A comparison of scavenging and deposition processes in global models: results from the WCRP Cambridge Workshop of 1995   总被引：2，自引：1，他引：1  

P. J. RASCH  J. FEICHTER  K LAW  N. MAHOWALD  J. PENNER  C. BENKOVITZ  C. GENTHON  C. GIANNAKOPOULOS  P. KASIBHATLA  D. KOCH  H. LEVY  T. MAKI  M. PRATHER  D. L. ROBERTS  G.&#;J. ROELOFS  D. STEVENSON  Z. STOCKWELL  S. TAGUCHI  M. KRITZ  M. CHIPPERFIELD  D. BALDOCCHI  P. McMURRY  L. BARRIE  Y. BALKANSKI  R. CHATFIELD  E. KJELLSTROM  M. LAWRENCE  H. N. LEE  J. LELIEVELD  K. J. NOONE  J. SEINFELD  G. STENCHIKOV  S. SCHWARTZ  C. WALCEK  D. WILLIAMSON 《Tellus. Series B, Chemical and physical meteorology》2000,52(4):1025-1056

We report on results from a World Climate Research Program workshop on representations of scavenging and deposition processes in global transport models of the atmosphere. 15 models were evaluated by comparing simulations of radon, lead, sulfur dioxide, and sulfate against each other, and against observations of these constituents. This paper provides a survey on the simulation differences between models. It identifies circumstances where models are consistent with observations or with each other, and where they differ from observations or with each other. The comparison shows that most models are able to simulate seasonal species concentrations near the surface over continental sites to within a factor of 2 over many regions of the globe. Models tend to agree more closely over source (continental) regions than for remote (polar and oceanic) regions. Model simulations differ most strongly in the upper troposphere for species undergoing wet scavenging processes. There are not a sufficient number of observations to characterize the climatology (long‐term average) of species undergoing wet scavenging in the upper troposphere. This highlights the need for either a different strategy for model evaluation (e.g., comparisons on an event by event basis) or many more observations of a few carefully chosen constituents.  相似文献   

Crystal Accumulation and Shearing in a Megacrystic Quartz Monzonite: Bodoco Pluton, Northeastern Brazil   总被引：1，自引：0，他引：1  

McMURRY  J. 《Journal of Petrology》2001,42(2):251-276

The Bodocó pluton, typical of numerous felsic intrusionsin northeastern Brazil that are characterized by blocky megacrystsof K-feldspar, consists mainly of porphyritic coarse-grainedquartz monzonite (SiO₂ 58–70 wt %) and is reversely zonedfrom a granitic margin to a quartz monzodioritic core. Thereis little variation in mineral composition throughout the pluton,despite a range of variation in mineral proportions. Isotopiccharacteristics also are homogeneous, with ¹⁸O_quartz between+9·3 and +9·8 and initial ⁸⁷Sr/⁸⁶Sr within limitsof 0·7056–0·7063. Petrogenetic modellingindicates that in situ crystal accumulation processes, accompaniedby the upward migration of a crystal-poor felsic melt, can accountfor many of the observed chemical and isotopic features, petrographictextures, and spatial relationships of rock types. Localizedshearing associated with regional ductile deformation producedextensive kilometre-wide bands of strongly foliated megacrysticquartz monzonite intruded by mafic dykes. Shear-related magmamingling and/or mixing were localized post-emplacement differentiationprocesses, particularly at the upper level of the intrusionand in quartz monzonite border units along the southeast margin. KEY WORDS: accumulation; Brazil; megacryst; petrogenesis; shearing  相似文献