Climate regionalization of Uruguayan viticulture for ecological sustainability

Abstract

Ecological sustainability refers to developing viticulture in adequate environmental conditions. The first climate regionalization for Uruguayan viticulture was done 20 years ago (using a historical 30-year climate database (from 1961 to 1990). It is well known that the climate has changed in the last decades, and it is therefore imperative to update the agro-climatic regionalization of the country for grapevine growing to increase knowledge that would help to adapt viticulture to climate change. In addition, there is now a greater density of weather stations and, therefore, more data available for this purpose. This study aimed to evaluate a new agro-climatic regionalization for grapevine cultivation in Uruguay, considering the bioclimatic indices commonly used to assess spatial and temporal climate variability for viticulture.  For that purpose, a 31-year climatic database stretching from 1993 to 2024 from a network of 22 weather stations (WS) of Instituto Nacional de Meteorología (INUMET) and Instituto Nacional de Investigación Agropecuaria (INIA) was used. WS are standardized with the World Meteorological Organization (WMO) norms. The daily climatic variables were minimum, mean and maximum temperatures and precipitation (mm). After a quality data control, various climatic and bioclimatic indices for viticulture were calculated, such as the Huglin Index, Growing Degree Days, Cool Night Index, and Precipitations during the growing season (Sept. to March), as well as phenological indices, i.e. Grapevine Flowering Veraison, Grapevine Sugar Ripeness. Spatial modelling of the indices was performed over Uruguay and for different periods to assess both spatial and temporal climate variability. Maps showed different climatic regions compared to the previous regionalization. Differences in time scales were established depending on the bioclimatic indices under consideration. The climate zoning well portrays the influence of the Rio de la Plata estuary and the Atlantic Ocean. These results are of great value in determining potential new terroirs and contributing to more specific decisions related to the ecological sustainability of a region (e.g. when selecting grapevine varieties). Studying climate regionalization for the future period with different climate change scenarios and time horizons can also improve current decision-making.