Characterization and comparison of mean temperatures and Winkler index evolution between observed and simulated data (1970-1989) in wine-growing regions of Argentina.

BRICHE ELODIE; CABRE M .F.; SAULO C.; NUÑEZ M. ; QUENOL H.

Dresden

Conferencia; International Conference Climate Change and International Response. Impacts and adaptation strategies for public, commercial and private actors.; 2013

Global change will necessarily affect local climates of agrosystems and have implications on vineyards regions. In this context, potential impacts of climate change raise a lot of interrogations concerning impacts and adaptation. Wine growing in Argentina is affected by effects of temperatures changes: phenology is perturbed. According to the latest statistics of the International Organization of Vine and Wine, Argentina is the 5th largest producer of wine in the world (15.5 million hl in 2011, excluding juice) and 8th domestic market (9.7 million hl of wine consumed in 2011). General circulation models (GCMs) are the most promising tools to determine the response of the climate system to increasing greenhouse gas concentration and to assess how the system will evolve under different emission scenarios. Nevertheless, due to the complexity of these models and the fact that they operate globally, their spatial resolution, typically of several hundred kilometers, is considered insufficient for many purposes. Nowadays, the regional climate modeling is the most appropriate tool to simulate the regional climate with greater accuracy than the low-resolution global models, accounting for small-scale features related to the thermal contrast due to the complex topography or other inhomogeneities in the surface. This research is integrated in the GICC-TERADCLIM project, which searches tools and scientific techniques in order to assess current and future agro climatic potentialities of vineyards regions in particular with a better knowledge of local climate spatial variations. The aim is to establish a methodology including field (meteorological and agronomic) measurements and spatial modeling of climate adapted to fine scales in order to prevent future consequences of climate change at local scales. To achieve this purpose in vineyards of Argentina, it?s necessary to acquire meteorological data and then downscale GCMs forced with IPCC emissions scenarios, in order to disclose plausible climate changes at the regional scale. We used regional meteorological data of Claris-LPB (Europe-South America Network for Climate Change Assessment) with 14 stations, generally located in the airport and next to the four principal wine-growing of Argentina (in the provinces of Neuquén, Mendoza, La Rioja and Salta). The selected series of observed data allow us to analyze climate temperatures trends and evolution of Winkler index. Active monthly mean temperatures (above 10°C) are used to compute the Winkler index. This one is widely used for assessing the main overall characteristics of geographical zones as well as the local adaptation of varieties. A class of viticulture climate corresponds to a class interval of the index values in degree-days. We compare those results with MM5 regional model (Mesoscale Model MM5 version 3.6, developed by Penn State University and the National Centre for Atmospheric Research) simulated data. Monthly mean temperature of about 20 model grid points over the control period (1970-1989) with horizontal resolution about 40 km are analyzed and validated in comparison with 14 observed data of meteorological data located near wine regions. Statistical tests and analysis of biases and interannual variability have been used to compare model data with observations. In general, the MM5 model is able to adequately reproduce the distribution of temperature in Argentina wine-growing regions. Even if the general distribution of temperature is well represented, we discuss the biases and different results between the four wine-regions of Argentina.