Changes in Land Use in the Western Amazon and the Microclima’s Response to the Occurrence of Extreme Events

Abstract The reports of the Intergovernmental Panel on Climate Change constantly reveal the possibility that climatic extremes will increase in the coming years. The Amazon Region has experienced these events frequently, which has contributed to the fact that more studies about its susceptibility are carried out. This study aimed to identify the microclimate response to droughts of 2005 and 2010 in areas of native forest and pasture in the Western Amazon by analyzing specific air humidity, air temperature and net radiation. The data used come from towers belonging to Large Scale Biosphere-Atmosphere Experiment in Amazonia. The results indicate that in the years studied there were significant changes in the variables studied at both sites, with reductions of approximately 16% in specific humidity and increases of up to 3.76% in temperature. However, the effects of the 2010 drought may have been softened in the forest due to the event being preceded by an extreme flood event (2009). The results show that the conversion of forest areas to pasture, together with extreme events, can interfere in the meteorological variables, being necessary the continuous study of this dynamics for the microclimatic implications to be elucidated.

摘要 政府间气候变化专门委员会（Intergovernmental Panel on Climate Change）的报告持续披露，未来数年极端气候事件的发生概率将有所提升。亚马孙地区已频繁遭遇此类极端气候事件，这推动针对区域气候敏感性的相关研究数量持续增长。本研究旨在通过分析比湿（specific air humidity）、气温与净辐射数据，探究亚马孙西部原生林与牧场区域对2005年及2010年干旱事件的微气候响应。本研究所用数据源自亚马孙大规模生物圈-大气试验（Large Scale Biosphere-Atmosphere Experiment in Amazonia）的观测塔。研究结果显示，在所涉研究年份中，两个研究站点的各观测变量均出现显著变化：比湿降幅约16%，气温升幅最高达3.76%。但2010年干旱事件对森林区域的影响可能已被缓解，原因是该事件发生前曾出现2009年极端洪水事件。研究结果表明，森林向牧场的土地利用转换叠加极端气候事件，会对气象变量产生干扰；因此需持续开展此类动态研究，以阐明其微气候影响机制。