V9

Question 1

Nature-based solutions against wind extremes: Monschauer Heckenland

Answer 1

• domestic hedges (European beech): climatic house protection
  
  • winter: protection against cold wind
  • summer: protection against heat (shade)
• field hedges (European beech): protection from grazing cattle and climatic effects
  
  • reduction of wind speed
  • reduction of soil erosion
  • protection from drying out
  • habitats for rodents and resting sites for migrating birds
  • provision of fire wood

Question 2

Snow cover:

Answer 2

• Snow remains at temperature of 0°C until it is melted

Question 3

Precipitation extremes:

Answer 3

• Heavy rain
• Floods
• Erosion
• Hail (especially on hot summer days with strong convection)
• Drought

Question 4

Precipitation records Germany and global:

Answer 4

• 8 min: 126 mm (Füssen, 25.5.1920)
• Day: 312 mm (Zinnwald / Erzgebirge, 12.8.2002)
• Month: 777 mm (Oberreute, 1933 / Stein 1954) •
• Year: 3503 mm (Balderschwang / Allgäu, 1970)
• Minute 38 mm (Barot, Guadeloupe, 1970)
• Day: 1870 mm (Cilaos / La Reunion, 15.3.1952)
• Month: 9300 mm (Cherrapunji / India, 07/1861)
• Year: 26461 mm (Cherrapunji / India, 1860/61)
• annual mean: 11684 mm (Mount Waialeale / Hawaii, 1912-1945)
• Lowest precipitation in the long-term annual mean: Dachla Oasis / Egypt: 0.7 mm (1932 - 1985)

Question 5

Drought:

Answer 5

• Development:
  
  • prolonged absence / reduction of precipitation
  • high evaporation
  • dry winds

⇒ dehydration of the root zone

⇒reduction of productivity

• Examples drought indices (mainly soil moisture):
  
  • Keetch-Byram Drought Index (KBDI)
  • Palmer Drought Severity Index (PDSI)

Question 6

Artificial rain - cloud seeding:

Answer 6

• Goal: avoidance of damage, especially in agriculture
• “inoculation” of clouds with salts / chemicals (e.g. sodium / magnesium / calcium chloride mixtures)
• small particles: act as condensation nuclei from airplane or ground
• only possible if cold clouds are present
• silver iodide (AgI) to avoid formation of large hailstones by aircraft
• also: major events: e.g. Olympic Games 2008 Beijing
• So far difficult to assess, many questions still open
• other sources: Emission from industrial plants, combustion

Question 7

Soil erosion by washout and blowout:

Answer 7

• Heavy rain
• Winds
• Washout mainly in low mountain ranges, stepped country, foothills of the Alps
• Blowout mainly in the North German Lowlands

Question 8

Radiation damage (UV-B):

Answer 8

• DNA damage
• Biomembranes
• Photosynthetic apparatus
• Phytohormones

⇒ e.g. necroses on leaves

⇒ in apple fruit: changes in the skin base color of the fruit, cracking, formation of rotting spots

⇒ sunburn

⇒ possible losses in quantity and quality

Question 9

Frequency of extremes:

Answer 9

Question 10

Ecohydrology – Water balance in ecosystems:

Answer 10

Question 11

Global hydrologic cycle:

Answer 11

Question 12

Hydrologic cycle on land:

Answer 12

Question 13

Water balance of a plant stand:

Answer 13

Question 14

Example: Short weak rain event (beech)

Answer 14

Question 15

Example: Long rain event with interruption (beech)

Answer 15

• Verdunstungsverlust bei Niederschlägen durch Abgabe von Feuchtigkeit an die Außenluft, besonders im Wald

Question 16

Compartment apportionment: all events

Answer 16

Question 17

Throughfall, stem flow, interception:

Answer 17

Question 18

Importance:

Answer 18

• Important parameters for regional water balancing
• Input for hydrological models (e.g. BROOK90, WaSiM)
• Input for soil erosion assessment and modelling

Question 19

Water balance in plant stands:

Answer 19

Question 20

Typical water balance for a Central European forest:

Answer 20

Question 21

Effects of plant stands on landscape water balance​:

Answer 21

• • interception ⇒ less water reaches the soil ⇒ less discharge
• forest soil = large water storage reservoir ⇒ less and delayed runoff during heavy rains
• forest soil = large water storage reservoir ⇒ more runoff during drought (compared to agricultural or sealed areas)
• vegetation ⇒ less runoff due to transpiration ⇒ Water balance at landscape level: less and more balanced runoff

Question 22

Evapotranspiration:

Answer 22

• Evapotranspiration bezeichnet in der Meteorologie die Summe aus Transpiration und Evaporation, also der Verdunstung von Wasser aus Tier- und Pflanzenwelt sowie von Boden- und Wasseroberflächen

Question 23

Runoff​ (Abfließen):

Answer 23

Question 24

Soil water:

Answer 24

Question 25

Soil water:

Answer 25

Question 26

Soil water models:

Answer 26

Question 27

Soil water models:

Answer 27

Question 28

Watershed:

Answer 28

Question 29

Effects of deforestation on stream flow:

Answer 29

Question 30

Effects of deforestation on streamflow:

Answer 30

Question 31

Rainstorms:

Answer 31

Question 32

Discharge:

Answer 32