MEGACHIROTTERA: STORIA DELLA GEOINGEGNERIA: Punti salienti dell'eruzione vulcanica

giovedì 23 aprile 2020

STORIA DELLA GEOINGEGNERIA: Punti salienti dell'eruzione vulcanica - Enigma della scia Marzo 2009

Punti salienti dell'eruzione vulcanica - Enigma della scia

Marzo 2009

Geoengineering • Artificial Clouds

"Un singolo velivolo che opera in condizioni favorevoli alla formazione persistente di scia di condensazione sembra esercitare una forza radiativa indotta da scia di forza circa 5000 volte maggiore (in W m − 2 km − 1) rispetto alle recenti stime della forza radiativa di scia di contrabbando persistente media dell'intera aviazione civile flotta. Questo studio sottolinea la necessità di stabilire se eventi simili sono comuni o molto insoliti per una valutazione sicura dell'effetto climatico complessivo dell'aviazione da effettuare. "

Haywood, JM, RP Allan, J. Bornemann, P. Forster, PN Francis, S. Milton, G. Rädel, A. Rap, KP Shine e R. Thorpe (2009), Un caso di studio del forzante radiativo di persistente scie che si evolvono in cirri indotti dalla scia, J. Geophys. Ris., 114, D24201, doi: 10.1029 / 2009JD012650.

A case study of the radiative forcing of persistent contrails evolving into contrail-induced cirrus

James M. Haywood,1 Richard P. Allan,2 Jorge Bornemann,1 Piers M. Forster,3
Peter N. Francis,1 Sean Milton,1 Gaby Rädel,4 Alexandru Rap,3 Keith P. Shine,4
and Robert Thorpe1

Received 11 June 2009; revised 17 September 2009; accepted 24 September 2009; published 19 December 2009.

[1] The radiative forcing due to a distinct pattern of persistent contrails that form into contrail-induced cirrus near and over the UK is investigated in detail for a single case study during March 2009. The development of the contrail-induced cirrus is tracked using a number of high-resolution polar orbiting and lower-resolution geostationary satellite instruments and is found to persist for a period of around 18 h, and at its peak, it covers over 50,000 km2. The shortwave (SW) and longwave (LW) radiative forcing of the contrail-induced cirrus is estimated using a combination of geostationary satellite instruments, numerical weather prediction models, and surface observation sites. As expected, the net radiative effect is a relatively small residual of the much stronger but opposing SW and LW effects, locally totaling around 10 W m 2 during daylight hours and 30 W m 2 during nighttime. A simple estimate indicates that this single localized event may have generated a global-mean radiative forcing of around 7% of recent estimates of the persistent contrail radiative forcing due to the entire global aircraft fleet on a diurnally averaged basis. A single aircraft operating in conditions favorable for persistent contrail formation appears to exert a contrail-induced radiative forcing some 5000 times greater (in W m 2 km 1) than recent estimates of the average persistent contrail radiative forcing from the entire civil aviation fleet. This study emphasizes the need to establish whether similar events are common or highly unusual for a confident assessment of the total climate effect of aviation to be made.

Citation: Haywood, J. M., R. P. Allan, J. Bornemann, P. M. Forster, P. N. Francis, S. Milton, G. Rädel, A. Rap, K. P. Shine, and R. Thorpe (2009), A case study of the radiative forcing of persistent contrails evolving into contrail-induced cirrus, J. Geophys. Res., 114, D24201, doi:10.1029/2009JD012650.

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