Satellite and reanalysis products are used to study the atmospheric environment, aerosols and trace gases in smoke plumes over South America in the period 2000-2018. Climatic conditions and fire density maps provide context to link biomass burning across the southern Amazon (5-15S, 50-70W) to thick near-surface plumes of trace gases and fine aerosols. Intra-seasonal weather patterns that underpin greater fire emissions in the dry season (Jul-Oct) are exacerbated by high pressure over a cool east Pacific, for example in September 2007. Smoke plume dispersion simulated with HYSPLIT reveal a slowing of westward transport between sources in eastern Brazil and the Andes Mountains. During cases of thick smoke plumes over the southern Amazon, an upper ridge and sinking motions confine trace gases and fine aerosols below 4 km. Long-term warming tends to coincide with the zone of biomass burning are +0.03C/yr in the air and +0.1C/yr at the land surface. Our study suggests that weather conditions promoting fire emissions also tend to limit dispersion.

Spanish-speaking populations in the U.S. are more vulnerable in disaster contexts due to inequities, such as language barriers, that prevent them from receiving life-saving information. For the past couple of decades, governmental organizations have addressed these issues by translating weather watches, warnings, and advisories into Spanish. Previous studies suggest that these Spanish translations do not communicate the same level of urgency as their English counterparts. To identify whether these translated products result in inequities between English and Spanish speaker reception and comprehension of forecast information, we asked a representative sample of U.S. English (n=1,550) and Spanish (n=1,050) speakers to correctly identify the translations of weather watches and warnings and found significant language inequities. Additionally, we asked U.S. Spanish speakers to indicate the urgency they felt when shown different Spanish words used in weather watch and warning translations. When presented with various translations for watch and warning terminology, respondents consistently rated aviso, the current translation of warning by the NWS and FEMA, as less urgent than many other alternatives. To increase the effectiveness of severe weather messaging in multilingual contexts, translations should take into consideration factors such as culture and dialects of Spanish speakers in the U.S. and focus on translating the meaning, not the words, of key risk statements in weather products. We recommend vigilancia for “watch” and alerta for “warning” as research-supported terminologies to communicate urgency in Spanish.