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Seasonal Evolution of the Surface Radiation Balance in the City of São Paulo

Seasonal Evolution of the Surface Radiation Balance in the City of São Paulo. Amauri Pereira de Oliveira Jacyra Soares Grupo de Micrometeorologia Departamento de Ciências Atmosféricas – IAG/USP. City Climate.

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Seasonal Evolution of the Surface Radiation Balance in the City of São Paulo

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  1. Seasonal Evolution of the Surface Radiation Balance in the City of São Paulo Amauri Pereira de Oliveira Jacyra Soares Grupo de Micrometeorologia Departamento de Ciências Atmosféricas – IAG/USP

  2. City Climate The characterization of the climate in city is a very complex task due to the large heterogeneity of the land use and topography (Oke, 1982; Oke et al., 1999, Gambi et al., 2000).

  3. Land use of São Paulo SOURCE:ATLAS AMBIENTAL DO MUNICÍPIO DE SÃO PAULO”

  4. Topography of São Paulo Area = 50 km x 50 km centered at CUASO (GTOP)

  5. Objective • Estimate the components of radiation balance at the surface; • Seasonal evolution of the net radiation at the surface for São Paulo city.

  6. Part 1Data set, sites and sensors

  7. Data set 9 years 7 years 5 years

  8. Localization of observations • CUASO – IAG Micrometeorológical Plataform, University Campus “Armando Salles de Oliveira” at Butantã, at 744 m above the mean sea level (23033' S, 46043' W); • PEFI – IAG Meteorological Station, “Parque Estadual das Fontes do Ipiranga” at “Parque do Estado”, at 780 m above the mean sea level (23039' S, 46037’ W).

  9. Tietê river CUASO 20 km PEFI Localization - Regional land use

  10. Micrometeorological Platform - CUASO Atmospheric long wave emission Pyrgeometer Eppley Net radiation components Net Radiometer Kipp Zonen

  11. PEFI Air Temperature Surface Temperature

  12. Part 2Solar radiation effects on pyrgeometer Pyrgeometer model PIR Eppley

  13. Schematic of wiring and connections for the Eppley PIR

  14. Manufacturer recommendation The value of s1 is provided by the manufacturer is 3.63  0.04 V W-1 m-2.

  15. Fairall, C. W., Persson, P. O. G., Bradley, E. F., Payne, R. E. and Anderson, S. P., 1998: A New Look at Calibration and Use of Eppley Precision Infrared Radiometers. Part I: Theory and Application, Journal of Atmospheric and Oceanic Technology, 15, 1229 – 1242. According to Fairall et al (1998) the error ~ 5.5 % using manufacturer recommendation.Too much for radiation balance studies at the surface.

  16. Dome Effect Correction proposed by Fairall et al. (1998) Where L1DW is the corrected value of longwave radiation, V is the thermopile voltage, Tc and TD are, respectively, the case and dome temperatures, s0 and B are calibration factors which depend of the sensor direct calibration.

  17. Sensor temperature

  18. Problem of Fairall corrections • Requires TC and TD measurements; • Due to data acquisition limitations measurements of dome and case temperatures started only in October of 2003; • Measurements of LDW started in September 1997.

  19. Perez Allados-Arboledas (1999) Where is the corrected long wave radiation L2DW is the long wave radiation obtained using expression proposed by manufacturer, IDW is the global solar radiation in Wm-2 and Vis the wind intensity in ms-1.

  20. Longwave atmospheric emission Fairall et al. (1998) Manufacturer Perez and Allados-Arboledas (1999)

  21. Corrections for pyrgeometer PIR • Correction proposed by Perez and Allados-Arboledas (1999) was applied to estimate the monthly averaged longwave atmospheric emission measured by the pyrgeometer PIR at CUASO using: • Diurnal evolution of monthly averaged wind speed from CETESB (Oliveira et al., 2003); • Monthly averaged values of global solar radiation measured in CUASO.

  22. PEFI representativity Part 3

  23. Monthly averaged Air temperature Sea Breeze

  24. Hourly values of Temperature Sea Breeze

  25. Surface longwave emission

  26. Reflected solar radiation

  27. Part 4 Seasonal evolution of radiation balance components

  28. Global solar radiation ( IDW ) Top Reflected solar radiation ( IUP )

  29. Surface longwave emission ( LUP ) SurfaceTemperature ( TG )at PEFI

  30. Seasonal Evoluation of net radiation

  31. Conclusion • Seasonal evolution of the monthly average hourly values of net radiation indicates: • Nighttime maximum in winter (June) of +50 W.m-2 and a nighttime minimum in summer (December) near zero; • Daytime maximum in the summer (December) of -500 W.m-2 and a daytime minimum in winter (June) of -370 W.m-2;

  32. Acknowledgement • CNPq and FAPESP; • IAG/USP meteorological station at PEFI.

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