Drought Coverage Research Articles

Long-range hydrological drought forecasting using multi-year cycles in the North Atlantic Oscillation

With global temperatures, populations and ecological stressors expected to rise, hydrological droughts are projected to have progressively severe economic and environmental impacts. As a result, hydrological drought forecasting systems have become increasingly important water resource management tools for mitigating these impacts. However, high frequency behaviours in meteorological or atmospheric conditions often limit the lead times of hydrological drought forecasts to seasonal timescales, either through poorer performance of multi-year meteorological forecasts or the lack of multi-year lags in atmosphere-hydrology systems. By contrast, low frequency behaviours in regionally important teleconnection systems (such as the North Atlantic Oscillation, NAO) offer a novel way to forecast hydrological drought at longer lead times. This paper shows that, by using a data-driven modelling approach, long-term behaviours within the NAO can be skilful predictors of hydrological drought conditions at a four-year forecasting horizon. Multi-year semi-periodic patterns in the NAO were used to forecast regional groundwater drought coverage in the UK (proportion of groundwater boreholes in drought), with the greatest forecast performance achieved for longer duration droughts, and for hydrogeological regions with longer response times. Model errors vary from 14 % (proportion of boreholes, (MAE)) in flashy hydrological regions or short droughts (<3 months), to 2 % for longer duration droughts (>8 months). Model fits of r2 up to 0.8 were produced between simulated and recorded regional drought coverage. As such our results show that teleconnection indices can be a skilful predictor of hydrological drought dynamics at multi-year timescales, opening new opportunities for long-lead groundwater drought forecasts to be integrated within existing drought management strategies in Europe and beyond.

Flash droughts in a hotspot region: Spatiotemporal patterns, possible climatic drivings and ecological impacts

Northeast China, recognized as a global flash drought hotspot and a region of nationally important commercial grains and ecological fragility, is highly susceptible to the profound impacts of droughts on both food security and ecological safety. However, the regional-scale characteristics, possible causes and impacts of flash droughts across Northeast China are rarely investigated. Soil moisture data from 2000 to 2022 were utilized to identify the onset, frequency and duration of flash droughts using the quantile method. The spatial trajectories of flash droughts were determined based on the patch-scale centroid transfers. Further, the possible drivings and ecological impacts of flash droughts were analyzed using datasets of climatic variables and gross primary productivity. We found that flash drought coverage with short onset (1- pentad onset) was generally larger than that with long onset (2-, 3- and 4-pentad onset). The affected area of flash droughts generally decreased, while the onset speed increased over the past two decades. Flash droughts frequently occurred the intersection of western Jilin Province, southern Inner Mongolia Autonomous Region, and northern Liaoning Province but with short duration. Compared with 2001–2011, the start, middle and end centroids of flash droughts in 2012–2021 showed more spatial dynamic changes, mainly shifting towards the northeast-southwest and southeast-northwest directions. The onset of flash drought due to potential evapotranspiration, temperature, precipitation deficit, and vapor pressure anomalies account for an average of 33%, 28%, 22%, and 16%, respectively. However, the contributions of dominant meteorological factors and their combinations varied remarkably in different sub-regions. Long onset flash droughts exhibited larger impact on GPP than short onset flash droughts. This study highlights that due to climate change, the affected area of flash droughts in hotspot regions decreased, but the onset speed and spatial dynamics increased, and followed by a more severe ecological impact of short-onset flash drought. Therefore, it is imperative to incorporate the increasing impacts of flash droughts, which is critical to ensuring regional food security and ecological safety in the Northeast China.

Temperature vegetation dryness index (TVDI) for drought monitoring in the Guangdong Province from 2000 to 2019.

Drought monitoring is crucial for assessing and mitigating the impacts of water scarcity on various sectors and ecosystems. Although traditional drought monitoring relies on soil moisture data, remote sensing technology has have significantly augmented the capabilities for drought monitoring. This study aims to evaluate the accuracy and applicability of two temperature vegetation drought indices (TVDI), TVDINDVI and TVDIEVI, constructed using the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) vegetation indices for drought monitoring. Using Guangdong Province as a case, enhanced versions of these indices, developed through Savitzky-Golay filtering and terrain correction were employed. Additionally, Pearson correlation analysis and F-tests were utilized to determine the suitability of the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) in correlation with TVDINDVI and TVDIEVI. The results show that TVDINDVI had more meteorological stations passing both significance test levels (P<0.001 and P<0.05) compared to TVDIEVI, and the average Pearson'R correlation coefficient was slightly higher than that of TVDIEVI, indicating that TVDINDVI responded better to drought in Guangdong Province. Our conclusion reveals that drought-prone regions in Guangdong Province are concentrated in the Leizhou Peninsula in southern Guangdong and the Pearl River Delta in central Guangdong. We also analyzed the phenomenon of winter-spring drought in Guangdong Province over the past 20 years. The area coverage of different drought levels was as follows: mild drought accounted for 42% to 64.6%, moderate drought accounted for 6.96% to 27.92%, and severe drought accounted for 0.002% to 1.84%. In 2003, the winter-spring drought in the entire province was the most severe, with a drought coverage rate of up to 84.2%, while in 2009, the drought area coverage was the lowest, at 49.02%. This study offers valuable insights the applicability of TVDI, and presents a viable methodology for drought monitoring in Guangdong Province, underlining its significance to agriculture, environmental conservation, and socio-economic facets in the region.

‘The Long, Continued Dry’

Droughts are a canonical feature of Australian history and climate, and Australia’s paleoclimate and colonial past is dotted with extended periods of low rainfall. The Federation Drought was one such period. The result of a series of El Niño events, it parched much of Australia between 1895 and 1903 and remains one of the most significant and prolonged periods of rainfall deficiency since European colonisation. It also coincided with, and fuelled, a substantial increase in press coverage of the weather. In this article we examine reportage of the Federation Drought through two newspapers from the Victorian city of Bendigo: The Bendigo Advertiser and The Bendigo Independent. We identify themes that have persisted in drought coverage to the present day, highlighting the role the press has played in shaping how communities and policy makers have understood and managed the extremities of Australia’s climate. We also offer insights into the evolution of current drought reportage and the perspectives it enables or silences.

Decadal spatio-temporal dynamics of drought in semi-arid farming regions of Zimbabwe between 1990 and 2020: a case of Mberengwa and Zvishavane districts

Drought severity and frequency are increasing in tropical regions and its occurrence is not uniform in space and time. The study assessed the spatio-temporal dynamics of agrometeorological drought in Mberengwa and Zvishavane districts between 1990 and 2020. An empirical research design was adopted in this study. GIS and remote sensing techniques were used to determine and analyze agricultural drought conditions and the standardized precipitation generator was used to compute SPI for meteorological drought monitoring and analysis. Microsoft Excel 2011 was adopted for the analysis of drought coverage and performing the Mann–Kendall trend test for precipitation trend analysis. Results indicated that the area covered by drought declined between the 1990 and 2000 and 2001–2010 decades before increasing during the 2011–2020 decade. Results indicated significant spatial dynamics of drought severity and frequency in Mberengwa and Zvishavane districts and the majority of wards experienced increased frequency of severe droughts during the 2011–2020 decade. It was highlighted that meteorological drought was not evenly distributed across all decades. Dry conditions in the first months (October and November) of the rainy season have been indicated during the 1990–2000 decade, followed by wetter conditions during the 2001–2010 decade and comparatively drier conditions in the same months during the 2011–2020 decade. This indicated the late onset of the rainfall season during the 1990–2000 and 2011–2020 decades compared to the 2001–2010 decade. It was also shown that rainfall cessation was earlier during the 2001–2010 and 2011–2020 decades and late during the 1990–2000 decade. The study concludes that drought has increased both in severity and frequency in Mberengwa and Zvishavane districts; hence, there is a need for more support to drought resilience-building initiatives in these areas. The government of Zimbabwe is advised to set up climate research centers in all provinces of the country to improve the availability of climate change–related data which is useful when addressing the impacts of climate change.

Analysis of the critical components of flash drought using the standardized evaporative stress ratio

Flash droughts develop rapidly (∼1 month timescale) and produce significant ecological, agricultural, and socioeconomical impacts. Recent advances in our understanding of flash droughts have resulted in methods to identify and quantify flash drought events. However, few studies have been done to isolate the individual rapid intensification and drought components of flash drought, which could further determine their causes, evolution, and predictability. This study utilized the standardized evaporative stress ratio (SESR) to quantify individual components of flash drought from 1979 – 2019, using evapotranspiration (ET) and potential evapotranspiration (PET) data from the North American Regional Reanalysis (NARR) dataset. The temporal change in SESR was utilized to quantify the rapid intensification component of flash drought. The drought component was also determined using SESR and compared to the United States Drought Monitor. The results showed that SESR was able to represent the spatial coverage of drought well for regions east of the Rocky Mountains. Furthermore, the rapid intensification component agreed well with previous flash drought studies, with the overall climatology of rapid intensification events showing similar hotspots to the flash drought climatology east of the Rocky Mountains. The rapid intensification climatology suggested areas west of the Rocky Mountains experience rapid drying more often than east of the Rocky Mountains.

Spatiotemporal Variations of Drought and the Related Mitigation Effects of Artificial Precipitation Enhancement in Hengyang-Shaoyang Drought Corridor, Hunan Province, China

It is important to reveal the spatial and temporal variations of drought and evaluate the alleviating effects of artificial precipitation on drought severity, as it will contribute immensely to the formulation of drought prevention and mitigation measures and the provision of guidance to artificial precipitation enhancement operation. Based on the monthly precipitation data of 28 meteorological stations in Hengyang-Shaoyang Drought Corridor (HSDC) from 1960 to 2019, the standardized precipitation index (SPI) at multiple time scales were calculated to estimate drought frequency, drought station ratio, and drought intensity. Then the spatiotemporal variations of drought in the study area were unveiled, and the effects of artificial precipitation enhancement were evaluated in line with the relevant data from 2005 to 2019. The results show that at the annual scale, drought occurred in 3/4 of past sixty years in the study area, where almost 1/3 of such years experienced area-wide droughts. Drought coverage in HSDC exhibited a decreasing trend, but drought intensity, as well as the number of area-wide droughts and regional droughts showed an increasing one. Mild and moderate droughts occurred in an extensive part of the HSDC, whereas severe and extreme droughts were mainly found in a few stations. At the seasonal scale, winter drought occurred most frequently, followed by summer and autumn droughts, while spring drought events had the lowest frequency. Overall, drought is more serious in spring, autumn, and winter, but less severe in summer; although drought intensity decreased slightly in summer, both its intensity and coverage showed an increasing trend in other seasons. At the monthly scale, the ratio of positive to negative SPI values in HSDC was basically balanced in the past six decades, exhibiting no distinct variation characteristics. In addition, artificial precipitation enhancement effectively eased monthly and even seasonal drought in HSDC. These findings, which fully reflect the characteristics of drought in the study area, can also raise awareness of the contribution that artificial precipitation could make to drought mitigation, which in turn will contribute to the formulation of appropriate strategies for climate change mitigation and adaptation.

Drought analysis during the growth stages of grape in the main grape-growing regions in China

In China, grape is one of the top five fruit crops for both bearing acreage and production. Recently, national grape production has been stalling because of an increase in drought events. In order to combat the adverse effects of drought on grape production, it is imperative to understand the historical drought trend and frequency during the growing season. In this study, we focused on agricultural drought during the four growth periods of grape: bud break-flowering, flowering-veraison, veraison-berry maturation, and berry maturation-leaf fall. Based on the weather data from 429 meteorological stations, we computed the Crop Water Deficit Index (CWDI) in the five main grape-growing regions of China: Northeast China, North China, Northwest China, Southwest China, and Southeast China. Then, we evaluated the CWDI-based drought distribution and trend in the study regions, as well as the frequency of different degrees of drought. The results showed that exceptional drought was occurring frequently in Xinjiang Uyghur Autonomous Region, northern Gansu province, and northern Ningxia Hui Autonomous Region. Among the four study growth periods of grape, exceptional drought was the most expansive during bud break-flowering. What’s more, exceptional drought coverage during bud break-flowering in the study regions was increasing from 1981 to 2016. Analysis of butterfly structure showed that the occurrence of drought was continuous and persistent in northern China. Our study results could serve as guideposts to highlight Chinese grape production industry’s vulnerability to agricultural drought against the background of climate change.

Seasonal dynamics of agro-meteorological drought in Mberengwa and Zvishavane districts between 2017 and 2020, Zimbabwe

Drought severity is increasing in Southern Africa which is affecting rain-fed agriculture, the main source of livelihood in most countries in this region. The study assessed the seasonal spatio-temporal dynamics of agro-meteorological drought between 2017 and 2020 in Mberengwa and Zvishavane districts. An empirical research design supported by quantitative geographical information system techniques for data analysis was adopted in this study. Remote sensing data and precipitation records from the Meteorological Services Department were main data sources in this study. Microsoft excel 2013, SPI generator and ArcMap 10.5 software were used for data analysis in this study. Results showed that both Mberengwa and Zvishavane districts experienced an increasing trend in spatial coverage of drought from 2017 to 2019 before a slight decline in 2020. From 2017, drought severity increased in terms of spatial coverage with this spatial distribution increasing to almost over ¾ of the wards in both Mberengwa and Zvishavane districts between 2018 and 2020. Since 2017, on a ward level basis, both districts have been experiencing late onset and early cessation of the rain season as shown by increasingly dry October, November and March, months which determine the length of crop growing season in these two districts. Results indicated that the month of March was drier in Mberengwa whilst the month of December was drier in Zvishavane, an indication of more mid-season dry spells in Zvishavane and earlier rainfall cessation in Mberengwa. Drought is worsening in both Mberengwa and Zvishavane districts; hence, long-term drought resilience interventions are required to improve drought resilience of communities in these areas. The study recommends the Government of Zimbabwe and other stakeholders of drought resilience building like CARE International, World Vision among others to prioritise launching of resilience building initiatives in most vulnerable areas whilst guided by fine empirical information on spatial distribution of drought.

Simulation and mapping of drought and soil erosion in Central Yunnan Province, China

Central Yunnan Province is the political, economic, cultural, and transportation hub of Yunnan Province, China. Climate change has resulted in increased seasonality of global averaged precipitation, temperature, runoff, and evapotranspiration, thereby exacerbating extreme events such as drought and soil erosion. The simulation and mapping of drought and soil erosion within Central Yunnan Province is important for achieving sustainable development. This study constructed a comprehensive drought monitoring model and a soil erosion model based on multiple sources of remote sensing data, considering numerous drought and soil erosion factors. The temporal and spatial characteristics of dry-season drought and soil erosion for 2010 to 2018 in Central Yunnan Province were explored, and the extents of soil erosion in different parts of Central Yunnan Province were quantified using the soil erosion intensity index. The results showed that: (1) The multi-year average percentage dry-season drought coverage and average drought frequency were 33.98% and 18.33 months, respectively. Although drought frequency was higher in areas with high drought intensity, dry-season drought showed a long-term weakening trend. (2) Over the study period, the multi-year average soil erosion of Central Yunnan Province was 1,551.45 t km −2 ·yr −1 . Soil erosion showed an initial overall increasing trend, followed by a decreasing trend, dominated by micro erosion, mild erosion, and moderate erosion, whereas the mountains and valleys in north and southwest parts of Central Yunnan Province experienced severe erosion. Vegetation coverage and slope were identified as the main factors driving soil erosion. (3) The soil erosion intensity index was a good indicator of soil erosion severity across different spatial scales and different drought grades. The soil erosion intensity index showed a positive relationship with drought grade. The correlation coefficients between soil erosion intensity and drought frequency and between soil erosion intensity and drought intensity were 0.2623 and −0.2679, respectively. This study demonstrated that drought affects soil erosion and that water and soil conservation measures such as afforestation and vegetation greening are beneficial to mitigating soil erosion and drought in Central Yunnan Province.

No Longer Buried?

When AWWA published its landmark report Buried No Longer in 2012, its title was a play on the proverb “out of sight, out of mind.” Because valuable water distribution and collection pipelines are buried underground, they are easy to forget and potentially neglect. Research in that report projected the cost at the time to replace existing water systems in the United States as they reached the end of their useful lives and expand them to serve a growing population would be at least US$1 trillion over the following 25 years (we're almost in year 10). Buried No Longer provided a straightforward approach for cost estimation, and the related Buried No Longer online tool can still be used to provide individual utilities a 20- to 30-year economic forecast for pipe repair and replacement based on pipe size or pipe material categories. But while Buried No Longer shed light on the United States’ water infrastructure needs, it only touched on the necessary communication, stating that “. . . in many cases, difficult choices may need to be made between competing needs if water bills are to be kept affordable. Water utilities are willing to ask their customers to invest more, but it's important this investment be in things that bring the greatest actual benefit to the community.” In the nearly 10 years since Buried No Longer was released, the infrastructure has stayed buried, but the public's awareness of water issues has not. According to Google Trends, interest in the online search terms water and drinking water has steadily increased in North America since 2004, with annual peaks coming in the summer months. There are numerous significant news items on water every day, and many different media organizations have departments dedicated to covering water through their particular lenses. However, within the now-daily coverage of drought, floods, and industrial groundwater contamination, water professionals need to keep the original message from Buried No Longer at the front of the conversations—namely, that water systems need ongoing reinvestment and postponing those investments only makes problems worse. The public must better understand that investments in water systems are opportunities to improve their communities’ long-term sustainability while protecting the health of themselves and those around them. Water professionals need to effectively communicate within the larger discourse to keep the focus on safe drinking water from source to tap, which now includes the entire water cycle as well as well as managing relationships with customers, regulators, and other stakeholders. Ongoing communication is vital so that the public understands and appreciates the value of water services and the systems they rely on to provide them. This issue of Journal AWWA features articles on water system resilience, water quality monitoring, asset management, and other topics highlighted in Buried No Longer that are still important to the water industry. If you are interested in submitting an article, please contact me at journaleditor@awwa.org.

Communicating water availability to improve awareness and implementation of water conservation: A study of the 2018 and 2020 drought events in the Republic of Ireland

Public communication on water availability is pivotal in highlighting water conservation needs as droughts impact water resources for critical use, such as drinking water quality and accessibility. This paper presents the results of research into public communication on water availability and the implementation of water conservation measures in the Republic of Ireland. The paper analyses social media (Twitter and Facebook) communication and newspaper publications from 2018 to 2020 on water conservation and drought events, in addition, to undertaking six key stakeholder interviews made up of journalists (n = 4), political representatives (n = 1), and a water and communication expert (n = 1). Our analysis indicates that Irish newspapers' coverage of drought and water availability was greater in 2018 compared to 2020. Uncertainty and risk was also identified as the prevalent frame, used by newspapers to cover drought events. Although the sentiments in communications on drought by the national utility, Irish Water, were scored as positive (63%), its engagement with the public on social media was considerably limited. Accessible information platforms that provides data and information on water resources were also found; nevertheless, no comprehensive national drought information management system nor national drought plan have been developed. Based on our findings, we demonstrate the need for public engagement and collaborative efforts to communicate drought and water conservation measures led by An Fóram Uisce|The Water Forum. Recommendations made in this study also aim to influence decision-making and awareness among stakeholders regarding drought communication on water conservation and resources availability.

Temporal analysis of drought coverage in a watershed area using remote sensing spectral indexes

The development of several time series analysis programs using satellite images has provided many applications based on resources from geostatistics field. Currently, the use of statistical tests applied to vegetation indexes has enabled the analysis of different natural phenomena, such as drought events in watershed areas. The objective of this article is to provide a comparative analysis between NDVI and EVI vegetation index data made available by MOD13Q1 project of MODIS sensor for drought mapping using vegetation condition index (VCI) in the Serra Azul stream sub-basin, MG. The methodology adopted the Cox-Stuart statistical test for seasonality analysis and Pearson's linear correlation to verify the influence of different indexes on delimitation of drought in a watershed. The results indicated the NDVI vegetation index as more efficient than EVI in spatial characterization of studied watershed region, mainly in identification of seasonality. The VCI proved to be highly feasible for monitoring drought in study period between 2013 and 2018, allowing the effective delimitation of drought conditions in the Serra Azul stream sub-basin. In addition, the effectiveness of MODIS sensor data in characterizing drought events that affected the study area was proven.

Spatio\u2010temporal characteristics of meteorological drought under changing climate in semi\u2010arid region of northern Ethiopia

BackgroundBelow-normal availability of water for a considerable period of time induces occurrence of drought. This paper investigates the Spatio-temporal characteristics of meteorological drought under changing climate. The climate change was analyzed using delta based statistical downscaling approach of RCP 4.5 and RCP 8.5 in R software packages. The meteorological drought was assessed using the Reconnaissance Drought Index (RDI).ResultsThe result of climate change projections showed that the average annual minimum temperature will be increased by about 0.8–2.9 °C. The mean annual maximum temperature will be also increased by 0.9–3.75 °C. The rainfall projection generally showed an increasing trend, it exhibited an average annual increase of 3.5–13.4 % over the study area. The projected drought events reached its maximum severity indicated extreme drought in the years 2043, 2044, 2073, and 2074. The RDI value shows drought will occurred after 1–6 and 2–7 years under RCP 4.5 and RCP 8.5 emission scenarios respectively over the study area. Almost more than 72 % of the current and future spatial coverage of drought in the study area will be affected by extreme drought, 22.3 % severely and 5.57 % also moderate drought.ConclusionsTherefore, the study helps to provide useful information for policy decision makers to implement different adaptation and mitigation measures of drought in the region.

A spatiotemporal analysis of extreme agrometeorological events during selected growth stages of maize (Zea mays L.) from 1960 to 2017 in Northeast China

Against the background of global warming, extreme agrometeorological events have become more intense and frequent during the growing season of maize (Zea mays L.). In this study, we focused on the five types of extreme agrometeorological events that greatly affect maize production in Northeast China, including chilling injury, drought, rainstorm, frost, and gale. We averaged the actual timing of phenological events from the study agrometeorological stations and divided the maize growing season into four growth stages: emergence—jointing, jointing—flowering, flowering—kernel milk, and kernel milk—physiological maturity. Based on the historical weather data from 1960 to 2017 in the study region, we derived the values of pertinent indices for the five types of study extreme agrometeorological events during the four selected maize growth stages. The results showed that chilling injury and drought were relatively more frequent during the four growth stages of maize from 1960 to 2017 in the Northeast China. As time goes on during the growing season of maize, the spatial coverage of chilling injury, frost, and gale all showed a decreasing trend. By contrast, the spatial coverage of drought showed an increasing trend during the study growth stages of maize. During growth stages of maize, chilling injury was the main extreme agrometeorological event before the 2000s, while drought became the main extreme agrometeorological event after the 2000s. Identifying the main extreme climate events that could cause yield loss is imperative, and it is important for farmers to acknowledge ongoing changes in these extreme climate events in order to take preventive measures if necessary.

Calibrating Human Attention as Indicator Monitoring #drought in the Twittersphere

AbstractState climatologists and other expert drought observers have speculated about the value of monitoring Twitter for #drought and related hashtags. This study statistically examines the relationships between the rate of tweeting using #drought and related hashtags, within states, accounting for drought status and news coverage of drought. We collected and geolocated tweets, 2017–18, and used regression analysis and a diversity statistic to explain expected and identify unexpected volumes of tweets. This provides a quantifiable means to detect state-weeks with a volume of tweets that exceeds the upper limit of the prediction interval. To filter out instances where a high volume of tweets is related to the activities of one person or very few people, a diversity statistic was used to eliminate anomalous state-weeks where the diversity statistic did not exceed the 75th percentile of the range for that state’s diversity statistic. Anomalous state-weeks in a few cases preceded the onset of drought but more often coincided with or lagged increases in drought. Tweets are both a means of sharing original experience and a means of discussing news and other recent events, and anomalous weeks occurred throughout the course of a drought, not just at the beginning. A sum-to-zero contrast coefficient for each state revealed a difference in the propensity of different states to tweet about drought, apparently reflecting recent and long-term experience in those states, and suggesting locales that would be most predisposed to drought policy innovation.

Assessment of Drought across Kaduna State, Nigeria Using MODIS Dataset

Introduction: Kaduna state in Nigeria is located within the Guinea Savannah of the African Continent. The state is susceptible to desertification and the risks of drought.&#x0D; Aim and Objectives: The aim of the study is to access magnitude and extent drought in Kaduna state Nigeria using MODIS dataset.&#x0D; Study Design: The study examined people’s perception; precipitation data and satellite imageries for assessing and monitoring drought. Descriptive statistics were used to present the some of the data.&#x0D; Methodology: The dataset were analysed using Idrisi remote sensing and Geographical Information (GIS) softwares to determine the aerial coverage of drought and its magnitude. Furthermore, run off were determined, VCI calculated, cross-tabulation were made from classified imageries and the views of respondents were also sought to complement the analysis.&#x0D; Results: The study revealed that there have been several episodes of drought in Kaduna state within the period under review. Runoff decreased from 72.50mm in 2000 to just about 48.00mm in 2009. The study also revealed that there is a positive relationship (0.72) between rainfall and vegetation vigour/biomas in the state. Similarly, vegetation condition index (VCI) revealed a value 10.2% indicating a severe drought in the state based on Kogans drought classification.&#x0D; Conclusion: The study concluded that both rainfall and vegetation/biomas vigour are generally decreasing suggesting a strong positive correlation value of 0.71. While a better high spatial resolution satellite dataset be utilised for further studies in this direction, the study also recommends that individuals and organisations be encouraged to engage in the habit of tree planting in order to curtail the decrease in vegetation biomass in the state. In addition, research and extension services should be strongly promoted in order to develop particular breed of seeds that can survive the drought in this period of food insecurity.

Future changes in meteorological drought characteristics over Bangladesh projected by the CMIP5 multi-model ensemble

Drought is an inconspicuous natural disaster. In a warmer world, the severity and coverage of drought are expected to change, and it is essential to study these changes at smaller scale. This study detected changes in drought frequency, severity, and intensity in Bangladesh from a bias-corrected CMIP-5 multi-model projection of 11 members under a business-as-usual RCP8.5 scenario. We have used two well-known meteorological drought indices, Standardized Precipitation Index (SPI) and Standardized Precipitation and Evaporation Index (SPEI). SPI is solely based on precipitation, while SPEI considers climatic water balance and incorporates the effect of temperature. Two different methods of estimation of potential evapotranspiration (PET), namely Thornthwaite and Hargreaves methods, are explored. SPEI-based drought identification is found to have high sensitivity among these PET estimation methods. In Bangladesh, SPI-based analysis suggests virtually no change in the long-term drought (12-monthly) condition and a minor change in short-term (6-monthly or less) droughts. SPEI evaluated with Hargreaves method projects a similar scenario for long-term droughts but an increase in both drought frequency and severity in short timescales. At seasonal scale, winter and pre-monsoon are projected to be potentially more affected by water stress in the future. A spatially coherent shift in wet-dry regime is also found over the northern part of Bangladesh under the warming world.

Precipitation variability and its trend detection for monitoring of drought hazard in northern mountainous region of Pakistan

The Standardized Precipitation Index (SPI) is a powerful tool, requiring only precipitation data for calculating the intensity, duration, magnitude, severity and frequency of drought. Moreover, it provides helpful coverage of drought impacts on multi time scales. In this study, the SPI technique was applied to the dataset of 30 years (1986–2015) to detect drought condition in Northern Pakistan, which is a frequent drought-hit area. The coefficient of variability (CV) was used to analyze precipitation trend, while linear regression model was adopted to detect trend. The detected precipitation variability was spatially interpolated by applying the Inverse Distance Weighted (IDW) technique. It is evident from the analysis that there is great variability in precipitation pattern and trend in the study area. During the winter season, a positive trend in the precipitation variability was detected in the Himalaya and Karakorum region. In the Hindukush region, only Pattan weather station has observed a positive variability trend. In contrast to winter variability, pre-monsoon season has observed an increased variability in the Hindukush region, while the Karakorum and Himalayas regions observed a negative trend. The monsoon season has observed a decreased variation in precipitation throughout the study area except for Pattan. In post-monsoon, Skardu weather station of Himalayas, Gupis and Bunji of Karakorum region and Pattan of Hindukush region have witnessed increased precipitation variability. The meteorological stations of Karakoram and Himalaya have noticed a negative trend of precipitation variability, while in the Hindukush region, all the meteorological stations have witnessed a positive trend of variability except Saidu Sharif and Dir stations. The results of SPI also indicated a drought condition in the study area. Similarly, the SPI results of all return periods have shown a significant drought condition in the Himalayas followed by—in terms of frequency and magnitude—Karakoram and Hindukush, respectively. Based on the above findings, it is recommended that the agriculture experts should work on drought-resilient crops in order to cope up with the harsh prevalent climatic condition in Northern Pakistan.

Morphological assessment of water stressed sugarcane: A comparison of waterlogged and drought affected crop.

Abiotic stress is recurrent occurring problem for sugarcane crop in terms of hindrance in achieving good and high production. In India, drought coverage is 2.97 lakh ha while 2.5 lakh ha under coverage of waterlogging which is one of the reasons behind low cane production and productivity due to alteration in metabolism, growth and development of the plant either in direct or indirect way. Therefore, we investigated the comparison of morphological losses in drought and waterlogging sugarcanes. Morphological parameters assessed were leaf length, leaf width, leaf area, stalk diameter, cane height, cane weight, internodes number and average internodal length. Also, total root weight, dry matter production of stalk, leaves and roots were observed. Results showed that leaf length was marginally increased in drought canes but it was not so in case of waterlogged canes. Besides, there was decrease in total root weight of sugarcane affected by drought by 16.99% while there was increase by 10.06% in waterlogging affected canes in comparison to normal grown canes. In cane height and stalk diameter, decrease by 18.28%, 7.52%, respectively, in drought and 11.41%, marginal decrease, respectively, in waterlogged affected canes as compared to normally grown canes. Average internodal length was also found to increase in both drought as well as waterlogged canes by 39.02% and 36.60%, respectively, in comparison to normal grown canes. Number of internodes was decreased more in drought affected canes than in waterlogged canes. This study concluded that there are higher morphological losses in sugarcane in drought condition than in waterlogging conditions with respect to normal grown canes.