Evaporation tagging and atmospheric water budget analysis with WRF: A regional precipitation recycling study for West Africa

Arnault, Joël; Knoche, R.; Wei, Jianhui; Kunstmann, Harald

doi:10.1002/2015wr017704

Cited by 49 publications

(88 citation statements)

References 61 publications

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“…This is potentially because atmospheric pressure patterns in these regions are more stable, and because these regions may not be important sources of moisture for other areas downwind, preventing the drought signal from propagating farther through reduced moisture exports [e.g. Giannini et al, 2003;Keys et al, 2014;Arnault et al, 2016]. Conversely, short arrows or their absence indicate that there were no regional coherent displacement patterns (e.g.…”

Section: Spatial Patterns Of Drought Displacementmentioning

confidence: 99%

Spatiotemporal dynamics of global drought

Herrera-Estrada

Satoh

Sheffield

2017

Geophysical Research Letters

161

112

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Understanding the evolution and physical drivers of drought is critical to informing forecasting efforts. One aspect that has seldom been explored is the joint evolution of droughts in space and time. Most studies fix the reference area and focus on their temporal variability or study their spatial heterogeneity over fixed durations. This work implements a Lagrangian approach by aggregating contiguous areas under drought into clusters. These clusters become the frame of reference and are tracked as they evolve through space and time. Clusters were identified from soil moisture data from the Climate Forecast System Reanalysis (1979–2009). Evapotranspiration, moisture fluxes, and precipitation were used to explore the relevance of possible mechanisms of drought propagation. While most droughts remain near their origin, the centroid of 10% of clusters traveled at least 1400–3100 km, depending on the continent. This approach also revealed that large‐scale droughts often lock into further growth and intensification.

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Section: Spatial Patterns Of Drought Displacementmentioning

confidence: 99%

Spatiotemporal dynamics of global drought

Herrera-Estrada

Satoh

Sheffield

2017

Geophysical Research Letters

161

112

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“…Notably, while previous moisture tracer configurations in WRF focused on tracking water that evap-J. Eiras-Barca et al: Moisture sources in ARs using WRF tracers orated from a two-dimensional region at the surface (e.g., Dominguez et al, 2016;Arnault et al, 2016), in this study all the moisture in a three-dimensional volume (including the water vapor evaporated and advected into the masked region) is tracked in space and time. For details, see Insua-Costa and Miguez-Macho (2017).…”

Section: The Eulerian Tracer Toolmentioning

confidence: 99%

Evaluation of the moisture sources in two extreme landfalling atmospheric river events using an Eulerian WRF tracers tool

Eiras‐Barca

Domínguez

et al. 2017

Earth Syst. Dynam.

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Abstract.A new 3-D tracer tool is coupled to the WRF model to analyze the origin of the moisture in two extreme atmospheric river (AR) events: the so-called "Great Coastal Gale of 2007" in the Pacific Ocean and the "Great Storm of 1987" in the North Atlantic. Results show that between 80 and 90 % of moisture advected by the ARs, and a high percentage of the total precipitation produced by the systems have a tropical origin. The tropical contribution to precipitation is in general above 50 % and largely exceeds this value in the most affected areas. Local convergence transport is responsible for the remaining moisture and precipitation. The ratio of tropical moisture to total moisture is maximized as the cold front arrives on land. Vertical cross sections of the moisture content suggest that the maximum in tropical humidity does not necessarily coincide with the low-level jet (LLJ) of the extratropical cyclone. Instead, the amount of tropical humidity is maximized in the lowest atmospheric level in southern latitudes and can be located above, below or ahead of the LLJ in northern latitudes in both analyzed cases.

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“…Nevertheless, evaporative source regions for precipitation in the nearby located western Sahel can probably not be diagnosed adequately using the 2-D approximation due to the strong generation of vertical inhomogeneities by surface evaporation and by directional shear [11]. On the other hand, in a recent study Arnault et al [12] describe how local evaporation in WA is not the dominant factor controlling local precipitation over this region. These authors implemented a set of two methods (tracking of tagged atmospheric water species originating from evaporation in a source region, i.e., E-tagging, and three-dimensional budgets of total and tagged atmospheric water species) developed in the weather research and forecasting (WRF) model for investigating regional precipitation recycling mechanisms.…”

Section: Introductionmentioning

confidence: 99%

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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Evaporation tagging and atmospheric water budget analysis with WRF: A regional precipitation recycling study for West Africa

Cited by 49 publications

References 61 publications

Spatiotemporal dynamics of global drought

Spatiotemporal dynamics of global drought

Evaluation of the moisture sources in two extreme landfalling atmospheric river events using an Eulerian WRF tracers tool

The Niger River Basin Moisture Sources: A Lagrangian Analysis

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