Smoke inputs to climate models: optical properties and height distribution for nuclear winter studies

Conference · Mon Apr 01 04:00:00 EST 1985

OSTI ID:5733149

Penner, J E; Haselman, Jr, L C

Smoke from fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in land surface temperatures. The extent of the decrease and even the sign of the temperature change depend on the optical characteristics of the smoke and how it is distributed with altitude. The height distribution of smoke over a fire is determined by the amount of buoyant energy produced by the fire and the amount of energy released by the latent heat of condensation of water vapor. The optical properties of the smoke depend on the size distribution of smoke particles which changes due to coagulation within the lofted plume. We present calculations demonstrating these processes and estimate their importance for the smoke source term input for climate models. For high initial smoke densities and for absorbing smoke ( m = 1.75 - 0.3i), coagulation of smoke particles within the smoke plume is predicted to first increase, then decrease, the size-integrated extinction cross section. However, at the smoke densities predicted in our model (assuming a 3% emission rate for smoke) and for our assumed initial size distribution, the attachment rates for brownian and turbulent collision processes are not fast enough to alter the smoke size distribution enough to significantly change the integrated extinction cross section. Early-time coagulation is, however, fast enough to allow further coagulation, on longer time scales, to act to decrease the extinction cross section. On these longer time scales appropriate to climate models, coagulation can decrease the extinction cross section by almost a factor of two before the smoke becomes well mixed around the globe. This process has been neglected in past climate effect evaluations, but could have a significant effect, since the extinction cross section enters as an exponential factor in calculating the light attenuation due to smoke. 10 refs., 20 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5733149
• Report Number(s): UCRL-92523; CONF-8408122-3; ON: DE85011363
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
290600 -- Energy Planning & Policy-- Nuclear Energy
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
450202* -- Explosions & Explosives-- Nuclear-- Weaponry-- (-1989)
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AEROSOLS
CLIMATES
COLLOIDS
DIFFUSION
DISPERSIONS
EARTH ATMOSPHERE
ENVIRONMENTAL IMPACTS
FIRES
MATHEMATICAL MODELS
NUCLEAR WEAPONS
NUCLEAR WINTER
PARTICLE SIZE
RESIDUES
SIZE
SMOKES
SOLS
TEMPERATURE EFFECTS
WEAPONS