Climate and Weather Flashcards
1
Q
What is Climate?
A
The long-term regional pattern of weather, usually established over a 30 year history.
2
Q
What is Weather?
A
The daily pattern of localized atmospheric changes, primarily temperature, precipitation, and wind.
3
Q
How are Macroclimates classified?
A
Average temperature of the growing season and continentality (difference between average temperature of the hottest and coldest months)
4
Q
Cool Climate temperature range
A
Average temperature of <16°C
5
Q
Moderate Climate temperature range
A
Average temperature of 16.5°C-18.5°C
6
Q
Warm Climate temperature range
A
Average temperature of 18.5°C-21°C
7
Q
Hot Climate temperature range
A
Average temperature of >21.5°C
8
Q
The description of climate zones was introduced by whom and when?
A
Wladimir Köppen, 1900
9
Q
Which climate zone does the Vitis genus find comfort in?
A
Temperate zone
10
Q
What are the three most important subzones for Vitis Vinifera cultivation?
A
Maritime
Mediterranean
Continental
11
Q
What are the characteristics of the Maritime climate?
A
Typically found near large bodies of water
Low annual range of temperatures
Higher rainfall averages (typically during the growing season), thus more cloud cover
Risk of excessively low summer temperatures
Risk of spring frost and cool/wet conditions at fruit set
Ideal for production of medium bodied wines with moderate alcohol
12
Q
What are the characteristics of the Mediterranean climate?
A
Low annual range of temperatures
Dry summers and rainfall in the winter
Ideal for production of full bodied, richly textured red wines with ripe tannins
13
Q
What are the characteristics of the Continental climate?
A
Areas are inland and isolated from influences of large bodies of water
Wide annual range of temperatures (hot/warm summers, cool/cold winters)
Uniform annual precipitation but drier than maritime climates
Shorter growing season due to rapid temperature drop in Autumn
14
Q
What are the characteristics of a Tropical climate?
A
Minimal temperature variation
Seasons defined by rainfall
Vines do not receive temperature signals for dormant/growth cycles, may crop more than once per year
Generally unsuitable for quality viticulture even in zones moderated by altitude or oceans
15
Q
What is the primary climatic control of grapevine growth?
A
Temperature
16
Q
What is Heat Summation?
A
The total number of heat degree days (HDDs) calculated by
The Monthly Mean Temperature minus 10°C multiplied by the Number of Days in the Month
with the average of each month of the growing season added together.
17
Q
Who invented Heat Summation and when was the concept published?
A
Amerine and Winkler, 1944, for matching cultivars with appropriate heat zones in California
18
Q
What is a Growing Degree Day?
A
An alternate name of Heat Degree Day.
19
Q
What are Amerine and Winkler’s degree day region classifications?
A
Category 1 | <1370°C
Category 2 | 1370°C - 1650°C
Category 3 | 1650°C - 1930°C
Category 4 | 1930°C - 2200°C
Category 5 | >2200°C
20
Q
What is the Heat Summation of Category 1 and what is it good for producing?
Name some regions in this category.
A
<1370°C
Light bodied white wines
Chablis, Mosel, and Champagne
21
Q
What is the Heat Summation of Category 2 and what is it good for producing?
Name some regions in this category.
A
1370°C - 1650°C
Medium bodied red wines
Napa Valley, Bordeaux, and Northern Rhône
22
Q
What is the Heat Summation of Category 3 and what is it good for producing?
Name some regions in this category.
A
1650°C - 1930°C
Full bodied red wines
Barossa Valley, Stellenbosch, and Southern Rhône
23
Q
What is the Heat Summation of Category 4 and what is it good for producing?
Name some regions in this category.
A
1930°C - 2200°C
Fortified Wines
24
Q
What is the Heat Summation of Category 5 and what is it good for producing?
Name some regions in this category.
A
> 2200°C
Adapted for bulk wines, table grapes, and drying grapes
25
What is the limitation of applying Heat Summation as defined by Amerine and Winkler?
It is less successful in regions with less reliable temperature, sunlight, and humidity than California. It is also important to note that the relationship between vine growth and temperature is not linear, with growth slowing significantly over 30°C.
26
What are Biologically Effective Degree Days, who introduced it, and how are they different from Growing Degree Days?
A modification of Growing Degree Days by Gladstones in 1992 that groups cultivars by ripening times. It applies a 19°C cutoff temperature in the monthly average mean temperature to provide a best-fit for cultivars across different regions.
27
What is the Mean Jan/July Temperature (MJT)?
The most widely used alternative to HDD developed by Smart and Dry in 1980. It uses the mean temperature of the warmest growing month with corrections for continentality, sunlight hours, day length related to latitude, humidity, rainfall, and evaporation.
28
What is Growing Season Temperature (GST)?
A system designed by Jones et. al. in 2005 to categorize growing regions by average temperature across the growing season, enabling comparisons of regions, wine styles, and quality to be drawn. It shows what grapes are able to ripen in specific conditions and why.
29
What factors influence regional climate (Macroclimate)?
Latitude
Altitude
Mountain Ranges
Ocean Currents
30
What effect does Latitude have on Macroclimate?
Atmosphere diffuses solar radiation. The latitudinal range of 30° to 50° on either side of the equator provides sufficient diffusion that Vitis vines can photosynthesize without stress.
Lower latitudes do not diffuse enough light while higher latitudes diffuse too much light.
Day length is also longer at lower latitudes, allowing for longer periods of photosynthesis and lower likelihood of heat and water stress.
31
What effect does Altitude have on Macroclimate?
Temperature drops by about .6°C per 100 meters of elevation.
Higher altitudes are, therefore, preferable at lower latitudes.
32
What effect do Mountain Ranges have on Macroclimate?
Mountains cast a rain shadow that prevents moist air from reaching vineyards on the leeward side of a mountain. The air condenses and precipitates on the windward side, rises above the mountain and then warms and descends the leeward side.
33
Aside from being a rain shadow, what is an additional benefit of the Andes?
It is a source of irrigation from snow melt that can be usefully channeled during the summers.
34
The absence of significant mountain barriers across parts of Europe and the Mediterranean Sea has what effect on the viticultural climate?
The change to a Continental climate from a Mediterranean climate is more gradual.
35
What effect do Ocean Currents have on Macroclimate?
They bring warming or cooling influences to broad areas.
36
Describe the Gulf Stream and its effect on grape growing.
A current that starts in the Gulf of Mexico and branches into the Atlantic Current. It warms Western Europe to 11°C above the latitudinal average, making viticulture possible in Germany, England, and Wales.
37
Describe the Benguela Current and its effect on grape growing.
A current that starts in Antarctica and flows along the west coast of South Africa to cool vineyards along the coast.
38
Describe the Humboldt Current and its effect on grape growing.
A current that starts in Antarctica and flows along the west coast of Chile to cool vineyards on the coast and in areas the wind can access via gaps in the coastal mountain ranges.
39
Describe the California Current and its effect on grape growing.
A current that flows south along the west coast of North America, bringing thick morning fogs that offer protection from sunlight and heat.
40
What is Aspect?
The direction a vineyard slope faces
41
Describe the benefits of Aspect and Slope in relation to sunlight and grape growing.
Sloped fields facing toward the sun increase the amount of light available to a vine by reducing the diffusion of sunlight.
In high latitude vineyards, exposure towards the equator increases the amount of light a vine receives.
East facing slopes receive the greatest benefit as morning sunlight is less diffused than afternoon sunlight.
42
Describe the benefits of Aspect and Slope in relation to temperature and soil.
Cold air is more dense than warm air and tends to sink down slopes, forcing warmer air to rise. This air movement reduces frost risk, slightly improves ripening potential, and creates a pocket of warmer air in the middle of a slope.
Soils on slopes tend to be coarser and better drained, moderating vine vigor.
Vineyards sloping towards the equator at high latitudes receive more heat from direct sunlight than flat sites. The greater the slope, the more exposure to sunlight vines can receive.
43
What are disadvantages to Aspect and Slope in relation to grape growing?
Increased risk of soil erosion.
Higher labor cost at harvest. Steep slopes require exclusive hand harvesting.
Slopes facing west receive less sunlight than east facing slopes due to dust and other particles in the air as a result of daily warming.
44
What is Slope?
The degree at which a vineyard site is angled from 0 degrees (flat).
45
How do bodies of water affect Site Climate (Mesoclimate)?
All bodies of water reduce the risk of ground frost and reflect sunlight which can improve ripening.
Oceans can bring warming or cooling influences to vineyard sites.
Lakes and rivers can provide a source of irrigation and encourage air flow.
In warm and dry climates, provide a cooling influence.
In cool climates, provide a warming influence.
46
What effect do Forests have on Site Climate (Mesoclimate)?
They can act as wind breaks.
Trees store heat in the winter and cool air in the summer, providing an annual moderating influence.
Forests can harbor birds that act as pests, preying on grapes.
47
What is Macroclimate?
Regional Climate
The history of climate on a scale of tens to hundreds of kilometers that is distinct from specific, smaller scale climatic zones.
48
What is Mesoclimate?
Site Climate
A scale of tens of meters to kilometers that are defined by topographical features which modify the local climate.
49
What is Microclimate?
Canopy Climate
The influences on the fruiting zone of a vine that measures from millimeters to meters and is affected by vineyard practices.
50
What practices can influence Canopy Climate (Microclimate)?
Vine trellising and training systems
Annual vineyard management
51
What are vineyard practices meant to alter regarding Canopy Climate (Microclimate)?
Sunlight quality and quantity (on the leaves and berries)
Temperature (below the canopy)
Humidity
Wind
Evaporation
52
What effect can an overly dense canopy have on grape growth?
Reduce flower initiation and berry set due to shading
Higher levels of acid retention due to cooling
Reduce sugar accumulation due to increases in humidity and shade
Encourage vigorous vegetative growth, causing competition for sugar between berries and green growth
53
What is the major factor determining the suitability of a region for viticulture?
Temperature
54
Are vines for quality winemaking planted in the temperature that is most suitable for its biological success?
No. Most vines for high quality wines are planted in climates that are just suitable enough for grape growth.
It is argued that slow, cool berry ripening produces finer aromatics and flavors.
55
Temperature directly affects vineyard yield in what ways?
Rate of growth (Vigor)
The size and number of flower clusters produced
The success of flowers setting into berries
56
Temperature affects the quality of a vineyard yield in what ways?
The amount of yield obtained
The accumulation of sugars and reduction of acidity in the berry
The development of wine aromas and their precursors
57
What winter temperatures are considered dangerous for grape vines?
-15°C
Freeze injury to dormant vinifera wood
-20°C
Serious risk
-25°C
Can be fatal without insulation from mounding up around the vine
58
At what low temperature(s) will a site be considered unsuitable for viticulture?
If the temperature falls below -20°C more than once every 20 years
If the mean temperature of the coldest month is less than -1°C.
59
What is the optimal temperature range for photosynthesis?
25°C - 30°C
60
What is an inflorescence?
A flower cluster and potential future grape bunch
61
What temperature range in the canopy (generally, disregarding cultivar variation) promotes the production of inflorescences?
25°C - 35°C
62
What is (generally, disregarding cultivar variation) the optimal temperature for flowering?
20°C
63
What nighttime temperatures are desirable to reduce energy losses from respiration?
15°C - 20°C
64
At or below what temperature does pollen germination remain low or nonexistent?
15°C
65
What is the ideal daytime and nighttime temperature range and what effect do they have on the grape vine?
Daytime: 20°C - 25°C
Nighttime: 10°C - 15°C
This diurnal range promotes anthocyanin creation
66
What temperature range inhibits anthocyanin synthesis?
+35°C
67
What effect does high temperature have on the vine?
High temperature increases respiration rates, forcing the vine to consume more sugar to cool itself than it can create via photosynthesis.
68
Sunlight can also be described as
Solar Radiation
Insolation
Sunshine uninterrupted by cloud cover
69
Why is it difficult to separate the influence of sunlight from temperature?
Increases in the intensity of sunlight generally lead to increases in temperature.
70
In what way can the effects of sunlight be distinguished from the effects of temperature?
Photosynthesis
71
What are the risks and benefits of cloud cover regarding sunlight?
Clouds can prevent sunlight from oversaturating vine leaves, ensuring effective photosynthesis.
In hot climates, clouds can block too much light and restrict photosynthesis and the vine's self-regulation.
Clouds can also cool vineyards by reflecting solar heat back into the atmosphere.
72
What is the effect of sunlight on inflorescence and fruitfulness?
Generally positive. Buds exposed to sunlight have more flowers per inflorescence than buds that are shaded.
The fruit may be sunburned if exposed to too much sunlight.
73
How is the grapes' exposure to sunlight managed?
In cool climates, the berries are generally exposed to more sunlight by removing leaves or altering their position.
Leaf plucking is typically not recommended in hot climates and may be maneuvered to provide shade to the berries during parts of the day.
74
Do cool climates require more or less leaf area to initiate photosynthesis?
More leaf area. Vines do not work as hard to respirate in cool climates, therefore do not photosynthesize as readily. They require more leaf area as a result.
75
Regarding latitude, what effect does day length have on vine maturation?
At higher latitudes, day length increases the amount of time the vine can photosynthesize, enabling some cultivars to ripen.
Otherwise, temperature is the prime factor in determining rate of vine growth.
76
What additional effects does sunshine have on the vine apart from grape development?
It improves the browning maturation of canes and allows carbohydrate reserves to be built up.
77
Why do vines need water?
Conduct photosynthesis
Access nutrients in the soil
Ensure vine growth, yield potential, and fruit quality
Prevent its cells from collapsing and to function properly
78
What are the estimates for necessary precipitation per year in cool and warmer climates?
Cool Climates: 500mm
Warmer Climates: 750mm
79
What is the average annual rainfall for global viticultural regions?
700-800mm
80
Name two regions where annual precipitation greatly deviates from the global average?
Vinho Verde: ~1,500mm
Mendoza: ~200mm
81
What factors determine how available rainfall is to the vine?
Total amount of annual rainfall
When during the year it precipitates
How quickly it evaporates
Soil type
82
In what climate is drainage most important and why?
Mild Maritime Climates
Vines may become waterlogged due to low rate of evaporation if the water is not sufficiently drained.
83
What are the risks of excess water in the vineyard?
Ideal for fungal diseases (mildew, grey rot, phomopsis)
Cools the mesoclimate
Reduce fruit set (especially w/ low temperatures)
Cause bunch compaction and eventual berry splitting before harvest
Dilute the must if it rains before/during harvest
84
What effect does water stress have on berry maturation?
Some water stress can improve the quality of the crop.
Too much can halt vegetative growth and cause leaf loss.
85
Water availability is a significant factor in climates with what type of rainfall pattern?
Seasonal
Enough water is needed to avoid water stress at critical times for the vine
86
Describe the rainfall patterns in a Mediterranean climate and why irrigation might or might not be necessary.
Mediterranean climates receive most of their precipitation in the winter. If the soil is not able to retain the water during the growing season, irrigation may be necessary to ensure the vines have access to water.
87
How can a grower compensate for poor water retention in soils without irrigating and why does this work?
Reducing crop density.
The roots of the vines can spread out and access more of the soil, thus improving access to water reserves.
88
What is the formula to determine how much water is available to a vine?
(Millimeters of water per Square Meter x 10,000 Square Meters) / Vine Density per Hectare
Simplified Formula:
([L / m^2]ha) / (Vines / ha)
L = Liter = Millimeters per Square Meter
ha = Hectare = 10,000 Square Meters
89
How much water can a vine access in La Mancha, where annual precipitation is 300mm and vine density is 1,000 vines per hectare?
300mm / m2 = 300L
(300L x 10,000) / 1,000 = 3,000L per vine
90
How much water can a vine access in Bordeaux, where annual precipitation is 850mm and vine density is 9,000 vines per hectare?
850mm / m2 = 850L
(850L x 10,000) / 9,000 = 944L per vine
91
Why would vines in La Mancha require access to more water than vines in Bordeaux?
Evapotranspiration, the sum of evaporation and plant transpiration, is higher in warmer climates. Vines in La Mancha require more water due to this phenomenon.
92
At what times are soil drainage most critical?
Flowering, fruit set, and harvest
93
Where are irrigated vineyards generally located?
Regions where annual, including growing season, rainfall is less than what the vines need.
94
Describe the effects of rainfall during different seasons.
Winter
Little effect, though some is saved for later use
Spring
Moderate rain can promote shoot growth
Summer
Some can be useful, but can promote disease and reduce fruit set
Autumn
Almost always harmful to crop quality
95
Describe the risks of hail on a vineyard.
It can destroy leaves, bunches, and vines. Such storms are localized and difficult to predict, so they are rarely taken into account when choosing a vineyard site.
96
What are some of the anthropogenic factors driving climate change?
Human population growth
Chlorofluorocabon release
Carbon release from large scale deforestation
Fossil fuel use
97
What are the main gases driving climate change and which is the greatest?
Carbon Dioxide (CO2) - the greatest
Methane (Me)
Nitrogen Dioxide (NO2)
98
How much has global temperature risen in the past century?
.75°C
99
According to the International Panel on Climate Change, what effect will climate change have on vineyards with regards to the Winkler regions?
Vineyards will be pushed into the next warmer Winkler region by 2057.
100
What are some significant regional changes to be experienced during climate change that will affect grapes?
More frequent severe weather events
Higher temperatures, leading to increased heat damage of grapes
101
What temperature is used to model regional climate classifications? Why?
10°C
This is the temperature at which bud break occurs in the V. Vinifera species
