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The Role of large scale
Vegetation and Land Use in
Water Cycle and
climate in Monsoon Asia
By: Jannat Iftikhar 16
Nimrah Z...
Monsoon
• Monsoon is traditionally defined as
“a seasonal reversing wind accompanied by corresponding
changes in precipita...
Major Monsoon Systems
• The major monsoon systems of the world consist of
a) The West African and Asia-Australian monsoons...
Asian Monsoon as a Huge Water
Cycling system
• Well known land-atmosphere-ocean system.
• Two water channels
a) From Tibet...
5
Asian Monsoon
• This monsoon transports huge amount of water vapours over
south, southeast and east Asia.
• This plays an ...
Asian Countries
7
Impacts of Monsoon
• Monsoon circulation results in cool, dry winters and warm,
wet summer over the continents.
• This hum...
Precipitation
• Most important factor for life on land
vegetation and water resources
• Origins: Tropical monsoon Asia, wa...
• Humid tropics: Both C and E contribute, C is main source
• The Indian sub- continent and indo china peninsula, C is larg...
• Tropics: C plays role in P, E from vegetative surface is equally
important, compare to mid/ high latitudes.
11
Is monsoonrainfall decreasing?
Impact of deforestationon watercycle
In Thailand rainfall in late monsoon show a remarkable...
• According to recent model decreasing trend of
September rainfall may be due to recent deforestation in
Thailand which li...
Sensible heat and surface heat
• Sensible heat is a thermal energy whose transfer to or
from a substance results in a chan...
15
• Change in surface heating, affects the atmospheric
stability, cumulus convection and rainfall.
• However the effect of d...
17
Do Water-FedRice PaddyFields Increase
Rainfallin Monsoon Asia?
• Rice paddy fields occupy a huge area in Southeast and Eas...
Thailand
• Deforestation and widespread mixed shrub/paddy fields
reduce rainfall
19
Surface roughness
Bowen ratio
Evaporat...
Southern China
• Water-fed paddy fields increase evaporation compared to
drier farmland and fields.
• In June and July, th...
• Based upon cloud-resolving meso-scale model:
Water-fed paddy fields latent heat flux dominates
Farmland sensible heat ...
Fig. Land use affects rainfall: simulations by Shinoda and Uyeda (2001) show that where rice
paddy fields exist (upper gra...
Taiga-permafrost system in
Siberia
• It is well known that one climatic zone corresponds well with
one dominant vegetation...
• This implies that we should
consider vegetation and climate
as an interactive system rather
than one way relation from o...
• Long-term energy and water flux
measurement in typical Taiga
forest of Lena river basin has
revealed some interesting
fe...
• In spring snow melt occurs from April to May but sensible heat flux
was dominant and latent heat flux was very small or ...
• When depth of melted layer reached 20cm where a large portion
of larch roots are present the foliation and transpiration...
Taiga-permafrost symbiotic
system
• The hydro-meteorological studies in Siberia have strongly
suggested a symbiotic system...
• This rapid Global warming in Siberia which may be inducing
melting of permafrost may affect this “ Taiga-permafrost
symb...
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The Role of large scale Vegetation and Land Use in Water Cycle and climate in Monsoon Asia

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The Role of large scale Vegetation and Land Use in Water Cycle and climate in Monsoon Asia

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The Role of large scale Vegetation and Land Use in Water Cycle and climate in Monsoon Asia

  1. 1. The Role of large scale Vegetation and Land Use in Water Cycle and climate in Monsoon Asia By: Jannat Iftikhar 16 Nimrah Zahid 17 Summayya Tahir 18 Salma Shehzadi 19 Tayyaba Latif 20 1
  2. 2. Monsoon • Monsoon is traditionally defined as “a seasonal reversing wind accompanied by corresponding changes in precipitation”. • But now it is used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. 2
  3. 3. Major Monsoon Systems • The major monsoon systems of the world consist of a) The West African and Asia-Australian monsoons. b) The North and South American monsoons. c) Asian monsoon Indian monsoon (South-Asian) East-Asian monsoon 3
  4. 4. Asian Monsoon as a Huge Water Cycling system • Well known land-atmosphere-ocean system. • Two water channels a) From Tibetan Plateau to Indian Ocean b) From Tropical Pacific Ocean towards east and southeast Asian countries 4
  5. 5. 5
  6. 6. Asian Monsoon • This monsoon transports huge amount of water vapours over south, southeast and east Asia. • This plays an essential role in maintaining cumulus convection and precipitation over “monsoon Asia”. • Which reinforces the monsoon circulation system through latent heat release. 6
  7. 7. Asian Countries 7
  8. 8. Impacts of Monsoon • Monsoon circulation results in cool, dry winters and warm, wet summer over the continents. • This humid monsoon climate maintains dense vegetation zone called “the green belt”. (from tropical southeast Asia to sub- polar Siberia) • Changes in this convectively active region can result in severe draught, or flood over the large densely populated regions. 8
  9. 9. Precipitation • Most important factor for life on land vegetation and water resources • Origins: Tropical monsoon Asia, water vapour transport with C should be moisture source • Evapotranspiration • Data from analysis of atmospheric water balance by ECMWF revealed time space characteristics of P C E relationship. 9
  10. 10. • Humid tropics: Both C and E contribute, C is main source • The Indian sub- continent and indo china peninsula, C is larger than E • In mid to high latitudes: E is source, P is far smaller than in tropics • Contribution of E to P suggests the essential role of vegetation in surface water balance by transpiration 10
  11. 11. • Tropics: C plays role in P, E from vegetative surface is equally important, compare to mid/ high latitudes. 11
  12. 12. Is monsoonrainfall decreasing? Impact of deforestationon watercycle In Thailand rainfall in late monsoon show a remarkable trend from 1950. •Decrease in rainfall •Change the surface water balance •Change the vegetation 12
  13. 13. • According to recent model decreasing trend of September rainfall may be due to recent deforestation in Thailand which likely to induce • Reduction of surface roughness • Evaporation efficiency • Increase of albedo • Which result evaporation sensible heating 13
  14. 14. Sensible heat and surface heat • Sensible heat is a thermal energy whose transfer to or from a substance results in a change of temperature. • When the Sun warms the Earth, warm air rises into the atmosphere. As it rises, it expands and cools. Water vapor condenses out of the cool air to form a cloud, this is called surface heat. 14
  15. 15. 15
  16. 16. • Change in surface heating, affects the atmospheric stability, cumulus convection and rainfall. • However the effect of deforestation decreasing rainfall is noticeably only in September when southern monsoon current has become week. • In July and August when monsoon current is still strong it tend to change the distribution of rainfall rather then decrease the overall rainfall amount over the deforested area. 16
  17. 17. 17
  18. 18. Do Water-FedRice PaddyFields Increase Rainfallin Monsoon Asia? • Rice paddy fields occupy a huge area in Southeast and East Asia. • Thailand • Southern China 18
  19. 19. Thailand • Deforestation and widespread mixed shrub/paddy fields reduce rainfall 19 Surface roughness Bowen ratio Evaporative efficiency
  20. 20. Southern China • Water-fed paddy fields increase evaporation compared to drier farmland and fields. • In June and July, the China plain is strongly affected by the Meiyu (or Baiu in Japanese) frontal activity, which is a major part of the Asian monsoon system in East Asia. • The southwest monsoon current from South and Southeast Asia is a main moisture source for rainfall in the Meiyu frontal zone.
  21. 21. • Based upon cloud-resolving meso-scale model: Water-fed paddy fields latent heat flux dominates Farmland sensible heat flux dominates 21
  22. 22. Fig. Land use affects rainfall: simulations by Shinoda and Uyeda (2001) show that where rice paddy fields exist (upper graph), the atmospheric boundary layer becomes wetter than that for the farmland (lower graph), and deep convection easily develops to produce strong rainfall 22
  23. 23. Taiga-permafrost system in Siberia • It is well known that one climatic zone corresponds well with one dominant vegetation type. • However, we should also note that vegetation over a broad region effects the atmosphere and also the climate of a country. 23
  24. 24. • This implies that we should consider vegetation and climate as an interactive system rather than one way relation from one to other. • Eastern Siberia is a broad permafrost zone and taiga forest is distributed on it. 24
  25. 25. • Long-term energy and water flux measurement in typical Taiga forest of Lena river basin has revealed some interesting features in the seasonal change of this eco-climate system. • The east Siberia has the Lena river that starts from south and ends in north in Arctic sea. • It is the 11th longest river in the world and the 3rd largest river in Asia. 25
  26. 26. • In spring snow melt occurs from April to May but sensible heat flux was dominant and latent heat flux was very small or negligible. • The latent heat flux suddenly increased in June when foliation of trees started. • Now question arises that why did evapotranspiration started so suddenly? • The best answer to it is that the melting process of the permafrost and root depth are likely to be closely related to this problem. 26
  27. 27. • When depth of melted layer reached 20cm where a large portion of larch roots are present the foliation and transpiration from the leaves may have started. • On the other hand we noted that most water vapor for precipitation in summer is occupied by evapotranspiration from surface of this area implying that most water is recycling between vegetation and atmosphere in summer. 27
  28. 28. Taiga-permafrost symbiotic system • The hydro-meteorological studies in Siberia have strongly suggested a symbiotic system of climate and vegetation through the hydrological cycle, where Taiga maintains itself by recycling water between atmosphere and vegetated surface of permafrost layer. • While the permafrost is also maintained by the Taiga through suppressing sensible heating in summer. 28
  29. 29. • This rapid Global warming in Siberia which may be inducing melting of permafrost may affect this “ Taiga-permafrost symbiotic system” 29

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