livestock production. Conservation Agricultural (CA) practices was therefore introduced to address the challeges of conventional tillage. CA has therefore been identified as a substitute to conventional agriculture for sustainable agricultural productivity. The objective of the study was to assess the rate of adoption of CA practices in the Bawku Municipality in the Upper East region of Ghana. The study was conducted in the Bawku Municipal area of Ghana. The research design used for the study was the mixed methods. The purposive sampling technique was used Ito select the Bawku Municipality as the major area where agricultural conservation practices occurs in the Upper East region. The simple random sampling technique was used to select ten (10) communities in the Municipality, whilst the systematic random sampling was used to select forty (40) respondents from each community for the study. The target population for the study was maize farmers in the Bawku Municipality. In all, a total of 358 respondents were interviewed for the study. Data was taken on socio-cultural and socio-economic characteristics of respondents. Data analysis was done using the Statistical Package for Social Sciences (SPSS). Descriptive statistics, such as frequencies, percentages, and means were computed. Cross tabulations of variables were also computed and the chi-square tests used to establish relationships. The study revealed that age, sex, level of education, religion, household size, government policy, access to credit, source of income, farm size, and access to extension services were found to have significantly influenced adoption of CA practices. The results of the study indicated that majority of farmers were aware and had knowledge about CA practices. “No-tillage with cover crops, minimum tillage with cover crops, and crop rotation with cover crops” were the main practices of conservation agriculture in the study area. The study further revealed that majority of the farmers indicated that the practices of conservation agriculture reduces soil erosion, increases soil fertility, increases soil organic matter and improves agricultural productivity. The survey also reveals that 81% of farmers adopted CA practices in full. It is recommended that the Ghanaian government should boost CA practices by instituting an annual nation award scheme to award hardworking CA practioners in Ghana.

Land use/land cover and climate change interaction in the derived savannah region of Nigeria.

The interaction of land use/land cover (LULC) and climate change, to a large extent, involves anthropogenic activities. This study was carried out in the derived savannah of Nigeria, a delicate, transition ecological zone between the rainforest and savanna zones where the interaction of LULC and climate change could be well appreciated. Using the remote sensing and GIS, Land Change Modeler (LCM), and multivariate geostatistics tools, the study evaluated coupled interaction between LULC and climate change and assessed the changes in the land use/land cover patterns for the periods 1972, 1986, 2002, and 2019. It also evaluated the present (1941-2019) and future (2020-2050) variability in rainfall patterns and made an attempt to predict the interaction between LULC and climate change in future climate. The results suggest that the urban (built-up) area, waterbody, woodland, and farmland experienced a rapid increase of about 2,400%, 583%, 277%, and 32%, respectively, while the forest cover lost about 39% between 1972 and 2019. Furthermore, the study predicted 46% and 29% reduction in the forested area between 2002 and 2050 and 2019 and 2050, respectively. The study concludes that rainfall will be the major driver of LULC change within the study area under a future climate.

Temporal variations in rainfall patterns in Kilembe, Uganda

AbstractThis study investigated rainfall variabilities in Kilembe. Secondary (monthly rainfall) data for the study were obtained from the Uganda National Meteorological Authority in Kampala, Uganda, for the period 1986–2016. To determine the temporal variation of rainfall, a Mann–Kendall method and Sen's slope estimator test were used. The results showed that March, April, May, October, and November represented the smallest coefficient of variation indicating modest variability of rainfall in these months, whereas June and July had the largest coefficient of variation. The month of July recorded an overall lowest average rainfall and a decreasing trend in rainfall. The study further revealed a historical general upward trend in rainfall between 1986 and 2016 in Kilembe. The trend in the monthly and annual rainfall is partly attributed to the Intertropical Convergence Zone, influx of moisture from Congo Forest, and climate change. The area recorded also two peaks of rainfall in the year, one in April and another in September, revealing a bimodal pattern of rainfall. The findings indicate that the government should adopt policy measures in the form of an adaptive strategy in order to save the people in the impacted areas.

Delineation of Locations for Water Storage Systems Using Future Precipitation Data – A Case Study of Sri Lanka

Paying less attention to the expected precipitation changes when implementing new water-related projects, does not seem supportive in mitigating water crisis arising from climatic changes. Sri Lanka is a country possessing a large number of water storage systems compared to its extent and population. Besides, the year-round rainfall delivers a considerable water input throughout the year. Yet, the country reports frequent water scarcities as a result of spatial and temporal variations in rainfall patterns. In addition, irregular distribution of water storage systems and accumulation of water withdrawal have been identified as the main reasons for the current water crisis. When observing the predicted changes in the precipitation pattern, this issue is expected to accelerate in the future. In order to tackle the issue, this particular study proposes to consider the future precipitation prediction data in delineating locations for new water storage projects in the country. The preliminary selection of locations was carried out considering the widely used data types. Thresholds and weighted linear combination methods were utilized in prioritizing the related conditions at the primary location selection. Pairwise comparison method was utilized in assigning the weights. These locations were then filtered by the favorable locations based on the present and future precipitation data. The result of the study reveals that the districts of Colombo, Kalutara, Gampaha and Galle located within the wet zone should be prioritized in large scale water storage projects. The study further reveals that the dry zone can self-sustain with the available water storages. It also points out that 96% of the existing tanks in the country will be dried out mainly due to the reduction of water input and over exploitation in the future.

Modelling impacts of climate change on coastal West African rainfall

Several tropical regions of the world, including West Africa are strong climatic hotspots where increase in extreme climatic events (e.g., droughts) impact water resources and hydro-ecological systems. Even though the West African Sahel has been widely studied, reports on the rainfall climatology of coastal West Africa are considerably limited. Assessing the evolutionary changes in rainfall in this region is crucial to improving the understanding on the impacts of global climate systems on rainfall variability. The main aim of this study is to assess the impact of climate change on the characteristics (mean annual, wettest month, driest month, and mean monthly) of coastal West African rainfall using General Circulation Model and two representative concentration pathways (RCP 4.5 and RCP 8.5 emission scenarios). Climate teleconnection induced rainfall is quantified using the partial least squares regression, and the dominant patterns of rainfall variability in the region are also assessed. The results indicate that areas along the coast with leading modes of rainfall variability and characterized by bimodal rainfall patterns are projected to receive highest rainfall in the mid (2041–2070) and end (2071–2100) of the century. However, inland areas are expected to receive low rainfall under the influence of both emission scenarios. An exception to this is the inland middle belt in Nigeria, which is projected to receive more rainfall than its surrounding areas. These results imply an intensification of the water cycle along the coastal region that could lead to increasing propensity of flood and drought events. Finally, Togo, Côte d’Ivoire, southern Ghana, Benin are hotspots in coastal West Africa where climate teleconnection patterns induce changes in rainfall.

Impact of climate adaptation strategies on the net farm revenue of underutilised indigenous vegetables’ (UIVs) production in Southwest Nigeria

This paper examined the impact of climate adaptation strategies employed by Underutilised Indigenous Vegetables (UIVs) farmers on UIVs’ net revenue of adopters and non-adopters of adaptation strategy in Southwest Nigeria. This was with a view to determine the factors that determined UIVs net revenue in the study area. Both quantitative and qualitative primary household data from 191 UIVs producers, with secondary climate data from Nigeria Meteorological agency were used. An efficient endogenous switching regression model (ESRM) was used to estimate the effect of climate change adaptation strategy on UIVs net revenue. The results show that farmers’ perception of climate change showed a high temperature and a high variability in rainfall pattern. The adaptation strategies mostly employed by the UIVs farmers is cultivating along river banks (98%) while the least was agroforestry and perennial plantation (4%). Meanwhile, all the farmers who adopted farmers that adopted Agroforestry and perennial plantation and Agricultural good practices did not experience loss in UIVs production. The factors that determined the likelihood of adopting climate adaptation strategy include years of experience (0.0335, p<0.1) in UIVs production, access to climate information (0.7895, p<0.1) and agro ecological zone (0.7889, p<0.1). Further, factors that determine the net revenue from UIVs for adopters were access to information on climate change 0.2428, p<0.1), off-farm income (0.6526, p<0.01), precipitation (0.0045, p<0.1), precipitation square (0.−0.00002, p<0.1) and Ondo location (0.4470, p<0.05). Age (0.1261, p<0.1), agro ecological zone (4.2682, p<0.1), off-farm income (−1.1765, p<0.05) and precipitation square (0.0001, p<0.01) determined the UIVs revenue for non-adopters. The promotion of UIVs should therefore be advocated by the government and non-government agencies since high temperature does not have significant effect on its revenue. Also, provision of relevant information on climate change is essential for farmers as this will enhance farmers’ likelihood of adopting appropriate climate change adaptation strategy considering the type of crop they cultivate and the peculiarity of their agro ecological zones. Also, vegetables’ farmers are encouraged to engage in agroforestry and perennial plantation. • Underutilised Indigenous Vegetables for climate change mitigation. • Factors that determined adoption of climate adaptation strategies; climate change information. • Adoption of adaptation strategies impacts farmers’ net revenue.

Evaluation of Pollutant Removal Efficiency by Small-Scale Nature-Based Solutions Focusing on Bio-Retention Cells, Vegetative Swale and Porous Pavement

Rapid urbanization, aging infrastructure, and changes in rainfall patterns linked to climate change have brought considerable challenges to water managers around the world. Impacts from such drivers are likely to increase even further unless the appropriate actions are put in place. Floods, landslides, droughts and water pollution are just a few examples of such impacts and their corresponding consequences are in many cases devastating. At the same time, it has become a well-accepted fact that traditional (i.e., grey infrastructure) measures are no longer effective in responding to such challenges. Nature-based solutions (NBS) have emerged as a new response towards hydro-meteorological risk reduction and the results obtained to date are encouraging. However, their application has been mainly in the area of water quantity management with few studies that report on their efficiency to deal with water quality aspects. These solutions are based on replicating natural phenomena and processes to solve such problems. The present paper addresses the question of three NBS systems, namely, bio-retention cells, vegetative swales and porous pavements, for the removal of total suspended solids (TSS), total nitrogen (TN) and total phosphorus (TP) when applied in different configurations (single or networked). The results presented in this paper aim to advance the understanding of their performances during varying rainfall patterns and configurations and their potential application conditions.

Mode of Precipitation Variability Generated by Coupling of ENSO With Seasonal Cycle in the Tropical Pacific

AbstractTropical precipitation anomalies show very different patterns over the central‐eastern equatorial Pacific between the developing and decay phases of extreme El Niño despite similar patterns of sea surface temperature (SST) anomalies. Using observational data and atmospheric simulations for 1979–2018, we identified a meridional dipole mode of tropical precipitation variability, called the Pacific precipitation dipole mode (PPDM), which is critical for seasonally varying rainfall patterns related to extreme El Niño. We examined the mechanism of PPDM using a numerical model and found that the seasonal shift of the warm SST band in the eastern equatorial Pacific, when coupled with extreme SST anomalies, causes phase reversal of the PPDM. The PPDM can be regarded as a different manifestation of the El Niño/Southern Oscillation combination mode, as revealed by the surface wind anomalies, which also explains the distinct impact of extreme El Niño events over East Asia.

Less rain and rainy days—lessons from 45 years of rainfall data (1971–2015) in the Kathmandu Valley, Nepal

Understanding spatiotemporal variability in rainfall patterns is crucial for evaluating water balances needed for water resources planning and management. This paper investigates spatiotemporal variability in rainfall and assesses the frequency of daily rainfall observations from seven stations in the Kathmandu Valley, Nepal, from 1971 to 2015. Daily rainfall totals were classified into five classes, namely, A (light rain, daily rainfall < 10 mm in a day), B (moderate rain, between 10 and 50 mm), C (heavy rain, between 50 and 100 mm), D (storm, between 100 and 150 mm), and E (large storm, > 150 mm). An ordinary kriging method was used for spatial interpolation using QGIS. We performed Mann–Kendall (MK) test in conjunction with Theil-Sen’s (TS) slope estimator to detect monotonic trends, their significance, and magnitude. We find that the mountain stations depict a decreasing rainfall trend for all seasons, ranging from − 8.4 mm/year at Sankhu to − 21.8 mm/year at Thankot, whereas a mixed pattern is found on the Valley floor. Since the surrounding mountains are the chief source of surface runoff across the valley, rivers, and rivulets are substantially affected by falling rainfall tendency. Both annual rainfall amount and the number of rainy days decreased in the Kathmandu Valley over the study period. We observe a significant reduction in rainfall after 2000. As springs and shallow groundwater are the primary sources of water supply in the Kathmandu valley, it is apparent that decreasing rainfall will have (and is already having) an adverse impact on domestic, industrial, and agricultural water supplies and the livelihoods of people.