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Poate de aceea au pus semnul intrebarii pe Amazon? Ca nu ar mai veni praful?

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Asa interactioneaza clima cu natura. Padurea aia taiata nu se mai reface singura. Evident ca sunt dereglari si vor fi din ce in ce mai accentuate.

Nu se stie daca intr-adevar Amazonul depinde atat de mult de praful din Sahara.Asta ar fi insemnat ca de fiecare data cand Sahara a fost savana, padurea din Amazon sa fi devenit istorie, ceea ce nu cred.E mult mai complexa situatia decat pare

Corecte observatiile. Dar cumva trebuie si padurea Amazoniana sa fie exploatata, desi stiti ca as fi ultima care as sustine defrisarile. Dar ma gandesc si ce pagube fac incendiile de padure si cat material lemnos e pierdut.
Sau imaginile din taigaua Siberiana dupa fenomenul Tungus, cu atatia copaci doborati si neutilizati.
Totusi, se pare ca o mare parte a oxigenului atmosferic e regenerat in oceane, si culmea am aratat o adevarata explozie de vegetatie in apele arctice in scurta vara.
Incerc sa inteleg, nu sa militez pentru defrisari! Dar se regenereaza.

Vegetatia acum 18 000 ani


Vegetatia acum 8 000 ani


Vegetatia acum 5 000 ani


Vegetatia-prezent.

LEGENDA:
1. Tropical rainforest (evergreen or semi-evergreen forest of humid tropics, usually tall)

(corresponds to Olson seasonal tropical forest and broad-leaved humid forest. Also includes swamp forest).

Leaf cover above a level 8m off ground, >60% . No more that 50% loss of canopy leaf cover at any one time during average year.


(1a= Rainforest of well-drained soils <25% loss of canopy leaf cover, 1b=semi-evergreen forest 25-50% loss of canopy leaf cover,




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2. Monsoon or dry forest (medium height, deciduous or mainly deciduous forest of warm climates)

(not corresponding to an Olson category; approximately a sub-division of seasonal tropical forest)


Leaf /branch cover above a level 8m off the ground, >60% during peak month of leafiness. >50% loss of canopy leaf cover at some stage in average year, except for Australian Eucalyptus dry forests, where limit of rainforest is defined by where Eucalyptus becomes >50% of canopy.




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3. Tropical woodland (relatively low, open tree canopy, usually deciduous)

(Corresponds to subdivision of Olson tropical savanna and woodland;).


Leaf /branch cover above 8m off ground, 60%-20%.




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4. Tropical thorn scrub and scrub woodland (low, woody, usually deciduous)

(Incorporates Olson succulent and thorn woods, and also overlaps with warm or hot shrub and grassland)


Leaf /crown cover above 8m off ground less than 20%, but total leaf cover between 0.8-8m off ground greater than 20%.




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5. Tropical semi-desert (sparse scrub or sparse grassland)

(Corresponds to subdivision of Olson desert and semi-desert)


Less than 2% vegetation cover above 80cm off the ground. 25-4% vegetation cover between 0 and 80cm off the ground, during an average year.




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6. Tropical grassland (fairly closed grassland without many trees or shrubs)

(Corresponds to subdivision of Olson tropical savanna and woodland, and overlaps with warm or hot shrub and grassland)


(6a= dense sward tropical grasslands, 6b= sparse sward tropical grasslands)

Leaf/branch cover above 80cm off ground less than 2%. But total cover above ground level, greater than 25%.




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7. Tropical extreme desert (very sparse vegetation, or completely barren)

(Corresponds to subdivision of Olson desert and semi-desert)


Total cover above ground level, less than 4% at any time during average year.




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9. Savanna (dense grassland with a scattering of trees and/or bushes)

(subdiv of Olson tropical savvanna & woodland).

(9a=Tree-dominated savanna, 9b=bush-dominated savanna)


Leaf/branch cover above 80cm of the ground, 2-20%.
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22. Temperate desert (very sparsely vegetated, cold winters)

(Subdivision of Olson cool desert and semi-desert types)

Vegetation cover less than 4%.




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23. Temperate semi-desert (sparse shrubland or grassland)

(Subdivision of Olson desert and semi-desert)


(23a=grassy temperate semi-desert, 23b= shrub-dominated temperate semi-desert; not distinguished here)

Less than 2% cover above 80cm off the ground. 4-25% total above ground cover.




Si url-ul, extrem de interesant!
http://www.esd.ornl.gov/projects/qen/new_africa.html

Africa in ultimii 150 000 ani...
http://www.esd.ornl.gov/projects/qen/nercAFRICA.html

Si...Africa "in full glacial conditons"...mai rau decat acum...

http://www.esd.ornl.gov/projects/qen/afr(22-.gif

SAHARA
(dates in Guo et al are given in 14C years ago on the left, approximate calibrated of 'real' dates are given on the right)

Moist 9,500-8,200 14C ya (10,400-9,100 ya)
Slight drying 8,200-8,000 14C ya (9,100-8,900 ya)
Moist 8,000-7,000 14C ya (8,900-7,900 ya)
Moderately dry 7,000-5,700 14C ya (7,900-6,500 ya)
Moist 5,700-4,000 14C ya (6,500-4,500 ya)
Very dry - as dry as at present - 4,000-3,800 14C ya (4,500-4,100 ya)
Slightly moister than present 3,800-3,500 14C ya (4,100-3,700 ya)
After 3,500 14C ya (3,700 ya). Remaining about as dry as at present

Acum 9 000 de ani.

Chiar acum pe History, un documentar despre Sahara de acum 8 000 ani...

CLIVAR (Climate Variability and Predictibility)
sectiunea Africa. Interesanta si partea referitoare la Lacul Victoria.
http://eprints.soton.ac.uk/344314/1/NOC_Clivar_Exchanges_Autumn_A4_36pp.pdf

WCRP Africa (World Climate Research Program)

http://www.clivar.org/sites/default/files/VACS/Newsletter/Africa_Newsletter_Nov12.pdf

AMMA (African Monsoon Multidisciplinary Analysis)
http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-87-12-1739

Aici sunt destule articole si carti interesante ale AMMA si nu numai.
http://journals.ametsoc.org/doi/abs/10.1175/BAMS-87-12-1739

Interesanta legatura dintre SST si temperatura atmosferei pana la 50 de metri de suprafata marii. Vantul reactioneaza imediat. Este chiar foarte important, asta nu aveam notat in carnetel la "efecte de feed-back". In largul oceanelor, efecte de briza deci, pot apare...Vantul tinde sa se auto-intretina si sa consume energia. Cu cat energia(diferenta de temperatura) va fi mai mare, cu atat vantul va fi mai puternic si valurile mai mari, absorbind si mai multa energie...e limpede. ...Apoi efectul asupra norilor, schimbarea albedoului in consecinta...
Dar aici poate apare accelerarea sau franarea procesului, depinde de mai multi factori...
Nu, trebuie sa scriu articol separat, nu aici... e mult de scris.
Se bifurca...unu ocean cald-atmosfera rece si doi...invers. Apoi depinde direct de valoarea temperaturii "initiale", inainte de saturarea atmosferei cu vapori. (formule, formule...)
Interesant de studiat in cazuri reale. (de aceea imi pare rau ca nu stau la mare...)
Dar si asa, am acces la date. E o ideie buna!
Poate iesi un articol superb. Si va fi studiata zona oceanica din vecinatatea Saharei, influenta acestui fenomen asupra alizeului insusi. Dar pe ocean, unde nu sunt date Va trebui sa deduc, direct nu am cum. Interesant.
Intai sa analizez la Constanta, unde am date apoi pot extrapola. OK.
http://journals.ametsoc.org/doi/pdf/10.1175/2010JCLI3665.1