Meteorological Drought Analysis and Return Periods over North and West Africa and Linkage with El Niño–Southern Oscillation (ENSO)

Droughts are one of the world’s most destructive natural disasters. In large regions of Africa, droughts can have strong environmental and socioeconomic impacts. Understanding the mechanism that drives drought and predicting its variability is important for enhancing early warning and disaster risk management. Taking North and West Africa as the study area, this study adopted multi-source data and various statistical analysis methods, such as the joint probability density function (JPDF), to study the meteorological drought and return years across a long term (1982–2018). The standardized precipitation index (SPI) was used to evaluate the large-scale spatiotemporal drought characteristics at 1–12-month timescales. The intensity, severity, and duration of drought in the study area were evaluated using SPI–12. At the same time, the JPDF was used to determine the return year and identify the intensity, duration, and severity of drought. The Mann-Kendall method was used to test the trend of SPI and annual precipitation at 1–12-month timescales. The pattern of drought occurrence and its correlation with climate factors were analyzed. The results showed that the drought magnitude (DM) of the study area was the highest in 2008–2010, 2000–2003, and 1984–1987, with the values of 5.361, 2.792, and 2.187, respectively, and the drought lasting for three years in each of the three periods. At the same time, the lowest DM was found in 1997–1998, 1993–1994, and 1991–1992, with DM values of 0.113, 0.658, and 0.727, respectively, with a duration of one year each time. It was confirmed that the probability of return to drought was higher when the duration of drought was shorter, with short droughts occurring more regularly, but not all severe droughts hit after longer time intervals. Beyond this, we discovered a direct connection between drought and the North Atlantic Oscillation Index (NAOI) over Morocco, Algeria, and the sub-Saharan countries, and some slight indications that drought is linked with the Southern Oscillation Index (SOI) over Guinea, Ghana, Sierra Leone, Mali, Cote d’Ivoire, Burkina Faso, Niger, and Nigeria.

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Impacts of large-scale atmospheric circulation changes due to winter sea-ice retreat on Black Carbon transport and deposition to the Arctic

10.5194/acp-2016-1007 ◽

2016 ◽

Author(s):

Luca Pozzoli ◽

Srdan Dobricic ◽

Simone Russo ◽

Elisabetta Vignati

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

North Atlantic ◽

Large Scale ◽

Southern Oscillation ◽

The Arctic ◽

The North ◽

Ice Retreat ◽

The North Atlantic Oscillation ◽

Sea Ice Retreat

Abstract. Winter warming and sea ice retreat observed in the Arctic in the last decades determine changes of large scale atmospheric circulation pattern that may impact as well the transport of black carbon (BC) to the Arctic and its deposition on the sea ice, with possible feedbacks on the regional and global climate forcing. In this study we developed and applied a new statistical algorithm, based on the Maximum Likelihood Estimate approach, to determine how the changes of three large scale weather patterns (the North Atlantic Oscillation, the Scandinavian Blocking, and the El Nino-Southern Oscillation), associated with winter increasing temperatures and sea ice retreat in the Arctic, impact the transport of BC to the Arctic and its deposition. We found that the three atmospheric patterns together determine a decreasing winter deposition trend of BC between 1980 and 2015 in the Eastern Arctic while they increase BC deposition in the Western Arctic. The increasing trend is mainly due to the more frequent occurrences of stable high pressure systems (atmospheric blocking) near Scandinavia favouring the transport in the lower troposphere of BC from Europe and North Atlantic directly into to the Arctic. The North Atlantic Oscillation has a smaller impact on BC deposition in the Arctic, but determines an increasing BC atmospheric load over the entire Arctic Ocean with increasing BC concentrations in the upper troposphere. The El Nino-Southern Oscillation does not influence significantly the transport and deposition of BC to the Arctic. The results show that changes in atmospheric circulation due to polar atmospheric warming and reduced winter sea ice significantly impacted BC transport and deposition. The anthropogenic emission reductions applied in the last decades were, therefore, crucial to counterbalance the most likely trend of increasing BC pollution in the Arctic.

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Influence of Modes of Climate Variability on Global Temperature Extremes

Journal of Climate ◽

10.1175/2008jcli2125.1 ◽

2008 ◽

Vol 21 (15) ◽

pp. 3872-3889 ◽

Cited By ~ 139

Author(s):

Jesse Kenyon ◽

Gabriele C. Hegerl

Keyword(s):

North America ◽

Climate Variability ◽

Large Scale ◽

Southern Oscillation ◽

Temperature Extremes ◽

Modes Of Variability ◽

The North ◽

The Pacific ◽

The North Atlantic Oscillation ◽

Modes Of Climate Variability

Abstract The influence of large-scale modes of climate variability on worldwide summer and winter temperature extremes has been analyzed, namely, that of the El Niño–Southern Oscillation, the North Atlantic Oscillation, and Pacific interdecadal climate variability. Monthly indexes for temperature extremes from worldwide land areas are used describe moderate extremes, such as the number of exceedences of the 90th and 10th climatological percentiles, and more extreme events such as the annual, most extreme temperature. This study examines which extremes show a statistically significant (5%) difference between the positive and negative phases of a circulation regime. Results show that temperature extremes are substantially affected by large-scale circulation patterns, and they show distinct regional patterns of response to modes of climate variability. The effects of the El Niño–Southern Oscillation are seen throughout the world but most clearly around the Pacific Rim and throughout all of North America. Likewise, the influence of Pacific interdecadal variability is strongest in the Northern Hemisphere, especially around the Pacific region and North America, but it extends to the Southern Hemisphere. The North Atlantic Oscillation has a strong continent-wide effect for Eurasia, with a clear but weaker effect over North America. Modes of variability influence the shape of the daily temperature distribution beyond a simple shift, often affecting cold and warm extremes and sometimes daytime and nighttime temperatures differently. Therefore, for reliable attribution of changes in extremes as well as prediction of future changes, changes in modes of variability need to be accounted for.

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Analysis of meteorological and agricultural droughts in Serbia

Facta universitatis - series Architecture and Civil Engineering ◽

10.2298/fuace1403253m ◽

2014 ◽

Vol 12 (3) ◽

pp. 253-264 ◽

Cited By ~ 3

Author(s):

Mladen Milanovic ◽

Milan Gocic ◽

Slavisa Trajkovic

Keyword(s):

Standardized Precipitation Index ◽

Meteorological Drought ◽

Precipitation Index ◽

Precipitation Extreme ◽

Agricultural Drought ◽

Drought Intensity ◽

The North ◽

Rainfall Index ◽

The Standardized Precipitation Index ◽

Year 2000

Drought represents a combined heat-precipitation extreme and has become an increasingly frequent phenomenon in recent years. In order to access the entire analysis of drought, it is necessary to include the analysis of several types of drought. In this paper, impacts of meteorological and agricultural drought were analyzed across the Standardized Precipitation Index (SPI) and Agricultural Rainfall Index (ARI) on the territory of Serbia for the period from 1980 to 2010. For both types of drought, year 2000 is notable as the year when most of the observed stations had the highest drought intensity. It was found that meteorological drought for year 2000 has a higher intensity in the central and southeastern parts of the country, as well as in the north. Of all the stations, the highest intensity of meteorological drought was observed at Loznica station in 1989. Agricultural drought in 2000 had the lowest intensity in western Serbia.

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Drought Variability and Characteristics in the Muda River Basin of Malaysia from 1985 to 2019

Atmosphere ◽

10.3390/atmos12091210 ◽

2021 ◽

Vol 12 (9) ◽

pp. 1210

Author(s):

Zibeon bin Luhaim ◽

Mou Leong Tan ◽

Fredolin Tangang ◽

Zed Zulkafli ◽

Kwok Pan Chun ◽

...

Keyword(s):

River Basin ◽

Large Scale ◽

Response Rate ◽

Southern Oscillation ◽

Standardized Precipitation Index ◽

Kendall Test ◽

Dry Period ◽

The Indian Ocean ◽

The Standardized Precipitation Index ◽

Almost All

This study aimed to analyze the spatiotemporal changes of historical droughts over the Muda River basin (MRB), Malaysia, from 1985 to 2019 using the Standardized Precipitation Index (SPI) and the Standardized Streamflow Index (SSI). The Mann–Kendall test and Sens’ slope were used to evaluate the trends and magnitude changes in the droughts, respectively, while Spearman’s rho was applied to understand the relationships of the droughts with large-scale atmospheric circulations, such as the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Madden–Julian Oscillation (MJO). The results show that the intense droughts in the MRB mostly occurred in 1991–1992, 1995, 1998, 2002–2003, 2005–2006, 2008, 2012–2013, and 2016. In addition, a declining SPI trend was found from May to December at most of the stations. About 80% of the stations experienced about 10 severely dry droughts, while almost all stations experienced at least 5 extremely dry events. Moreover, a higher response rate of the SSI than the SPI was found during low-rainfall months from January to May. Lastly, ENSO had a larger impact on the drought formations over the MRB compared to the IOD and MJO, especially during the dry period.

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Variability of extreme precipitation over Europe and its relationships with teleconnection patterns

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-10-12331-2013 ◽

2013 ◽

Vol 10 (10) ◽

pp. 12331-12371 ◽

Cited By ~ 3

Author(s):

A. Casanueva ◽

C. Rodr&iacute;guez-Puebla ◽

M. D. Fr&iacute;as ◽

N. González-Reviriego

Keyword(s):

Extreme Precipitation ◽

Large Scale ◽

Hydrological Cycle ◽

Southern Oscillation ◽

Global Climate ◽

Atlantic Multidecadal Oscillation ◽

Physical Factors ◽

Teleconnection Patterns ◽

The North ◽

The North Atlantic Oscillation

Abstract. A growing interest in extreme precipitation has spread through the scientific community due to the effects of global climate change on the hydrological cycle and their threat on natural systems more than averaged climatic values. Understanding the variability of hydrological indices and their association to atmospheric processes could help to project the frequency and severity of extremes. This paper evaluates the trend of three precipitation extremes: the number of consecutive dry/wet days (CDD/CWD) and the quotient of the precipitation in days where daily precipitation exceeds the 95th percentile of the reference period and the total amount of precipitation (or contribution of very wet days, R95pTOT). The aim of this study is twofold. First, extreme indicators are compared against accumulated precipitation (RR) over Europe in terms of trends using non-parametric approaches. Second, we analyse the geographic opposite trends found over different parts of Europe by considering their relationships with large-scale processes, using different teleconnection patterns. The study is accomplished for the four seasons using the gridded E-OBS dataset developed within the EU ENSEMBLES project. Different patterns of variability were found for CWD and CDD in winter and summer, with north-south and east–west configurations, respectively. We consider physical factors to understand the extremes variability by linking large-scale processes and hydrological extremes. Opposite association with the North Atlantic Oscillation in winter and summer, and the relationships with the Scandinavian, East Atlantic patterns and El Niño/Southern Oscillation events in spring and autumn gave insight into the trend differences. Significant relationships were found between the Atlantic Multidecadal Oscillation and very extreme precipitation (R95pTOT) during the whole year. The largest extreme anomalies were analysed by composite maps using atmospheric variables and sea surface temperature. The association of extreme precipitation indices and large-scale variables found in this work could pave the way of new possibilities for the projection of extremes in downscaling techniques.

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Meteorological Drought and its Relationship with Southern Oscillation Index (SOI)

Civil Engineering Journal ◽

10.28991/cej-2020-03091588 ◽

2020 ◽

Vol 6 (10) ◽

pp. 1864-1875 ◽

Cited By ~ 1

Author(s):

Donny Harisuseno

Keyword(s):

Southern Oscillation Index ◽

Drought Index ◽

Southern Oscillation ◽

Pearson Correlation ◽

Standardized Precipitation Index ◽

Meteorological Drought ◽

Drought Risk ◽

Drought Event ◽

Association Analyses ◽

The Standardized Precipitation Index

Drought monitoring, including its severity, spatial, and duration is essential to enhance resilience towards drought, particularly for overcoming drought risk management and mitigation plan. The present study has an objective to examine the suitability of the Standardized Precipitation Index (SPI) and Percent of Normal Index (PN) on assessing drought event by analyzing their relationship with the Southern Oscillation Index (SOI). The monthly rainfall data over twenty years of the observation period were used as a basis for data input in the drought index calculation. The statistical association analyses, included the Pearson Correlation (r), Kendal tau (τ), and Spearman rho (rs) used to assess the relationship between the monthly drought indexes and SOI. The present study confirmed that the SPI showed a more consistent and regular pattern relationship with SOI basis which was indicated by a moderately high determination coefficient (R2) of 0.74 and the magnitude of r, τ, and rs that were of 0.861, 0.736, and 0.896, respectively. Accordingly, the SPI showed better compatibility than the PN for estimating drought characteristics. The study also revealed that the SOI data could be used as a variable to determine the reliability of drought index results.

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Aerosol-Induced Large-Scale Variability in Precipitation over the Tropical Atlantic

Journal of Climate ◽

10.1175/2009jcli2531.1 ◽

2009 ◽

Vol 22 (19) ◽

pp. 4970-4988 ◽

Cited By ~ 20

Author(s):

Jingfeng Huang ◽

Chidong Zhang ◽

Joseph M. Prospero

Keyword(s):

Large Scale ◽

Southern Oscillation ◽

Boreal Winter ◽

Tropical Atlantic ◽

Weather Factors ◽

Light Rain ◽

The North ◽

Order Of Magnitude ◽

The North Atlantic Oscillation ◽

Rain Rates

Abstract Multiyear satellite observations are used to document a relationship between the large-scale variability in precipitation over the tropical Atlantic and aerosol traced to African sources. During boreal winter and spring there is a significant reduction in precipitation south of the Atlantic marine intertropical convergence zone (ITCZ) during months when aerosol concentrations are anomalously high over a large domain of the tropical Atlantic Ocean. This reduction cannot be linearly attributed to known climate factors such as El Niño–Southern Oscillation, the North Atlantic Oscillation, and zonal and meridional modes of tropical Atlantic sea surface temperature or to meteorological factors such as water vapor. The fractional variance in precipitation related to aerosol is about 12% of the total interannual variance, which is of the same order of magnitude as that related to each of the known climate and weather factors. A backward trajectory analysis confirms the African origin of aerosols that directly affect the changes in precipitation. The reduction in mean precipitation mainly comes from decreases in moderate rain rates (10–20 mm day−1), while light rain (<10 mm day−1) can fluctuate in the opposite direction. The results cannot be readily explained in terms of wet deposition or uncertainties in satellite retrievals, and suggest that the observations demonstrate clearly identifiable effects of African aerosol on large-scale variability in precipitation in the tropical Atlantic region.

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Assessment of Meteorological Drought in Korea under Climate Change

Advances in Meteorology ◽

10.1155/2016/1879024 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Jaewon Kwak ◽

Soojun Kim ◽

Jaewon Jung ◽

Vijay P. Singh ◽

Dong Ryul Lee ◽

...

Keyword(s):

Climate Change ◽

Spatial Distribution ◽

Climate Model ◽

Regional Climate ◽

Standardized Precipitation Index ◽

Joint Probability ◽

Meteorological Drought ◽

Copula Method ◽

The Standardized Precipitation Index ◽

Near Future

Drought has become one of the most important elements for water resources planning and management in Korea. The objective of this study is to estimate the spatial distribution of drought and change in the drought characteristics over time due to climate change. For the spatial characterization of drought, the standardized precipitation index (SPI) is calculated from the 45 observatories in Korea and the spatial distribution is also estimated based on the joint probability analysis using the copula method. To analyze the effect of climate change, spatial distribution of drought in the future is analyzed using the SPI time series calculated from Representative Concentration Pathways (RCPs) scenarios and HADGEM3-RA regional climate model. The results show that the Youngsan River and the northwest of Nakdong River basins in Korea have nearly doubled drought amount compared to the present and are most vulnerable to drought in near future (2016 to 2039 years).

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Spatio-temporal associations of albacore CPUEs in the Northeastern Pacific with regional SST and climate environmental variables

ICES Journal of Marine Science ◽

10.1093/icesjms/fst238 ◽

2014 ◽

Vol 71 (7) ◽

pp. 1717-1727 ◽

Cited By ~ 10

Author(s):

A. Jason Phillips ◽

Lorenzo Ciannelli ◽

Richard D. Brodeur ◽

William G. Pearcy ◽

John Childers

Keyword(s):

North Pacific ◽

Large Scale ◽

Environmental Variability ◽

Southern Oscillation ◽

Spatial Dynamics ◽

Catch Per Unit Effort ◽

Variable Effect ◽

Positive Effects ◽

The North ◽

Additive Mixed Models

Abstract This study investigated the spatial distribution of juvenile North Pacific albacore (Thunnus alalunga) in relation to local environmental variability [i.e. sea surface temperature (SST)], and two large-scale indices of climate variability, [the Pacific Decadal Oscillation (PDO) and the Multivariate El Niño/Southern Oscillation Index (MEI)]. Changes in local and climate variables were correlated with 48 years of albacore troll catch per unit effort (CPUE) in 1° latitude/longitude cells, using threshold Generalized Additive Mixed Models (tGAMMs). Model terms were included to account for non-stationary and spatially variable effects of the intervening covariates on albacore CPUE. Results indicate that SST had a positive and spatially variable effect on albacore CPUE, with increasingly positive effects to the North, while PDO had an overall negative effect. Although albacore CPUE increased with SST both before and after a threshold year of 1986, such effect geographically shifted north after 1986. This is the first study to demonstrate the non-stationary spatial dynamics of albacore tuna, linked with a major shift of the North Pacific. Results imply that if ocean temperatures continue to increase, US west coast fisher communities reliant on commercial albacore fisheries are likely to be negatively affected in the southern areas but positively affected in the northern areas, where current albacore landings are highest.

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Developing Objective Operational Definitions for Monitoring Drought

Journal of Applied Meteorology and Climatology ◽

10.1175/2009jamc2088.1 ◽

2009 ◽

Vol 48 (6) ◽

pp. 1217-1229 ◽

Cited By ~ 88

Author(s):

Steven M. Quiring

Keyword(s):

Water Conservation ◽

Standardized Precipitation Index ◽

Meteorological Drought ◽

Severity Index ◽

Decision Makers ◽

Drought Severity ◽

Specific Method ◽

The Standardized Precipitation Index ◽

Spatially Variant ◽

Objective Methodology

Abstract Drought is a complex phenomenon that is difficult to accurately describe because its definition is both spatially variant and context dependent. Decision makers in local, state, and federal agencies commonly use operational drought definitions that are based on specific drought index thresholds to trigger water conservation measures and determine levels of drought assistance. Unfortunately, many state drought plans utilize operational drought definitions that are derived subjectively and therefore may not be appropriate for triggering drought responses. This paper presents an objective methodology for establishing operational drought definitions. The advantages of this methodology are demonstrated by calculating meteorological drought thresholds for the Palmer drought severity index, the standardized precipitation index, and percent of normal precipitation using both station and climate division data from Texas. Results indicate that using subjectively derived operational drought definitions may lead to over- or underestimating true drought severity. Therefore, it is more appropriate to use an objective location-specific method for defining operational drought thresholds.

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