The elevational gradient of species richness is often claimed to mirror the latitudinal gradient and has traditionally been explained by assuming a decrease in productivity with elevation and more recently by Rapoport's rule. The influence of area on the pattern has rarely been considered. Analyses of all South American tropical land birds (more than one-fourth of the extant bird species on Ear...

The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experime...

We describe a strategy for development of chronological control in tropical trees lacking demonstrably annual ring formation, using high resolution O measurements in tropical wood. The approach applies existing models of the oxygen isotopic composition of alpha-cellulose (Roden et al., 2000), a rapid method for cellulose extraction from raw wood (Brendel et al., 2000), and continuous flow isoto...

Dissolved noble gases in groundwater are used to reconstruct paleotemperature, but also yield information about "excess air", a component of dissolved gases in excess of solubility equilibrium, derived from dissolution of trapped air in the ground. A good characterization of the excess air component is necessary not only to obtain reliable noble gas temperatures, but also to investigate the pot...

Tropical ecosystems harbor the world’s greatest diversity of avian species. Latitudinal patterns of climate and productivity, alongside historical factors, have been evoked to explain such characteristics, and there is increasing knowledge that the complex ecological interactions found in the tropical zone play a very important role in this process, regulating competition and allowing an increa...

Present study was carried out at the research farm of ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala during 3 summer seasons 2016–17, 2017–18 and 2018–19 to assess crop water requirement upland taro (Colocasia esculenta L. Schott) arrive a suitable irrigation schedule under humid tropical conditions Kerala. The experiment conducted in randomized block design (RBD), with...

This study investigates how anthropogenic aerosols, alone or in conjunction with radiatively active gases, affect the tropical circulation with an atmosphere/mixed layer–ocean general circulation model. Aerosolinduced cooling gives rise to a substantial increase in the overall strength of the tropical circulation, a robust outcome consistent with a thermodynamical scaling argument. Owing to the...

The world is urbanizing most rapidly in tropical to sub-temperate areas and coastal zones. Climate change along with other global forcings will diminish the opportunities for sustainability of cities, especially low-income countries. include temperature heatwave increases that are expanding equatorial belt, sea-level rise, an increase frequency intense cyclones, both decreases freshwater inputs...

The influence of some atmospheric phenomena such as the Quassi Biennial Oscillation, the El Nino Southern Oscillation (ENSO) and the extratropical suction pump action on total ozone concentration over the region spreading from latitude 30 south to 30 north were studied using o o satellite data from 1997 to 2002. These phenomena were observed to contribute significantly to the variability of ozo...