Near-surface atmospheric behavior over complex tropical topography in Puerto Rico dominated by seasonal patterns despite frequent environmental changes

Abstract

Understanding near-surface atmosphere behavior in the tropics is imperative given the role of tropical energy fluxes in Earth’s climate cycles, but this area is complicated by a land-atmosphere interaction that includes rugged topography, seasonal weather drivers, and frequent environmental disturbances. This study examines variation in near-surface atmosphere behaviors in northeastern Puerto Rico using a synthesis of data from lowland and montane locations under different land covers (forest, urban, and rural) during 2008 to 2021, when a severe drought, large hurricanes (Irma and Maria), and the COVID-19 mobility-reducing lockdown occurred. Ceilometer, weather, air quality, radiosonde, and satellite data were analyzed for annual patterns and monthly time series of data and data correlations. The results showed a system strongly dominated by easterly trade-winds transmitting regional oceanic patterns over terrain. Environmental disturbances affected land-atmosphere interaction for short time periods after events. Events that reduce the land signature, (reducing greenness: e.g., drought and hurricanes, or reducing land pollution: e.g., COVID-19 lockdown) were evidenced to strengthen the transmission of the oceanic pattern. The most variation in near-surface atmosphere behavior was seen in the mountainous areas that were influenced by both factors, trade-winds and terrain-induced orographic lifting. As an exception to the rest of the near-surface atmosphere behavior, pollutants other than ozone did not correlate positively or negatively with stronger trade-winds at all sites across the region. Instead, these pollutants were hypothesized to be more anthropogenically influenced. Once Covid-19 lockdown persisted for three months, urban pollution decreased, and cloud base may have increased.