Dissertation Defense
Jorge Armando Piscoya Santibañez
Program: Meteorology
Title: "Influence of Vegetation Cover on Atmospheric CO 2 Mixing Ratios in the São Paulo Metropolitan Area"
Advisor: Prof. Dr. Marco Aurélio de Menezes Franco - IAG/USP
Judging Committee:
- Prof. Dr. Marco Aurélio de Menezes Franco – Presidente e Orientador - IAG/USP
- Profa. Dra. Lívia Souza Freire Grion – ICMC (por videoconferência)
- Prof. Dr. Giuliano Maselli Locosselli – CENA (por videoconferência)
Alternate Members:
- Profa. Dra. Maria de Fátima Andrade - IAG/USP
- Prof. Dr. Márcio José Teixeira – UNICAMP
- Prof. Dr. Alexandre Cacheffo - UFU
Abstract: Urban vegetation is a key regulator of atmospheric carbon dioxide (CO 2 ) in megacities. This thesis examines how vegetation cover modulates CO 2 mixing ratios in the Metropolitan Area of São Paulo (MASP) during 2020–2022, using four sites with contrasting vegetation cover: Pico do Jaraguá (PJ; 59.75%), IAG (36.38%), ICESP (22.42%), and UNICID (10.42%). Vegetation fractions were retrieved from Sentinel-2 imagery via NDVI pixel classification; CO 2 was obtained from the METROCLIMA network and interpreted with concurrent meteorology (temperature, humidity, wind). Analyses proceeded in three phases: (i) data acquisition and preprocessing; (ii) descriptive and inferential characterization of CO 2 and vegetation dynamics; and (iii) quantification of vegetation effects using regression models and probability distribution functions (PDFs). Seasonality and diurnal cycles were clear: CO 2 was lower in summer and during afternoon hours, and higher in winter and at night; weekday peaks aligned with commuting periods. Vegetation was predominantly healthy; PJ, greener and less urban, showed the lowest and most stable CO 2 levels, while UNICID, highly urban, showed the highest values. IAG’s elevated CO 2 despite notable vegetation indicates influence from local emissions and meteorology, whereas ICESP’s relatively low levels likely reflect altitude and microclimate. A bimodal phenology (April–May; October–November) emerged from NDVI and was mirrored by CO 2 at PJ. Among 132 PDFs, the Normal Inverse Gaussian best represented CO 2 variability: greener sites displayed flatter, more symmetric distributions; urban sites were more peaked and skewed. Trends pointed to rising CO 2 at all sites except ICESP (limited data). Temporal coherence between IAG and UNICID suggests shared boundary-layer controls. Regression results confirmed a vegetation signal: per 0.1 NDVI increase, CO 2 decreased by ∼3.92 ppm (PJ), 2.81 ppm (IAG), and 7.66 ppm (ICESP; likely conditional on site features), with no significant effect at UNICID. Overall, vegetation influences both mean CO 2 levels and the distributional shape of CO 2 . PJ is not a pristine background, but constitutes the most stable urban reference. Findings support integrating green infrastructure and phenology into MASP’s urban carbon management and policy.
Keywords: carbon dioxide, vegetation cover, linear regression, Metropolitan Area of São Paulo