The role of the Amazon Basin moisture in the atmospheric branch of the hydrological cycle: a Lagrangian analysis

Drumond, Anita; Marengo, José A.; Ambrizzi, Tércio; Nieto, Raquel; Moreira, Lorena; Gimeno, Luis

doi:10.5194/hess-18-2577-2014

Cited by 130 publications

(115 citation statements)

References 62 publications

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“…In other words, the 90th percentile criteria would show the 10% grid points with the highest positive (E -P)i10 values in the map. This criterion has been applied for similar purposes in Drumond et al [41], Drumond et al [43], and Drumond et al [44]. The NRB itself was considered a moisture source area.…”

Section: Methodsmentioning

confidence: 99%

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The Niger River Basin Moisture Sources: A Lagrangian Analysis

2017

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Abstract:The Niger River basin (NRB) is located in the important climatic region of the African Sahel. In this study we use the Lagrangian tridimensional model FLEXPART v9.0 to identify and characterise the moisture sources for the NRB. This method allows the integration of the budget of evaporation minus precipitation over 10-day backward trajectories, thereby identifying the origins of the air masses residing over the NRB. The analysis was performed for the 35-year period from 1980 to 2014, which allowed us to identify the main semi-annual climatological moisture sources of the NRB, for November-April (NDJFMA) (dry season) and May-October (MJJASO) (wet season), and to quantify the respective moisture uptakes. Throughout the year, the NRB main moisture sources are located on the tropical eastern North Atlantic Ocean near Africa, the tropical eastern South Atlantic Ocean in the Gulf of Guinea, in the regions surrounding the Sahel and in the Mediterranean Sea. The extents of these sources vary between dry and wet seasons. In NDJFMA two regions appear in the east of the basin, which then join up, forming a larger source to the northeast of the basin in MJJASO, when three other less important moisture sources can be seen in central-equatorial Africa, the tropical western Indian Ocean and the Persian Gulf. In NDJFMA the majority of the moisture uptake comes from the NRB itself but then, later in MJJASO, when the precipitation increases over the basin the greatest uptake of moisture occurs over the tropical eastern South Atlantic Ocean, northeast Africa and the NRB, which suggests that these are the effective sources of precipitation in the basin in overall terms. The seasonal moisture uptake quantification over the moisture sources of the NRB, reveals that largest fraction of moisture income to the basin from outside its boundaries. Despite providing moisture to the NRB the source located in the tropical eastern North Atlantic Ocean does not contribute that much to precipitation in the basin. A daily (ten-day) backward analysis shows the importance of the moisture uptake within the NRB and from near moisture sources during the first few (backward) days, while the Atlantic Ocean sources and the Mediterranean became more important during the last five (backward) days of the analysis.

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Section: Methodsmentioning

confidence: 99%

“…FLEXPART has been applied in the pursuit of similar goals in several regions of the world, including the Sahel [6], the Sahelian Sudan [38], the Orinoco River Basin [39], China [40], the Amazon River Basin [41], and several continental regions [42].…”

Section: Methodsmentioning

confidence: 99%

The Niger River Basin Moisture Sources: A Lagrangian Analysis

2017

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“…FLEXPART has been previously applied for investigating the hydrological cycle at different river basins, as the whole ARB [14], the Congo River basin [22], the Yangtze River basin [23], the Danube River basin [24] and several worldwide river basins [20]. FLEXPART utilizes data from ERA-interim reanalysis datasets [25].…”

Section: Methodsmentioning

confidence: 99%

“…Particularly, moisture transport in and out of the Amazon basin has been studied since the 1990's using a variety of upper air and global reanalyses datasets, as well as from climate model simulations [13]. Drumond et al [14] investigated the annual cycle of the main sources of moisture for the Amazon Basin, as well as its own contribution as a moisture source for the rest of the continent. The diagnosis of moisture sources has become a major research tool in the analysis of extreme events (e.g., floods, droughts), and can be thought of as a basic tool for regional and global climatic assessments [15].…”

Section: Introductionmentioning

confidence: 99%

Drought and wet episodes in Amazonia: the role of atmospheric moisture transport

Sorí

Marengo

Nieto

et al. 2017

Proceedings of First International Electronic Conference on the Hydrological Cycle

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Abstract:The Amazon River basin (ARB) in South America contains the largest rainforest and biodiversity in the world, and plays an important role in the regional and global hydrological cycle. It consists of several sub-basins as the Negro River basin (NRB) in the north and the Madeira River basin (MRB) to the south, both considered of utmost importance in the Amazonia for the Amazon River. The precipitation annual cycle in both basins experiences an opposite annual cycle. Here we utilized the Standardized Precipitation Index (SPEI) to identify drought and wet conditions in the NRB and MRB along the period 1980-2016. Besides, the Lagrangian dispersion model FLEXPART v9.0 was used to track backward in time the air masses residing over the basins and to calculate along the trajectories the budget of (E -P). This permitted to identify those regions from where air masses gain humidity (E -P > 0) before arriving at the basins, what we consider as moisture sources. FLEXPART has been successfully utilized for the same goal in several studies. This study examines the variability of moisture uptake by the basins from these sources during drought and wet episodes in the basins. We consider this a new approach to be a useful method for understanding the causes and variability of drought and wet events in other regions worldwide.

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“…The hydroclimatic regime variability of the AMZ is affected by local climate feedbacks, i.e., the evapotranspiration (ET) plays an important role in the precipitation, and it is affected, as well, for large scale climate patterns, as for example Sea Surface Temperatures (SST) anomalies [10,11,12]. According to [12], the tropical Atlantic is a remote source of humidity for AMZ basin with the northern tropical Atlantic contributing mainly during the austral summer.…”

Section: Introductionmentioning

confidence: 99%

Land use change over Amazon Forest and its impact on the climate

Llopart

Reboita

Rocha

2017

Proceedings of First International Electronic Conference on the Hydrological Cycle

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This study describes the physical processes associated with the impact of the Amazon (AMZ) deforestation on the climate in the north-northwest sector of South America (SA). Two simulations with RegCM4, from 1979 to 2009, were carried out: one using a default land cover map (CTRL) and other one using deforestation scenario (LUC), i.e., all broadleaf evergreen trees tropical were changed by C3 grass. RegCM4 was integrated with a horizontal grid spacing of about 50 km and considering 18 sigma-pressure vertical levels for SA CORDEX domain. The lateral and boundary conditions for driving the model were obtained from the ERA-Interim reanalysis. The climate change signal due to AMZ deforestation was evaluated by comparing the climatology of the CTRL with the LUC experiment. AMZ deforestation causes a dipolar response in the precipitation consisting of reduced (increased) precipitation over western (eastern) side of the basin. Concerning the temperature, there is a warmer anomaly over the deforested areas, and it contributes to decrease the surface pressure. The higher air temperature is associated with an increase of the sensible heat flux and a decrease of the latent heat flux over the deforested areas.

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The role of the Amazon Basin moisture in the atmospheric branch of the hydrological cycle: a Lagrangian analysis

Cited by 130 publications

References 62 publications

The Niger River Basin Moisture Sources: A Lagrangian Analysis

The Niger River Basin Moisture Sources: A Lagrangian Analysis

<strong>Drought and </strong><strong>wet episodes in Amazonia: the role of atmospheric moisture transport</strong>

<span>Land use change over Amazon Forest and its impact on the climate</span>

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