Congo Basin Hydrology, Climate, and Biogeochemistry. Группа авторов

Чтение книги онлайн.

СКАЧАТЬ M., & Momha, A. B. (2009). Adaptive Water Management in the Lake Chad Basin: Addressing Current Challenges and Adapting to Future Needs. Seminar at World Water Week, Stockholm.

      56 Sandjon, A. T., Nzeukou, A., & Tchawoua, C. (2012). Intraseasonal atmospheric variability and its interannual modulation in Central Africa. Meteorology and Atmospheric Physics, 117(3–4), 167–179. doi: 10.1007/s00703‐012‐0196‐6

      57 Shekhar, R., & Boos, W. R. (2017). Weakening and shifting of the Saharan shallow meridional circulation during wet years of the West African monsoon. Journal of Climate, 30(18), 7399–7422. doi: 10.1175/jcli‐d‐16‐0696.1

      58 Sinclaire, Z., Lenouo, A., Tchawoua, C., & Janicot, S. (2015). Synoptic Kelvin type perturbation waves over Congo basin over the period 1979–2010. Journal of Atmospheric and Solar‐Terrestrial Physics, 130–131, 43–56. doi: 10.1016/j.jastp.2015.04.015

      59 Sonkoué, D., Monkam, D., Fotso‐Nguemo, T. C., Yepdo, Z. D., & Vondou, D. A. (2018). Evaluation and projected changes in daily rainfall characteristics over Central Africa based on a multi‐model ensemble mean of CMIP5 simulations. Theoretical and Applied Climatology, 137(3–4), 2167–2186. doi: 10.1007/s00704‐018‐2729‐5

      60 Suzuki, T. (2010). Seasonal variation of the ITCZ and its characteristics over central Africa. Theoretical and Applied Climatology, 103(1–2), 39–60. doi: 10.1007/s00704‐010‐0276‐9

      61 Taguela, T. N., Vondou, D. A., Moufouma‐Okia, W., Fotso‐Nguemo, T. C., Pokam, W. M., Tanessong, R. S., et al. (2020). CORDEX Multi‐RCM hindcast over central Africa: Evaluation within observational uncertainty. Journal of Geophysical Research: Atmospheres, 125(5). doi: 10.1029/2019jd031607

      62 Tamoffo, A. T., Moufouma‐Okia, W., Dosio, A., James, R., Pokam, W. M., Vondou, D. A., et al. (2019). Process‐oriented assessment of RCA4 regional climate model projections over the Congo Basin under 1.50C and 20C global warming levels: influence of regional moisture fluxes. Climate Dynamics, 53, 1911–1935. https://doi.org/10.1007/s00382‐019‐04751‐y

      63 Tamoffo, A. T., Dosio, A., Vondou, D. A., & Sonkoué, D. (2020). Process‐based analysis of the added value of dynamical downscaling over central Africa. Geophysical Research Letters, 47(17). doi: 10.1029/2020gl089702

      64 Taylor, C. M., Fink, A. H., Klein, C., Parker, D. J., Guichard, F., Harris, P. P., & Knapp, K. R. (2018). Earlier seasonal onset of intense mesoscale convective systems in the Congo Basin since 1999. Geophysical Research Letters, 45(24). doi: 10.1029/2018gl080516

      65 Tchotchou, L. A., & Kamga, F. M. (2010). Sensitivity of the simulated African monsoon of summers 1993 and 1999 to convective parameterization schemes in RegCM3. Theoretical and Applied Climatology, 100(1–2), 207–220. doi: 10.1007/s00704‐009‐0181‐2

      66 Thorncroft, C. D., Nguyen, H., Zhang, C., & Peyrillé, P. (2011). Annual cycle of the West African monsoon: Regional circulations and associated water vapour transport. Quarterly Journal of the Royal Meteorological Society, 137(654), 129–147. doi: 10.1002/qj.728

      67 Uccellini, L. W., & Johnson, D. R. (1979). The coupling of upper and lower tropospheric jet streaks and implications for the development of severe convective storms. Monthly Weather Review, 107(6), 682–703. doi: 10.1175/1520‐0493(1979)1072.0.co;2

      68 Vondou, D. A., Nzeukou, A., Lenouo, A., & Kamga, F. M. (2010). Seasonal variations in the diurnal patterns of convection in Cameroon‐Nigeria and their neighboring areas. Atmospheric Science Letters, 11(4), 290–300. doi: 10.1002/asl.297

      69 Vondou, D. A., Yepdo, Z. D., Steve, T. R., Alain, T. S., & Tchotchou, L. D. (2017). Diurnal cycle of rainfall over Central Africa simulated by RegCM. Modeling Earth Systems and Environment, 3(3), 1055–1064. doi: 10.1007/s40808‐017‐0352‐6

      70 Vondou, D. A., & Haensler, A. (2017). Evaluation of simulations with the regional climate model REMO over Central Africa and the effect of increased spatial resolution. International Journal of Climatology, 37, 741–760. doi: 10.1002/joc.5035

      71 Washington, R., James, R., Pearce, H., Pokam, W. M., & Moufouma‐Okia, W. (2013). Congo Basin rainfall climatology: Can we believe the climate models? Philosophical Transactions of the Royal Society B: Biological Sciences, 368(1625), 20120296. doi: 10.1098/rstb.2012.0296

      72 Wu, M., Nikulin, G., Kjellström, E., Belušić, D., Jones, C., & Lindstedt, D. (2019). The impact of RCM formulation and resolution on simulated precipitation in Africa. Earth System Dynamics, 11(2), 377–394. doi: 10.5194/esd‐2019‐55

      73 Zipser, E. J., Cecil, D. J., Liu, C., Nesbitt, S. W., & Yorty, D. P. (2006). Where are the most intense thunderstorms on Earth? Bulletin of the American Meteorological Society, 87(8), 1057–1072. doi: 10.1175/bams‐87‐8‐1057

3 The Rainfall and Convective Regime over Equatorial Africa, with Emphasis on the Congo Basin

       Sharon E. Nicholson

       Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida, USA

      ABSTRACT

      The paper examines the character of the rainfall and convective regime over equatorial Africa, in order to better understand the meteorological processes governing rainfall and convection in this region. Emphasis is placed on the Congo Basin region. Included is a review of the meteorological factors shaping the rainfall and convective regimes around the Congo Basin. Several aspects of rainfall and its seasonality are examined, along with the interannual variability of rainfall in key regions. In several regions a downward trend is documented, with a change toward increasing aridity occurring around 1970. However, the trends are weak, are generally not significant, and do not continue to present. The nature of the convective regime, in particular the contribution of mesoscale convective systems, is also described. Finally, a comparison is made with the rainfall and convective regime over the Amazon, an equatorial region that is considerably wetter than the Congo Basin. Large areas of the Amazon receive 2500 mm to over 3000 mm per year on average, while few areas of the Congo Basin receive more than 1750 mm per year on average. Peak rainfall tends to occur in the afternoon over the Amazon, but at night or early morning over the Congo Basin. This suggests the mesoscale convective systems play a greater role in the Congo Basin. Several reasons are suggested for the relatively dry conditions over the Congo Basin, including lower moisture flux convergence and lower relative humidity.

3.1. INTRODUCTION

The Congo Basin (Figure 3.1) is the location of the world’s second‐largest expanse of rainforest. The region has much in common climatologically and ecologically with the Amazon rainforest. However, there are some hydrologic peculiarities that have not been adequately explained. One of these is the relatively low amount of annual rainfall in the region compared to the Amazon. Several papers have suggested explanations, including lower precipitable water content over the Congo (Jackson et al., 2009; McCollum et al., 2000) and low‐level subsidence (Dezfuli & Nicholson, 2013; Nicholson & Dezfuli, 2013).

      This paper does not attempt to solve the controversy. Rather, it intends to use both a literature review and several new analyses to increase our understanding of the rainfall and convective regime over equatorial Africa, and the Congo Basin in particular. Secondarily, it provides a very rudimentary comparison of some of СКАЧАТЬ