Assessment of the Intertropical Convergence Zone over the Atlantic Ocean through an Algorithm Based on Precipitation

Source:
By:Natan Chrysostomo de Oliveira Nogueira, Pedro Henrique Gomes Machado, Michelle Simões Reboita, André Luiz Reis

DOI: https://doi.org/10.30564/jasr.v7i1.6188

Abstract:

The Intertropical Convergence Zone (ITCZ) is a key atmospheric system on a global scale, primarily driven by trade wind convergence near the equator. The ITCZ plays a crucial role in modulating the climate of the borders of tropical continental areas. For instance, Northeastern Brazil experiences a climate influenced by the ITCZ over the Atlantic Ocean. In some periods, the ITCZ exhibits double bands, known as the double ITCZ. While the features of the ITCZ have been described using various approaches and atmospheric variables, there is still a lack of regional studies focusing on the ITCZ and double ITCZ in the Atlantic Ocean. In this context, the main goals of this study are (1) to describe a simple algorithm based on precipitation to identify the ITCZ and double ITCZ, (2) to present a climatology (1997–2022) of the position, width, and intensity of these two convective bands, and (3) to investigate variabilities in the ITCZ characteristics associated with anomalies of sea surface temperature (SST) in the tropical Pacific and Atlantic oceans. The double ITCZ typically occurs southward of the main cloud band, and between February and April, both bands are more distant (~4.5°). In the western sector of the Atlantic Ocean, the ITCZ and its double band extend to more southerly latitudes in austral autumn. Considering the entire Atlantic basin, the annual mean of the latitudinal position, width, and intensity of the ITCZ is 4.9°N, 4.2°, and 11 mm/day, respectively, while for the double ITCZ, it is 0.4°N, 2.6°, 10.3 mm/day, respectively. While the SST anomalies in the Pacific Ocean (El Niño and La Niña episodes) affect more the ITCZ width, the SST anomalies in the Tropical South Atlantic affect both its position and width.

References:

[1] Asnani, G.C., 1993. Tropical meteorology. Indian Institute of Tropical Meteorology: Pune. [2] Waliser, D.E., Somerville, R.C.J., 1994. Preferred latitudes of the intertropical convergence zone. Journal of Atmospheric Sciences. 51(12), 1619–1639. DOI: https://doi.org/10.1175/1520-0469(1994)051<1619:PLOTIC>2.0.CO;2 [3] Xie, S.P., Philander, S.G.H., 1994. A coupled ocean‐atmosphere model of relevance to the ITCZ in the eastern Pacific. Tellus A. 46(4), 340–350. DOI: https://doi.org/10.3402/tellusa.v46i4.15484 [4] Waliser, D.E., Gautier, C., 1993. A satellite-derived climatology of the ITCZ. Journal of Climate. 6(11), 2162–2174. DOI: https://doi.org/10.1175/1520-0442(1993)006<2162:ASDCOT>2.0.CO;2 [5] Diaz, H.F., Bradley, R.S., 2004. The Hadley circulation: Present, past, and future. The Hadley circulation: Present, past and future. Advances in global change research. Springer: Dordrecht. DOI: https://doi.org/10.1007/978-1-4020-2944-8_1 [6] Wang, C., Xie, S.P., Carton, J.A., 2004. Tropical Atlantic variability: Patterns, mechanisms, and impacts. Earth’s Climate: The Ocean-Atmosphere Interaction. 147, 121–142. DOI: https://doi.org/10.1029/147GM07 [7] Krishnamurti, T.N., Stefanova, L., Misra, V., 2013. Tropical meteorology—An introduction. Springer: New York. [8] Aimola, L., Moura, M., 2016. The influence of the Atlantic Meridional overturning circulation in the definition of the mean position of the ITCZ north of the equator. A review. Revista Brasileira de Meteorologia. 31(4 suppl 1). (in Portuguese). DOI: https://doi.org/10.1590/0102-7786312314b20150059 [9] Liu, C., Liao, X., Qiu, J., et al., 2020. Observed variability of intertropical convergence zone over 1998–2018. Environmental Research Letters. 15(10), 104011. [10] Iyer, S., Drushka, K., 2021. Turbulence within rain-formed fresh lenses during the SPURS-2 experiment. Journal of Physical Oceanography. 51(5), 1705–1721. DOI: https://doi.org/10.1175/JPO-D-20-0303.1 [11] Windmiller, J.M., Stevens, B., 2023. The inner life of the Atlantic Intertropical Convergence Zone. Quarterly Journal of the Royal Meteorological Society. DOI: https://doi.org/10.1002/qj.4610 [12] Misra, V., 2023. Intertropical Convergence Zone. An introduction to large-scale tropical meteorology. Springer: Cham. pp. 91–109. DOI: https://doi.org/10.1007/978-3-031-12887-5_4 [13] Schneider, T., Bischoff, T., Haug, G., 2014. Migrations and dynamics of the intertropical convergence zone. Nature. 513, 45–53. DOI: https://doi.org/10.1038/nature13636 [14] Philander, S.G.H., Gu, D., Lambert, G., et al., 1996. Why the ITCZ is mostly north of the equator. Journal of Climate. 9(12), 2958–2972. DOI: https://doi.org/10.1175/1520-0442(1996)009<2958:WTIIMN>2.0.CO;2 [15] Bony, S., Stevens, B., Frierson, D.M.W., et al., 2015. Clouds, circulation and climate sensitivity. Nature Geoscience. 8, 261–268. DOI: https://doi.org/10.1038/ngeo2398 [16] Kang, S.M., Shin, Y., Xie, S.P., 2018. Extratropical forcing and tropical rainfall distribution: Energetics framework and ocean Ekman advection. npj Climate and Atmospheric Science. 1, 20172. DOI: https://doi.org/10.1038/s41612-017-0004-6 [17] Tomaziello, A.C.N., Carvalho, L.M.V., Gandu, A.W., 2016. Intraseasonal variability of the Atlantic Intertropical Convergence Zone during austral summer and winter. Climate Dynamics. 47, 1717–1733. DOI: https://doi.org/10.1007/s00382-015-2929-y [18] Khrgian, A., 1977. Physical meteorology. Summaries of scientific progress: Meteorology and climatology, Volume 2. G.K. Hall: Boston. [19] Monsoons [Internet]. World Meteorological Organization (WMO); 1986. Available from: https://library.wmo.int/idurl/4/37019 [20] Hastenrath, S., 1991. Climate dynamics of the tropics. Kluwer Academic Publishers: Dordrecht. [21] Mendonça, F., Danni-Oliveira, I.M., 2007. Climatology: Basic concepts and Brazilian climatates. Oficina de Textos Publisher: São Paulo. (in Portuguese). [22] Carvalho, M.A.V., Oyama, M.D., 2013. Atlantic Intertropical Convergence Zone width and intensity variability: Observational aspects. Revista Brasileira de Meteorologia. 28(3), 305–316. (in Portuguese). DOI: https://doi.org/10.1590/S0102-77862013000300007 [23] Kousky, V.E., 1988. Pentad outgoing longwave radiation climatology for the South American sector. Revista Brasileira de Meteorologia. 3(1), 217–231. [24] Uvo, C. R. B., 1989. The Intertropical Convergence Zone (ITCZ) and its relationship with precipitation in the northern region of northeast Brazil. (in Portuguese). [25] Liu, W.T., Xie, X., 2002. Double intertropical convergence zones—A new look using scatterometer. Geophysical Research Letters. 29(22), 291–294. DOI: https://doi.org/10.1029/2002GL015431 [26] Teodoro, T.A., Reboita, M.S., Escobar, G.C.J., 2019. Characterization of the double band of the Intertropical Convergence Zone (ITCZ) over the Atlantic Ocean. Yearbook of the Institute of Geosciences. 42(2), 282–298. (in Portuguese). DOI: https://doi.org/10.11137/2019_2_282_298 [27] Hubert, L.F., Krueger, A.F., Winston, J.S., 1969. The double intertropical convergence zone-fact or fiction? Journal of the Atmospheric Sciences. 26(4), 771–773. DOI: https://doi.org/10.1175/1520-0469(1969)026<0771:TDICZF>2.0.CO;2 [28] Zhang, C., 2001. Double ITCZs. Journal of Geophysical Research: Atmospheres. 106(D11), 11785–11792. DOI: https://doi.org/10.1029/2001JD900046 [29] Henke, D., Smyth, P., Haffke, C., et al., 2012. Automated analysis of the temporal behavior of the double Intertropical Convergence Zone over the east Pacific. Remote Sensing of Environment. 123, 418–433. DOI: https://doi.org/10.1016/j.rse.2012.03.022 [30] Meenu, S., Rajeev, K., Parameswaran, K., et al., 2007. Characteristics of the double intertropical convergence zone over the tropical Indian Ocean. Journal of Geophysical Research: Atmospheres. 112(D11). DOI: https://doi.org/10.1029/2006JD007950 [31] Talib, J., Woolnough, S.J., Klingaman, N.P., et al., 2018. The role of the cloud radiative effect in the sensitivity of the intertropical convergence zone to convective mixing. Journal of Climate. 31(17), 6821–6838. DOI: https://doi.org/10.1175/JCLI-D-17-0794.1 [32] Berry, G., Reeder, M.J., 2014. Objective identification of the intertropical convergence zone: Climatology and trends from the ERA-Interim. Journal of Climate. 27(5), 1894–1909. DOI: https://doi.org/10.1175/JCLI-D-13-00339.1 [33] Teresinha de Maria Bezerra, X., Tércio, A., Maria Elisa S, S., 2017. Applications of models and techniques in the detection of climate variability and extremes. Bank of Northeast Brazil. (in Portuguese). [34] Hastenrath, S., Greischar, L., 1993. Circulation mechanisms related to northeast Brazil rainfall anomalies. Journal of Geophysical Research: Atmospheres. 98(D3), 5093–5102. DOI: https://doi.org/10.1029/92JD02646 [35] Reboita, M.S., Santos, I.A., 2014. Teleconnection influences in some precipitation standards. Brazilian Journal of Climatology. 15, 28–48. (in Portuguese). DOI: https://doi.org/10.5380/abclima.v15i0.37686 [36] Reboita, M.S., Ambrizzi, T., Crespo, N.M., et al., 2021. Impacts of teleconnection patterns on South America climate. Annals of the New York Academy of Sciences. 1504(1), 116–153. DOI: https://doi.org/10.1111/nyas.14592 [37] Pezzi, L., Cavalcanti, I., 2001. The relative importance of ENSO and tropical Atlantic sea surface temperature anomalies for seasonal precipitation over South America: A numerical study. Climate Dynamics. 17, 205–212. DOI: https://doi.org/10.1007/s003820000104 [38] Gadgil, S., Guruprasad, A., 1990. An objective method for the identification of the intertropical convergence zone. Journal of Climate. 3(5), 558–567. DOI: https://doi.org/10.1175/1520-0442(1990)003<0558:AOMFTI>2.0.CO;2 [39] Elsemüller, L., 2021. Quantifying the Intertropical Convergence Zone using wind convergences [Master’s thesis]. Tübingen: Eberhard Karls Universität Tübingen. [40] Samuel, S., Mathew, N., Sathiyamoorthy, V., 2023. Characterization of intertropical convergence zone using SAPHIR/Megha-Tropiques satellite brightness temperature data. Climate Dynamics. 60, 3765–3783. DOI: https://doi.org/10.1007/s00382-022-06549-x [41] Adler, R.F., Gu, G., Sapiano, M., et al., 2017. Global precipitation: Means, variations and trends during the satellite era (1979–2014). Surveys in Geophysics. 38, 679–699. DOI: https://doi.org/10.1007/s10712-017-9416-4 [42] Hersbach, H., Bell, B., Berrisford, P., et al., 2020. The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society. 146(730), 1999–2049. DOI: https://doi.org/10.1002/qj.3803 [43] Study of the vertical and horizontal structure of precipitation and atmospheric circulation in the region of the ITCZ, 2002. (in Portuguese). [44] Gomes, H.B., Ambrizzi, T., Pontes da Silva, B.F., et al., 2019. Climatology of easterly wave disturbances over the tropical South Atlantic. Climate Dynamics. 53, 1393–1411. DOI: https://doi.org/10.1007/s00382-019-04667-7 [45] Ferreira, G.W.S., Reboita, M.S., da Rocha, R.P., 2020. Upper level cyclonic vortices in the vicinity of Northeast Brazil: Climatology and analysis of the isentropic potential vorticity. Yearbook of the Institute of Geosciences. 42(3), 568–585. (in Portuguese). DOI: https://doi.org/10.11137/2019_3_568_585 [46] Jafari, M., Lashkari, H., 2020. Study of the relationship between the intertropical convergence zone expansion and the precipitation in the southern half of Iran. Journal of Atmospheric and Solar-Terrestrial Physics. 210, 105439. DOI: https://doi.org/10.1016/j.jastp.2020.105439 [47] Lashkari, H., Jafari, M., 2021. Annual displacement and appropriate index to determine ITCZ position in East Africa and the Indian Ocean regions. Meteorology and Atmospheric Physics. 133, 1111–1126. DOI: https://doi.org/10.1007/s00703-021-00797-y