Meteorological information. A new methodology has
completely changed the traditional approach to climatology
in recent years, which previously was generally affected
by a lack of available environmental information.
Past observations (from ground, satellite, soundings), generally
characterized by spatial/temporal discontinuity, were
reprocessed and combined with output of weather forecast
models in order to derive a more comprehensive spatial/
temporal description of the environment at a global
level. This method is known as “reanalysis” and makes
possible the reconstruction of atmospheric analyses (and,
consequently, of all meteorological variables) for the entire
earth’s surface with spatial/temporal continuity. All meteorological
information was provided by NOAA-CIRES Climate
Diagnostics Center, Boulder, CO (http://www.cdc.
noaa.gov/). Data were processed by NCEP/NCAR Reanalysis
Project (Kalnay et al. 1996) and were available from
1948 onward (spatial resolution: each pixel of 2.5° x 2.5°).
In particular air temperature, cumulated precipitation,
500 hPa geopotential height, and sea surface temperature
(SST) were used. Air temperature was directly available as
monthly average values, while cumulated precipitation
was in terms of precipitation rate (mm/s); however, this
was recalculated in mm/month; both variables were used
in terms of average value over the wine production area of
the six wines. The 500 hPa geopotential height represents
the altitude in meters of the layer in the atmosphere where
the air pressure is 500 hPa, and it is well correlated with
weather characteristics at ground. SST represents the temperature
of the surface of the sea.