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Adjustment of modeled values to reflect the observed distribution and statistics. Bias correction is necessary to overcome large biases in climate models and avoid unrealistic results of applications that use climate data as an input (for example yield models or phenological models).
Variable derived from environmental climate variables that are related to the crop cycle. It can represent annual trends (e.g. mean annual temperature, annual precipitation), seasonality (e.g. annual range in temperature and precipitation), and extreme or limiting environmental factors (e.g. temperature of the coldest and warmest month, and precipitation of the wet and dry quarters of the year).


The average weather conditions prevailing at a specific region over a long period. It commonly refers to measurements of meteorological variables, such as temperature, precipitation, wind, etc.
The collection and manipulation of climate data in order to produce meaningful information, improve accuracy and facilitate data management.
A climate prediction or climate forecast is the result of an attempt to produce (starting from a particular state of the climate system) an estimate of the actual evolution of the climate in the future, for example, at seasonal, interannual or long-term time scales. Because the future evolution of the climate system may be highly sensitive to initial conditions, such predictions are usually probabilistic in nature.
The probability, based on climatological statistics, that unfavorable weather will occur at a particular location or region over a certain period of time.
In general, a mutual relationship between variables or other entities. In statistical terminology, it is a form of statistical dependence.


Derivation of local- to regional-scale (10-100 km) information from larger-scale modelled or observed data. There are two main approaches: dynamical downscaling and statistical downscaling.
Naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious hydrological imbalances that adversely affect land resource production systems.


A collection of model simulations characterizing a climate prediction or projection. Differences in initial conditions and model formulation result in different evolutions of the modelled system. In the case of climate forecasts, these simulations may give information on uncertainty associated with model errors and errors in the initial conditions. For projections of longer-term climate change, these simulations provide can provide information on uncertainty associated with model errors and with internally generated climate variability.
Physical, chemical or biological variable or a group of linked variables that critically contributes to the characterization of Earth’ s climate. These include precipitation, tempearture and pressure, among many others.
The presence of someone or something in a place and setting that could cause them to be adversely affected. It can refer to: people; livelihoods; species or ecosystems; environmental functions, services, and resources; infrastructure; or economic, social, or cultural assets.



Average of daily average temperatures between April 1st and October 31st (Northern Hemisphere). GST provides information onto which are the best suited varieties for a given site or inversely, which are the best places to grow a specific variety. In a climate change scenario, it becomes an important index to use when making decisions about planting or replanting a vineyard. For existing vineyards, GST also informs on the suitability of its varieties for the climate of specific years, explaining quality and production variation. This index became popular when climate change started becoming an issue, as a clear and intuitive way to have a general idea of which areas would gain or lose suitability to produce quality wines. Many grapevine varieties across the world have been characterized in function of their GST optimum.


Total rainfall during usual harvest period: aug 21st to Oct 21st (Northern Hemisphere). Wet harvests are one of the major risks for winegrowers and winemakers alike. Scarce and moderate rainfall values during summer can be positive, especially in dry and semi-arid to arid areas as they provide necessary water and humidity for the physiological processes of the grapevine to occur, thus avoiding the need to irrigate. However, heavy rain downpours are detrimental to quality as berries will absorb water and dilute quality compounds such as sugars, acids, polyphenols and aroma precursors. They may also reduce quantity if hail events occur. Continued rainfall during harvest time set the conditions for widespread fungal infections (Botrytis being the most prevalent, but also Armilaria, Pennicillium, etc.) destroying berries, causing grapes to develop acetic acid bacteria and increasing levels of acetic, gluconic acids, ethyl acetate and other compounds very detrimental for wine quality.
The risk of tempeartures that are higher or lower than normal condictions to the crop yield and quality, consequently affecting wine production.
Hindcast or retrospective forecast: A forecast made for a period in the past using only information available before the beginning of the forecast. Hindcasts can be used to calibrate the forecast system and/or provide a measure of the average quality (skill) that the forecast system has exhibited in the past as a guide to the skill that might be expected in the future.





Climate events occurring further into the future, typically ranging from the next months to years or centuries.


The average (mean) squared difference between the observed values and the values estimated by climate models.


Annual count of days when daily maximum temperatures exceed 35°C. 35°C is the average established threshold for photosynthesis to occur in the grapevine. Above this temperature, the plant closes its stomata. If this situation occurs after veraison, maturation will be arrested for as long as the situation holds, decreasing sugar, polyphenol and aroma precursor levels, all essential for grape and wine quality. Deprived from its normal source of energy, the plant will turn to use organic acids which will lower berry acidity contents decreasing its quality. The plant will also
use more water to cool down its tissues, mainly after temperatures decrease in the evening. The higher the index, the lower will be berry quality and aptitude to produce quality grapes. The loss of acidity will, even for lower index levels, mean higher costs from acidity correction and water needs. There are inter- and intra-varietal variations in grapevines towards this threshold.



One of a set of numbers on the random-variable axis that divides a probability distribution into 100 equal areas; it is a quantile equal to one one-hundredth of a total population.

The extent to which the future state of a system may be predicted based on knowledge of its current and past states. Predictability is inherently limited, since knowledge of the system’s past and current states is insufficient, and the models that utilize this knowledge to produce a prediction are generally imperfect. Even with arbitrarily accurate models and observations, there may still be limits to the predictability of a physical system.

The chance that a prescribed event will occur, expressed as a pure number in the range of 0-1. A probability of zero indicates an impossible event, while a probability of 1 indicates an inevitable event.



Regional Climate Models (RCMs) are climate models which run over limited area at a high spatial resolution instead of the considering the entire planet at a lower resolution. They are used in downscaling global model simulations over specific regions.


Weather and climate events occurring within a short period of time in the future, typically the following days or weeks.
Statistical measure that assesses the performance of a prediction in relation to some standard (e.g. climatology, persistence, etc.). These values are based on the performance of the system in the past.
Total rainfall from April 21st to June 21st (Northern Hemisphere). Dry springs will delay vegetative growth and reduce vigour and leaf area total surface. Fungal disease pressure will be lower and therefore there will be less need for protective and / or curative treatments, translating as less costs. Wet springs will promote higher vigour, increase the risk of fungal disease and disrupt vineyard operations as it may prevent machinery from getting in the vineyard due to mud. They are usually associated with higher costs.
An indication of how reliable is the estimation of a statistical parameter. Results with a probability (P) value that is below the predifined significance level (commonly either 0.05 or 0.01) are considered to be statistically significant.
A phenomenon that occurs during the polar winter in which stratospheric air moves in a circular motion, with an area of relatively still air in its centre. It usually extends from the tropopause (the dividing line between the stratosphere and troposphere) through the stratosphere and into the mesosphere (above 50 km). Low values of ozone and cold temperatures are associated with the air inside the vortex.
An event of rapid warming (up to 50­°C in just a couple of days) occuring in the stratosphere (between 10 km and 50 km above the Earth’s surface). While this does not cause an immediate effect on the temperature at the surface (troposphere), it can lead to changes in the weather usually a few weeks later due to knock-on effects on the jet stream.


Terciles are two values (lower and higher terciles) that divide a set of data (for example, the average temperature for the last 30 years) into three groups: one with the lowest 33% of values (those below the lower tercile), one with the highest 33% (those above the higher tercile) and the remaining 33%, centred around the middle value, between both terciles. In climate science, values that lie below the lower tercile (lowest 33%) or above the upper tercile (highest 33%) are commonly considered as anomalies.
A climate change characterized by a reasonably smooth, monotonic increase or decrease of the average value of one or more climatic elements during the period of record.




Annual count of days with at least 6 consecutive days when the daily temperature maximum exceeds its 90th percentile. Considered an index for heatwaves, the same considerations as SU35 apply here. This index, however, signals when warm regions start to become too extreme and causing additional losses because of flowering disruption (when too early in the season) or extreme berry and leaf dehydration and scalding (berry skin sunburn, leaf and shoot desiccation), on top of excessive water depletion.




This project has received funding from the European Union's Horizon 2020 Research and Innovation programme under Grant agreement No. 776467