Quasi-Geostrophic Potential Vorticity Transport in the Northern and Southern Hemispheres and Simple Climate Models

Abstract

The meridional transport of quasi

Transport of potential vorticity and Eliassen-Palm fluxes for two contrasting years: 1995–1996 (La Niña) and 1997–1998 (El Niño)

“…Figures 2a-d show the same for July 1995, October 1995, January 1996and April 1996. In general, the spatial pattern of PV transport in all figures agrees with those obtained in previous studies (Wiin-Nielsen and Sela, 1971;Franchito and Rao, 1991). PV transport is negative over almost the entire troposphere, with the exception of a thin layer near the surface and some regions in the middle and upper troposphere.…”

A Coupled Biosphere–Atmosphere Climate Model Suitable for Studies of Climatic Change Due to Land Surface Alterations

“…Here, f , r fIR , and z ov are obtained from BATS for each type of vegetation; r s ϭ 0.2; and z oL ϭ 0.01 m. The wind speed in the foliage layer is equal to V a (C D ) 1/2 , where V a is the wind speed at the anemometer level; b 2 and c 2 are prescribed constants as in Saltzman and Vernekar (1971). In the present model the value of c 2 is modified (ϭϪ115 W m Ϫ2 ) in order to couple the vegetation model to the SDM developed by Franchito and Rao (1992).…”

“…Gutman (1984) used this model for studying the hemispheric response of land surface alterations like desertification, deforestation, and irrigation. Franchito and Rao (1992) extended this study for both the hemispheres using a global primitive equation SDM. Recently, Zhang (1994) developed a biosphere model based on BATS suitable for SDMs.…”

“…Recently, Zhang (1994) developed a biosphere model based on BATS suitable for SDMs. The equations of BATS were adapted to the energy flux formulations proposed by Saltzman and Vernekar (1971), which are commonly used in SDMs (e.g., Saltzman and Vernekar 1972;Taylor 1980;Franchito and Rao 1991, 1995Rao and Franchito 1993;Oglesby and Saltzman 1990). Although this biosphere model is suitable for SDMs, only tests with the vegetation model decoupled from the SDM were made.…”

“…Comparisons with experiments conducted with GCMs are also made. The SDM used in this study is that developed by Franchito and Rao (1992), where the original parameterizations of the surface and atmospheric fluxes are modified by adapting the vegetation model proposed by Zhang (1994). To couple the models, new parameterizations of the fluxes relative to the fraction of the earth's surface covered by ocean ice, and snow following a similar procedure as in Zhang (1994), are developed.…”