3.4 Climate Classifications Flashcards
How is a region’s climate is defined?
- The annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over several years (30 years in the timescale generally agreed).
- The climate does not change from one year to the next, although it can alter over a period of decades.
How is the Growing Degree Days (GDD) calculated? (Celsius)
- Subtract 10 (the temperature in Celsius below which vines cannot grow) from the average mean temperature of a month in the growing season.
- Multiply this by the number of days in that month
- Make the same calculation for each month in the growing season (April to October in the Northern Hemisphere, October to April in the Southern Hemisphere)
- Add together the totals to get the GDD. (Any months with a negative value would not be counted.)
What is Growing Degree Days (GDD)? Who created it? When? How many zones?
- Who: Amerine and Winkler
- When: 1944
- Zones: V (I is cool, V is very hot)
- Model of heat summation during the growing season
- GDDs are grouped in five ranges making the data easier to use and communicate.
How is the Growing Degree Days (GDD) calculated? (Fahrenheit)
- Subtract 50 (the temperature in Fahrenheit below which vines cannot grow) from the average mean temperature (in Fahrenheit) of a month in the growing season.
- Multiply this by the number of days in that month
- Make the same calculation for each month in the growing season (April to October in the Northern Hemisphere, October to April in the Southern Hemisphere)
- Add together the totals to get the GDD. (Any months with a negative value would not be counted.)
What is the Huglin Index? Who created it? When? Where is it used widely?
- Who: Huglin
- When: 1978
- Similar formula to GDD
- Calculation takes into account:
- both mean and maximum temperatures
- increased day length experienced at higher latitudes
- The index is split into ranges, with the most suitable grape varieties mapped to each range.
- This model is widely used in Europe.
What is the Mean Temperature of the Warmest Month (MJT)? Who created it? When? How many ranges?
- Who: Smart and Dry
- When: 1980
- Ranges: 6 bands (cold to very hot)
- Uses the mean temperature of either July (Northern Hemisphere) or January (Southern Hemisphere)
- Termed MJT (mean January/July temperature)
- Measures of continentality, humidity and hours of sunshine.
What is the Growing Season Temperature model?
- Uses the mean temperature of the whole growing season
- Temperatures are grouped into climatic bands ranging from cool to hot.
- It is very closely correlated to GDD and is easier to calculate.
What is Koppen’s Classification? What factors do they consider? Where do they not apply?
- Factors: temperature, rainfall patterns
- Majority of the world’s wine regions are categorised under three headings: maritime, Mediterranean and continental.
- Categories based very loosely on part of Köppen’s climate classification (1900)
- The categories apply to wine regions in temperate zones, not vineyards located in the tropics.
Describe a Maritime climate. Give an example.
- Low annual differences between summer and winter temperatures
- Rainfall is relatively evenly spread throughout the year
- Example: Bordeaux
Describe a Mediterranean climate. Give 2 examples.
- Low annual differences between summer and winter temperatures
- Annual rainfall tends to fall in the winter months, giving dry summers
- Examples: Napa Valley and Coonawarra
Describe a Continental climate. Give 2 examples.
- More extreme differences between summer and winter temperatures
- Short summers and cold winters
- Temperatures rapidly changing in the spring and autumn
- Examples: Burgundy and Alsace
What average Growing Season Temperature range (GST) defines a Cool climate?
Average GST of 16.5°C (62°F) or below.
What average Growing Season Temperature range (GST) defines a Moderate climate?
Average GST of 16.5–18.5°C (62–65°F).
What average Growing Season Temperature range (GST) defines a Warm climate?
Average GST of 18.5–21°C (65–70°F).
What average Growing Season Temperature range (GST) defines a Hot climate?
Average GST in excess of 21°C (70°F).
