Publication: Influence of the North Atlantic Oscillation on the Canary Islands precipitation
Loading...
Full text at PDC
Publication Date
2001-10
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
American Meteorological Society
Citations
Exportar
Abstract
The aim of this paper is to investigate the relationship between the Canary Island rainfall and the Atlantic large-scale circulation, characterized by the North Atlantic oscillation (NAO) index. The Canary Islands are located in the Atlantic subtropical belt under the direct influence of the Azores high and the trade winds. Their steep orography makes the islands very sensitive to small variations in a synoptic situation, thus providing an excellent natural observatory for the North Atlantic variability associated with changes in pressure patterns. A significant relationship between rainfall and the NAO is found for five of the seven Canary Islands. In order to characterize the physical mechanisms involved, a set of automatic objective techniques for identification and detection of disturbances is applied to the 1000- and 500- hPa geopotential from the NCEP-NCAR reanalysis for the period from 1955 to 1998. This method allows for the identification and detection of four main synoptic systems-either at the surface or at 500 hPa-that are responsible for 80% of the precipitation over the Canary Islands: Atlantic surface lows (ASLs), 500-hPa lows (UALs), 500- hPa troughs over the Canary Islands (TROs), and deep Atlantic lows (DALs), which affect the entire troposphere. Three of the detected disturbances (ASLs, TROs, and DALs) exhibit a dipolar structure with a low pressure center over 35 degreesN associated with a positive anomaly at higher latitudes, resembling the NAO negative pattern. The analysis of the variability of the disturbance occurrence and the changes in their associated anomaly patterns shows that deeper and more frequent ASLs and TROs affect the Canary Islands during the negative phase of the NAO. However, UAL disturbances are less frequent, and DALs do not exhibit significant variations with the NAO phase. The standard deviation of the 2.5-8-day bandpass-filtered geopotential height shows that the maximum variability associated with the NAO occurs over the Canary Island area, confirming its sensitivity to NAO variations. The study provides a comprehensive view of the mechanisms involved in the precipitation generation over the Canary Islands, documenting a sensitivity to the NAO influences for a group of islands that have been poorly studied so far.
Description
© 2001 American Meteorological Society. The authors wish to thank to the two anonymous referees for their useful comments, which have contributed to the improvement of the quality and presentation of this work. This study is supported by the Spanish Comisión Interministerial de Ciencia y Tecnologia under Grant CLI98-0649.
UCM subjects
Unesco subjects
Keywords
Citation
Barnston, A. G., and R. E. Livezey, 1987: Classification, seasonality and persistence of low-frequency atmospheric circulation patterns. Mon. Wea. Rev., 115, 1083–1126.
Blender, R., K. Fraedrich, and F. Lunkeit, 1997: Identification of cyclone-track regimes in the North Atlantic. Quart. J. Roy. Meteor. Soc., 123, 727–741.
Christoph, M., U. Ulbrich, and U. Haak, 1995: Faster determination of the intraseasonal variability of storm tracks using Murakami’s recursive filter. Mon. Wea. Rev., 123, 578–581.
Folland, C. K., T. N. Palmer, and D. E. Parker, 1986: Sahel rainfall and worldwide temperatures, 1901–1985. Nature, 320, 602–607.
Font, I., 1956: El Tiempo Atmosférico en las Islas Canarias. Servicio Meteorologico Nacional, 96 pp.
Gallego, D., R. García, E. Hernández, L. Gimeno, and P. Ribera, 2001: An ENSO signal in the North Atlantic subtropical area. Geophys. Res. Lett., 28, 2939–2942.
Gibson, J. K., P. Kallberg, S. Uppala, A. Hernández, A. Nomura, and E. Serrano, 1997: ERA description. ECMWF Re-analysis Project Report Series 1, ECMWF, Reading, United Kingdom, 66 pp.
Hoskins, B. J., M. E. McIntyre, and A. W. Robertson, 1985: On the use and significance of isentropic potential vorticity maps. Quart. J. Roy. Meteor. Soc., 111, 877–946.
Hurrell, J. W., 1995a: Decadal trends in the North Atlantic oscillation regional temperatures and precipitation. Science, 269, 676–679.
——, 1995b: Transient eddy forcing of the rotational flow during northern winter. J. Atmos. Sci., 52, 2286–2301.
——, 1996: Influence of variations in extratropical wintertime teleconnections on Northern Hemisphere temperature. Geophys. Res. Lett., 23, 685–668.
Jones, P. D., T. Jonsson, and D. Wheeler, 1997: Extension to the North Atlantic Oscillation using early instrumental pressure observations from Gibraltar and south-west Iceland. Int. J. Climatol., 17, 1433–1450.
Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–471.
Kushnir, Y., and J. M. Wallace, 1989: Low-frequency variability in the Northern Hemisphere winter: Geographical distribution, structure and timescale dependence. J. Atmos. Sci., 46, 3122–3142.
Kutzbach, J. E., 1967: Empirical eigenvectors of sea-level pressure, surface temperature and precipitation complexes over North America. J. Appl. Meteor., 6, 791–802.
Lamb, P. J., 1978: Large-scale tropical Atlantic circulation patterns associated with subsaharan weather anomalies. Tellus, 30, 240–251.
——, and R. A. Peppler, 1987: North Atlantic oscillation: Concept and an application. Bull. Amer. Meteor. Soc., 68, 1218–1225.
Molinari, R. L., D. A. Mayer, J. F. Festa, and H. F. Bezdek, 1997: Multi-year variability in the near-surface temperature structure of the midlatitude western North Atlantic Ocean. J. Geophys. Res., 102, 3267–3278.
Moses, T., G. N. Kiladis, H. F. Diaz, and R. G. Barry, 1987: Characteristics and frequency reversals in mean sea level pressure in the North Atlantic sector and their relationships to long-term temperature trends. J. Climatol., 7, 13–30.
Murakami, M., 1979: Large-scale aspects of deep convective activity over the GATE area. Mon. Wea. Rev., 107, 994–1013.
Osborn, T. J., K. R. Briffa, S. F. B. Tett, P. D. Jones, and R. M. Trigo, 1999: Evaluation of the North Atlantic Oscillation as simulated by a coupled climate model. Climate Dyn., 15, 685–702.
Parker, D. E., and C. K. Folland, 1988: The nature of climate variability. Meteor. Mag., 117, 201–210.
Peixoto, J. P., and A. H. Oort, 1992: Physics of Climate. American Institute of Physics, 520 pp.
Preisendorfer, R. W., 1988: Principal component analysis in meteorology and oceanography. Developments in Atmospheric Sciences, C. D. Mobley, Ed., Vol. 17, Elsevier, 425 pp.
Reverdin, G., D. R. Cayan, and Y. Kushnir, 1997: Decadal variability of hydrography in the upper northern North Atlantic, 1948–1990. J. Geophys. Res., 102, 8505–8533.
Rogers, J. C., 1990: Patterns of low-frequency monthly sea level pressure variability (1899–1986) and associated wave cyclone frequencies. J. Climate, 3, 1364–1379.
——, 1997: North Atlantic storm track variability and its association to the North Atlantic oscillation and climate variability of northern Europe. J. Climate, 10, 1635–1647.
Serreze, M. C., F. Carse, R. G. Barry, and J. C. Rogers, 1997: Icelandic low cyclone activity: Climatological features, linkages with the NAO, and relationships with recent changes in the Northern Hemisphere circulation. J. Climate, 10, 453–464.
Trigo, I. F., T. D. Davies, and G. R. Bigg, 1999: Objective climatology of cyclones in the Mediterranean region. J. Climate, 12, 1685–1696.
Ulbrich, U., M. Christoph, J. G. Pinto, and J. Corte Real, 1999: Dependence of winter precipitation over Portugal on NAO and baroclinic wave activity. Int. J. Climatol., 19, 379–390.
van Loon, H., and J. Williams, 1976: The connection between trends of mean temperature and circulation at the surface. Part I: Winter. Mon. Wea. Rev., 104, 365–380.
——, and J. C. Rogers, 1978: The seesaw in winter temperatures between Greenland and northern Europe. Part I: General description. Mon. Wea. Rev., 106, 296–310.
von Storch, H., and F. W. Zwiers, 1999: Statistical Analysis in Climate Research. Cambridge University Press, 484 pp.
Walker, G. T., and E. W. Bliss, 1932: World weather V. Mem. Roy. Meteor. Soc., 4, 53–84.
Wallace, J. M., Y. Zhang, and J. A. Renwick, 1995: Dynamic contribution to hemispheric mean temperature trends. Science, 270, 780–783.
Ward, M. N., P. J. Lamb, D. H. Portis, M. El Hamly, and R. Sebbari, 1999: Beyond El Niño: Decadal and Interdecadal Climate Variability. Springer, 374 pp.
Zorita, E., V. Kharin, and H. von Storch, 1992: The atmospheric circulation and sea surface temperature in the North Atlantic area in winter: Their interaction and relevance for Iberian precipitation. J. Climate, 5, 1097–1108.