References

ACP

Atmospheric Chemistry and Physics

ACP

Atmos. Chem. Phys.

1680-7324

Copernicus Publications

Göttingen, Germany

10.5194/acp-8-5565-2008

ENSO surface shortwave radiation forcing over the tropical Pacific

Pavlakis

K. G.

¹ ² ³ Hatzianastassiou

¹ ⁴ Matsoukas

¹ ⁵ Fotiadi

¹ ³ Vardavas

¹ ³

Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece

Department of General Applied Science, Technological Educational Institute of Crete, Greece

Department of Physics, University of Crete, Crete, Greece

Laboratory of Meteorology, Department of Physics, University of Ioannina, Greece

Department of Environment, University of the Aegean, Greece

18 09 2008

8 18 5565 5577

2008

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

This article is available from https://acp.copernicus.org/articles/8/5565/2008/acp-8-5565-2008.html

The full text article is available as a PDF file from https://acp.copernicus.org/articles/8/5565/2008/acp-8-5565-2008.pdf

We have studied the spatial and temporal variation of the downward shortwave radiation (DSR) at the surface of the Earth during ENSO events for a 21-year period over the tropical and subtropical Pacific Ocean (40° S–40° N, 90° E–75° W). The fluxes were computed using a deterministic model for atmospheric radiation transfer, along with satellite data from the ISCCP-D2 database, reanalysis data from NCEP/NCAR for the key atmospheric and surface input parameters, and aerosol parameters from GADS (acronyms explained in main text). A clear anti-correlation was found between the downward shortwave radiation anomaly (DSR-A) time-series, in the region 7° S–5° N 160° E–160° W located west of the Niño-3.4 region, and the Niño-3.4 index time-series. In this region where the highest in absolute value DSR anomalies are observed, the mean DSR anomaly values range from −45 Wm−2 during El Niño episodes to +40 Wm−2 during La Niña events. Within the Niño-3.4 region no significant DSR anomalies are observed during the cold ENSO phase in contrast to the warm ENSO phase. A high correlation was also found over the western Pacific (10° S–5° N, 120–140° E), where the mean DSR anomaly values range from +20 Wm−2 to −20 Wm−2 during El Niño and La Niña episodes, respectively. There is also convincing evidence that the time series of the mean downward shortwave radiation anomaly in the off-equatorial western Pacific region 7–15° N 150–170° E, precedes the Niño-3.4 index time-series by about 7 months and the pattern of this anomaly is indicative of ENSO operating through the mechanism of the western Pacific oscillator. Thus, the downward shortwave radiation anomaly is a complementary index to the SST anomaly for the study of ENSO events and can be used to assess whether or not El Niño or La Niña conditions prevail.

References 1

Allan, R. P, Slingo, A., and Ringer, M. A.: Influence of dynamics on the changes in tropical cloud radiative forcing during the 1998 El Niño, J. Climate, 15, 1979–1986, 2002.

Amador, J. A., Alfaro, E. J., Lizano, O. G., and Magan, V. O.: Atmospheric forcing of the eastern tropical Pacific: A review, Prog. Oceanogr., 69, 101–142, 2006.

Bjerknes, J.: A possible response of the atmospheric Hadley circulation to equatorial anomalies of ocean temperature, Tellus, 18, 820–829, 1966.

Bjerknes, J.: Atmospheric teleconnections from the equatorial Pacific, Mon. Weather Rev., 97, 163–172, 1969.

Cane, M. A., Matthias, M., and Zebiak, S. E.: A study of self excited oscillations of the tropical ocean–atmosphere system, Part I: Linear analysis, J. Atmos. Sci., 47, 1562–1577, 1990.

Cess, R. D., Wang, P. H., and Wielicki, B. A.: Cloud structure anomalies over the tropical Pacific during the 1997/1998 El Niño, Geophys. Res. Lett., 28, 4547–4550, 2001

Chou,~Shu-Hsien, Chou,~Ming-Dah, Chan,~Pui-King, Lin,~Po-Hsiung, Wang,~Kung-Hwa: Tropical warm pool surface heat budgets and temperature: Contrasts between 1997/98 El Niño and 1998/99 La Niña, J. Climate, 17, 1845–1858, 2004.

Curtis, S. and Adler, R.: ENSO indices based on patterns of satellite-derived precipitation, J. Climate, 13, 2786–2793, 2000.

Dijkstra, H. A.: The ENSO phenomenon: theory and mechanisms, Adv. Geosci., 6, 3–15, 2006.

Fedorov, A. V., Harper, S. L., Philander, S. G., Winter, B., and Wittenberg, A.: How predictable is El Niño?, B. Am. Meteorol. Soc., 84, 911–919, 2003

Fotiadi, A., Hatzianastassiou, N., Matsoukas, C., Pavlakis, K. G., Drakakis, E., Hatzidimitriou, D., and Vardavas, I.: Analysis of the decrease in the tropical mean outgoing shortwave radiation at the top of atmosphere for the period 1984–2000, Atmos. Chem. Phys., 5, 1721–1730, 2005,

Fotiadi, A., Hatzianastassiou, N., Stackhouse, P. W., Matsoukas, C., Drakakis, E., Pavlakis, K. G., Hatzidimitriou D, and Vardavas, I.: Spatial and temporal distribution of long-term short-wave surface radiation over Greece, Q. J. R. Meteorol. Soc., 132, 2693–2718, 2006

Hanley, D. E., Bourassa, M. A., O'Brien, J. J., Smith, S. R., and Spade, E. R.: A quantitative evaluation of ENSO indices, J. Climate, 16, 1249–1258, 2003.

Harrison, M. J., Rosati, A., Soden, B. J., Galanti, E., and Tziperman, E.: An evaluation of air-sea flux products for ENSO simulation and prediction, Mon. Weather Rev., 130, 723–732, 2002.

Hatzianastassiou, N. and Vardavas, I.: Shortwave radiation budget of the Northern Hemisphere using International Satellite Cloud Climatology Project and NCEP/NCAR climatological data, J. Geophys. Res., 104, 24 401–24 421, 1999.

Hatzianastassiou, N. and Vardavas, I.: Shortwave radiation budget of the Southern Hemisphere using ISCCP C2 and NCEP/NCAR climatological data, J. Climate, 14, 4319–4329, 2001.

Hatzianastassiou, N., Fotiadi, A., Matsoukas, C., Drakakis, E., Pavlakis, K. G., Hatzidimitriou, D., and Vardavas, I.: Long-term global distribution of Earth's shortwave radiation budget at the top of atmosphere, Atmos. Chem. Phys., 4, 1217–1235, 2004a.

Hatzianastassiou, N., Katsoulis, B. and Vardavas, I.: Global distribution of aerosol direct radiative forcing in the ultraviolet and visible arising under clear skies, Tellus, 56B, 51–71, 2004b.

Hatzianastassiou, N., Fotiadi, A., Matsoukas, C., Drakakis, E., Pavlakis, K. G., Hatzidimitriou, D., and Vardavas, I.: Global distribution of Earth's surface short-wave radiation budget, Atmos. Chem. Phys., 5, 2847–2867, 2005.

Jin, F. F.: An equatorial ocean recharge paradigm for ENSO, Part I: Conceptual model, J. Atmos. Sci., 54, 811–829, 1997a.

Jin, F. F.: An equatorial ocean recharge paradigm for ENSO, Part II: A stripped-down coupled model, J. Atmos. Sci., 54, 830–847, 1997b.

Kistler, R., Kalnay, E., Collins, W., Saha, S., White, G., Woollen, J., Chelliah, M., Ebisuzaki, W., Kanamitsu, M., Kousky, V., van den Dool, H., Jenne, R., and Fiorino, M.: The NCEP-NCAR 50-Year Reanalysis: Monthly Means CD ROM and Documentation, Bulletin of the American Meteorological Society, 82, 247–268, 2001.

Koepke, P., Hess, M., Schult, I., and Shettle, E. P.: Global aerosol data set, Rep. No. 243, Max-Planck Institut für Meteorologie, 44 pp., Hamburg, Germany, 1997.

McCreary, J. P., and Anderson, D. L. T.: An overview of coupled ocean-atmosphere models of El Niño and the Southern Oscillation, J. Geophys. Res., 96, 3125–3150, 1991.

McPhaden, M. J., Busalacchi, A. J., Cheney, R., et al.: The tropical ocean-global atmosphere observing system: A decade of progress, J. Geophys. Res., 103, 14 169–14 240, 1998.

Neelin, J. D., Battisti, D. S., Hirst, A. C.,. Jin, F. F, Wakata, Y., Yamagata, T., and Zebiak, S. E.: ENSO theory, J. Geophys. Res., 103, 14 262–14 290, 1998.

Ohmura, A. and Gilgen, H.: Re-evaluation of the global energy balance, Interactions between global climate subsystems: The legacy of Hann, Geophys. Monogr., No. 75, International Union of Geodesy and Geophysics, 93–110, 1993.

Ohmura, A., Gilgen, H., Hegner, H., Mueller, G., Wild, M., Dutton, E. G., Forgan, B., Froehlich, C., Philippona, R., Heimo, A., Koenig-Langlo, G., McArthur, B., Pinker, R., Whitlock, C. H., and Dehne, K.: Baseline Surface Radiation Network (BSRN/WCRP): New precision radiometry for climate research, Bull. Am. Meteorol. Soc., 79, 2115–2136, 1998.

Pavlakis, K. G., Hatzidimitriou, D., Drakakis, E., Matsoukas, C., Fotiadi, A., Hatzianastassiou, N., and Vardavas, I.: ENSO surface longwave radiation forcing over the tropical Pacific, Atmos. Chem. Phys., 7, 2013–2026, 2007.

Philander, S. G.: El Niño, La Niña, and the Southern Oscillation, Academic Press, San Diego, CA, USA, 1–289, 1990.

Picaut, J., Masia, F., and du Penhoat, Y.: An advective–reflective conceptual model for the oscillatory nature of the ENSO, Science, 277, 663–666, 1997.

Rossow, W. B. and Schiffer, R. A.: Advances in understanding clouds from ISCCP, Bull. Am. Meteorol. Soc., 80, 2261–2288, 1999.

Suarez, M. J., and P. S. Schopf: A delayed action oscillator for ENSO, J. Atmos. Sci., 45, 3283–3287, 1988.

Tian, B. and Ramanathan, V.: Role of tropical clouds in surface and atmospheric energy budget, J. Climate, 15, 296–305, 2002.

Trenberth, K. E.: The definition of El Niño, Bull. Amer. Meteor. Soc., 78, 2771–2777, 1997.

Trenberth, K. E. and Caron, J. M.: The Southern Oscillation revisited: Sea level pressure, surface temperatures, and precipitation, J. Climate, 13, 4358–4365, 2000.

Trenberth, K. E. and D. P. Stepaniak: Indices of El Niño evolution, J. Climate, 14, 1697–1701, 2001.

Vardavas, I. and Carver, J. H.: Solar and terrestrial parameterizations for radiative convective models, Planet. Space Sci., 32, 1307–1325, 1984.

Vardavas, I. M., and Taylor, F. W.:Radiation and Climate, International Series of Monographs on Physics, No. 138, Oxford University Press, Oxford, 1–512, 2007.

Wagner, T., Beirle, S., Grzegorski, M., Sanghavi, S., and Platt, U.: El Niño induced anomalies in global data sets of total column precipitable water and cloud cover derived from GOME on ERS-2, J. Geophys. Res., 110, D15104, https://doi.org/10.1029/2005JD005972, 2005.

Wang, C., Weisberg, R. H., and Virmani, J. I.: Western Pacific interannual variability associated with the El Niño–Southern Oscillation, J. Geophys. Res., 104, 5131–5149, 1999.

Wang, C. and Weisberg, R. H.: The 1997–1998 El Niño evolution relative to previous El Niño events, J. Climate, 13, 488–501, 2000.

Wang, C.: On the atmospheric responses to tropical Pacific heating during the mature phase of El Niño, J. Atmos. Sci., 57, 3767–3781, 2000.

Wang, C.: A unified oscillator model for the El Niño–Southern Oscillation, J. Climate, 14, 98–115, 2001.

Wang, C.: Atmospheric circulation cells associated with the El Niño–Southern Oscillation, J. Climate, 15, 399–419, 2002.

Wang, C. and Picaut, J.: Understanding ENSO Physics: A review in Earth's Climate, in: The Ocean-Atmosphere Interaction, edited by: Wang, C., Xie, S.-P., and Carton, J. A., American Geophysical Union, 21–48, 2004.

Wang, C. and Fiedler, P. C.: ENSO variability and the eastern tropical Pacific: A review, Prog. Oceanography, 69, 239–266, 2006.

Weisberg, R. H. and Wang,C.:A western Pacific oscillator paradigm for the El Niño – Southern Oscillation, Geophys. Res. Lett., 24, 779–782, 1997.

Wolter, K., and Timlin, M. S.: Measuring the strength of ENSO events: How does 1997/1998 rank?, Weather, 53, 315–324, 1998.