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The objective of this study is to assess the climate simulations and projections over South America using the regional climate Eta Model driven by fully coupled Earth System Model HadGEM2-ES of the Met Office Hadley Centre. The HadGEM2-ES was designed to run the major scenarios for IPCC AR5 and comprises Earth system components such as terrestrial and ocean carbon cycle and tropospheric chemistry. Over the past years the regional climate Eta Model has been used to produce climate change scenarios over South America (Pesquero et al. 2009, Chou et al. 2012, Marengo et al. 2012). In this study, Eta model was configured with 38 vertical layers, 20-km grid size and was run over 19602005 based on historical emissions, and 20062100 based on RCP4.5 scenarios to simulate possible future changes. We have evaluated the regional climate simulation for some areas in Brazil, particularly for Amazon and Northeast, Southeast and South regions of Brazil. Annual cycle of precipitation and surface temperature for these areas was compared with CRU (Climatic Research Unit) observational data. Simulated and projected patterns of mean fields of precipitation, temperature and upper and low-level circulation were analyzed for austral summer and winter. The regional model reproduces reasonably well the spatial patterns of the precipitation and temperature. The downscaling with Eta model improved the simulation of the seasonal cycle of precipitation and temperature over Brazil and some regions when compared with HadGEM2-ES. The projections suggested increases in DJF and JJA temperature of up to 4 °C in continental South America, with more intense changes occurring in the second half of the twenty-first century. The precipitation projections showed the major changes in summer.

Upward lightning from tall objects can be either self-initiated (SIUL), that is, leaders originating due to locally strong electric fields but without any preceding lightning, or triggered by prior lightning discharges in the general vicinity, termed lightning-triggered upward lightning (LTUL). The LTULs can be triggered by (1) nearby +CG return strokes propagating through previous leader networks near the tall object, or (2) the overhead proximity of horizontally propagating negative stepped leaders from either IC or +CGs. Examples of both modes of LTULs are presented. The meteorological environments in which LTULs occur in the U.S. high plains show a strong similarity to the convective regimes (trailing MCS stratiform regions) and the parent lightning which trigger sprites.

Electromagnetic emissions from lightning flashes are observed by a slitless spectrum spectrograph. A Phantom V9.1 high-speed camera is used with a spatial resolution of 1632 x 400 pixels, at 3000 fps and exposure time of 330 μs. A grism (diffraction grating plus prism) that has 600 lines/mm and a spectral ranger 600-1050 nm were coupled to this camera. The lightning observations were made in the city of São José dos Campos (latitude: 23° 11’25.15”S, longitude: 45°53’3.44”W), Sao Paulo, Brazil, focusing on cloud-to-ground lightning events, with both negative or positive polarities. Data from sensors of the BrasilDAT and RINDAT networks were also used to gather additional information (location, polarity and peak current estimation). The objective of this work is to observe for the first time the time-resolved characteristics of lightning emission in the near infrared in Brazil.

Rainfall brings nutrient from atmosphere to the ground scavenging them from the atmosphere column. Furthermore, throughfall washout material deposited on plant tissues as well as leachates exudate products resulting in changes in the rainwater chemistry. Inputs of nutrients into the soil through such processes are important for nutrient recycling and it depends intimately on the hydrological characteristics of the environment. These relationships are poorly understood for environments with low water availability and high temporal and spatial variability like the arid and semiarid ones. For instance, in some years, rainfall events are regular but in some years, it can delay or even not occur. The knowledge of the consequences of these hydroclimatic pattern on nutrient cycling is still rare.