Regional Precipitation Southern Mexico and Central America: Community-informed Science

The Southern Mexico and Central America (SMCA) is a geographically and climatically connected region. Subsistence agriculture -crop production mainly for household self-consumption and regularly with very limited use of technology (e.g., irrigation systems)- is an extended practice in rural farming communities across the region, making these communities' livelihoods highly dependent of seasonal rainfall and especially vulnerable to its variability and extremes. In this work, we use climate science and social science methods to understand (1) the precipitation spatial and temporal variability at a fine resolution, and (2) communities farming practices as well as their perceptions on climate variability and change to inform instrumental data analysis. We call this community informed science. In November 2020, we conducted an exploratory ethnographic field work in two rural-agricultural communities in eastern El Salvador. We aim to account for and learn from their living repository of climate knowledge which we argue is transgenerational and collective. Using 40 years (1981-2020) of daily gridded rainfall estimates from the CHIRPS (Climate Hazards group Infrared Precipitation with Stations), we found that the canonical bimodal seasonal distribution of precipitation over the region has a large spatial variability across the region which is largely overlooked in climate studies focusing on regional averages. This suggests not only important differences on the sowing-farming cycle at the community level in the SMCA region but also in adaptability and vulnerability.