3.1 Temperature & Sunlight Flashcards
1
Q
What are the main factors that affect the growing environment of a vine?
A
- Sunlight
- Warmth
- Water
- Nutrients
- The above are also a function of the vineyard location, thus - geo location is also a factor.
2
Q
What is the main source of both heat and sunlight?
A
Solar radiation
3
Q
What temperature ensures the dormancy of the wine?
A
Cold Temperatures (under 10°C / 50°F)
4
Q
What temperature can cause winter freeze and vine damage?
A
Extreme temperatures (around -20°C / -4°F)
5
Q
What temperatures stimulate budburst? What is needed for successful and uniform budburst?
A
- Temperatures above 10°C (50°F)
- Significant rise in temperatures at this time
6
Q
What is the optimum temperature range for photosynthesis?
A
18–33°C (64–91°F)
7
Q
What temperatures promote successful, uniform flowering?
A
Above 17°C / 63°F
8
Q
What temperature range promotes successful, uniform fruit set?
A
26–32°C / 79–90°F
9
Q
How do temperatures during flowering and fruit set affect the next growing season?
A
Warm temperatures promote increased bud fruitfulness (above 25°C / 77°F is best) in the next year, and therefore affects yields in the next growing season.
10
Q
Why is sugar accumulation in the grapes generally faster at warm temperatures?
A
- Warm Temperatures mean optimum rates of photosynthesis producing sugars
- Increased grape transpiration promotes the movement of sugar into the grape
11
Q
What temperatures can lead to a rapid loss of acidity in the final month of ripening?
A
Mean temperatures above 21°C (70°F)
12
Q
What temperatures during the ripening phase can reduce acid loss to a point that acidity levels in the must are too high?
A
Mean temperatures below 15°C (59°F)
13
Q
Generally, what aroma/flavours are associated with grapes grown in warmer climates? Cooler climates?
A
- Warmer Climates: riper aroma/flavours
- Cooler Climates: hinder the breakdown of methoxypyrazines, which can give herbaceous aromas.
14
Q
In black grapes, anthocyanin synthesis (and therefore the development of colour) is optimum at what temperature range?
A
15–25°C (59–77°F)
15
Q
What can happen to the vine during extreme heat (especially when paired with dry conditions)? Why?
A
- Photosynthesis can slow or stop
- Slows vine growth and grape ripening
- The enzymes that catalyse photosynthesis are heat-sensitive
16
Q
Do late-ripening varieties require a greater or lesser amount heat through the growing season to ripen sufficiently?
A
Greater
17
Q
Do early-ripening varieties require a greater or lesser amount heat through the growing season to ripen sufficiently?
A
Early-ripening varieties will need less heat in total and will ripen very early in warm climates.
18
Q
How much sunshine is needed for photosynthesis?
A
- Full sunshine (intense sunlight, not blocked by cloud) is not required.
- generally amount of light only becomes the limiting factor to rate of photosynthesis if light levels drop below one third of full sunshine.
19
Q
Name a weather condition that can slow photosynthesis (other than sun or water stress).
A
Fog
20
Q
Name 6 positive effects that sunshine exposure has on grapes.
A
- Enhances the development of anthocyanins (colour pigments) in black grapes
- Reduces methoxypyrazines
- Promotes accumulation of tannins pre-véraison
- Promotes tannins polymerisation after véraison (less bitterness)
- Promotes favourable aroma precursors and aroma compounds (such as terpenes - fruity and floral aromas in wine e.g. Muscat)
- Increases the rate at which malic acid is used up in grape respiration (lower acidity levels)
21
Q
What negative effects does sunshine exposure have on grapes?
A
- Can lead to sunburn on sun-exposed grapes, which has a negative effect on grape quality and yields
22
Q
Name 2 reasons sunshine in late spring / early summer is beneficial.
A
- Associated with successful fruit set
2. The exposure of compound buds to sunshine promotes bud fruitfulness in next year’s growing season
23
Q
Which will receive MORE solar radiation per annum: regions at lower latitudes (nearer the Equator) OR regions at higher latitudes (nearer the Poles)?
A
Regions at lower latitudes (nearer the Equator)
24
Q
Why do regions nearer to the Equator receive more intense solar radiation than those nearer the poles?
A
- Solar radiation is adsorbed and scattered as it travels through the Earth’s atmosphere, decreasing its intensity.
- The curvature of the Earth means that nearer the poles solar radiation must travel through a larger section of atmosphere to reach the Earth’s surface.
- Radiation hits the Earth at a low angle near the poles (due to curvature), so the radiation is spread over a larger area
25
Broadly speaking, grapes grown at lower latitudes can have _____ levels of sugar, _____ levels of acidity, ____ aromas and, in black grapes, ____, ____ tannins and ____ colour intensity than those at higher latitudes.
- higher (sugar)
- lower (acidity)
- riper (aromas)
- more, riper (tannins)
- more
26
How does latitude effect hours of daylight?
- Low latitude regions receive similar daylight hours (and hence heat and sunlight) throughout all seasons of the year.
- High latitude regions have longer daylight hours in the summer and shorter daylight hours in the winter.
27
What is the target latitude range for grapes for wine production?
Between 30° and 50° latitude on each side of the Equator
28
What issues would regions closer than 30° to the equator run into?
- Too hot during the day
- Water stress
- Sunburn
29
What issues would regions farther than 50° to the equator run into?
- Simply not warm enough during the growing season (despite long daylight hours) for enough sugar to accumulate in the grapes
30
By how much does temperature fall over every 100 m increase in altitude?
Temperature falls by approximately 0.6°C (1.1°F)
31
Give an example of a low latitude region whose altitude allows it to be successful in grape growing.
Salta Province in Argentina (3000 m above sea level)
32
Give an example of a high latitude region whose altitude allows it to be successful in grape growing.
Burgundy and Loire Valley (low altitude)
33
Is sunshine is more intense at high altitudes or low altitudes? Why?
- High altitudes
| - Because the solar radiation travels through less atmosphere before it reaches these sites
34
Name 7 natural factors that effect temperature and sunlight.
1. Latitude
2. Altitude
3. Slopes/Aspect
4. Proximity to Water
5. Winds
6. Characteristics of the soil
7. Fogs, Mists, Clouds
35
What is diurnal range?
The average difference between day and night temperatures
36
How does altitude affect diurnal range? Why?
- Higher altitude = Higher diurnal range
- Ground absorbs energy from solar radiation during the day, releases energy into the atmosphere during the night
- Lower altitudes = the air in the atmosphere (particularly the water vapour) absorbs some of this energy, meaning some heat is retained at night.
- High altitudes = air is thinner and holds less moisture and therefore heat rapidly escapes, leading to relatively cool night-time temperatures
37
What is aspect?
The direction a particular slope faces
38
Vineyards at what aspect receive the most solar radiation?
- Vineyards that face the sun throughout most of the day
(south-facing in the northern hemisphere)
(north-facing in the southern hemisphere)
39
Is the aspect and the steepness of the slope more important at higher or lower latitudes?
- Higher
- Slope increases the angle (nearer to perpendicular) at which the solar radiation hits the Earth, increasing intensity of heat and light
40
Name 2 cool climate regions where slope is crucial.
Burgundy and Alsace Grand Cru
| south-east facing slopes
41
How might one limit the amount of heat and light in warm climates?
Planting on slopes that face away from the sun throughout most of the day.
With shade from the canopy
42
Name 1 warm climate region where slope is crucial.
Stellenbosch
| south-facing slopes to retain acidity
43
What are the benefits of east-facing slopes?
- Morning sunshine heats up the atmosphere when air and soil temperatures are at their lowest.
- Extends the hours of vine growth and grape ripening each day, especially in cool climates
- The grape canopy (dew-y in the morning) dries out earlier, reducing the spread of fungal disease
44
What is problematic about west-facing slopes? What can mitigate this?
- Afternoon sun
- May become too hot, especially in warm climates
- Increases risk of sunburnt grapes
- Mitigate: in areas with coasts to the west, e.g. California and Western Australia, cool afternoon sea breezes
45
Aside from proximity to sunlight, what 4 other benefits can slopes provide?
Slopes potentially offer
1. Shallower, poorer soils
2. Better drainage
3. Shelter from wind and rain (rain shadow)
4. Protection from frost
46
What are some of the problems with slopes?
- Soil erosion
| - Inability to use machinery on steep slopes
47
How can a large body of water impact nearby vineyards during the day?
During the day, the water and the air above a body of water remains relatively cool, and lowers the average temperature in the local area.
48
How can a large body of water impact nearby vineyards overnight?
The water retains the warmth gained during the day, whereas, without solar radiation, the land loses heat relatively quickly. The warmth of the body of water keeps the local area warmer.
49
Are large bodies of water beneficial in cool climates, warm climates or both?
BOTH
50
Name a cool climate region that significantly benefits from large bodies of water. Describe why.
- Finger Lakes in New York
- Close proximity to the lakes reduces the severity of winter freeze
- The movement of air also helps to protect against spring frosts that could reduce yields
51
Name a warm climate region that significantly benefits from large bodies of water. Describe why.
- Carneros, California, proximity to the San Pablo Bay
- Early-ripening grape varieties Chardonnay and Pinot Noir can be grown here (for still and sparkling wine), benefitting from cooling breezes off the ocean which is cooled by the Cold California current from the Antartic
52
Name some ocean currents, and describe their effect on the climate in the relative region?
Cool Benguela Current from Antartica - South Africa brings cool breezes to the warm climate of the coastal region.
Cold California Current - cools regions in CA - Los Carneros, Santa Maria Valley, Russian River valley, and in Oregon - Willamette Valley
Warm Gulf Stream - warms and moderates cool temps in Margaux, Bordeaux effectively ensuring that late ripening Cab Sauv can successfully ripen
53
Name a warming ocean current and a region that it affects.
- Gulf Stream (flows from the Gulf of Mexico)
| - warms Margaux in Bordeaux
54
Name a cooling ocean current and a region that it affects.
- California current
| - cools Willamette Valley in Oregon and in CA Los Carneros, Santa Maria Valley, and Russian River Valley
55
Name 2 ways cool climate vineyards benefit from close proximity to large bodies of water.
1. Water retains the warmth gained during the day, keeps surrounding area warmer into the night - extending ripening time/reducing effects of cold nights
2. Radiation reflected from the water surface can help where there is not enough sunshine
56
What is El Niño-Southern Oscillation (ENSO)?
- A climatic cycle in the Pacific Ocean that has a significant effect on weather patterns.
- It has two opposite phases, El Niño and La Niña
57
How does El Niño start? What does it bring?
- El Niño starts when warm water in the western Pacific Ocean moves eastwards along the Equator towards the Caribbean.
East Pacific WARMER than average.
Brings:
- High rainfall, hurricane risk - South America, California.
- Warmer, drier than average - Washington and Oregon
- Warmer temp/ drought -Australia
58
How frequently does El Niño occur?
- Once every 3–7 years, with extreme El Niño events being rarer.
- More frequent as a part of climate change.
59
What starts La Niña? What does it bring?
- La Niña is caused when the
Eastern Pacific Ocean is COOLER average.
Brings:
- Cool, wet - Washington, Oregon, Australia
- Warm, dry - California, South America
60
Can winds have a cooling or warming influence, or both?
BOTH
61
Would areas near a body of water experience cooler or warmer breezes during the day?
How does this influence the area's diurnal range?
- Cooler
| - Moderates the diurnal range
62
How can valleys enhance the effects of wind? Give an example.
- Valleys that face the coast or other areas of low land (e.g. the Petaluma Gap in California) can mean that winds are felt even relatively far inland.
- Valleys can also lead to stronger winds as the moving air is funnelled
63
What effect would winds that have travelled over hot land masses have on a vineyard? Give an example.
- These winds can bring warm air that heats the vineyard area
- The Zonda in Mendoza
64
What effect do winds and breezes have on the development of fungal diseases?
- Reduce the occurrence of humid, stagnant air in the vine canopy that encourages the development of fungal diseases
65
What are some possible downfalls to wind?
- Increase evapotranspiration rates in the vine (vine needs more water, can lead to water stress)
- Damage to wines and trellising (lower yields and higher equipment and labour costs)
66
How can a wine grower protect against wind damage? What are the cons of each method?
- Rows of trees can be planted at the edges of vineyards to act as windbreaks; however, care must be taken as they can compete with the nearest vines for water and nutrients.
- Fences can also be used, but are less aesthetic and require maintenance.
Train the vines low (bush vines in Southern Rhone)
67
What types of soils warm up more quickly in the Spring?
- Soils that drain freely, for example sandy or stony soils
68
Why is a rising soil temperature beneficial during the springtime?
- Encourages the breakdown of starch in the roots, which stimulates budburst and shoot growth
- Encourages root growth, which means the vine can absorb more water and nutrients.
69
What effects do light-coloured soils have on the vines?
- Light-coloured soils reflect some energy from solar radiation.
- Extra light energy into the lower parts of the canopy that may receive less sunlight from above can be beneficial to increase photosynthesis and grape ripening in cool and cloudy climates or where late-ripening grapes are used
70
In what climates might light-coloured soils be beneficial? Harmful?
- Beneficial: Cool/Cloudy climates (extra light energy)
| - Harmful: Warm (further increase warm temps)
71
Name an area with a light-coloured soil.
Sancerre and Champagne
| Soil is rich in chalk
72
Name an area with a dark-coloured soil.
From volcanic origin
| e.g. as found in Etna
73
What effects do dark-coloured soils have on the vines?
- Absorb more energy and re-radiate most of it when temperatures are cooler, for example at night.
74
In what climates might dark-coloured soils be beneficial?
- Beneficial: Cool climates (extra development during the night)
75
What is the benefit of stony soils?
- Stony soils, especially if the underlying soil is slightly damp, are very effective at absorbing heat and releasing it at night.
- Stone and water are good conductors compared to air.
76
How does mist form?
- Mists are formed by tiny drops of water collecting in the air just above an area of ground or water
- They are usually formed when warm air is rapidly cooled, causing water vapour in the air to condense
77
What is fog?
Dense mist
78
When is the most common time of day for mist to form?
Morning
79
Name 4 regions where morning mist is common.
1. Sonoma
2. Napa
3. Leyda Valley
4. Sauternes
80
What effects do mist and fog have on the vine?
- Limit sunlight (reduce photosynthesis)
- Lower temperatures
- Slow sugar accumulation
- Slow acid degradation
- Increase humidity (fungal diseases)
- Increase noble rot
81
In what climactic condition can mist and fog be beneficial? For what types of grape varieties?
- Warmer regions
| - Early ripening grape varieties
82
What regions have a higher diurnal range?
- Continental Climates
| - Higher altitudes
83
What regions have a lower diurnal range?
- Close proximity to a body of water
| - Lower altitudes
84
In what climates is a large diurnal range thought to be beneficial? Name 2 regions.
- Warm/Hot climates
- Cooler nights can slow the respiration of malic acid and be beneficial for the formation of anthocyanins (day time temps too hot)
(e. g. Mendoza, Ribera del Duero)
Remember anthocyanins increase optimally between 15 and 25 deg C.
85
In what climates is a low diurnal range thought to be beneficial? Name 2 regions.
- Cool/Moderate climates,
- Night-time temperatures still allow ripening (e.g. acid degradation, anthocyanin synthesis)
(e. g. Mornington Peninsula or Mosel)
86
What effect do night-time temperatures have on aroma compounds?
- Warmer night temperatures = greater breakdown of methoxypyrazines (important in cool climates)
- Cooler night temperatures = greater retention of some other compounds, such as rotundone (black pepper aroma)
87
Give an example where cold night-time temperatures (e.g. under 15°C / 59°F) seem to be beneficial in cool climates.
- Many of the top sites in the Wachau, Austria, see relatively cool days and cold nights
