Precipitation variability in São Paulo State, Brazil
- 470 Downloads
The State of São Paulo is the richest in Brazil, responsible for over 30% of the Brazilian gross rate. It has a population of around 30 million and its economy is based on agriculture and industrial products. Any change in climate can have a profound influence on the socio-economics of the State.
In order to determine changes in total and extreme rainfall over São Paulo State, climate change indices derived from daily precipitation data were calculated using specially designed software. Maps of trends for a subset of 59 rain gauge stations were analysed for the period 1950–1999 and also for a subset of this period, 1990–1999, representing more recent climate. A non-parametric Mann–Kendall test was applied to the time series.
Maps of trends for six annual precipitation indices (annual total precipitation (PRCPTOT), very heavy precipitation days (R20 mm), events greater than the 95th percentile (R95p), maximum five days precipitation total (RX5day), the length of the largest wet spell (CWD) and the length of the largest dry spell (CDD)) were analysed for the entire period. These exhibited statistically significant trends associated with a wetter climate. A significant increase in PRCPTOT, associated with very heavy precipitation days, were observed at more than 45% of the rain gauge stations. The Mann–Kendall test identified that the positive trend in PRCPTOT is possibly related to the increase in the R95p and R20 mm indices. Therefore, the results suggest that there has been a change in precipitation intensity.
In contrast, the indices for the more recent shorter time series are significantly different to the longer term indices. The results indicate that intense precipitation is becoming concentrated in a few days and spread over the period when the CDD and R20 mm indices show positive trends, while negative ones are seen in the RX5day index.
The trends found could be related to many anthropogenic aspects such as biomass burning aerosols and land use.
KeywordsAmazon Basin Precipitation Index Recent Climate Annual Total Precipitation Kendall Test
Unable to display preview. Download preview PDF.
- Alexander, LV, Zhang, X, Peterson, TC, Caesar, J, Gleason, B, Klein Tank, AMG, Haylock, M, Collins, D, Trewin, B, Rahimzadeh, F, Tagipour, A, Rupa Kumar, K, Revadekar, J, Griffiths, G, Vincent, L, Stephenson, DB, Burn, J, Aguilar, E, Brunet, M, Taylor, M, New, M, Zhai, P, Rusticucci, M, Vazquez-Aguirre, JL 2005Global observed changes in daily climate extremes of temperature and precipitationJ Geophys Res111D05109doi: 10.1029/2005JD006290CrossRefGoogle Scholar
- Barros V, Castañeda ME, Doyle M (2000) Recent precipitation trends in southern South America east of the Andes: an indication of climatic variability. In: Smolka PP, Volkheimer W (eds) Southern Hemisphere paleo and neo-climates. SpringerGoogle Scholar
- Brazilian Institute of Geography and Statistics – IBGE (2006) Reports availably in the website http://www.ibge.gov.br/home/
- Freitas, SR, Longo, KM, Silva Dias, MAF, Artaxo, P 1996Numerical modeling of air mass trajectories from the biomass burning areas of the Amazon BasinAnaes da Academia Brasileira de Ciências68193206Google Scholar
- Haylock, MR, Peterson, T, Alves, LM, Ambrizzi, T, Anunciação, YMT, Baez, J, Barros, VR, Berlato, MA, Bidegain, M, Coronel, G, Corradi, V, Garcia, VJ, Grimm, AM, Karoly, D, Marengo, JA, Marino, MB, Moncunill, DF, Nechet, D, Quintana, J, Rebello, E, Rusticucci, M, Santos, JL, Trebejo, I, Vincent, L 2006Trends in total and extreme south American rainfall 1960–2000 and links with sea surface temperatureJ Climate1914901512CrossRefGoogle Scholar
- Intergovernmental Panel on Climate Change, IPCC (2001) Climate Change 2001 – The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the IPCC. Cambridge Univ. Press, CambridgeGoogle Scholar
- Intergovernmental Panel on Climate Change, IPCC (2007) Climate Change 2007 – The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the IPCC. Cambridge Univ. Press, CambridgeGoogle Scholar
- Marengo J (2007) Mudanças Climáticas Globais e seus Efeitos sobre a Biodiversidade: Caracterização do Clima Atual e Definições das Alterações Climáticas para o Território Brasileiro ao longo do Século XXI. Ministério do Meio Ambiente. Secretaria de Biodiversidade e Florestas, 1–201Google Scholar
- Marengo J, Camargo CGC (2007) Trends in Extreme air temperatures in Southern Brazil. Int J Climatol (accepted)Google Scholar
- Martin, L, Absy, ML, Flexor, JM, Fournier, M, Mouguiart, P, Siferdine, A, Turcq, BJ 1992Enregistrement de conditions de type El Nino, en Amerique du Sud, au cours des 7000 dernieres anneesC R Acad Sci Paris31597102Google Scholar
- Minetti, JL, Vargas, WM, Poblete, AG, Acuna, LR, Casagrande, G 2003Non-linear trends and low frequency oscillations in annual precipitation over Argentina and Chile, 1931–1999Atmosfera16119135Google Scholar
- Nepstad, DC, Klink, C, Uhl, C, Viera, IC, LeFebvre, P, Pedlowski, M, Matricardi, E, Negreiros, G, Brown, IF, Amaral, E, Homma, A, Walker, R 1997Land-use in Amazonia and Cerrado of BrazilCiência e Cultura J Brazil Assoc Adv Sci497386Google Scholar
- Sneyers R (1990) On the statistical analysis of series of observation. WMO, Technical Note No. 143, Geneve, SwitzerlandGoogle Scholar
- Xavier, TMBS, Xavier, AFS, Silva Dias, MAF 1994Evolução da precipitação diária num ambiente urbano: o caso da cidade de São PauloRev Bras Meteo94453Google Scholar
- Zhang X, Yang F (2004) RClimDex (1.0) User manual. Climate Research Branch, Environment Canada, Downsview, Ontario CanadaGoogle Scholar