Navigation – Plan du site

Dune fields in Jericoacoara: human intervention as a possible indicator of changes in the morphological dynamics

Champs de dunes à Jericoacoara: les interventions humaines comme indicateur possible de changement dans la dynamique morphologique
Campos de dunas em Jericoacoara: intervenções humanas como possível indicador de mudança na dinâmica morfológica
Antonio Jeovah Meireles, Adryane Gorayeb et Narcélio de Sá Pereira Filho
Traduction(s) :
Campos de dunas em Jericoacoara: intervenções humanas como possível indicador de mudança na dinâmica morfológica

Résumés

Les dunes côtières ont un rôle important dans le transport des sédiments dans la zone côtière. La morphologie du parc national Jericoacoara dans l’État nordesti du Ceará est un promontoire couvert par un champ de dune mobile avec de champs grands de dunes barkhanes qui migrent d’est en ouest. Ces dunes sont responsables du contournement et du transport des sédiments, essentiales pour la maintenance du littoral sans des effets érosifs. Cette étude est concentrée sur la évolution morpho-dynamique de ces dunes mobiles isolées, par la récupération des images multi-temporelles des satellites Landsat et QuickBird des années 1975 a 2010. La analyse spatiotemporelle de la distribution et morphologie de ces dunes pendant ce période de 35 ans a révélé des changes significatifs en leur surface, périmètre e modèles de mouvement. Il était possible confirmer que la circulation de matériel et énergie est liée a un processus continu de migration en direction a la plage. Le dynamique de la migration des dunes en les années depuis 2000 a été établi et indique possibles impacts sur la morphologie des dunes résultant du augmentation du tourisme dans le région. Ces changes ont été plus significatifs entre 2001 et 2005, peut-être comme un résultat des impacts anthropiques.

Haut de page

Notes de la rédaction

Uma tradução em português do texto encontra-se no artigo "Campos de dunas em Jericoacoara: intervenções humanas como possível indicador de mudança na dinâmica morfológica"no mesmo número da revista.

Texte intégral

Lagoa e dunas no CearáAfficher l’image
Crédits : Hervé Théry 2009

1Coastal dunes are morphological features derived from complex interactions between topography, vegetation, sediment sources, climatic conditions, and eolian processes, as well as the influence of human activities. Understanding the origin and quaternary evolution of these features requires the systematic analysis of a complex set of environmental and socio-economic elements. Coastal dunes are also important in integrated approaches of the analysis of coastal landscapes, principally with regard to the habitats and sediments they provide, which contribute to the control of coastal erosion (Andrews and Gares 2002, Montreuil and Bullard 2011, IPCC 2013).

2Barchans dunes have been the subject of numerous studies around the world and are the best-known type of dune. The half-moon shape of these dunes is derived from a combination of continuous wind action in the same direction over the course of the year and the absence of enough sand to cover the entire surface (Herrmann et al. 2005). The movement of these dunes is proportional to wind speeds and inversely proportional to their height (Meireles et al. 2006, Jimenez 1999, Lima and Sauermann 2002).

3A number of studies have focused on different aspects of barchans dunes, such as their genesis, evolution, dynamics, and geomorphology (Parteli et al. 2014, Komar et al. 2011, Cooper et al. 2007 and Sauermann et al. 2003), although few data are available on long-term patterns. Most of the available studies on the dynamics of dune morphology have focused on short to medium-term periods (Hesp 2013, Al-Masrahy and Mountney 2013, Bishop 2010, Cabrera-Vega 2013, Yizhaq 2013, Carter et al. 1997).

4Recent technological advances allow ever more detailed analyses of coastal systems, in particular, dune fields and their morphological diversity. The multitemporal coverage of high-resolution satellite images provides new insights into the behavior of dune fields in relation to their distribution, as well as precise measurements of the movements of mobile dunes (Andrews and Gares 2002, Woolard and Colby 2002). The advent of Geographic Information Systems (GIS) provided potential for a range of analytic approaches, which have been amplified and perfected over the years through technological improvements in computing hardware and GIS software (Al-Masrahy and Mountney 2002, Andrews and Gares 2002).

5This study presents a 35-year history (1975-2010) of the evolution of a barchans dune field based on multitemporal recovery of a series of medium and high-resolution satellite images (Landsat and Quickbird) covering the Jericoacoara National Park in Ceará, Brazil. The objective was to describe and quantify the morphodynamic changes that occurred in the dunes over the course of this period, evaluate changes in morphology (area, perimeter, and shape), and movement patterns (evolution of the mobile dunes). It was also possible to characterize the dynamics of the local environment in relation to the modifications caused by the impacts of the ongoing increase in tourism-related activities in the region.

Study area

6The State of Ceará, located in northeastern Brazil, has a coastline of approximately 572 km, consisting predominantly of extensive sandy beaches interrupted primarily by small estuaries and rocky points. Extensive fixed and mobile dune fields are found along the whole coast.

7The study area is located on the coastal plain of Jericoacoara in the northern extreme of the state, which includes parts of the municipalities of Jijoca de Jericoacoara, Cruz, and Camocim, approximately 300 km west of the state capital, Fortaleza. The area includes most of the Jericoacoara National Park, an integral protection conservation unit established on February 4th, 2002, with a total area of 8416.08 ha (Figure 1).

8The principal features of this environment are dunes, lagoons and coastal lakes, estuaries, mangrove forests and paleo-mangrove (muddy beaches), tidal channels, marine terraces, promontories, abrasion shelves, pre-coastal plateaus, and rocky and sandy beaches. These morphological components indicate the occurrence of eustatic events, reflecting the interaction of mainland-oceanic-atmospheric processes in the formation of the coastal plain. Together with fluctuations in climate and relative sea level, dynamic processes can be discerned in relation to sediment transport by wind action, estuarine hydrodynamics, and seasonal fluctuations in groundwater levels, landslides and slips on the slopes of the Jericoacoara Ridge, as well as waves and tides (Meireles 2011). The present study includes a short analysis of local socio-economic and cultural activities related to tourism, fisheries, and subsistence agriculture. These data were used to evaluate possible anthropogenic influences on the speed and direction of dune migration.

Figure 1. Location of the study area in Ceará, northeastern Brazil.

Figure 1. Location of the study area in Ceará, northeastern Brazil.

Climatic characteristics

9The coastal plain of Jericoacoara is characterized by a set of morphological units directly related to local and regional climate patterns. Wind action, seasonal rainfall fluctuations, and intense solar radiation; all these factors contribute to the dynamics of sediment transport, the formation of coastal lakes, and the ecological configuration of the fauna and flora of the national park.

10The winds of this region are influenced by a marked annual climate cycle, related to seasonal fluctuations in the position of the Intertropical Convergence Zone (ITCZ), which are determined by the confluence of the northeasterly and southeasterly trade winds, resulting in intense cloud cover and low atmospheric pressure (Philander and Pacanowski 1986).

11The annual variation in rainfall levels is determined by seasonal shifts in the location of the ITCZ, the principal synoptic system determining precipitation patterns in the region, which provokes intense rains during part of the year, depending on its position. While there is some variation, these rains normally fall during the first half of the year, mainly between March and May (Brandão 1995). Dry anomalies in northeastern Brazil correlate with negative sea surface temperature (SST) anomalies in the southern tropical Atlantic and positive anomalies in the northern tropical Atlantic. This SST pattern strengthens the southeast trade winds, displacing the ITCZ to the north (Moura and Shukla 1981, Nobre and Shukla 1996, Wang et al. 2004).

12Mean annual precipitation in the region is approximately 823.8 mm (IPECE, 2014), with a rainy season concentrated into a five-month period, which usually begins in February, reaching its highest monthly levels in March and April. Rainfall tends to decrease from July on and remains low until November (Figure 2). Typically, 90% of annual precipitation is recorded during the first half of the year (Zanella 2005).

13Wind is an important component of the natural dynamics of coastal landscapes and plays an important role in the composition of local morphology, principally in relation to the migration of dune fields and the input of sand for the eolian abrasion plain. The prevailing winds on this coastal plain blow from the SE, ESE, E, and NE. Mean wind speeds may exceed 4 m/s during the dry season (second half of the year). During the rainy season, the ITCZ – the primary factor determining the amount of rainfall on the northern coast of the Brazilian Northeast – migrates from its northernmost position, at approximately 14°N (August—October) to its southernmost position, at approximately 2–4°S, between February and April (Melo and Ferreira, 2005). During this cycle, the prevailing winds change direction, blowing predominantly from the northeast (Figure 2); during the dry season, the winds tend to be more intense, blowing from the southeast. The average speed of winds in Jericoacoara is 4.8 ms-1, with frequent records of speeds exceeding 10 ms-1 (Maia, et al., 2000; Carvalho and Santos 2010).

14The integration of rainfall levels, wind speeds, and sunlight intensity provides an important index for the analysis of the morphogenetic dynamics of the coastal plain located within the study area. During the first half of the year, increased rainfall levels are accompanied by a reduction in wind speeds and a reduced incidence of solar radiation. During the second half of the year, reduced rainfall is reflected in increased wind speeds and more intense sunlight. This combination of factors contributes to the more effective displacement of the dunes during the second half of the year, together with a reduction of the hydrostatic level of the water table, and, as a consequence, the number of lakes on the coastal plain.

Fig. 2. Study area location and preferred direction of marine currents (

Fig. 2. Study area location and preferred direction of marine currents (

a); monthly variation in mean precipitation, wind trade and direction in the study area (b) and annual variation of rainfall with a tendency to a decrease (c). NBC, North Brazil Current; BC, Brazil Current; SEC, South Equatorial Current.

Material and methods

15Recent historical-scale (decadal) change in the coastal dune field of Jericoacoara was examined using satellite images to set the approximate average of migrating barchans dunes, climatic data, and anthropogenic impacts, to investigate its relationship with the trends in dune stability.

16Satellite images, GPS stations, and geoprocessing techniques were used to obtain data on the morphodynamic evolution of the dunes of the study area. The migration of the dunes located in the study area was estimated based on the analysis of a series of satellite images from the period within 1975 and 2010. Three individual dunes were identified from the set of images for analysis. The migration of these dunes was measured based on the configuration of a set of points located around the perimeter of the dunes in each year, which allowed the measurement of the displacement of the dune, a procedure successfully used in previous studies in the same area (Jimenez 1999). Restrictions regarding methodology and limits of a quantitative comparative interpretation of satellite images with a different resolution were overcome by the integration of satellite images and data collected by a Geodesic GPS in field activities. To compare images with different pixel sizes (resolution), it was necessary to define the midline of the texture contrast between the wind sediments mobility (mobile dunes morphology) and their contours in contrast with the soil of the Coastal Plain. For a more precise spatial precision of the images, it would be necessary to resize the images to a common spatial resolution.

Satellite images

17A total of 20 medium and high-resolution satellite images of the study dunes were obtained for the 35-year period between 1975 and 2010. The Landsat images were acquired from the DGI/INPE collection (www.dgi.inpe.br/siteDgi/index_pt.php), which is available online in the TIF format. The images obtained referred to scene 234/062 of the Landsat 1-MSS satellite for 1975, Landsat 2-MSS (for 1979,1980, and 1981), and scene 218/62 of the Landsat 5-TM (for 1985, 1987, 1991, 1992, 1993, 1994,1999, 2000, 2001, 2002, 2006, 2007, 2008, and 2010) and Landsat 7-ETM+, as well as a Quickbird image from 2005 (Table 1). The morphological components of the coastal plain were defined using an SRTM radar image obtained from the National Aeronautics and Space Administration (NASA).

Table 1. Satellite images used for the extraction of spatial data and the definition of the displacement of the dune fields on the Jericoacoara coastal plain.

Date

Satellite

Sensor

Bands

Resolution

Composition

26/05/1975

Landsat

MSS

4, 5, 6,7

80m

5R, 4G, 6B

07/07/1979

Landsat

MSS

4, 5, 6,7

80m

5R, 4G, 6B

06/08/1980

Landsat

MSS

4, 5, 6,7

80m

5R, 4G, 6B

07/14/1981

Landsat

MSS

4, 5, 6,7

80m

5R, 4G, 6B

27/07/1985

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

17/07/1987

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

10/06/1991

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

31/08/1992

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

10/06/1993

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

10/06/1994

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

10/06/1999

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

Geocover Nasa

Landsat

ETM+

1, 2, 3, 4, 5, 6, 7, PAN

15m

2R, 4G, 7B + PAN

19/08/2000

Landsat

ETM+

1, 2, 3, 4, 5, 6, 7, PAN

15m

5R, 4G, 3B + PAN

01/09/2001

Landsat

ETM+

1, 2, 3, 4, 5, 6, 7, PAN

15m

5R, 4G, 3B + PAN

19/08/2002

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

2005

QuickBird

0,70m

22/06/2006

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

25/08/2007

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

12/09/2008

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

30/09/2010

Landsat

TM

1, 2, 3, 4, 5, 6,7

30m

5R, 4G, 3B

Source:www.dgi.inpe.br/siteDgi/index_pt.php

18All the images were georeferenced and treated with ENVI 4.7, based on the UTM (Universal Transverso de Mercator) cartographic projection, with the WGS-84 Datum. Georeferencing was based on the mosaic of Landsat ETM+ images for 2000, available in NASA’s Geocover program. The precision of the existing georeferencing was defined using GPS stations. In the case of the high-resolution Quickbrid images, precise geographic information was extracted using Navstar GPS geodesic receivers, with a nominal precision of 5 mm + 1 ppm. The data were processed in the maker’s software. Ground support for the determination of the planialtimetric coordinates used for georeferencing and for the generation of contours was obtained from the Ceará state GPS reference station in the town of Sobral, 100 kilometers to the south. The points were tracked using the cinematic method, with a 5-second recording interval. The “bar” method was used for initialization, as recommended by the maker, with single frequency receptors.

19The composite georeferenced images allowed the creation of overlapping images in a GIS environment in the QGIS software. The images were superimposed for the definition of the dune displacement patterns, and, by the use of the transparency resource, it was possible to compare the morphological alterations that occurred during the migration process. These data were digitalized in the form of vector shapefiles and processed using geoprocessing techniques for the calculation of the area and perimeter of each dune during each phase of the study period.

Results and discussion

20The initial results included the spatial distribution of the different geo-environmental components of the study dunes (Figure 3). Based on a spatiotemporal comparison of the dune morphology between 1975 and 2010, significant changes were found in the area, perimeter, and movement patterns of all dunes. It was possible to confirm the constant flow of material and energy linked to the continuous migration of the dunes in the direction of the beach (sediment bypassing sector). A general tendency for a reduction in the area of the dunes and frequent and complex alterations of their perimeters were observed, mainly in the areas closest to the urban environment of the main village and the Jericoacoara Ridge.

Figure 3. Geo-environmental components of the study dunes

Figure 3. Geo-environmental components of the study dunes

(Meireles et al, 2005).

21The Pôr do Sol dune (DDPS), which had a mean area of 198,472 m² between 2005 and 2010, decreased in size by approximately 18,500 m², due to the constant deficit of sediments that occurred during its movement. This was related to the fact that the dune was moving over the promontory and had reached the beach bypass sector, where the sediments become transported by wave, rather than wind forces, in the early 1990s. During this period, the perimeter was consistently of the order of 3331 m. In recent years, the perimeter has tended to expand due to the increasing complexity of the dune’s shape, which may be related to the alteration in the dynamics of sediment transport, occurring since the dune reached the edge of the beach (avalanche slope in contact with the waves), and the interference in wind dynamics, caused by the physical barrier of the Jericoacoara Ridge.

22During the same period, the decrease in the area of the Papai Noel dune (DPN), which covered a mean area of 380,562 m², was of the order of 61,100 m². Simultaneously, there was a reduction in the perimeter of the order of 663 m (with a tendency to maintain the barchans morphology). In recent years, possibly since 2001, the perimeter has remained relatively constant, with a mean value of 3373 m.

23During the study period (1975-2010), the Arraia dune (DA) decreased in area by approximately 71,545.5 m². During this same period, it was possible to identify an increase in the perimeter of the dune of the order of only 193.5 m (lowest value), reflecting its more compact shape, despite the fact that it was the largest of the dunes studied here, with a mean area of approximately 419,050 m².

24The reduction in the area of the dunes analyzed in the present study may be associated with the dispersal of sediments by the action of winds and waves, principally in the case of PdS. While winds provoke the displacement of the dunes, they also remove sand from the body of the dune (effects of the transport of suspended sand by winds of higher speed), especially during the second half of the year, when mean speeds may reach 8 m/s (ANNEL 2015) and rainfall is negligible.

25The DDPS dune moved 12 m⋅y-1, on average, to the south of the Jericoacoara Ridge within 1975 and 2010, with an overall displacement of approximately 350 m. Within the years of 2005 and 2010, however, the total displacement was only 50 m, with a mean value of 10 m⋅y-1 (Figure 4). The DPN dune migrated more rapidly than DPDS, with a mean displacement of 16 m⋅y-1, for a total of 470 m over the study period. By contrast with DPDS, this dune migrated more rapidly over the last 5 years of the study period, moving 22 m⋅y-1, for a total of 110 m (Figure 5).

Figure 4. Displacement of the DDPS based on the 2005 Quickbird image and tendency curve plotted for the study period.

Figure 4. Displacement of the DDPS based on the 2005 Quickbird image and tendency curve plotted for the study period.

Figure 5. Displacement of the DPN, based on the 2005 QuickBird image and tendency curve plotted for the study period.

Figure 5. Displacement of the DPN, based on the 2005 QuickBird image and tendency curve plotted for the study period.

26The DA dune moved over the Jericoacoara promontory to the southeast of the other dunes and, like these dunes, presented a distinct pattern of displacement over the last 5 years of the study period, with a mean displacement of 30 m⋅y-1 (total of 150 m), the fastest speed recorded among the dunes. During earlier years, this dune migrated more slowly, however, with a mean value of only 10,6 m⋅y-1, and a total displacement, for the 35 years of the study period, of only 320 m (Figure 6). Overall, the data indicate that the size of the dune does not have a direct influence on its displacement velocity.

Fig. 6. Displacement of the DA dune based on the 2005 QuickBird image and tendency curve plotted for the study period.

Fig. 6. Displacement of the DA dune based on the 2005 QuickBird image and tendency curve plotted for the study period.

27It seems likely that the increase in tourism within the study area, principally following the establishment of the national park (that is, from 2000 onwards), led to an increase in the numbers of visitors to the PDPS dune (Meireles et al 2011) , which attracts large numbers of tourists, who, at the end of each day, climb up to the top of the avalanche slope of the dune to watch the sunset. An increase in the process of gravity-induced sediment slide can be observed when visitors descend the dune, provoking significant alterations in its morphology.

28The results presented here on area, perimeter, and displacement speed of the study dunes are the first long-term data on these phenomena based on the analysis of satellite images. The observed tendency of increased displacement speed during the last 5 years of the study period may be related to the ongoing growth in the influx of tourists (Figure7). In addition to a considerable increase in the numbers of tourists, growing numbers of all-terrain vehicles have been transiting through the area of the PNJ (Priskin 2003, Meireles et al. 2013).

Figure 7. Accumulated displacement of the dune field.

Figure 7. Accumulated displacement of the dune field.

29Shifting wind patterns and corresponding ocean changes can explain climate responses across the continent. This fact, the gradual decrease in area, could be an inductor of different changes in the littoral processes in the regions. And it can be possibly influenced by the intertropical convergence zone (ITCZ), changing the water balance (rainfall and groundwater), the standard for winds and, altering the behavior of the dynamics regional winds (Provoost, et al. 2011, Jakson and Cooper 2011). Also, it will probably work in a network with sediment transport agents. The most intense winds linked to more arid climate trends by climate change also influenced wind transport, potentializing the decline in rainfall. Millennial temperature variations were related to reorganizations of the ocean-atmosphere system in the last glacial period, global in scope and in the tropics. (Peterson et al. 2011, Sydeman et al. 2014). During the last glacial period, Earth’s climate underwent frequent large and abrupt global changes. This behavior seems to reflect the ability of the ocean’s thermohaline circulation to assume more than one mode of operation (Barker et al. 2009, Broecker, 1997).

30The systematic analysis of the data on mean wind velocities and climatic variation presented here may provide the basis for the identification of regional or global patterns, such as those identified by IPCC (2013). The promontory (Jericoacoara headland) has a clear effect on wind dynamics and sediment transport and, thus, on the speed of dune displacement. The dunes closest to the beach and to the ridge move the slowest (Figure 8). It is important to note that abrupt changes in the type of coast (promontory, cliffs, deltas, for example) and its outline may cause marked changes in the configuration of local waves and winds, imposing a specific pattern of sediment transport on this stretch of the littoral. This transport is responsible for longitudinal sandbars, banks, and sandy spits, in the fore and backshores, interfering in the eolian transport of the sand. These morphological features together with the sand bypass through the dunes in the promontories are also directly affected by the action of the waves and tides (Mclachlan and Burns 1992 and Cacho et al. 1999). As it was determined that in our study area there was an increase in the velocity of the dunes of contemporary migration, it is possible to show its relationship with climate change (Ashkenazy et al. 2012, Singhvi et al, 2010). In the places where there was increased rainfall, it was possible to detect a tendency for fixing the dune field (increased precipitation and decreased wind velocity) (Jackson and Cooper 2011). It was found, in the dunes field of Jericoacoara, a trend of increased migration velocity of dunes away from morphological interference (Jericoacoara headland). The year of 2005 was, thus, demarcated as the trigger year for the increase in the migration speed of the dunes. The dynamics of the dune migrations recorded prior to 2005 should be re-analyzed in more detail and over a broader timescale to provide a more reliable analysis of the possible link with climate change.

Figure 8. Morphological features of the study area and their influence on the dynamics of the local barchans dunes.

Figure 8. Morphological features of the study area and their influence on the dynamics of the local barchans dunes.

31The dunes migrate preferably in conditions of low rainfall, high solar radiation and wind speed (in the study area, these conditions occur in the second half of the year), therefore, ruled by atmospheric components altered by human activities (Mendoza-Gonzalez, et al.). The possibility of a reduced Atlantic thermohaline circulation in response to increases in greenhouse-gas concentrations has been demonstrated in a number of simulations with general circulation models of the coupled ocean-atmosphere system (Clark 2002). It has been possible to detect an increasing displacement in the migration process in barchans dunes. Considering the short time of the monitoring, it was possible to just demonstrate a tendency, but it is possible to define the relationship between climate change and migration of the dunes. The water cycle of coastal ecosystems is likely to be affected by the combination of altered precipitation and sea level rise as climate change proceeds (Greaver and Sternberg 2010).

32Finally, the data demonstrated the tendency of sectors (DDPS and DPN) increase in migration velocity (increasing the action of the wind, the higher insolation and decreased rainfall), which might provide in the medium term, taking as based on the climatic evolution indicators systematized in IPCC (2014), the decrease in volume of wind sediments in the coastal plain (Figure 9). Process incremented by sea level rise (less sand supply to feed the bypassing sectors) and conjugated by other environmental systems associated with the dune field (Meireles et al. 2005, Ewinrc and Kocurek 2010).

Figure 9. Evolution of the reduction area (m) of the dune bodies as possible indicator of decreased sediment source.

Figure 9. Evolution of the reduction area (m) of the dune bodies as possible indicator of decreased sediment source.

Conclusion

33The application of geoprocessing techniques for the mapping of the morphodynamic evolution of the dune field of the Jericoacoara National Park provided an essential tool for the production of diagnostic guidelines for the ongoing planning of the park’s environmental management. In particular, the spatial dynamics and evolution of the displacement of the local mobile dunes were configured.

34The environmental components of the coastal morphological features related to the sediment bypass sectors linked to the beach were diagnosed and characterized. The comparison of satellite images obtained between 1975 and 2010 allowed the identification of significant changes in the physiographic features - area and perimeter - of the local dunes. These changes were more prominent in the period between 2001 and 2005, which may be related to an increase in anthropogenic impacts (numbers of tourists). These impacts included an increase in the traffic of all-terrain vehicles and the appearance of random trails leading to the village of Jericoacoara, the degradation of sediment-anchoring vegetation, compaction of the soil, reactivation of sediment transport, and larger numbers of visitors walking on the mobile dunes, in particular, on the DPDS.

35The results of this study reinforce the need for a more detailed investigation, including the definition of sectoral shifts in seawater temperatures related to the long-distance continent-ocean-atmosphere connections with higher latitudes (Broecker 2001). The dunes of Jericoacoara, related to the evidence of high-frequency changes in relative sea levels, may be linked to the abrupt and cyclical alterations in the temperature of the oceans. This evidence is possibly superimposed by higher orbital cycles, such as the Dansgaard-Oeschger cycles and Younger Dryas cooling event, and general circulation models of the coupled ocean-atmosphere system (Cacho et al. 1999, Montreuil and Bullard 2011). We also believe it is necessary to investigate the seasonality of migration of the barchans dune field through the rhythm of the oscillations of the water table level (Luna et al. 2012), governed by alternations between the two annual well-defined meteorological stations - the first station, with rain and milder winds (in the first half of the year), and, in the second half, dry and competent winds that intensify the migration of the dune field.

36However, it was not possible to correlate regional climate models to determine the evolution of the Neogene sedimentary processes on the continental shelf and on the fluctuations of the aquifers that possibly interfere with the migration of the barchans dune field. It is concluded, therefore, that the deficient results of this research could be clarified by conducting a stratigraphic and isotopic analysis of the likely rhythmic overlay of revealing sediment deposition associated with high frequency alternating climate.

37Overall, the results of this study provide important insights into coastal dynamics and the impacts on these processes provoked by an increase in tourism activities. Given this, further studies on the regional and global meteorological processes related to this dynamic will be important for the understanding of the influence of climatic changes on the evolution of coastal dunes. These data will be fundamental to the effective monitoring of the evolution of the dunes of the study area through multitemporal analysis of satellite images. In brief, the spatiotemporal approach has restrictions that limit the accuracy of the predictions for future, but the method can be supplied with a larger database on dune dynamics linked to climate change and sea level along the coastal area of northeastern Brazil, and thus improve the definition of defined results for coastal plain of Jericoacoara.

Haut de page

Bibliographie

Al-MASRAHY, M.A. AND MOUNTNEY, N.P.. Remote sensing of spatial variability in aeolian dune and interdune morphology in the Rub’ Al-Khali, Saudi Arabia. Aeolian Research, v.11, 155–170, 2013.

ANDREWS B., GARES P.A. AND COLBY, J. D. 2002 Techniques for GIS modeling of coastal dunes. Geomorphology, v. 48, nº 1-3, 289–308, 2012.

ANNEL. 2015. Agência Nacional de Energia Elétrica. Relatórios 2003 e 2006. Obtidos através de www.aneel. gov.br/15.htm [consulta realizada 22 junho de 2015].

ASHKENAZY, Y., YIZHAQ, H. AND TSOAR, H. 2012. Sand dune mobility under climate change in the Kalahari and Australian deserts. Climatic Change, 2012, v. 112, p.901–923, DOI 10.1007/s10584-011-0264-9.

BARKER, S., DIZ P., VAUTRA,V.M.J, PIKE J., KNORR, G.H. AND BROECKER, W.S.. Interhemispheric Atlantic seesaw response during the last deglaciation. Nature, v.457, 1097-1101, 2009.

BISHOP, M.A. Nearest neighbor analysis of mega-barchanoid dunes, Ar Rub’ al Khali, sand sea: The application of geographical indices to the understanding of dune field self-organization, maturity and environmental change. Geomorphology, v. 120, n° 3-4, 186–194, 2010.

BITTENCOURT, A.C.S.P.; MARTIN, L.; VILAS BOAS, G.S. y FLEXOR, G.M. Quaternary marine formations of the coast of the State of Bahia (Brazil). Simpósio Internacional sobre a Evolução Costeira no Quaternário, São Paulo (SP). Atas, 1979, 232-253, 1979.

BRANDÃO R.L. 1995. Sistema de Informações para Gestão e Administração Territorial da Região Metropolitana de Fortaleza - Projeto SINFOR: Diagnóstico Geoambiental e os Principais Problemas de Ocupação do Meio Físico da Região Metropolitana de Fortaleza. Serviço Geológico Brasileiro, Companhia de Pequisa e Recursos Minerais CPRM, 100p.

BROECKER, W.S. Thermohaline Circulation, the Achilles Heel of Our Climate System: Will Man-Made CO2 Upset the Current Balance? Science, v. 278, 1582-1588, 1997.

BROECKER, W.S. Was the medieval warm period global? Science, v. 291, 1497-1499, 2001.

CABRERA-VEGA, L. Morphological changes in dunes as an indicator of anthropogenic interferences in arid dune fields. Journal of Coastal Research, v. 65, 1271–1276, 2013.

CACHO, I., GRIMALT, J.O, PELEJERO, C., CANALS, M., SIERRO, F.J, FLORES, J.A. AND SHACKLETON, N.J. Dansgaard-Oeschger and Heinrich event imprints in Alboran Sea temperatures. Paleoceanography, v. 14, 698-705, 1999.

CARTER, R.W.G, HESP P.A. AND NODSTROM, K.F. Erosional landforms in coastal dunes. Ed. by Nords- trom, KF; Psuty, N. & Carter. Bill. Coastal dune – from and process, 217- 250, 1997.

CARTER, R.W.G. Near-future sea-level impacts on coastal dune landscapes. Landscape Ecology, v. 6, 29–39, 1991.

CARVALHO, I.V, SANTOS, J.S. 2010. Análise da velocidade do vento em dois municípios da costa do estado do Ceará – Jericoacoara e Beberibe. Available in http://connepi.ifal.edu.br/ocs/index.php/connepi/CONNEPI2010/paper/view/665. Accessed in 10 April 2016.

COOPER, J.A.G, MCKENNA, J., JACKSON, D.W.T AND O’CONNOR, M. 2007. Mesoscale coastal behavior related to morphological self-adjustment. Geology, 35: 187-190.

CRISTIANSEN, C., DALSGAARD, K., MOLLER, J.T AND BOWMAN, A.D. Coastal dune in denwark chronology in relation to sea level. In: Bakker, T.W., Jungerives, P.D. y Klijn, J.A. (ed.), Dunes of European coasts–Geomorphology–Hydrology– Soils. Journal of the international society of Soil Science, Supplement, v.18, p.61-70, 1990.

EWINRC, R.C. AND KOCUREK, G. Aeolian dune-field pattern boundary conditions. Geomorphology, v. 114, 175–187, 2010.

GREAVER, T.L, STERNBERG, L.S.L. Decreased precipitation exacerbates the effects of sea level on coastal sand dunes. Global Change Biology, v.16, 1860–1869, 2010.

HERRMANN, H.J, SAUERMANN, G. AND SCHWÄMMLE, V. The morphology of dunes. Physica A: Statistical Mechanics and its Applications, 258: 1, 2005, 30–38.

HESP, P.A. Conceptual models of the evolution of transgressive dune field systems. Geomorphology, v. 199, 138–149, 2013.

IPCC 2013. Climate Change. The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovern- mental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp, 2013.

IPECE. Instituto de Pesquisa e Estratégia Econômica do Ceará. Perfil básico municipal - Jijoca de Jericoacoara, 16p, 2014.

JACKSON, D.W.T. AND COOPER, J.A.G. Coastal dune fields in Ireland: rapid regional response to climatic change. Journal of Coastal Research, Special Issue 64, 2011, 293-297, 2011.

JIMÉNEZ, J.A, MAIA, L.P, SERRA, J AND MORAIS, J. Aeolian dune migration along the. Ceara coast, North-eastern Brazil. Sedimentology v. 46, 689–701, 1999.

KOMAR, P.D., ALLAN, J.C. AND RUGGIERO, P. Sea level variations along the U.S. Pacific Northwest coastal: tectonic and climate controls. J. Coast Res v. 27, n° 5, 808-823, 2011.

LADÁNYI, Z., BLANKA, V., MEYER, B., MEZOSI, G. AND RAKONCZAI, J. Multi-indicator sensitivity analysis of climate change effects on landscapes in the Kiskunság National Park, Hungary. Ecological Indicators v. 58, 8–20, 2015.

LIMA, A. AND SAUERMANN, G. Modeling a dune field. Physica A: Statistical, v. 310, 487–500, 2002.

LUNA, M.C.M.M., PARTELI, E.J.R. AND HERRMANN, H.J. Model for a dune field with an exposed water table. Geomorphology, v. 159-160, 169–177, 2012.

MCLACHLAN, A. AND BURNS, M. Headland bypass dunes on the South African coast: 100 years of (mis)management. Coastal dunes, Carter, Curtis & Sheehy-Skeffington (eds); Belkema, Rotterdam, p.71-79, 1992.

MEIRELES, A.J.A., ARRUDA, M.G.C., GORAYEB, A. AND THIERS, P.R.L. Integração dos indicadores geoambientais de flutuações do nível relativo do mar e de mudanças climáticas no litoral cearense. Revista Mercator, vol. 08, 109-134, 2005.

MEIRELES, A.J.A., GORAYEB, A., SILVA, D.F.R. AND LIMA, G.S. Socio-environmental impacts of wind farms on the traditional communities of the western coast of Ceará, in the Brazilian Northeast. Journal of Coastal Research, v. 65, 81-86, 2013.

MEIRELES, A.J.A, SILVA, E.V. AND THIERS, P.R.L. Os campos de dunas móveis: fundamentos dinâmicos para um modelo integrado de planejamento e gestão da Zona Costeira. Revista Geousp, vol. 20, 101-119, 2006.

MEIRELES, A.J.A. Geodinâmica dos campos de dunas móveis de Jericoacoara/Ce-Br. Revista Mercator, 10: 22, 169–190, 2011.

MENDOZA-GONZALEZ, G., MARTINEZ, M.L., ROJAS-SOTO, O.R., VAZQUEZ, G. AND GALLEGO-FERNANDEZ J.B. Ecological niche modeling of coastal dune plants and future potential distribution in response to climate change and sea level rise. Global Change Biology 19, 2524–2535, 2013.

MONTREUIL, A. AND BULLARD, J. Meso-scale Coastal Dune Evolution along the North Lincolnshire coast, UK. J. Coastal Research, 64: 665-668, 2011.

PARTELI E.J.R, DURÁN O., BOURKE M.C., TSOAR H., PÖSCHEL T. AND HERRMAN N.H. Origins of barchan dune asymmetry: Insights from numerical simulations. Aeolian Research, 12: 121–133, 2014.

PETERSON. L.C., HAUG G.H., HUGHEN K.A. AND RÖHL U. 201Rapid changes in the hydrologic cycle of the Tropical Atlantic during the Last Glacial. Science, 2000, v. 290, 1947-1951, 2000.

PHILANDER. S.G.H. AND PACANOWSKI. R.C. A model of the seasonal cycle in the tropical Atlantic Ocean. J. Geophys. Res. 91: 14192–14206, 1986.

POMAR F., FORNÓS J.J., GÓMEZ-PUJOL L. AND DEL VALLE L. El Pleistoceno superior de la zona de Tirant-Fornells (norte de Menorca, Illes Balears): un modelo de interacción eólica y aluvial. Geo‐Temas, VII Jornadas de Geomorfología Litoral, 2013, v.14, p.123-126.

PRISKIN, J. Physical impacts of four-wheel drive related tourism and recreation in a semi-arid, natural coastal environment. Ocean & Coastal Management, vol. 46, n° (1-2), 127-55, 2003.

PROVOOS S., JONES M.M. AND EDMONDSON S.E. Changes in landscape and vegetation of coastal dunes in northwest Europe: a review. J Coast Conserv., v.15, 207–226, 2011.

PYE. K. AND NEAL, A. Late Holocene dune formation on the Sfton coast, northwest England. In: The dynamics and environmental context of aeolian sedimentary systems; ed. by K. Pye. Geological Society Sedimentary; Special Publication, 1993, nº 72; 201-218p.

SAUERMANN. G., ANDRADE. J.S., MAIA L.P., COSTA. U.M.S., ARAUJO. A.D. AND HERRMANN. H.J. Wind velocity and sand transport on a barchan dune. Geomorphology, 54: 3-4, 245–255, 2003.

SINGHVI, A.K., WILLIAMS. M.A.J., RAJAGURU, S.N., MISRA, V.N., CHAWLA, S., STOKES, S., CHAUHAN, N., FRANCIS, T., GANJOO, R.K. AND HUMPHREYS, G.S. A ~200ka record of climatic change and dune activity in the Thar Desert, India. Quaternary Science Reviews, V.29, 3095-3105, 2010.

SUGUIO K., MARTIN L., BITTENCOURT, A.C.S.P.; Dominguez, J.M.L.; Flexor, J.M. y AZEVEDO, A.E.G. Flutuações do nível relativo do mar durante o Quaternário Superior ao longo do litoral brasileiro e suas implicações na sedimentação costeira. Rev. Bras. Geoc. 1985, v.15 (4), 273-286, 1995.

SYDEMAN, W.J., GARCÍA-REYES, M., SCHOEMAN, D.S., RYKACZEWSKI, R.R., THOMPSON, S.A., BLACK, B.A. AND BOGRAD, S.J. Climate change and wind intensification in coastal upwelling ecosystems. Science, 2014, v. 345, issue 6192, 77-80, 2014.

WOOLARD, J.M. AND COLBY, J.D. Spatial characterization, resolution, and volumetric change of coastal dunes using airborne LIDAR: Cape Hatteras, North Carolina. Geomorphology, 48, 269 – 287, 2002.

YIZHAQ, H. ASHKENAZY, Y., LEVIN, N. AND TSOAR, H. Spatiotemporal model for the progression of transgressive dunes. Physica A, 392: 4502–4515, 2013.

ZANELLA, M.E. 2005. As características climáticas e os recursos hídricos do Estado do Ceará. In: org. da Silva, J. B.; Cavalcante, T. C.; Dantas, E. W.C. [et al]. Ceará: um novo olhar geográfico. Fortaleza: Edições Demócrito Rocha, 480p.

ZAZO, C., DABRIO, C.J., BORJA, F., GOY, J.L., LEZINE, A.M., LARIO, J., POLO, M.D., HOYOS, M. AND BOERSMA, J.R. Pleistocene and Holocene aeolian facies along the Huelva coast (southern Spain): Climate and neotectonic implications. Geol. En Mijbouw, v.77, 209-224, 1999.

Haut de page

Table des illustrations

Titre Figure 1. Location of the study area in Ceará, northeastern Brazil.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-1.jpg
Fichier image/jpeg, 1,5M
Titre Fig. 2. Study area location and preferred direction of marine currents (
Légende a); monthly variation in mean precipitation, wind trade and direction in the study area (b) and annual variation of rainfall with a tendency to a decrease (c). NBC, North Brazil Current; BC, Brazil Current; SEC, South Equatorial Current.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-2.jpg
Fichier image/jpeg, 1012k
Titre Figure 3. Geo-environmental components of the study dunes
Crédits (Meireles et al, 2005).
URL http://journals.openedition.org/confins/docannexe/image/12872/img-3.jpg
Fichier image/jpeg, 848k
Titre Figure 4. Displacement of the DDPS based on the 2005 Quickbird image and tendency curve plotted for the study period.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-4.jpg
Fichier image/jpeg, 856k
Titre Figure 5. Displacement of the DPN, based on the 2005 QuickBird image and tendency curve plotted for the study period.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-5.jpg
Fichier image/jpeg, 996k
Titre Fig. 6. Displacement of the DA dune based on the 2005 QuickBird image and tendency curve plotted for the study period.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-6.jpg
Fichier image/jpeg, 1,1M
Titre Figure 7. Accumulated displacement of the dune field.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-7.jpg
Fichier image/jpeg, 540k
Titre Figure 8. Morphological features of the study area and their influence on the dynamics of the local barchans dunes.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-8.jpg
Fichier image/jpeg, 1,3M
Titre Figure 9. Evolution of the reduction area (m) of the dune bodies as possible indicator of decreased sediment source.
URL http://journals.openedition.org/confins/docannexe/image/12872/img-9.jpg
Fichier image/jpeg, 187k
Haut de page

Pour citer cet article

Référence électronique

Antonio Jeovah Meireles, Adryane Gorayeb et Narcélio de Sá Pereira Filho, « Dune fields in Jericoacoara: human intervention as a possible indicator of changes in the morphological dynamics  », Confins [En ligne], 34 | 2018, mis en ligne le 05 avril 2018, consulté le 15 juillet 2018. URL : http://journals.openedition.org/confins/12872 ; DOI : 10.4000/confins.12872

Haut de page

Auteurs

Antonio Jeovah Meireles

Prof. Dr. do Departamento de Geografia, Universidade Federal do Ceará UFC, meireles@ufc.br

Adryane Gorayeb

Profa. Dra. do Departamento de Geografia, Universidade Federal do Ceará UFC, adryanegorayeb@yahoo.com

Narcélio de Sá Pereira Filho

Companhia de Água e Esgoto do Ceará CAGECE, narceliosapereira@gmail.com

Haut de page

Droits d’auteur

Licence Creative Commons
Confins – Revue franco-brésilienne de géographie est mis à disposition selon les termes de la licence Creative Commons Attribution - Pas d’Utilisation Commerciale - Partage dans les Mêmes Conditions 4.0 International.

Haut de page
  • Logo Revue soutenue par l’Institut des sciences humaines et sociales du CNRS
  • Logo DOAJ - Directory of Open Access Journals
  • Logo Index Latindex
  • Logo IHEAL (Institut des Hautes Études de l'Amérique Latine)
  • Logo CREDA (Centre de recherche et de Documentation sur les Amériques)
  • Logo USP (Universidade de São Paulo)
  • OpenEdition Journals