Weakened seasonality of the African rainforest precipitation in boreal winter and spring driven by tropical SST variabilities

Springer Science and Business Media LLC - Tập 8 - Trang 1-12 - 2021
Xin-Yue Wang1,2, Jiang Zhu1,2, Meijiao Xin1,2, Chentao Song1,2, Yadi Li1,2, Yi Zhou1,2, Xichen Li1,3
1Institute of Atmospheric Physics Chinese Academy of Sciences, Beijing, China
2University of Chinese Academy of Sciences, Beijing, China
3State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China

Tóm tắt

Precipitation in the equatorial African rainforest plays an important role in both the regional hydrological cycle and the global climate variability. Previous studies mostly focus on the trends of drought in recent decades or long-time scales. Using two observational datasets, we reveal a remarkable weakening of the seasonal precipitation cycle over this region from 1979 to 2015, with precipitation significantly increased in the boreal winter dry season (~ 0.13 mm/day/decade) and decreased in the boreal spring wet season (~ 0.21 mm/day/decade), which account for ~ 14% (the precipitation changes from 1979 to 2015) of their respective climatological means. We further use a state-of-the-art atmospheric model to isolate the impact of sea surface temperature change from different ocean basins on the precipitation changes in the dry and wet seasons. Results show that the strengthening precipitation in the dry season is mainly driven by the Atlantic warming, whereas the weakening precipitation in the wet season can be primarily attributed to the Indian Ocean. Warming Atlantic intensifies the zonal circulation over the African rainforest, strengthening moisture convergence and intensifying precipitation in the boreal winter dry season. Warming Indian Ocean contributes more to reducing the zonal circulation and suppressing the convection in the boreal spring wet season, leading to an opposite effect on precipitation. This result has important implication on local ecology as well as global climate system.

Tài liệu tham khảo

Asefi-Najafabady S, Saatchi S (2013) Response of African humid tropical forests to recent rainfall anomalies. Phil Trans R Soc B 368(1625):20120306 Baccini A, Goetz S, Walker W, Laporte N, Sun M, Sulla-Menashe D, Hackler J, Beck P, Dubayah R, Friedl M (2012) Estimated carbon dioxide emissions from tropical deforestation improved by carbon-density maps. Nat Clim Chang 2(3):182–185 Balas N, Nicholson S, Klotter D (2007) The relationship of rainfall variability in West Central Africa to sea-surface temperature fluctuations. Int J Climatol 27(10):1335–1349 Camberlin P, Janicot S, Poccard I (2001) Seasonality and atmospheric dynamics of the teleconnection between African rainfall and tropical sea-surface temperature: Atlantic vs ENSO. Int J Climatol 21(8):973–1005 Chadwick R, Good P, Willett K (2016) A simple moisture advection model of specific humidity change over land in response to SST warming. J Clim 29(21):7613–7632 Chambers JQ, Roberts DA (2014) Drought in the Congo Basin. Nature 509(7498):36–38 Cook KH, Vizy EK (2016) The Congo Basin Walker circulation: dynamics and connections to precipitation. Clim Dyn 47(3–4):697–717 Creese A, Washington R (2018) A process-based assessment of CMIP5 rainfall in the Congo Basin: the September–November rainy season. J Clim 31(18):7417–7439 Dezfuli AK, Zaitchik BF, Gnanadesikan A (2015) Regional atmospheric circulation and rainfall variability in south equatorial Africa. J Clim 28(2):809–818 Diem JE, Ryan SJ, Hartter J, Palace MW (2014) Satellite-based rainfall data reveal a recent drying trend in central equatorial Africa. Clim Change 126(1–2):263–272 DiNezio PN, Vecchi GA, Clement AC (2013) Detectability of changes in the walker circulation in response to global warming. J Clim 26(12):4038–4048 Farnsworth A, White E, Williams CJ, Black E, Kniveton DR (2011) Understanding the large scale driving mechanisms of rainfall variability over Central Africa. In: Williams CJR, Kniveton DR (eds) African climate and climate change. Springer, Dordrecht, pp 101–122 Friedl MA, Sulla-Menashe D, Tan B, Schneider A, Ramankutty N, Sibley A, Huang X (2010) MODIS Collection 5 global land cover: Algorithm refinements and characterization of new datasets. Remote Sens Environ 114(1):168–182 Gaffen DJ, Ross RJ (1999) Climatology and trends of US surface humidity and temperature. J Clim 12(3):811–828 Ha K-J, Kim B-H, Chung E-S, Chan JCL, Chang C-P (2020) Major factors of global and regional monsoon rainfall changes: natural versus anthropogenic forcing. Environ Res Lett 15(3):034055 Hart NCG, Washington R, Maidment RI (2019) Deep convection over Africa: annual cycle, ENSO, and trends in the hotspots. J Clim 32(24):8791–8811 Hoerling M, Hurrell J, Eischeid J, Phillips A (2006) Detection and attribution of twentieth-century northern and southern African rainfall change. J Clim 19(16):3989–4008 Hua W, Zhou L, Chen H, Nicholson SE, Raghavendra A, Jiang Y (2016) Possible causes of the Central Equatorial African long-term drought. Environ Res Lett 11(12):124002 Huffman GJ, Adler RF, Bolvin DT, Gu G (2009) Improving the global precipitation record: GPCP Version 2.1. Geophys Res Lett. https://doi.org/10.1029/2009GL040000 Jackson B, Nicholson SE, Klotter D (2009) Mesoscale convective systems over western equatorial Africa and their relationship to large-scale circulation. Mon Weather Rev 137(4):1272–1294 James R, Washington R, Rowell DP (2013) Implications of global warming for the climate of African rainforests. Phil Trans R Soc B 368(1625):20120298 Jiang Y, Zhou L, Tucker CJ, Raghavendra A, Hua W, Liu YY, Joiner J (2019) Widespread increase of boreal summer dry season length over the Congo rainforest. Nat Clim Chang 9(8):617–622 Kamae Y, Li X, Xie S-P, Ueda H (2017) Atlantic effects on recent decadal trends in global monsoon. Clim Dyn 49(9–10):3443–3455 Kosaka Y, Xie S-P (2013) Recent global-warming hiatus tied to equatorial Pacific surface cooling. Nature 501(7467):403–407 Leduc-Leballeur M, De Coëtlogon G, Eymard L (2013) Air–sea interaction in the Gulf of Guinea at intraseasonal time-scales: wind bursts and coastal precipitation in boreal spring. Q J R Meteorol Soc 139(671):387–400 Li X, Xie S-P, Gille ST, Yoo C (2016) Atlantic-induced pan-tropical climate change over the past three decades. Nat Clim Chang 6(3):275–279 Lyon B, DeWitt DG (2012) A recent and abrupt decline in the East African long rains. Geophys Res Lett. https://doi.org/10.1029/2011GL050337 Maidment RI, Allan RP, Black E (2015) Recent observed and simulated changes in precipitation over Africa. Geophys Res Lett 42(19):8155–8164 Malhi Y, Wright J (2004) Spatial patterns and recent trends in the climate of tropical rainforest regions. Philos Trans R Soc Lond B Biol Sci 359(1443):311–329 Malhi Y, Adu-Bredu S, Asare RA, Lewis SL, Mayaux P (2013) African rainforests: past, present and future. Phil Trans R Soc B 368(1625):20120312 Mayaux P, Pekel J-F, Desclée B, Donnay F, Lupi A, Achard F, Clerici M, Bodart C, Brink A, Nasi R (2013) State and evolution of the African rainforests between 1990 and 2010. Phil Trans R Soc B 368(1625):20120300 McGregor S, Timmermann A, Stuecker MF, England MH, Merrifield M, Jin F-F, Chikamoto Y (2014) Recent Walker circulation strengthening and Pacific cooling amplified by Atlantic warming. Nat Clim Chang 4(10):888–892 Neale RB, Richter J, Park S, Lauritzen PH, Vavrus SJ, Rasch PJ, Zhang M (2013) The mean climate of the community atmosphere model (CAM4) in forced SST and fully coupled experiments. J Clim 26(14):5150–5168 Nicholson SE (2009) A revised picture of the structure of the “monsoon” and land ITCZ over West Africa. Clim Dyn 32(7–8):1155–1171 Nicholson SE (2018) The ITCZ and the seasonal cycle over equatorial Africa. Bull Am Meteor Soc 99(2):337–348 Nicholson SE, Dezfuli AK (2013) The relationship of rainfall variability in western equatorial Africa to the tropical oceans and atmospheric circulation. Part I: The boreal spring. J Clim 26(1):45–65 Otto FEL, Jones RG, Halladay K, Allen MR (2013) Attribution of changes in precipitation patterns in African rainforests. Phil Trans R Soc B 368(1625):20120299 Pokam WM, Djiotang LAT, Mkankam FK (2012) Atmospheric water vapor transport and recycling in Equatorial Central Africa through NCEP/NCAR reanalysis data. Clim Dyn 38(9–10):1715–1729 Rayner N, Parker DE, Horton E, Folland CK, Alexander LV, Rowell D, Kent E, Kaplan A (2003) Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J Geophys Res. https://doi.org/10.1029/2002JD002670 Redelsperger J-L, Thorncroft CD, Diedhiou A, Lebel T, Parker DJ, Polcher J (2006) African monsoon multidisciplinary analysis: an international research project and field campaign. Bull Am Meteor Soc 87(12):1739–1746 Richard GO (1987) Statistical methods for environmental pollution monitoring. Wiley Richard Y, Fauchereau N, Poccard I, Rouault M, Trzaska S (2001) 20th century droughts in southern Africa: spatial and temporal variability, teleconnections with oceanic and atmospheric conditions. Int J Climatol 21(7):873–885 Saatchi SS, Harris NL, Brown S, Lefsky M, Mitchard ET, Salas W, Zutta BR, Buermann W, Lewis SL, Hagen S (2011) Benchmark map of forest carbon stocks in tropical regions across three continents. Proc Natl Acad Sci 108(24):9899–9904 Satyamurty P, Wanzeler da Costa CP, Manzi AO (2013) Moisture source for the Amazon Basin: a study of contrasting years. Theor Appl Climatol 111(1–2):195–209 Sen PK (1968) Estimates of the regression coefficient based on Kendall’s tau. J Am Stat Assoc 63(324):1379–2000 Shanahan TM, Overpeck JT, Anchukaitis K, Beck JW, Cole JE, Dettman DL, Peck JA, Scholz CA, King JW (2009) Atlantic forcing of persistent drought in West Africa. Science 324(5925):377–380 Sultan B, Janicot S (2000) Abrupt shift of the ITCZ over West Africa and intra-seasonal variability. Geophys Res Lett 27(20):3353–3356 Thorncroft CD, Nguyen H, Zhang C, Peyrillé P (2011) Annual cycle of the West African monsoon: regional circulations and associated water vapour transport. Q J R Meteorol Soc 137(654):129–147 Todd MC, Washington R (2004) Climate variability in central equatorial Africa: Influence from the Atlantic sector. Geophys Res Lett. https://doi.org/10.1029/2004GL020975 Trenberth KE, Fasullo JT, Mackaro J (2011) Atmospheric moisture transports from ocean to land and global energy flows in reanalyses. J Clim 24(18):4907–4924 Washington R, James R, Pearce H, Pokam WM, Moufouma-Okia W (2013) Congo Basin rainfall climatology: can we believe the climate models? Phil Trans R Soc B 368(1625):20120296 Webster PJ (1973) Temporal variation of low-latitude zonal circulations. Mon Weather Rev 101(11):803–816 Williams AP, Funk C (2011) A westward extension of the warm pool leads to a westward extension of the Walker circulation, drying eastern Africa. Clim Dyn 37(11–12):2417–2435 Xie PP, Arkin PA (1997) Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull Amer Meteor Soc 78(11):2539–2558 Yin X, Gruber A (2010) Validation of the abrupt change in GPCP precipitation in the Congo River Basin. Int J Climatol 30(1):110–119 Yin XG, Gruber A, Arkin P (2004) Comparison of the GPCP and CMAP merged gauge-satellite monthly precipitation products for the period 1979–2001. J Hydrometeorol 5(6):1207–1222 Yu B, Zwiers FW (2010) Changes in equatorial atmospheric zonal circulations in recent decades. Geophys Res Lett. https://doi.org/10.1029/2009GL042071 Yu B, Zwiers FW, Boer GJ, Ting MF (2012) Structure and variances of equatorial zonal circulation in a multimodel ensemble. Clim Dyn 39(9–10):2403–2419 Zhou L, Tian Y, Myneni RB, Ciais P, Saatchi S, Liu YY, Piao S, Chen H, Vermote EF, Song C (2014) Widespread decline of Congo rainforest greenness in the past decade. Nature 509(7498):86–90