The Niger River Basin Moisture Sources: A Lagrangian Analysis

Sorí, Rogert; Nieto, Raquel; Drumond, Anita

doi:10.3390/atmos8020038

Cited by 12 publications

(19 citation statements)

References 45 publications

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“…In Figure 2a,b, light blue line represents the 95% percentile (p95) of annual (E-P) > 0 values; within the line are the 5% of grid points with the highest (E-P) > 0 values of the map which correspond to the (E-P) > 0 values of 0.12 mm/day and 0.15 mm/day for the wet and dry seasons, respectively. Although choosing a contour line is arbitrary, it should not be so large as to include regions with minor effects on precipitation or so small as not to include regions which have a notable effect on precipitation [28,35].…”

Section: Resultsmentioning

confidence: 99%

“…FLEXPART v9.0 developed previously [19,20] is a Lagrangian Particle Dispersion Model. The main advantage of using FLEXPART is its robustness to obtain the budget of (E-P) along air parcel trajectories tracked backward and forward in time and numerous and successful projects have been implemented by this method in the Sahel region [21], Iceland [22], Orinoco river basin [23], Central Brazil [24], Central America [25], China [26], the Danub River Basin [27], and the Niger River Basin [28]. In this study, the goal is to identify Iran's sources of moisture during the dry (May to October) and wet (November to April) seasons and to calculate the moisture uptake from these sources.…”

Section: Introductionmentioning

confidence: 99%

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The Identification of Iran’s Moisture Sources Using a Lagrangian Particle Dispersion Model

et al. 2018

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Iran has faced many water shortage crises in the past. Iran’s moisture sources for precipitation were identified by Lagrangian approach using the FLEXible PARTicle dispersion model (FLEXPART) v9.0 model. The results demonstrate that Iran receives its moisture from both continental and oceanic sources. During the wet season, moisture uptake from the Arabian Sea, the Persian Gulf, and the Mediterranean Sea is dominant, while during the dry season, the role of the Red Sea, the Caspian Sea, and the Persian Gulf is intensified. Studying drought conditions by comparing 1-month, 6-month, and 12-month standardized precipitation index (SPI) with (E-P) values of oceanic and continental moisture sources (E stands for the evaporation and P the precipitation) using multiregression model demonstrates that among oceanic sources the Arabian Sea, the Persian Gulf, the Mediterranean Sea, and the Indian Ocean affect SPI values and among continental sources, moisture from bare grounds and cultivated lands influences SPI values during wet season. However, no correlation exists between oceanic and continental (E-P) and SPI values during the dry season. The results obtained by this study can be used by meteorologists and hydrology scientists for future water management programmes in Iran.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Identification of Iran’s Moisture Sources Using a Lagrangian Particle Dispersion Model

et al. 2018

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“…To delimit the most important seasonal moisture sources according to the moisture uptake intensity, a percentile method was applied. This approach has been previously utilised for the same objective by several authors [28,46,47]. The sources are separated into marine and continental, which further allows comparing the amount of moisture uptake ((E − P) > 0) over each one.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the outputs of this model can be used to compute the gain and loss of moisture along air particle trajectories [1]. This model has been widely and successfully utilized in many projects in different parts of the world [21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

The Role of Moisture Sources and Climatic Teleconnections in Northeastern and South-Central Iran’s Hydro-Climatology

Heydarizad

Raeisi

Sorí

et al. 2018

Water

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Iran faces climate disparities due to extreme topographic anomalies, the Caspian Sea and the Persian Gulf water bodies, influences from diverse air masses and moisture sources, and its considerable area. FLEXPART model has been utilized to determine the main marine and continental moisture sources for south-central (Shiraz box) and northeastern (Mashhad box) parts of Iran. The marine moisture sources directly influenced extreme drought and wet conditions in Shiraz and Mashhad boxes during the wet period, while no correlation was observed during the dry period. In addition to local components, extreme drought and wet conditions have also been influenced by the climatic teleconnections. Extreme drought conditions mainly occurred during the La Niña phase, while wet conditions mainly occurred during the El Niño phase. Scrutinizing the effect of marine moisture sources on the hydrology of water resources demonstrated that the moisture contribution from the Arabian Sea directly influenced the discharges of Chenar-rahdar (in the Shiraz box) and Kardeh (in the Mashhad box) rivers during the wet period. However, the Red Sea inversely correlated with the discharges of both rivers during the dry period. Hydrogeologists, hydrologists, and meteorologists can utilize the outputs of this survey to develop climatology and hydrology models in the future.

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“…The determining factors are the positional shifts in the African Easterly Jet and West African Westerly Jet (AEJ and WAWJ, respectively), the African easterly waves and the Intertropical Convergence Zone (ITCZ) [6,8,9]. For West Africa (WA) and the NRB, dry season approximately occurs from November to April and rainy season from May to October [10,11]. Observed changes in the onset and demise of seasonal rains over WA and the Sahel region during the last few decades have been documented and are a discernible indication of climate change [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

On the Connection between Atmospheric Moisture Transport and Dry Conditions in Rainfall Climatological Zones of the Niger River Basin

Sorí

Nieto

Drumond

et al. 2019

Water

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The hydroclimatology of the Niger River basin, located in West Africa, is very complex. It has been widely studied because of its importance to the socioeconomic activities of the countries that share its natural resources. In this study, to better understand the causes and mechanisms that modulate the rainfall over the Niger River basin, we identified the most relevant moisture sources for precipitation within the basin. The Lagrangian model FLEXPART was utilised to track backward trajectories of air parcels initially losing humidity over climatological rainfall zones of the basin. Along 10-day backward trajectories, we computed the budget of the difference between evaporation and precipitation (E − P) from 1000 to 0.1 hPa, permitting the identification of those regions where moisture uptake ((E − P) > 0) prevail. The study was conducted for the period 1980–2017. Monthly maps of ((E − P) > 0 were developed to illustrate the regions from where moisture is transported, contributing to precipitation in the Niger River basin. The spatial variability of the sources matches the precipitation variability over the basin restricted to surrounding areas of the Niger River basin during months with low average precipitation and widely spreading over the continent and the Atlantic Ocean in months with high average precipitation. During climatological dry months (e.g., December, January and February) the continental sources of West and Northeast Africa and the climatological rainfall zones themselves provide most of the moisture for precipitation. However, during the rainy season, the moisture supplies from oceanic sources increase, becoming greater than the contribution from land-based sources during August (the rainiest month). Dry conditions were identified for each climatological rainfall zone using the Standardised Precipitation Index. Similar to many previous studies, we found that the 1980s were highlighted by dry conditions. Local recycling and particularly moisture uptake from the tropical South Atlantic Ocean seem to be highly related to dry and wet conditions in the basin. A reduction on the moisture uptake from surrounding continental sources and the tropical South Atlantic Ocean is almost persistent during extremely dry conditions. Ascending movements are restricted to the lower troposphere during extremely dry conditions and oscillate latitudinally as well as precipitation.

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The Niger River Basin Moisture Sources: A Lagrangian Analysis

Cited by 12 publications

References 45 publications

The Identification of Iran’s Moisture Sources Using a Lagrangian Particle Dispersion Model

The Identification of Iran’s Moisture Sources Using a Lagrangian Particle Dispersion Model

The Role of Moisture Sources and Climatic Teleconnections in Northeastern and South-Central Iran’s Hydro-Climatology

On the Connection between Atmospheric Moisture Transport and Dry Conditions in Rainfall Climatological Zones of the Niger River Basin

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