deCastro, M., Sousa, M. C., Santos, F., Dias, J. M. & Gmez-Gesteira, M. How will somali coastal upwelling evolve under future warming scenarios? So while most of Somalia lies in the Northern Hemisphere, a small part stretches into the Southern Hemisphere. The reason is that the core of the North East Monsoon Current is located at about 5N wtuch is about the latitude of zero . In alphabetical order, these areAwdal, Bakool, Banaadir, Bari, Bay, Galguduud, Gedo, Hiiraan, Jubbada Dhexe (Middle Jubba), Jubbada Hoose (Lower Jubba), Mudug, Nugaal, Sanaag, Shabeellaha Dhexe (Middle Shabeelle), Shabeellaha Hoose (Lower Shabeelle), Sool, Togdheer, Woqooyi Galbeed. 0000005201 00000 n Vishnu, S., Francis, P. A., Shenoi, S. S. C. & Ramakrishna, S. S. V. S. On the relationship between the Pacific Decadal Oscillation and monsoon depressions over the Bay of Bengal. Subsequently, these downwelling signals then propagate westward with an approximate speed of 25cm/s and interfere with the coastal signals along the coast of Somalia (Fig. Shimbiris 2,460m (8,070ft), Natural resources: However, thermocline in this part does shallow up by about 25m during the early phase of the summer monsoon (June and July), but as the monsoon peaks in August, it gets restored in the deeper depths. But the mixed layer depth deepens during entrainment whereas it shoals during upwelling and hence, are driven by different dynamics. Dyn. Madhupratap, M. et al. 308, 545547, https://doi.org/10.1126/science.1106610 (2005). New York: UNDP. Along the Somali Sea from Hobyo southwestward to near Mogadishu lies a stretch of dry coastal sand dunes, the Hobyo grasslands and shrublands ecoregion. ocean, g' stands for the reduced gravity [g(Ap/p)] in . The Indian Ocean Coast of Somalia - ScienceDirect ADS 0000001940 00000 n This vegetation gives way to a combination of low bushes and grass clumps in the highly arid areas of the northeast and along the Gulf of Aden. Further, in addition to the coastal upwelling, thermocline also shoals offshore at ~57E for 8N and 10N section owing to the return flow of GW. Clim. Much of this coast is thinly populated but overgrazing, particularly south of Mogadishu, has resulted in the destruction of the protective vegetation cover and the gradual movement of the once-stationary dunes inland. This is a list of the extreme points of Somalia, the points that are farther north, south, east or west than any other location. As per the bulk formulae, LHF is proportional to the product of surface wind speed and the humidity gradient between sea surface and at 10m height and goes in the direction of humidity gradient. Leetma, A. Rep., NOAA Atlas NESDIS 74 Available at https://data.nodc.noaa.gov/woa/WOA13/DOC/woa13_vol2.pdf (2013). arable land: 1.64% By early May, as the winds begin to blow parallel to the coast, a sharp SST cooling is observed along the entire stretch of Somalia coast (Fig. 0000003770 00000 n The model topography is based on modified ETOPO246 with minimum depth is set to 15m. Salinity and Temperature is relaxed to climatological values with a 30-day time scale in the 5 sponge layer along the open southern and eastern boundaries. 0000004452 00000 n As stated above, Ekman mass transport is positive and transporting water offshore with an average rate of 104kg m1s1 with maximum in the south and decreases almost linearly in the north in accordance with the strength of the alongshore wind components. PDF Printed in Great Britain The Indian Ocean Coast of Somalia 0000002191 00000 n Also, note here that the results are discussed based on climatology prepared using the interannual simulation of the model for 19932014 period. DVD. This model is used extensively earlier by many42,43,44. The data analysis and all the plots presented here are made using Ferret, PyFerret and Matlab. For example, at 8N, the thermocline (D22) close to the coast deepened from 20m in June/July to more than ~80m during August, a deepening of about 60m; indicating a possible downwelling over the major part of the Somali coast despite the strong upwelling favourable alongshore winds. In order to better document the temperature evolution of the upper water column of this region, we also looked at the near crosshore sections of temperature (Fig. Sea Res. This coastal strip is part of the Ethiopian xeric grasslands and shrublands ecoregion. Somalia Bordering Countries: signed, but not ratified: (a) Temperature time-series based on an ARGO float during summer of 2015. Sea Res. In Mogadishu, for instance, average afternoon highs range from 28 to 32C (82 to 90F) in April. The SC/SUC is characterized by narrow, fast jets that exhibit considerable variability in intensity, vertical profile and width on many time scales (see Schott and McCreary, 2001, and references therein). [3], The coastline of Somalia has different conditions throughout its length. The Great Whirl can be observed between 5-10N and 52-57E off the Somali coast in the summer season, a location typically around 200 km southwest of the Socotra Gyre (between . It is a particular feature of the Indian Ocean, due to the monsoon, that its western boundary current, the Somalia Current, is seasonal. Monsoon response of the Somali Current and associated upwelling The northern coastline is shared with the Gulf of Aden, the northeastern with Guardafui Channel, and the eastern with the Indian Ocean. A 265, 4592 (1969). lagged by about a month from the peak in the negative windstress curl. World ocean atlas 2013, vol. Ocean. Climatol., https://doi.org/10.1007/s00704-018-2493-6 (2018). A. Sindhu, B. et al. As shown here, upwelling along this coast is very limited to the early part of the monsoon and in small eddy driven regions, thus may not be much important to close the over turning circulations across the equator as was believed earlier. 136, 29993017 (2008). & Tucker, B. River discharge database, Version 1.0 (RivDis v1. Abstract. Notably, the results presented here are robust and independent of the section chosen along a slightly different isobath. Griffies, S. M. Elements of MOM4p1. The northwestern and southwestern parts of the nation, however, receive considerably more rain, with an average of 20 to 24 inches (510 to 610mm) falling per year. Clim. Piracy off the coast of Somalia - Wikipedia Arabian Sea | Indian Ocean, Climate & Marine Life | Britannica 118, 113, https://doi.org/10.1029/2012JC008198 (2013). Interestingly, Ekman pumping velocity is strongest in this region and crosses more than 4 m/day during the peak monsoon, indicating that windstress curl induced Ekman pumping may contribute significantly in the formation of GW front, and the associated cooling in this region. The initial model simulations are carried out on Aaditya HPC at IITM, Pune and the final simulations are done at Mihir HPC at NCMRWF, Delhi. J. Du- . In the more arid highlands of the northeast, Boswellia and Commiphora trees are sources, respectively, of the frankincense and myrrh for which Somalia has been known since ancient times. The near surface winds off Somalia are traveling from relatively warmer southern hemisphere/Equator and hence are warmer and therefore, carry large amount of moisture. In the NSEC, however, meridional velocity is close to zero and the zonal velocity field transport the coastal waters away thus helps in cooling the SST there. Tech. Langers Encyclopedia of World History, 594. We use a regional Indian Ocean model based on Modular Ocean Model (MOM4p141). The reanalysis data from Estimating the Circulation and Climate of the Ocean (ECCO) product is retrieved from https://ecco.jpl.nasa.gov/, the data from Operational Ocean Reanalysis System version 4 (ORAS4) are obtained from https://climatedataguide.ucar.edu/climate-data/oras4-ecmwf-ocean-reanalysis-and-derived-ocean-heat-content and the Simple Ocean Data Assimilation (SODA) version 2.2.4 data are retrieved from http://apdrc.soest.hawaii.edu:80/dods/public_data/SODA/soda_pop2.2.4. How will Somali coastal upwelling evolve under future warming scenarios In the Ogo's especially arid eastern part, the plateaubroken by several isolated mountain rangesgradually slopes toward the Somali Sea and in central Somalia constitutes the Mudug Plain. 627,337km2 (242,216sqmi) & McCreary, J. P. The monsoon circulation of the Indian Ocean. Map of global climatological SST (shading) from NIOA26 and surface winds (vector) from QuikSCAT for the month of July. Moreover, they are consistent with those of westward propagating Rossby waves. Annihilation of the Somali upwelling system during summer monsoon - Nature Table1 shows the values of Rossby wave speed with period P=2/ and wavelength n=2/kn for the first three baroclinic modes. World Population Prospects 2022, Online Edition", "GDP per capita, PPP (current international $) Somalia | Data", "World Economic Outlook Database, October 2019", United Nations Department of Economic and Social Affairs, "World Population Prospects 2022: Demographic indicators by region, subregion and country, annually for 1950-2100", "Middle East Policy Council Muslim Populations Worldwide", "Harvard-Educated Technocrat Chosen as Somalia Premier", "Somalia rising after two decades of civil war and unrest", "Somalia conflict: Al-Shabab 'collects more revenue than government', "Kenyan troops seize al-Shabaab base in Somalia", "Somalia: Somali Leaders Adopt Draft Constitution", "Somalia's newly-endorsed constitution widely hailed", "Somalia: UN Envoy Says Inauguration of New Parliament in Somalia 'Historic Moment', "Mogadishu: East Africa's newest business destination? The main rainy season, referred to as the Gu, lasts from April to June. Chatterjee, A. et al. Southwestern Somalia is dominated by the country's only two permanent rivers, the Jubba and the Shabeelle. Lett. A majority of these analyses on coastal upwelling focused mostly on the alongshore wind driven offshore Ekman transport and the associated Sea Surface Temperature (SST) cooling signatures19. Further, we show that the surface cooling of coastal waters are dominantly driven by subsurface entrainment and surface heat fluxes. Sorbonne Universit Abstract Surface currents and some surface temperatures in the Somali Basin have been plotted for May and June of each year from 1900 to 1973 when any data were available. A numerical study of the Somali coastal undercurrents Provided by the Springer Nature SharedIt content-sharing initiative. J. earth system science 121, 559593 Available at http://www.nio.org/index/option/com_nomenu/task/show/tid/2/sid/18/id/229 (2012). Monthly climatological SST for July from TRMM TMI is shaded with a scale (above). Hot conditions prevail year-round along with monsoon (periodic seasonal reversing wind accompanied by corresponding changes in precipitation) winds and irregular rainfall. During summer monsoon Somali current flows poleward and exhibits a maximum transport of ~375Sv4. Therefore, the thermocline structure off the Somali coast is determined by the relative strength of the local winds and remotely forced Rossby waves: in regions where strength of the currents are much stronger, e.g. Evolution of each term of the climatological heat budget of the mixed layer given in Eq. & Giese, B. Favorable rainfall and soil conditions make the entire riverine region a fertile agricultural area and the center of the country's largest sedentary population. National Marine Ecosystem Diagnostic Analysis. Sci. PDF Reconnaissance of the Somali Current during the Southwest Monsoon - JSTOR The only a similar, albeit weaker and smaller, upwelling is seen along the coast of Somalia and Arabia in the western Arabian Sea. Furthermore, as stated earlier, Ekman transport is also weakest in this part of the section. "Female Genital Cutting: Nursing Implications". The radiation (shortwave and longwave), momentum (windstres) fluxes and 2m specific humidity and air temperature are obtained from TropFlux data47,48. The Somali Current is a warm ocean boundary current that runs along the coast of Somalia and Oman in the Western Indian Ocean and is analogous to the Gulf Stream in the Atlantic Ocean. %PDF-1.3 % ~30) and the period is annual and therefore, excite those baroclinic modes which fit better with this prescribed length and time scale. Res. The negative curl over the interior Arabian Sea further intensifies during July and persists till late September. Leetma, A. Further, during summer, cold surface temperature off the coast of Somalia and Arabia create much needed thermal gradient for moisture transport for the Indian summer monsoon. A. 139, 11321161 (2013). 4). Physio-graphically, Somalia is a land of limited contrast. Climate change and wind intensification in coastal upwelling ecosystems. )(2003) The Howard and Moore Complete Checklist of the Birds of the World. Human Development Report 2001-Somalia. 4). Farther southward the terrain gradually changes to semiarid woodlands and grasslands as the annual precipitation increases. 6) during May to September along the 4N, 6N, 8N and 10N latitude belts off Somalia coast (dashed blue lines in Fig. UNDP (2006). New York: UNDP. Historical evidence for two gyres in the Somali Current - ResearchGate Hum. Tech. 0000006822 00000 n The range extends from the country's border with Ethiopia in the west up to the tip of the Horn of Africa. Previous studies suggest that non-linearity associated with the strong cross-equatorial currents plays an important role in the formation of the SG1, whereas, strong Findlater Jet north of the equator drives the formation of GW16. Rev. Hot conditions prevail year-round, along with periodic monsoon winds and irregular rainfall. 8 is that the slope of the phase lines are consistent in the observation and model. Lakshadweep High Propagation and Impacts on the Somali Current and Seasonal Wind-Driven Coastal Upwelling Systems | SpringerLink The occasional interchange of sign in temperature tendency may likely be linked to intrasesonal variability of the monsoon winds. [16] This area is covered with scattered scrub and grass clumps where rainfall is sufficient although unpredictable. As a first approximation, the barotropic response to the wind stress curl was computed . The images or other third party material in this article are included in the articles Creative Commons license, unless indicated otherwise in a credit line to the material. World Bank and UNDP (2003). mostly flat to undulating plateau rising to hills in north, Elevation extremes: 247, 198201 (1990). This weaker upwelling signature noticed near the northern tip of Somalia (10N) also likely linked to the initial phase of the formation of GW. The black contours represent D22 and the cyan fonts represent the depth of the D22 right adjacent to the coast marked by cyan arrow. The model spans over 30120E and 30S30N with uniform 0.25 horizontal resolution and 40 vertical levels with 5m resolution in top 60m42. Climatological windstress curl (shaded) and windstress (vectors) derived from TropFlux data during 19932014. Somali upwelling system is considered to be the fifth largest upwelling system of the global ocean and the strongest in the Indian Ocean [Fig. [9] In January 2023, the Indian Ocean High Risk Area (HRA) was lifted by the International Maritime Bureau (IMB) due to a significant absence of Somali pirate attacks in previous years, although Somali pirates still reportedly possess the ability and resources to conduct attacks in the Gulf of Aden region. Beyond this plain is the maritime mountain range of the Karkaar Mountains (marked on the map) hosting the highest point in the country, the 2,460 m tall Mount Shimbiris. Rev. This indicates that the cooling observed in the SSEC, as shown in the previous section, is dominated by wind driven upwelling, which acts as a combination of strong offshore Ekman transport and upwelling favorable Ekman suction. Parts of this area have been under cultivation since the 1930s, producing sorghum and maize; in the 1990s it constituted the only significant region of sedentary cultivation outside southwestern Somalia. 1: Temperature. High biological productivity in the central Arabian Sea during the summer monsoon driven by Ekman pumping and lateral advection. 637,657km2 (246,201sqmi) 20, 397400, https://doi.org/10.1016/0011-7471(73)90062-4 (1973). Smith, S. L. & Codispoti, L. A. Southwest monsoon of 1979: Chemical and biological response of Somali coastal waters. HUr0AG*Q$b~@51H 0} 9 ?% >Wc}]3,G0&+E| CY6'iF00&[^-8GKQFk#)!f.u~0B# /vRG$a0[?qtM0 6y)Q Soc. Exclusive Economic Zone: Geophys. The outline map represents the mainland territory of Somalia. Rep. 6, https://doi.org/10.1038/srep30137 (2016). 1].In contrast to the other eastern boundary . Here dashed box represents central part of the section. Enhancing the value of the Haud are the natural depressions that during periods of rain become temporary lakes and ponds. 2-b).The direction of the Somali Current is controlled by the seasonal variations of the monsoonal . 1). 0000004430 00000 n Chatterjee, A., Shankar, D., McCreary, J., Vinayachandran, P. & Mukherjee, A. Dynamics of andaman sea circulation and its role in connecting the equatorial indian ocean to the Bay of Bengal. J Atmos Sol. A Reanalysis of Ocean Climate Using Simple Ocean Data Assimilation (SODA). Nonetheless, thermocline lifts up north of 9N and to a lesser extent between 23N, suggesting signatures of upwelling and shoals down between the vast swath of these upwelling zones in both the observations and model simulations, though their magnitude mismatches. Please consider splitting content into sub-articles, condensing it, or adding subheadings. Veldhuis, M., Kraay, G. W., Bleijswik, J. D. L. V. & Baars, M. A. The simulated seasonal evolution of thermocline off Somalia compares well with the observations (Fig. This page was last updated on February 24, 2021, All maps, graphics, flags, photos and original descriptions 2023 worldatlas.com. In 1948, under pressure from their World War II allies and to the dismay of the Somalis,[12] the British "returned" the Haud (an important Somali grazing area that was presumably 'protected' by British treaties with the Somalis in 1884 and 1886) and the Ogaden to Ethiopia, based on an 1897 treaty in which the British ceded Somali territory to the Ethiopian Emperor Menelik in exchange for his help against plundering by Somali clans. The dispersion relation of Rossby wave is, and therefore the group speed can be found as. Google Scholar. Sign up for the Nature Briefing newsletter what matters in science, free to your inbox daily. Google Scholar. The southwest monsoon winds are generally upwelling favorable during the first 3 months after onset and coastal SSTs confirm the drifter-observed cold wedge in July; note that there are no . Finally, Somali region is considered to be one of the most productive place of the Indian Ocean driven by huge amount nutrient upwelled from subsurface water10. 0000006844 00000 n The Somali Coastal system lies mostly in the northern Indian Ocean, and is composed by the following dynamic oceanographic features: The East African Coastal Current (EACC), the Southern Gyre (SG), the Somali Current (SC), the South Equatorial Countercurrent (SECC), and the Great Whirl (GW) (Fig. 7). Cite this article, An Author Correction to this article was published on 06 December 2019. Revised and enlarged third edition. States Map Where is Somalia? 0000003089 00000 n Ocean. The only perennial rivers of the country are the Jubba and the Shabeelle to the south of the country. Most important, the western area has permanent wells to which the predominantly nomadic population returns during the dry seasons. Summer upwelling also plays an important role in this regions ecology by elevating nutrient concentration in the upper surface layer, thus making it as one of the most productive marine ecosystems in the world oceans6,7,8,9,10,11,12. During winter, the flow of the upper ocean is directed westward from near the Indonesian Archipelago to the Arabian Sea. Earth Syst. [6] Geology suggests the presence of valuable mineral deposits. As a result, even though the surface cooling is uniform along the coast, the forcing mechanisms for such homogeneous cooling varies from south to north along the coast. 4, the blue dotted box represents CSEC and the numbers in black, red and blue fonts represent the depth of the D22 averaged over the blue box from model, NIOA and WOA13, respectively. McCreary, J. P., Kohler, K. E., Hood, R. R. & Olson, D. B. Global Heat Map: Tracking Extreme Heat Across Europe and Asia - The New 0000003792 00000 n Ocean. J. Phys. 1999, PAGE 219, Zarins, Juris (1990), "Early Pastoral Nomadism and the Settlement of Lower Mesopotamia", (Bulletin of the American Schools of Oriental Research), NEW ISSUES IN REFUGEE RESEARCH Working Paper No.

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